HUMAN PHYSIOLOGY; ILLUSTRATE!) BY NUMEROUS ENGRAVINGS. BY ROBLEY T^UNGLISON, M. D. PROFESSOR OF PHYSIOLOGY, PATHOLOGT, &C. IN THE UNIVERSITY OF VIRGINIA, MEMBER OF THE AMERICAN PHILOSOPHICAL SOCIETY, &C. "Vastissimi studii primas quasi lineas circumscripsi."—Hallee. VOL. II. PHjHbADELPHIA: CAREY & LEA 1832. 2 -'it* I23X [Entered according to the Act of Congress, in the year one thousand eight hundred and thirty-two, by Robley Dunglison, M. D. in the clerk's office of the District Court of the Eastern District of Pennsylvania.] SKERRETT—NINTH STREET, PHILADELPHIA. CONTENTS OF VOL. II. Absorption............ b,b. Lymphatic glands. The arrows rings of the trachea. It is formed of lobes, indicate the direction m which the,?, i i • • i • ., 1 1 1 i i chyle passes. which subdivide into lobules and granula; has a red and sometimes a yellow colour; and presents, internally, vesicles, filled with a fluid, which is viscid and colourless or yel- lowish. It has no excretory duct; and, consequently, it is difficult to discover its use. It is larger in the foetus than in the adult; and has, therefore, been supposed to be, in some way, inservient to foetal existence. It continues, however, through life, receives large arteries, as well as a number of nerves and lymphatics, and hence, it has been supposed, fills some important office through the whole of existence. This, however, is all conjecture. The thyroid gland is the seat of goitre or bronchocele, the swelled neck, Derbyshire neck, papas, &c. as it has been termed lymph. 29 in different quarters of the globe,—a singular affection, which is common at the base of lofty mountains in every part of the world; and, in the cure of which, we have a valuable remedy in the iodine. The sorbefacient property of this drug is particularly exert- ed on the thyroid gland and on the mammae; and it affords us an ad- ditional instance, to the many already known, of remedial agents, not only exerting their properties upon a particular system, but even upon a small part of such system, without our being able, in the slightest degree, to account for the preference. The iodine stimulates the absorbent vessels of the gland to augmented action; and the consequence is, the absorption of the morbid deposit. Lastly, the supra-renal or atrabiliary capsules or glands, are small bodies in the abdomen, without the peritoneum, and above each kidney. The arteries, distributed to them, are large; and the glands themselves are larger in the foetus than in the adult. They, likewise, remain during life. These bodies consist of small sacs with thick, parenchymatous parietes; are lobular and granular; the internal cavity being filled with a viscid fluid, which is reddish in the foetus, yellow in childhood, and brown in old age. With their uses we are totally unacquainted. By the ancients, they were believed to be the secretory organs of the imaginary atrabilis; and hence their name. Lymph may be procured in two wayg, either by opening a lym- phatic vessel, and collecting the fluid, that issues from it,—but this is an uncertain method,—or by making an animal fast for four or five days, and then obtaining the fluid from the thoracic duct. This has been considered pure lymph; but it is obvious, that it must be mixed with the product of the digestion of the different secretions from the part of the digestive tube above the origin of the chyli- ferous vessels. The fluid, thus obtained, is of a rosy, slightly opaline tint, of a marked spermatic smell, and saline taste. At times, it is of a de- cidedly yellowish colour; and, at others, of a madder red; circum- stances, which may have given occasion to erroneous inferences, in experiments, made on the absorption of colouring matters. Its specific gravity is, to that of distilled water, as 1022.28 to 1000.00. Its colour is affirmed to be more rosy, in proportion to the length of time the animal has fasted. When examined by the microscope, it exhibits globules like those of the chyle; and, like the chyle, bears considerable analogy, in its chymical composition, to the blood. When left at rest, it separates into two portions;—the one, a liquid, nearly like the serum of the blood; and the other a coa- gulum or clot of a deeper rosy hue; in which a multitude of reddish filaments appear, disposed in an arborescent manner; and,* in ap- pearance, very analogous to the vessels, which are distributed in the tissue of the organs. When a portion of coagulated lymph is examined, it seems to consist of two parts;—the one, which is solid, formed of numerous 30 ABSORPTION. cells containing the other or more liquid part; and, if the solid por- tion be separated, the latter coagulates. Mr. Brande collected the lymph from the thoracic duct of an animal, which had been kept without food for twenty-four hours. He found its chief constituent to be water; besides which, it con- tained muriate of soda and albumen;—the latter being in such mi- nute quantity, that it coagulated only by the action of galvanism. The lymph of a dog yielded to Chevreul, water, 926.4; fibrine, 4.2; albumen, 61.0; muriate of soda, 6.1; carbonate of soda, 1.8; phosphate of lime, phosphate of magnesia, and carbonate of lime, 0.5. It is impossible to estimate the quantity of lymph contained in the body. It would seem, however, that notwithstanding the great capacity of the lymphatic vessels, there is, under ordinary circum- stances, but little fluid circulating in them. Frequently, when ex- amined, they have appeared empty, or pervaded by a mere thread of lymph. Magendie endeavoured to obtain the whole of the lymph from a dog of large stature. He could collect but an ounce and a half; and it appeared to him, that the quantity increased, whenever the animal was kept fasting; but on this point he does not seem to express himself positively. Physiology of Lymphosis. The term lymphosis has been proposed by Chaussier for the ac- tion of elaboration, by which lymph is formed; as chylosis has been, for the formation of chyle; and hsematosis, for that of the blood. In describing the organs, concerned in this function, the striking si- milarity, we might almost say, identity, in structure and arrange- ment between them and the chyliferous organs, will have been ap- parent. A part, indeed, of the vascular apparatus is common to both; and they manifestly constitute one and the same system. This would be sufficient to induce us to assign them similar func- tions; and it would require powerful and positive testimony to es- tablish an opposite view. At one period, the lymph was consi- dered to be simply the watery portion of the blood; and the lym- phatic vessels were regarded as the mere continuation of the ulti- mate arterial ramifications. It was affirmed, that the blood on reaching the final arterial branches, separated into two parts; the red and thicker portion returning to the heart by the veins; and the white, serous portion passing by the lymphatics. The reasons for this belief were, the great resemblance between the lymph and serum of the blood; and the facility with which an injection passes, in the dead body, from the arterial, into the lymphatic, capillary vessels. Magendie has revived the ancient doctrine; and, of con- sequence, no longer considers the lymphatics to form part of the ab- sorbent system; but to belong to the circulatory apparatus, and to serve, as we shall see, the office of waste pipes, in cases of emer- LYMPHATICS. 31 gency. Without canvassing this subject, now, we may assume it for granted, that the lymph, which circulates in the lymphatic ves- sels, is identical in its nature, or as little subject to alteration as the chyle; and that, consequently, whatever may be the materials, that constitute it, an action of elaboration and selection must be exerted in its formation. That it strongly resembles the blood is no evidence of its being formed from that fluid; the chyle, which it resembles even more than it does the blood, is procured from materials differing largely from its own nature; more, indeed, than any of the substances, whence the lymph is formed, differ from that fluid. Assuming, for the present, that the lymph is obtained from ma- terials already deposited in the body; the next inquiry is;—into the mode in which the separation and simultaneous absorption are effected. On this topic, we have no additional arguments to em- ploy to those adduced, regarding the function of the chyliferous radicles. In every respect they are identically situated; and to their history we refer for an exposition of how little we know of this part of lymphosis. The causes of the progression of the lymph in the vessels are the same, also, as those that influence the chyle. In addition, how- ever, to those mentioned under chyliferous absorption, there is one, which applies equally to chyliferous and lymphatic vessels; and arises from the mode, in which the thoracic duct enters the subclavian vein. It has been already observed, that this occurs at the point of junc- tion between the jugular and sub- clavian, as at D, Fig. 100, where J represents the jugular; and V S, the subclavian, in which the blood flows from V to- wards S, the car- diac extremity. Now it is a physical fact, that when a small tube is insert- ed perpendicu- larly into the lower side of a horizontal coni- cal pipe, in which the water is flowing from the narrower to the wider portion; and if the small vertical tube he made, to dip into a vessel of water, not only will the water of the larger pipe not 32 ABSORPTION. descend into the vessel; but it will actually draw up the water through the small tube, so as to empty the vessel. Instead of sup- posing the canals in Fig. 100, to be veins and the thoracic duct; let us presume, that they are rigid mechanical tubes; and that the extremity of the tube D, which represents the thoracic duct, dips into the vessel B. As the fluids, proceeding from J to S and from V to S are passing from the narrower portions of conical tubes to wider, it follows, that the fluid will be drawn out of the vessel B, simply by traction, or, by what Venturi terms, the lateral communication of fluids. This would happen in whatever part of the vessel the tube B D terminated. But its insertion at D has another advantage. By the mode in which the current, from J to- wards S, unites with that from V towards S, a certain degree of diminished pressure must exist at D; so that the atmospheric pres- sure, on the surface of the water, in the vessel B, will likewise be exerted in propelling it forwards. In the progress of the chyle and lymph, then, along the thoracic duct, not only may the attraction of the more forcible stream along the veins draw the fluid in the thoracic duct along with it, but, owing to the diminished pressure at the mouth of the duct, atmospheric pressure may have some, although probably but little influence, in forcing the chyle and lymph from the chyliferous and lymphatic radicles onwards. The lymphatic glands have been looked upon as small hearts for the propulsion of the lymph ; and Malpighi accounts for the greater number in the groin in this way;—the lymph having to ascend to the thoracic duct against its own gravity: this appears, also, to have been somewhat the opinion of BiCHAT.There seems, however, to be nothing in their structure, which should lead to this belief; and, if not muscular or contractile, it is manifest, that their number must have the effect of retarding rather than of accelerating the flow of the lymph. The most prevalent sentiment is, that they are somehow concerned in the admixture of the lymph; and by many it is conceived, that some kind of elaboration is effected by them; but, on this topic, we have only conjectures for our guidance. Of their true functions we know nothing definite. On the subject of the moving powers of the lymph, Adelon has judiciously remarked, that if we admit the lymph to be the serous portion of the blood, and that the lymphatics are vessels of return, as the veins are, the heart might be considered to have the same influence over lymphatic, that it has been presumed to have over venous, circulation; and it is somewhat singular, that its action has not been invoked by those who embrace that opinion. Hereafter, however, we shall see, that even in the circulation in the veins the agency of the heart can have little or no influence. Still less can it be expected to exert an influence over a system, so obscurely connected with the arteries as the lymphatic, especially when regard is paid to the numerous ganglions, which must have the effect of destroying such force, if exerted. LYMPHOSIS. 33 The course of the lymph is by no means rapid. If, a lymphatic vessel be divided, in a living individual, the* lymph oozes out slowly, and never with a jet. Cruikshank estimated its velocity along the vessels to be four inches per second or twenty feet per minute ; but the data, for any such evaluation, are altogether ina- dequate. In man and in living animals, the lymphatics of the limbs, head, and neck rarely contain lymph ; their inner surface appearing to be merely lubricated by a very thin fluid. Occasionally, however, the lymph stops in different parts of the vessels ; distends them; and gives them an appearance very like that of varicose veins, except as to colour. Soemmering states that he has seen several in this condition on the top of the foot of a female; and Magendie one around the corona glandis of the male. In dogs, cats and other living animals, lymphatics, filled with lymph, are frequently seen at the surface of the liver, gall-bladder, vena cava, vena portae, and at the sides of the spine. Magendie remarks, that he has never met with the thoracic duct empty, even when the lymphatics of the rest of the body were entirely so. It must be recollected, how- ever, that the thoracic duct must always contain the product of the digestion either of food or of the secretions from the alimentary tube. This kind of stagnation of lymph in particular vessels has given occasion to the belief, that the lymph flows with different degrees of velocity in the different parts of the system; and this notion has entered into the pathological views of different writers, who have presumed, that something like determinations of lymph can occur, so as to produce lymphatic swellings. Bordeu, indeed, speaks of currents of lymph. The whole phenomena of the course of the lymph negative such presumption; and induce us to believe, that its progress is pretty uniform and always slow ; and when an accumulation or engorgement or stagnation occurs in any particular vessel, it is more probably owing to increased secretion by the lymphatic radicles, which communicate with the vessel in question, and the consequently augmented quantity of lymph. The lymph, which proceeds by the thoracic duct, is emptied, along with the chyle, into the subclavian vein. At the con- fluence, a valve is placed, which does not, however, appear to be essential, as the duct opens so favourably between the two cur- rents from the jugular and subclavian, that there is no tendency for the blood to reflow into it. It has been suggested, that its use may be,—to moderate the instillation of the fluid of the thoracic duct into the venous blood. With regard to the question, whether the lymph is the same at the radicles of the lymphatics as in the thoracic duct, or whether it does not gradually become more and more animalized in its course towards the venous system, and especially in its progress through the lymphatic glands, the re- Vol. II. 5 34 ABSORPTION. marks, made upon the subject, as respects the chyle, apply with equal force to the lymph ; and our ignorance is no less profound. The glands of the mesentery and of the lymphatics in general seem to be concerned in some of the most serious diseases. Swel- ling of the lymphatic glands of the groin indicates the existence of a venereal sore on the penis. A wound on the foot will pro- duce tumefaction of the inguinal glands; one on the hand will inflame the glands in the axilla. Whenever, indeed, a lymphatic gland is symptomatically enlarged, the source of irritation will be found at a greater distance from the vein into which the great lymphatic trunks pour their fluid, than the gland is. In plague, one of the essential symptoms is the appearance of swelling of the lymphatic glands of the groin and axilla; hence, it has been termed by some adeno-adynamic fever (from «^»;v, a gland.) In scrofula, the lymphatic system is generally deranged; and, in the doctrine of Broussais, a very active sympathy is affirmed to exist between the glands of the mesentery and the mucous surface of the stomach and intestines. This discovery, we are told, be- longs to the "physiological doctrine," which has shown, that all gastro-enterites are accompanied by tumefaction of the mesenteric glands: although chyle may be loaded with acrid, irritating or even poisonous matters, it traverses the glands with impunity, pro- vided it does not inflame the gastro-intestinal mucous surface. " Our attention," Broussais adds, " has been for a long time di- rected to this question, and we have not observed any instance of mesenteric ganglionitis, which had not been preceded by well- evidenced gastro-enteritis." The discovery will not immortalize the " doctrine." We should as naturally look for tumefaction of the mesenteric glands or ganglia, in cases of irritation of the intes- tine, as for enlargement of the glands of the groin when the foot is irritated. Lastly; the lymph, from whatever source obtained—united with the chyle—is discharged into the venous system. Both of these, therefore, go to the composition of the body. They are entirely analogous in properties; but differ materially in quantity;—the nu- tritious fluid, formed from materials obtained from without, being by far the most copious. A due supply of it is required for con- tinued existence ; yet the body can exist for a time, even when the supply of nutriment is entirely cut off. Under such circumstances the necessary proportion of nutritive fluid must be obtained from the decomposition of the tissues; but from the perpetual drain, that takes place through the various excretions, this soon becomes insufficient, and death is the result. We have seen, that both chyle and lymph are poured into the venous blood;—itself a compound of the remains of arterial blood, and of various heterogeneous absorptions. As an additional preli- minary to the investigation of the agents of internal absorption, VENOUS system. 35 let us now inquire into the nature and course of the fluid contained in the veins; but so far only as to enable us to understand the function of absorption; the other considerations, relating to the blood, appertaining to the function of circulation. Sect. III. VENOUS ABSORPTION. Anatomy of the Venous System. This system consists of myriads of vessels, called veins, which commence in the very textures of the body, by what are called capillary vessels; and from thence pass to the great central organ of the circulation—the heart; receiving, in their course, the pro- ducts of the various absorptions not only effected by themselves, but by the chyliferous and lymphatic vessels. The origin of the veins, like that of all capillary vessels, is im- perceptible. By some, they are regarded as continuous with the capillary arteries; Malpighi and Leeuenhoek state this as the result of their microscopic observations on living animals; and it has been inferred, from the facility with which an injection passes from the arteries into the veins. According to others, cells exist between the arterial and the venous capillaries, in which the former deposit their fluid and whence the latter obtain it. Others, again, substitute a spongy tissue for the cells. A question has also been asked,—whether the veins terminate by open mouths; or whether there may not be more delicate ves- sels, communicating with their radicles,—similar to the exhalants, which are presumed to exist at the extremities of the arteries, and are the agents of exhalation. All this is, however, conjectural. It has already been observed, that the mesenteric veins have been considered to terminate by open mouths in the villi of the intestines; and the same arrange- ment has been conceived to prevail with regard to other veins. Ribes concludes, from the results of injecting the veins, that some of the venous capillaries are immediately continuous with the mi- nute arteries, whilst others open into the cells of the laminated tissue, and into the substance of the different organs. When the veins become visible, they appear as an infinite num- ber of tubes, extremely small, and communicating very freely with each other; so as to form a very fine net-work. These vessels gra- dually become larger and less numerous, but still preserve their reticular arrangement; until, ultimately, all the veins of the body empty themselves into the heart, by three trunks,—the vena cava inferior, the vena cava superior, and the coronary vein. The first of these receives the veins from the lower part of the body, and extends from the fourth lumbar vertebra to the right auricle; the second receives all the veins of the upper part of the body; and 36 ABSORPTION. into it the subclavian opens, into which the chyle and lymph are discharged. It extends from the cartilage of the first rib to the right auricle. The coronary vein belongs to the heart exclusively. Between the superior and inferior cava a communication is formed by means of the vena azygos. Certain organs appear almost wholly composed of venous radi- cles. The spleen is one of these. Fig. 101. The accompanying figure represents the ramifications of the splenic artery, a, in the substance of that organ; and if we consider, that the splenic vein has corresponding ramifications, the viscus would seem to be almost wholly formed of blood-vessels. The same may be said of the corpus cavernosum of the penis and cli- toris, the nipple, urethra, glans penis, &c. If an injection be VENOUS SYSTEM. 37 thrown into one of the veins, that issue from these different tis- sues, they are wholly filled by the injection; which rarely occurs, if the injection be forced into the artery. Magendie affirms, lhat the communication of the cavernous tissue of the penis with the veins occurs through apertures two or three millimeters.—In. 0.117. —in diameter. In their course towards the heart, particularly in the extremities, the veins are divided into two planes ;—one subcutaneous or superfi- cial; the other deep-seated, and accompanying the deep-seated arte- ries. Numerous anastomoses occur between these, especially when the veins become small, or are more distant from the heart. We find that their disposition differs according to the organ. In the brain, they form, in great part, the pia mater; and enter the ventricles, where they contribute to the formation of the plexus choroides and tela choroidea. Leaving the organ, we find them situated between the laminse of the dura mater; when they take the name of sinuses. In the spermatic cord, they are extremely tortuous, anastomose repeatedly, and form the corpus pampini- forme; around the vagina, they constitute the corpus retiforme; in the uterus, the uterine sinuses, &c. The veins have three coats in superposition. The outer coat is cellular, dense, and very diffi- cult to rupture. The middle coat has been termed the proper membrane of the veins. The generality of anatomists describe it as composed of longitudinal fibres, which are more distinct in the vena cava inferior than in the vena cava superior ; in the su- perficial veins than in the deep-seated; and in the branches than in the trunks. Magendie states, that he has never been able to observe the fibres of the middle coat; but that he has always seen a multitude of filaments interlacing in all directions; and assum- ing the appearance of longitudinal fibres, when the vein is folded or wrinkled longitudinally, which is frequently the case in the large veins. It exhibits no signs of muscularity; even when the galva- nic stimulus is applied ; yet Magendie suspects its chemical na- ture to be fibrinous. If so, it is perhaps different from every other tissue in the body. It was remarked, in an early part of this work, that the bases of the cellular and muscular tissues were, respective- ly, gelatine, and fibrine; and that the various resisting solids could all be brought to one or other of these tissues. To which, then, ought the middle coat of the veins to be attached. Magendie, however, merely states its fibrinous nature to be a suspicion; and, like numerous suspicions, it may be devoid of foundation. Yet we have reason to believe, that the veins are contractile; and the possession of this property would be in accordance with their fibrinous character. Broussais affirms, that this action is one of the principal causes of the return of the blood to the heart. He conceives, that the alternate movements of contrac- tion and relaxation are altogether similar to those of the heart; 38 absorption. but that they are so slight as not to have been rendered perceptible by any process in the majority of the veins, although very visible in the vena cava of frogs, where it joins the right auricle. In some experiments by Sarlandiere on the circulation, he observed these movements to be independent of those of the heart. After the heart was removed, the contraction and relaxation of the vein con- tinued, for many minutes, in the cut extremity, and even after the blood had ceased to flow. The inner coat is extremely thin and smooth at its inner sur- > face. It is very extensible, and yet presents considerable resist- ance ; bearing a very tight ligature without being ruptured. In many of the veins, parabolic folds of the inner coat exist, like those in the lymphatics, and inservient to a similar purpose: the free edge of these valves is directed towards the centre of the circulation; showing that their office is to permit the blood to flow in that direction and to prevent its retrogression. They do not seem, however, in many cases, well adapted for the purpose, inas- much as their size is insufficient to obliterate the cavity of the vein. By most anatomists, this arrangement is considered to depend upon primary organization, but Bichat conceives it to be wholly owing to the state of contraction, or dilatation of the veins at the moment of death. Magendie, however, affirms, that he has never seen the distention of the veins exert any influence on the size of the valves; but that their shape is somewhat modified by the state of contraction or dilatation, and this he thinks probably misled Bi- chat. Their number varies in different veins. As a general principle, they are more numerous, where the blood proceeds against its gravity, or where the veins are very extensible and receive but a feeble support from the circumambient parts, as in the ex- tremities. They are entirely wanting in the veins of the deep- seated viscera;—in those of the brain and spinal marrow, of the lungs; in the vena portae and in the veins of the kidneys, bladder and uterus. They exist, however, in the spermatic veins; and, sometimes, in the internal mammary, and in the branches of the vena azygos. On the cardiac side of these valves cavities or sinuses exist, which appear externally in the form of varices. These dilata- tions enable the refluent blood to catch the free edges of the valves, and thus to depress them, so as to close the cavity of the vessel; serving, in this respect, precisely the same functions as the sinuses of the pulmonary artery and aorta in regard to the semilunar valves. The three coats united form a solid vessel,—according to Bichat devoid of elasticity, but, in the opinion of Magendie, elastic in an eminent degree. The elasticity is certainly much less than that of the arteries. VENOUS BLOOD. 39 The veins are nourished by vasa vasorum, or by small arteries, which have their accompanying veins. Every vessel, indeed, in the body, if we may judge from analogy, appears to draw its nu- triment, not from the blood circulating in it, but from small arte- rial vessels, hence termed vasa vasorum. This applies not only to the veins, but to the arteries. The heart, for example, is not nourished by the fluid constantly passing through it; but by ves- sels, which arise from the aorta, and are distributed over its sur- face, and in its intimate texture. The coronary arteries and their corresponding veins are, consequently, the vasa vasorum of the heart. In like manner, the aorta and all its branches, as well as the veins, receive their vasa vasorum. There must, however, be a term to this; and if our powers of observation were sufficient, we ought to be able to discover a vessel, which must derive its support or nourishment exclusively from its own stores. The nerves, that have been detected in the veins, are branches of the great sympathetic. The capacity of the venous, is generally esteemed to be double that of the arterial, system. It is obvious, however, that we can only arrive at an approximation, and that not a very close one. The size and number of the veins is generally so much greater than that of the corresponding arteries, that, when the vessels of a membranous part are injected, the veins are observed to form a plexus, and, in a great measure, to conceal the arteries: in the in- testines, the number is more nearly equal. The difficulty of arriv- ing at any exact conclusion, regarding the relative capacities of the two systems, is forcibly indicated by the fact; that whilst Borelli conceived the preponderance in favour of the veins to be as four to one; Sauvages estimated it at nine to four; Haller at sixteen to nine; and Keil at twenty-five to nine. There is one portion of the venous system, to which allusion has already been made, which is peculiar. We mean the abdominal venous or portal system. All the veins, that return from the di- gestive organs, situated in the abdomen, unite into a large trunk called the vena portae. This, instead of passing into a larger vein' into the vena cava, for example, proceeds to the liver, and ramifies, like an artery, in its substance. From the liver, other veins, called supra-hepatic, arise, which empty themselves into the vena cava • and which correspond to the branches of the hepatic artery as well as to those of the vena portae. The portal system is concerned only with the veins of the digestive organs situated in the abdomen; as, the spleen, pancreas, stomach, intestines and omenta. The veins of all the other abdominal organs,—of the kidney, supra-renal cap- sules, &c. are not connected with it. The first part of the vena portae is called, by some authors, vena portse abdominalis vel ventrahs, to distinguish it from the hepatic portion, which is of great size, and has been called the sinus of the vena portse. 40 ABSORPTION. The blood strongly resembles the chyle in its properties;—the great difference consisting in the colour; and the venous blood, and the chyle, and the lymph become equally converted into the same fluid—arterial blood—in the lungs. Venous blood, which chiefly concerns us at present, is contained in all the veins, in the right side of the heart, and in the pulmo- nary artery;—organs, which constitute the apparatus of venous cir- \ culation. As drawn from the arm, its appearance is familiar to every one. At first, it seems to be entirely homogeneous; but, after resting for some time, it separates into different portions. The colour of venous blood is much darker than that of the arterial ;— so dark, indeed, as to have had the epithet black blood applied to it. Its smell is faint and peculiar; by some compared to a fragrant garlic odour, but it is sui generis; its taste is slightly saline and also peculiar. It is viscid to the touch ; coagulable, and its tem- perature has been estimated at 96° of Fahrenheit ; simply, we believe, on the authority of the inventor of that thermometric scale, who marked 96° as blood heat. This is too low by at least three or four 'degrees. Rudolphi and the German writers in ge- neral, estimate it at 29° of Reaumur or " from 98° to 100° of Fahrenheit;" whilst, by the French writers in general, its mean temperature is stated at 31° of Reaumur or 102° of Fahrenheit. Magendie, who is usually very accurate, fixes the temperature of venous blood at 31° of Reaumur, or 102° of Fahrenheit ; and that of arterial blood at 32° of Reaumur, or 104° of Fahren- heit. 100° may be perhaps taken as the average. In many animals, the temperature is considerably higher than that of man. In the sheep it is 102 or 103°; but, of all animals, it is most elevated in birds. In the duck it is 107°. On this sub- ject, further information will be given under the function of calo- rification. Its specific gravity is differently estimated by different writers. Hence it is probable, that it varies in different individuals, and in the same individual at different periods. Compared with water, its mean specific gravity has been estimated to be as 1.0527 to 1.0000. It is stated, however, to have been found as high as 1.126; and, in disease, as low as 1.022. It has, moreover, been conceived, that the effect of disease is, invariably, to make it lighter; and that the more healthy the individual, the greater is the specific gravity of the blood, but our information on this point is vague. When blood is examined with a microscope of high magnifying powers, it appears to be composed of numerous, minute, red parti- cles or globules, suspended in the serum. These red particles have a different shape and dimension, according to the nature of the animal. In the mammalia, they are circular; and, in birds and cold-blooded animals, elliptical. In all animals, they are affirmed by some observers, to be flattened, and marked in the centre with a luminous point, of a shape analogous to the general shape of the VENOUS BLOOD. 41 globule. It must, however, be remarked, that here, as in every case, which rests on microscopic observation, the greatest discre- pancy prevails, not only as regards the shape but the size of these globules. They were first noticed by Malpighi, and were after- wards more minutely examined by Leeuenhoek, who at first de- scribed them, correctly enough, in general terms; but,subsequently, became hypothetical, and advanced the phantasy, that the red par- ticles are composed of a series of globular bodies, descending in regular gradations; each of the red particles being supposed to be composed of six particles of serum; a particle of serum of six par- ticles of lymph, &c. Totally devoid of foundation, as the whole notion was, it was implicitly believed for a considerable period, even until the time Haller wrote. Hewson described the globules, as consisting of a solid centre, surrounded by a vesicle, filled with a fluid; and to be "as flat as a guinea." Hunter, on the other hand, did not regard them as solid bodies, but as liquids, possessing a central attraction, which determines their shape. Della Torre supposed them to be a kind of disk, or ring, pierced in the centre; whilst Monro conceived them to be circular, flattened bodies, like coins, with a dark spot in the centre, which he thought was not owing to a perforation, as Della Torre had imagined, but to a depression. Cavallo, again, conceived, that all these appearances are deceptive, de- pending upon the peculiar modification of the rays of light, as affected by the form of the particle; and he concluded, that they are simple spheres. Amici found them of two kinds, both with angular margins; but, in the one, the centre was depressed on both sides; whilst, in the other, it was elevated. The observations of Dr. Young, of Sir JSverard Home and Mr. Bauer, and of MM. Prevost and Dumas, accord chiefly with those of Hewson. All these gentlemen consider the red par- ticles to be composed of a central globule, which is transparent and whitish, and of a red envelope, which is less transparent. Still more recently, however, Dr. Hodgkin has denied, that they are spherical, and that they consist of a central nucleus inclosed in a vesicle. He affirms, on the authority of a microscope, which, on comparison, was found equal to a celebrated one, taken a few years ago to Great Britain by Professor Amici, that the particles of human blood appear to consist of circular, flattened, transparent cakes, their thickness being about ^jth part of their diameter. These, when seen singly, appear to be nearly or quite colourless. Their edges are rounded, and being the thickest part, occasion a depression in the middle, which exists on both surfaces. His view, consequently, appears to resemble that of Monro. Amidst this discordance, it is difficult to know which view we ought to adopt. The belief in their consisting of circular, flattened, Vol. II. 6 42 ABSORPTION. transparent bodies, with a depression in the centre, appears to have the greatest weight of authority in its favour; and that they consist of an external envelope and of a central nucleus, the former of which is red and gives colour to the blood. The nucleus is devoid of colour, and it appears to be independent of the envelope; as, when the latter is destroyed, the central portion preserves its ori- ginal shape. The nucleus is much smaller than the envelope, be- ing, according to Dr. Young, only about one-third the length, and one-half the breadth of the entire particle. According to Sir Everard Home, the globules, when envelop- ed in the colouring matter, are -lyY^ri part of an inch in diameter, requiring 2,890,000 to a square inch; but, when deprived of their colouring matter, they appear to be ^vV^th part of an inch in dia- meter, requiring 4,000,000 of globules to a square inch. From these measurements, the globules, when deprived of their colour- ing matter, are not quite one-fifth smaller. The views of MM. Prevost and Dumas, who have investigated this subject with extreme care and signal ingenuity, are deserving of great attention. They conceive the blood to consist essentially of serum, in which a quantity of red particles is suspended; that each of these particles consists of an external red vesicle, which incloses, in its centre, a colourless globule; that, during the pro- gress of coagulation, the vesicle bursts, and permits the central glo- bule to escape; that, on losing their envelope, the central globules are attracted together; that they are disposed to arrange themselves in lines and fibres; that these fibres form a net-work, in the meshes of which they mechanically entangle a quantity both of the serum and of the colouring matter; that these latter substances may be removed by draining, and by ablution in water; that, when this is done,there remains only pure fibrine; and that, consequently, fibrine consists of an aggregation of the central globules of the red parti- cles, while the general mass, that constitutes the crassamentum or clot, is composed of the entire particle. So far this seems satisfactory; but, we have seen, Dr. Hodgkin does not recognise the existence of external vesicle or of central globule; and he affirms, contrary to the notion of Sir Everard Home and others, that the particles are disposed to coalesce in their entire state. This is best seen, when the blood is viewed be- tween two slips of glass. Under such circumstances, the following appearances, according to Hodgkin, are perceptible. When humfin blood, or that of any other animal having circular particles, is ex- amined in this manner, considerable agitation is, at first, seen to take place among the particles; but, as this subsides, they apply themselves to eaeh other by their broad surfaces, and form piles or rouleaux, which are sometimes of considerable length. These rouleaux often again combine amongst themselves,—the end of one being attached to the side of another,—producing, at times, very curious ramifications. VENOUS blood. 43 Nor are these microscopical discordances less evidenced by the estimates, which have been made of the size of the red globules, notwithstanding that all are adduced on the faith of positive ad- measurements. ^ Leaving out of view the older, and, consequently, it might-be presumed, less accurate observations, the following table will show their diameter in human blood, on the authority of some of the most eminent microscopic observers of more recent times. Bauer, with colouring matter, 1y10-0th part of an inch. Do. without do. smrs Hodgkin, - - - -j-^ Sprengel, - - - -joVo to -j-j^ Cavallo, ... tttoo" to -j^tnr Blumenbach, - - tjot KATER, - - - 4^olT t0 S~oW Prevost and Dumas, - \oi6 Wollaston, - - Tcnro Young, - - - ^Vr The blood of different animals is found to differ greatly, in the relative quantity of the red globules it contains;—the number seeming to bear a pretty exact ratio with the temperature of the animal. The higher the natural temperature the greater the propor- tion of particles; and arterial always contains a much greater pro- portion than venous blood. , MM. Prevost and Dumas have attempted an evaluation of the weight of the globules compared with that of the serum in which they are held in suspension. Admitting that the clot, pro- duced at the moment of coagulation, is impregnated with serum as a sponge would be if placed in that fluid, the proportion between each of these matters might be easily appreciated. We should have; first,—serum, consisting of water and solid matters ; and, secondly, clot, formed of globules and serum. By drying the serum, the proportion, between the water and the solid matters it contains, can be detected. By drying the clot, the quantity of water, which it contains, can be known; and if the fluid is in the state of serum, the quantity of dry matters, which ought to be left by the serum, must be deducted from the weight of the clot. The weight remaining will be that of the globules. By adding the water of the serum to that of the clot, we have the whole quantity of water contained in the blood. By adopting this course, MM. Prevost and Dumas obtained the following results from the blood of different animals: 44 absorption. 10,000 parts of blood contain, __A________________* Name of the Its mean r Albumen and , Animal. Temperature. Globules. Water. Soluble Salts. Pigeon, - - 108° Fah. 1557 469 7974 Hen, - - - 107° 1571 630 7799 Duck, - - - 109° 1501 847 7652 Rook, - - - 109° 1466 " 564 7970 Heron, - - 106° 1326 592 8080 Ape, - - - 96° 1461 779 7760 Man, - - - 102° 1292 869 7839 Guinea Pig, - 101° 1280 872 7848 Dog, - - - 100° 1238 655 8107 Cat, - - - 101° 1204 843 7953 Goat, - - - 103° 1020 834 8146 Calf, - - - << 912 828 8260 Rabbit, - - - 101° 938 683 8370 Horse, - - - 98° 920 897 8183 Sheep, arterial ~) blood, 5 101° 935 772 8293 Do. venous 5 blood, 3 a 861 775 8364 Trout, - - - a 638 79.5 8637 Burbot, > Gadus Lota, $ that of the air 481 657 8862 Frog, - \ 49° in waters at 46° 5 690 464 8846 Turtle, - - that of the air 1506 806 7688 Eel, - - - do. 600 940 8460 In the above table, we are struck with the difference between the number of globules in the arterial and venous blood of the sheep; as well as with the anomaly presented by the turtle. In all these experiments, MM. Prevost and Dumas found it indis- pensable to adopt numerous precautions, on account of the rapid changes, induced by bleeding in the composition of the blood. In proportion as the blood is drawn, water is absorbed from every organ, and it becomes, thus, impoverished in globules. It has been already remarked, that innumerable globules have been found in the chyle. These are colourless; and they have been asserted to be of precisely the same magnitude as the nucleus of the red globule of the blood. It is presumed too, that the globules of the chyle obtain their colour, and their external envelope on which it depends, in the lungs; and that this is the finish given to the process of digestion. The notion is,however, problematical. The following table exhibits the diameter of the circular and elliptical globules iu different animals, according to MM. Pbevost and Dumas. VENOUS BLOOD. 45 ANIMALS WITH CIRCULAR GLOBULES. Animal. Diameter in fractions of a Millimetre.* Callitrichus or green Monkey of Africa, -Man, the Dog, Rabbit, Hog, Hedge-hog, Guinea-pig and Dormouse,..... The Ass, - ..... The Cat, gray and white Mouse, field Mouse, -Sheep, Bat, Horse, Mule, Ox, -Chamois, Stag, - -Goat,........ T^rth. 1 40 Allen and Pepys, 16* Sprengel, J. Borelli, 15 to 40 Soemmering, Goodwyn, - 14 Thomson, Sir H. Davy, 13 to 17 Bostock, Abernethy, 12 Jurin, 35 to 38 Keutsch, 6 to 12 In passing through the mouth, nasal fossae, pharynx, larynx, tra- chea, and bronchi, the inspired air acquires pretty nearly the tem- perature of the body; and, if the air has been cool, the same quan- tity by weight occupies a much larger space in the lungs, owing to its rarefaction in those organs. In its passage, too, it becomes mix- ed with the halitus, which is constantly exhaled from the mucous membrane of the air-passages; and, in this condition, it enters the air-cells, and becomes mixed with the residuary air in the lungs after expiration. Expiration.—An interval, scarcely appreciable, elapses after the accomplishment of inspiration, before the reverse movement of ex- piration succeeds; and the air is expelled from the chest. The EXPIRATION. 85 ■great cause of this expulsion is the restoration of the chest to its former dimensions; and the elasticity of the yellow tissue compos- ing the bronchial ramifications, which have been put upon the stretch by the air rushing into them, during inspiration. The restoration of the chest to its dimensions may be effected simply by the cessation of the contraction of the muscles, that have raised it; and the elasticity of the cartilages, which connect the bony portion of the ribs with the sternum or breast-bone. In active ex- piration, however, the ribs are depressed, by the action of appro- priate muscles, and the chest is thus still farther contracted. The chief expiratory muscles are the triangularis sterni, the broad mus- cles of the abdomen, rectus abdominis, sacro-lumbalis, longissimus dorsi, serratus posticus inferior, &c. Haller conceived, that the ribs, in expiration, are successively depressed towards the last rib; which is first fixed by the abdominal muscles and quadratus lumbo- rum. The intercostal muscles then act and draw the ribs succes- sively downwards. Magendie contests the explanation of Haller; and the truth would seem to be, that the muscles, just mentioned, participate with the intercostals in every expiratory movement. By this action, the capacity of the chest is diminished; the lungs are correspondently pressed upon, and the air issues by the glottis. It has been already remarked, that, during expiration, the aryte- noidei muscles contract, and the glottis appears to close. Still space sufficient is left to permit the exit of the air. It has been asked—is the air expired precisely that which has been taken in by the previous inspiration ? It is impossible to empty the lungs wholly by the most forced expiration. A portion still remains; and hence it has been assumed, that the use of inspiration is to constantly renew the air remaining in the air-cells. On this subject we are not well informed; but it is probable, that the lighter and more rarefied air gives way to the newly-arrived and denser medium; and that, thus, fresh air is continually exposed to the blood of the pulmonary vessels. A multitude of experiments have been made to determine the change of bulk which air experiences by being respired. According to Sir Humphry Davy, it is diminished, by a single inspiration and expiration, from T^th to T^otn Part °f its bulk. Cuvier makes it about j^th; Allen and Pepys a little more than a half per cent. Berthollet from 0.69 to 3.70 per cent; and Bostock -g^fh* as the average diminution. Assuming this last estimate to be correct, and forty cubic inches to be the quantity of air drawn into the lungs at each inspiration, it will follow, that half a cubic inch disappears each time we respire. This, in a day, would amount to 14,400 cubic inches, or to rather more than eight cubic feet. The experiments of MM. Dulong and Despretz make the diminution considerable. The latter gentleman placed six small rabbits in forty-nine quarts of air for two hours, at the expiration of which time the air had diminished one quart. A portion of the in- spired air must consequently have been absorbed. 86 • respiration. Attempts have been made to estimate the quantity of air re- maining in the lungs after respiration; but the sources of discrepancy are here as numerous as in the cases of inspiration or expiration. Goodwyn estimated it at 109 cubic inches; Menzies at 179; Jurine at 220; Fontana at 40; and Cuvier, after a forced inspi- ration, at from 100 to 60. Davy concluded, that his lungs, after a forced expiration, still retained 41 cubic inches of air. After a natural expiration they contained - - 118 cubic inches. After a natural inspiration, - - - 135 After a forced inspiration, - 254 By a full forced expiration after a forced inspiration, he threw out ------- 190 cubic inches. After a natural inspiration, - 78.5 After a natural expiration, ... 67.5 It is impossible, from such variable data, to deduce any thing like a satisfactory conclusion; but if we assume with Bostock, (and Dr. Thomson is disposed to adopt the estimate,) 170 cubic inches as the quantity, that may be forcibly expelled, and that 120 cubic inches will be still left in the lungs, we shall have 290 cubic inches as the measure of the lungs in their natural or quiescent state; to this quantity, 40 cubic inches are added by each ordinary inspiration, giving 330 cubic inches as the measure of the lungs in their dis- tended state. Hence it would seem, that about one-eighth of the whole contents of the lungs is changed by each respiration; and that rather more than two-thirds can be expelled by a forcible expira- tion. Supposing, that each act of respiration occupies three seconds, or that we respire twenty times in a minute, a quantity of air, rather more than 2| times the whole contents of the lungs, will be ex- pelled in a minute, or about four thousand times their bulk in twenty four hours. The quantity of air, respired during this period, will be 1,152,000 cubic inches, about 666^ cubic feet. SuchisBosTocx's estimate. It is the residuary air, that gives to the lungs the property of floating on the surface of water, after they have once received the breath of life, and no pressure that can be employed, will force out the air, so as to make them sink. Hence, the chief proofs, whether a child has been born alive or dead, are deduced from the lungs. These proofs constitut ethe docimasia pulmonum, or Lungen- probe of the Germans. Expiration, like inspiration, has been divided into three grades: ordinary, free, and forced; but it must necessarily admit of multi- tudinous shades of difference. In ordinary passive respiration, expiration is effected solely by the relaxation of the diaphragm. In free active expiration, the muscles, that raise the ribs, are likewise relaxed, and there is a slight action of the direct expiratory mus- cles. In forced expiration, all the respiratory muscles are thrown into action. In this manner, the air makes its way along the air- passages through the mouth or nostrils or both; carrying with it a NUMBER OF RESPIRATIONS. 87 fresh portion of the halitus from the mucous membrane. This it deposits, when the atmosphere is colder than the temperature ac- quired by the respired air, and if the atmosphere be sufficiently cold, as in winter, the vapour becomes condensed as it passes out, and renders expiration visible. The number of respirations, in a given time, differs considerably in different individuals. Dr. Hales reckons them at twenty. A man, on whom Menzies made experiments, breathed only fourteen times in a minute. Sir Humphry Davy made between twenty-six and twenty-seven in a minute. Dr. Thomson about nineteen, and Magendie fifteen. Our own average is sixteen. The average de- duced from the few observers, that have recorded their statements, —or twenty per minute,—has generally been taken; but we are satis- fied it is above the truth; eighteen would be nearer the general average; and it has,accordingly,been admitted by many. Eighteen in a minute give twenty-five thousand nine hundred and twenty in the twenty-four hours. The number of respirations is influenced by various circum- stances. The child and the female breathe more rapidly than the adult male. We find'as much variety, too, in him as we do in the horse; whilst some men are short-winded, others are long-winded; and this last condition may be improved by appropriate training; to which the pedestrian, and the prize-fighter, equally with the horse, are sub- mitted for some time before they exhibit their powers. In sleep, the respiration is generally deeper, less frequent, and appears to be effected greatly by the intercostals and diaphragm. Motion has also a sensible effect in hurrying the respiration, as well as the distention of the stomach by food; certain mental emo- tions, &c. and its condition during disease becomes a subject of in- teresting study to the physician, and one that has been much facili- tated by the acoustic method, introduced by Laennec. To his in- strument—the stethoscope—allusion has already been made. By it or by the ear applied to the chest, we are able to hear distinctly the character of the respiration; and thus to judge of the nature of the existing pulmonary disease. But this is a topic that appertains to pathology. There are certain respiratory movements, concerned in effecting other functions, which require consideration. Some of these have already been topics of discussion. Adelon has classed them into:— First. Those employed in the sense of smell, either for the pur- pose of conveying the odorous molecules into the nasal fossae; or to repel them, and prevent their ingress. Secondly. The inspiratory action, employed in the digestive function, as in sucking. Thirdly. Those connected with muscular motion, when forcibly exerted; and particularly in straining or the employment of violent effort. Fourthly. Those concerned in the various excretions, either vo- luntary, as in defecation and spitting, or involuntary, as in 88 RESPIRATION. coughing, sneezing, vomiting, accouchement, &c; and lastlyy such as constitute phenomena of expression, as, sighing,yawning, laughing, crying, sobbing, &c. Some of these, that have already engaged our attention, do not demand comment, others are topics of considerable interest and re- quire investigation. Straining. The state of respiration is much affected during the more active voluntary movements. Muscular exertion, of whatever kind, when considerable, is preceded by a long and deep inspira- tion; the glottis is then closed; the diaphragm and respiratory mus- cles of the chest are contracted, as well as the abdominal muscles which press upon the contents of the abdomen in all directions. At the same time that the proper respiratory muscles are exerted, those of the face participate, owing to their association through the me- dium of the respiratory nerves. By this series of actions, the chest is rendered capacious; and the force, that can be developed, is aug- mented, in consequence of the trunk being rendered immovable as regards its individual parts; and thus serving as a fixed point for the muscles that arise from it, so that they are enabled to employ their full effect. The physiological state of muscular action, as connected with the mechanical function of respiration, is happily described by Shakes- peare, when he makes the 5th Harry encourage his soldiers at the siege of Harfleur:— " Stiffen the sinews, summon up the blood; " Now set the teeth, and stretch the nostrils wide: " Hold hard the breath and bend up every spirit "Tohis full height." In the effort required for effecting the various excretions, a simi- lar action of the respiratory muscles takes place. The organs, from which these excretions have to be removed, exist either in the tho- rax or abdomen; and, in all cases, the organs have to be compressed by the parietes of those cavities. See Fig. 107. A full inspiration is first made; the expiratory muscles, with those that close the glottis, are then forcibly and simultaneously contracted, and by this means the thoracic and abdominal viscera are compressed. Some difference, however, exists, according as the viscus, to be emptied, is seated in the abdomen or thorax. In the evacua- tion of the faeces, the lungs are first filled with air; and whilst the muscles of the larynx contract to close the glottis, those of the abdomen contract also; and as the lung, in consequence of the in- cluded air, resists the ascent of the diaphragm, the compression bears upon the large intestine. The same happens in the excretion of the urine and in accouchement. coughing, sneezing, &C. 89 When the organ, that has to be cleared, is in the thorax,—as in coughing to remove mu- jftvirw cus from the air-passages, ■ri6- lv'- the same action of the mus- cles of the abdomen is in- voked; but the glottis is open to allow of the exit of the mucus. In this case the expiratory muscles con- tract convulsively and for- cibly, so that the air is dri- ven violently from the lungs, and in its passage sweeps off the irritating matter and conveys it out of the body. To aid this, the muscular fibres, at the posterior part of the tra- chea and larger bronchial tubes, contract, so as to diminish the calibre of these canals; and, in this way, as Dr. Physick has suggested, the expectora- tion is facilitated. The action differs, how- ever, according as the ex- pired air is sent through the nose or mouth; in the fnrmpr pn<5P f (instituting A. Right lung.-B. Left lung.-C. Right ventricle of the IOrmer Case, COU&LlLULiuSheart_g. Rigla auricle of the heart.-E. Vena cava superior. nr)PPzin& • in the latter,— F,F. Subclavian veins.—G, G. Internal jugular veins.—H. Sneezing, *" "»c l* .»Ascending aorta.-l. Pulmonary artery.-K. Diaphragm.- COUghing. 1 he former IS L, L. Right and left lobes of liver.—M. Ligamentum rotun- 3 . °, ,, ,i„ i . dum.—N. Fundus of gall-bladder.—O. Stomach.—P. Spleen. more Violent tnan tne iai-_Q(q. situation of thekidneys, behind the intestines.-R, R. ter, and is involuntary; small intestines. whilst the latter is not necessarily so. In both cases, the movement is excited by some external irritant, applied directly to the mucous membrane of the windpipe or nose; or by some modified action in the very tissue of the part, which acts as an irritating cause. In both cases the air is driven forcibly forward, and both are accompanied by sounds that cannot be mistaken. In these actions we have striking exemplifications of the extensive association of muscles, through the system of respiratory nerves, to which we have so often alluded. The pathologist, too, has repeated opportunities for observing the extensive sympathy between dis- tant parts of the frame, as indicated by the actions of sneezing and coughing, especially of the former. If a person be exposed for a short period to the partial and irregular application of cold, so that Vol. II. 12 90 RESPIRATION. the capillary action of a part of the body is modified, as where we get the feet wet, or sit in a draught of air, a few minutes will fre- quently be sufficient to exhibit sympathetic irritation in the Schnei- derian membrane of the nose, and sneezing. Nor is it necessary, that the capillarji'action of a distant part shall be modified by the application of cold. We have had the most positive evidence, that if the capillary circulation be irregularly excited, even by the ap- plication of heat, whilst the rest of the body is receiving none of its influence, inflammation of the mucous membrane of the nasal fossae and fauces follows with no less certainty. Blowing the Nose.—The substance, that has to be excreted by this operation, is composed of the nasal mucus, the tears sent down the ductus ad nasum, and the particles deposited on the membrane by the air, in its passage through the nasal fossae. Commonly, this is only present in quantity sufficient to keep the membrane moist, the remainder being evaporated or absorbed. Frequently, however, it exists in such quantity as to fall by its own gravity into the pharynx, whence it is sent down into the stomach by degluti- tion, is thrown out at the mouth, or passes out at the anterior nares. To prevent this last effect more especially, we have recourse to blowing the nose. This is accomplished by taking in air, and driving it suddenly and forcibly out, closing the mouth at the same time, so that the air may issue by the nasal fossae and clear them; the nose being compressed so as to make its velocity greater, as well as to express all the mucus that may be forced forwards. Spitting differs somewhat according to the part in which the mucus or matter to be ejected is seated. At times, it is exclusively in the mouth; at others in the back part of the nose, pharynx, or larynx. When the mucus or saliva of the mouth has to be excreted, the muscular parietes of the cavity, as well as the tongue, contract so as to eject it from the mouth; the lips being at times approximated, so as to render the passage narrow, and impel the sputa more strongly forward. The air of expiration may be, at the same time, driven forcibly through the mouth, so as to send the matter to a consider- able distance. The practised spitter sometimes astonishes us with the accuracy and power of propulsion of which he is capable. When the matter to be evacuated is in the nose, pharynx, or larynx, it requires to be brought, first of all, into the mouth. If in the posterior nares, the mouth is closed, and air is drawn in forcibly through the nose; the pharynx being at the same time constricted so as to prevent the substances from passing down into the oesopha- gus. The pharynx now contracts, from below to above, in an in- verse movement from that required in deglutition, and the farther excretion from the mouth is effected in the manner just described. Where the matters are situated in the air-passages, the action may consist in coughing; or, if higher up, simply in hawking. A SIGHING, YAWNING, &C. 91 forcible expiration, unaccompanied by cough, is, indeed, in many cases, sufficient to detach the superfluous mucous secretion from even the bronchial tubes. In hawking, the expired air is forcibly sent forwards, and the parts about the fauces are suddenly contracted so as to diminish the capacity of the tube and propel the matters onwards. The noise is produced by their discordant vibration. Both these modes bear the general name of expectoration. When these secretions are swallowed, they are subjected to the digestive process; a part is taken up, and the remainder rejected; so that they belong to the division of recremento-excrementitial fluids of some physiologists. Lastly, it remains to speak of the expiratory phenomena, that strictly form part of the function of expression, and depict the mo- ral feeling of the individual who gives utterance to them. Sighing consists of a deep inspiration, by which a large quantity of air is received slowly and gradually into the lungs, to compen- sate for the deficiency in the due aeration of the blood which pre- cedes it. The most common cause of sighing is mental uneasiness; it also occurs at the approach of sleep, or immediately after waking. In all these cases, the respiratory efforts are executed more imper- fectly than under ordinary circumstances; the blood consequently does not circulate through the lungs in due quantity, but accumu- lates more or less in these organs, and in the right side of the heart; and it is to restore the due balance that the deep inspiration is now and then established. Yawning, oscitancy, oscitation, or gaping, is likewise a full, deep, and protracted inspiration, accompanied by a wide separation of the jaws, and followed by a prolonged and sometimes sonorous ex- piration. Yawning is excited by many of the same causes as sighing. It is not, however, the expression of any depressing passion, but is occasioned by any circumstance that impedes the necessary aeration of the blood; whether this be retardation of the action of the respira- tory muscles, or the air being less rich in oxygen. Hence, we yawn at the approach of sleep, and immediately after waking. The inspiratory muscles, fatigued from any cause, experience some difficulty in di- lating the chest; the lungs are consequently not properly traversed by the blood from the right side of the heart. Oxygenation is, therefore, not duly effected; an uneasy sensation is induced, which is put an end to by the action of yawning, which allows the admission of a consi- derable quantity of air. We yawn at the approach of sleep, because the agents of respiration, becoming gradually more debilitated, re- quire to be now and then excited to fresh activity, and the blood needs the necessary aeration. Yawning on waking seems to be partly for the purpose of stimulating the respiratory muscles to greater activity, the respiration being always slower and deeper during sleep. It is of course impossible to explain why the respi- ratory nerves should be those that are chiefly concerned under the 92 RESPIRATION. guidance of the brain, in these respiratory movements of an expres- sive character. The fact, however, is certain, and is remarkably proved by the circumstance, that yawning can be excited by even looking at another affected in this manner; nay, by simply looking at a sketch, and by even thinking of the action. The same also ap- plies to sighing and laughing, and especially to the latter. Pandiculation or stretching is a frequent concomitant of yawn- ing, and appears to be established instinctively to arouse the exten- sor muscles to a balance of power, when the action of the flexors has been predominant. In sleep, the flexor muscles exercise that preponderance which, in the waking state, is exerted by the exten- sors. This, in time, is productive of some uneasiness; and, hence, at times during sleep, but still more at the moment of waking, the extensor muscles are roused into action, to restore the equipoise; or perhaps, as the muscles of the upper extremities and those concern- ed, directly or indirectly, in respiration, are chiefly concerned in the action, it is exerted for the purpose of arousing the respiratory muscles to increased activity. By Dr. Good, yawning and stretching have been regarded as morbid affections and amongst the signs of debility and lassitude:— " Every one," he remarks, " who resigns himself ingloriously to a life of lassitude and indolence will be sure to catch these motions as a part of that general idleness, which he covets. And, in this manner, a natural and useful action is converted into a morbid habit; and there are loungers to be found in the world, who, though in the prime of life, spend their days as well as their nights in a perpetual routine of these convulsive movements over which they have no power; who cannot rise from the sofa without stretching their limbs, nor open their mouths to answer a plain question with- out gaping in one's face. The disease is here idiopathic and chro- nic; it may perhaps be cured by a permanent exertion of the will, and ridicule or hard labour will generally be found the best reme- dies for calling the will into action." Laughing \s a convulsive action of the muscles of respiration and voice, accompanied by a facial expression, which has been explain- ed elsewhere. It consists of a succession of short, sonorous expi- rations. The air is first inspired so as to fill the lungs. To this succeeds short interrupted expirations, with simultaneous contrac- tion of the muscles of the glottis, so that this aperture is slightly contracted, and the lips assume the tension, necessary for the pro- duction of sound. The interrupted character of the expirations is caused by convulsive contractions of the diaphragm, which consti- tute the greatest part of the action. In very violent laughter, the respiratory muscles are thrown into such forcible contractions, that the hands are applied to the sides to support them. The convulsive action of the thorax, likewise interferes with the circulation through the lungs; the blood, consequently, stagnates in the upper part of the body; the face becomes flushed; the sweat trickles down the WEEPING, SOBBING, PANTING, &C. 93 forehead, and the eyes are suffused with tears; but this is apparently owing to mechanical causes; not to the lachrymal gland being ex- cited to unusual action, as in weeping. At times, however, we find the latter cause in operation, also. The action of weeping is very similar to that of laughing; although the causes are so dissimilar. It consists in an inspiration, followed by a succession of short, sonorous expirations. The facial expres- sion, so diametrically opposite to that of laughter, has been depicted in another place. Laughter and weeping appear to be characteristic of humanity. Animals shed tears, but this does not seem to be accompanied with the mental emotion which characterizes crying in the sense in which we employ the term. It has, indeed, been affirmed by Steller, that the phoca ursina or ursine seal; by Pallas, that the camel; and by Humboldt, that a small American monkey shed tears when labour- ing under a distressing emotion. The last scientific traveller states, that " the countenance of the titi of-the Orinoco,—the simia sciu- rta of Linn-eus,—is that of a child;—the same expression of inno- cence; the same smile; the same rapidity in the transition from joy to sorrow. The Indians affirm, that it weeps like man, when it experiences chagrin; and the remark is accurate. The large eyes of the ape are suffused with tears, when it experiences fear or any acute suffering." Shakespeare's description of the weeping of the stag,— " That from the hunter's aim had ta'en a hurt," is doubtless familiar to most of our readers. *' The wretched animal heav'd forth such groans, That their discharge did stretch his leathern coat Almost to bursting; and the big round tears Cours'd one another down his innocent nose In piteous chase; and thus the hairy fool, Much marked of the melancholy Jaques, Stood on th' extremest verge of the swift brook, Augmenting it with tears." We have less evidence in favour of the laughter of animals. Le Cat, indeed, asserts that he saw the chimpanse both laugh and weep. The ourang-outang, carried to Great Britain from Batavia, by Dr. Clarke Abel never laughed; but he was seen occasionally to weep. Sobbing still more resembles laughing, except that, like weeping, it is usually indicative of the depressing passions; and generally accompanies weeping. It consists of a convulsive action of the dia- phragm; which is alternately raised and depressed, but to a greater extent than in laughing and with less rapidity. It is susceptible of various degrees and has the same physical effects upon the circula- tion as weeping. Lastly, panting or anhelation consists in a succession of alter- nate, quick and short inspirations and expirations. Their physio- 94 RESPIRATION. logy, however, does not differ from that of ordinary respiration. Thu object is, to produce a frequent renewal of air in the lungs, in cases where the circulation is unusually rapid; or where, owing to dis- ease of the thoracic viscera, a more than ordinary supply of fresh air is demanded. We can, hence, understand, why dyspnoea should be one of the concomitants of most severe diseases of the chest; and why it should occur whenever the air we breathe does not contain a sufficient quantity of oxygen. The panting, produced by running, is owing to the necessity for keeping the chest as immovable as pos- sible, that the whole effort may be exerted on the muscles of loco- motion; and thus suspending, for a time, the respiration or admitting only of its imperfect accomplishment. This induces an accumulation of blood in the lungs and right side of the heart; and panting is the consequence of the augmented action necessary for transmitting it through the vessels. Having studied the mode, in which air is received into, and ex- pelled from, the lungs, we have now to inquire into the changes produced on the venous blood—containing the products of the va- rious absorptions—in the lungs, as well as on the air itself. These changes constitute the function of sanguification, hxmatosis, res- piration properly so called, arterialization of the blood, aera- tion, &c. With the ancients this process was but little understood. It was generally believed to act as a means of cooling the body; and, in modern times, Helvetiu* revived the notion, attributing to it the office of refrigerating the blood, heated by its passage through the long and narrow channels of the circulation, by the cool air constantly received into the lungs. The reasons, that led to this opinion, were:—that the air, which enters the lungs in a cool state, issues warm;—that the pulmonary veins, which convey the blood from the lungs, are of less dimension than the pulmonary artery, which conveys it to them. From this it was concluded, that the blood, during its progress through the lungs, must lose somewhat of its volume or be condensed by refrigeration. The warmth of the expired air can, however, be readily accounted for; whilst it is not true that the pulmonary veins are smaller than the pulmonary arte- ry. The reverse is, indeed, the fact; and it is equally obvious that the doctrine of Helvetius does not explain how we can exist in a temperature superior to our own; this ought, in his hypothesis, to be impracticable. Another theory, which prevailed for some time, was:—that dur- ing inspiration, the vessels of the lungs are unfolded, as it were; and that thus the passage of the blood from the right side of the heart to the left through the lungs, is facilitated. Its progress was, in- deed, conceived to be impossible during expiration, in consequence of the considerable flexures of the pulmonary vessels. The disco- very of the circulation of the blood gave rise to this theory; and Haller attaches considerable importance to it, when taken in con- H-ffiMATOSIS. 95 nexion with the changes effected upon the blood in the vessels. It is inaccurate, however, to suppose, that the circulation of the blood through the lungs is interrupted, when respiration is arrested. It continues for some time afterwards, and when it ceases, it is owing to the heart, like every other part of the body, being incapable of acting without a due supply of arterial blood; which cannot, in this case, be sent to it, in consequence of the air no longer entering the lungs. Numerous other objections might be made to this view. In the first place, it supposes, that the lungs are emptied at each expi- ration ; and, again, if a simple development or unfolding of the vessels were all that is required, any gas ought to be sufficient for respiration, which is not the fact. In these different theories, the principal object of respiration is overlooked—the conversion of the venous blood and its various ab- sorptions, conveyed to the lungs by the pulmonary artery, into ar- terial blood. This is effected by the contact of the inspired air with the venous blood; in which they both lose certain elements, and gain others. Most physiologists have considered, that the whole function of hae- matosis or sanguification, is effected in the lungs. Chaussier, how- ever, has presumed, that the air, in passing through the cavities of the nose and mouth, and the different bronchial ramifications, expe- riences some kind of elaboration, by being agitated with the bron- chial mucus; similar to what he conceived to be effected in the ali- ment in its passage from the mouth to the stomach: but this is con- jectural in both one. case and the other. Legallois, again, thought, that hasmatosis commences at the part, where the chyle and lymph are mixed with the venous blood, or in the subclavian veins. This admixture, he conceives, occurs more or less immediately, is aided in the heart; and the conversion is completed in the lungs. To this belief he was led by the circum- stance, that when the blood quits the lungs, it is manifestly arterial, and he thought, that what the products of absorption lose or gain in the lungs, is too inconsiderable to account for the important and extensive change; and that therefore it must have commenced pre- viously. Facts, however, are not exactly in accordance with the view of Legallois. They seem to show, that the blood of-the pulmonary artery is analogous to that of the subclavian veins; and hence it is probable, that there is no other action exerted upon the fluid in this part of the venous system, than a more intimate admix- ture of the venous blood with the chyle and lymph in their passage through the heart. The changes, wrought on the air by respiration, are considerable. It is always immediately deprived of a portion of one of its consti- tuents—oxygen; and it always contains, when expired, a quantity of carbonic acid greater than it had when received into the lungs, along with an aqueous and albuminous exhalation to a considerable amount. 96 RESPIRATION. Oxygen is consumed by the respiration of all animals, from the largest quadruped to the most insignificant insect; and if we examine the expired air, the deficiency is manifest. Many attempts have been made to estimate the precise quantity of oxygen, consumed during respiration; but the results vary essen- tially from each other; partly owing to the fact, that the amount of oxygen, consumed by the same animal in different circumstances, is not identical. Menzies was, probably, the first that attempted to ascertain the quantity consumed by a man in a day. According to him, 36 cubic inches are expended in a minute; and, consequently, 51840 in the twenty-four hours, equal to 17496 grains. Lavoisier makes it 46048 cubic inches, or 15541 grains. This was the result of his earlier experiments; and in his last, which he was executing at the time when he fell a victim to the tyranny of Robespierre, he makes it 15592.5 grains; corresponding largely with the results of his earlier observations. The experiments of Sir Humphry Davy coincide greatly with those of Lavoisier. He found the quantity consumed in a minute, to be 31.6 cubic inches; making 45504 cubic inches, or 15337 grains in twenty-four hours. The result obtained by Messrs. Allen and Pepys is much less. They consider the average consumption to be, in the twenty-four hours, under ordinary circumstances, 39534 cubic inches, equal to 13343 grains. Now, if we regard the experiments of Lavoisier and Davy, between which there is the greatest coincidence, to be an approximation to the truth, it will follow, that in a day, a man con- sumes rather more than 25 cubic feet of oxygen; and as the oxygen amounts to only about one-fifth of the respired air, he must render 125 cubic feet of air unfit for supporting combustion and respiration. The experiments, however, of Crawford, Jurine, Lavoisier and Seguin, Prout, Fype, and Edwards, have proved, that the quantity of oxygen consumed, varies, according to the condition of the functions and of the system generally. Seguin found that muscular exertion increases it nearly four fold. Prout, who gave much attention to the subject, was induced to conclude, from his experiments, that moderate exercise increases the consumption; whilst, if the exercise be continued, so as to induce fatigue, a dimi- nished consumption takes place. The exhilarating passions also ap- peared to increase the quantity; whilst the depressing passions and sleep, the use of alcohol and tea diminished it. He discovered, also, that the quantity of oxygen consumed, is not uniformly the same during the twenty-four hours. Its maximum he found to occur be- tween 10 A. M. and 2 P. M., or generally between 11 A. M. and 1 P. M.; its minimum commenced about S3 P. M., and it continued nearly uniform till about 3% A. M. Dr. Fyfe found, that the quantity was likewise diminished by a course of nitric acid, by a vegetable diet, and by affecting the system with mercury. H.EMATOSIS. 97 Temperature also has an effect upon the consumption. Crawford found, that a Guinea-pig, confined in air at the temperature of 55°, consumed double the quantity which it did in air at 104°. He also observed, in such cases, that the venous blood, when the body was exposed to a high temperature, had not its usual dark colour; but, by its florid hue, indicated that no change had taken place in its constitution, in the course of circulation. We can thus understand the great lassitude and yawning, induced by the hot weather of summer; and the languor and listlessness, which are so character- istic of those who have long resided in torrid climes. Dr. Prout conceives, that the presence or absence of the sun alone regulates the variation in the consumption of oxygen, which he has described; but the deduction of Dr. Fleming appears to us more legitimate,—that it keeps pace with the degree of muscular action, and is dependent upon it. Consequently, a state of increased consumption is always followed by an equally great decrease, in the same manner as activity is followed by fatigue. The disagreement of experimenters, regarding the removal of nitrogen or azote from the air, during respiration, is still greater than in the case of oxygen. Priestley, Davy, Humboldt, Hen- derson, Cuvier, Pfaff, and Thomson found a less quantity ex- haled than was inspired. Spallanzani, Lavoisier and Seguin, Vauquelin, Allen and Pepys, Ellis, and Dalton, inferred, that neither absorption nor exhalation takes place; the quantity of that gas undergoing no change during its passage through the air-cells of the lungs; whilst Jurine, Nysten, Berthollet, and Dulong and Despretz, on the contrary, found an increase in the bulk of the azote. In this uncertainty, most physiologists have been of opinion, that the azote is entirely passive in the function. The facts, however, ascertained by Dr. John Edwards of Paris, shed considerable light on the causes of this discrepancy amongst observers. He has satisfactorily shown, that, during the respiration of the same animal, the quantity of azote may, at one time, be aug- mented, at another diminished, and, at a third, wholly unchanged. These phenomena he has traced to the influence of the seasons, and he suspects, that other causes have a share in their production. In nearly all the lower animals that were the subjects of experiment, an augmentation of azote was observable during summer. Some- times, indeed, it was so slight, that it might be disregarded; but, in numerous other instances, it was so great as to place the fact beyond the possibility of doubt; and, on some occasions, it almost equalled the whole bulk of the animal. Such were the results of his obser- vations until the close of October, when he noticed a sensible di- minution in the nitrogen of the inspired air, and the same continued throughout the whole of winter and the beginning of spring. Dr. Edwards considers it probable, that, in all cases, both exhalation and absorption of azote are going on; that they are frequently ac- curately balanced, so as to exhibit neither excess nor deficiency of Vol. II.- 13 98 respiration. nitrogen in the expired air, whilst, in other cases, depending, as it would appear, chiefly upon temperature, either the absorption or the exhalation is in excess, producing a corresponding effect upon the composition of the air of expiration. But, not only has the respired air lost its oxygenous portion, it has gained, as we have remarked, an accession of carbonic acid, and, likewise, a quantity of serous vapour. If we breathe through a tube, one end of which is inserted into a vessel of lime water, the fluid soon becomes milky, owing to the formation of carbonate of lime, which is insoluble in water. Car- bonic acid must consequently have been given off from the lungs. Here, again, the quantity formed in the day, has been attempted to be computed. Jurine conceived, that the amount, in air once respired in natural respiration, is in the enormous proportion of -j\fih or T\th. Menzies, that it is ■s\rtn> anc' ^rom ms estimate of the total quantity of air respired in the twenty-four hours, he deduced the amount of carbonic acid formed to be 51840 cubic inches, equal to 24105.6 grains. Lavoisier and Seguin, in their first experiments, valued it at 17720.S9 grains; but, in the very next year, they reduced their es- timate more than one-half;—to 8450.20 grains; and, in Lavoisier's last experiment, it was farther reduced to 7550.4 grains. Sir Humphry Davy's estimate nearly corresponds with that of the first experiment of Lavoisier and Seguin,—17811.36 grains; and MM. Allen and Pepys accord pretty nearly with him. The expe- riments and observations of Crawford, Prout, Edwards, and others, to which we have referred—as regards the consumption of oxygen, under various circumstances,—apply equally to the quan- tity of carbonic acid formed, which always bears a pretty close proportion to the oxygen consumed. These experiments also ac- count, in some degree, for the descrepancy in the statements of dif- ferent individuals on this subject. It has been a question, amongst physiologists, whether the quan- tity of carbonic acid gas, given out, is equal in bulk to the oxygen taken in. In Priestley's experiments, the latter had the prepon- derance. Menzies, and Crawford found them to be equal. La- voisier and Seguin supposed the oxygen, consumed in the twenty- four hours, to be 15661.66 grains; whilst the oxygen, required for the formation of the carbonic acid given out, was no more than 12924 grains; and Sir Humphry Davy, in the same time, found the oxygen, consumed, to be 15337 grains; whilst the carbonic acid pro- duced was 17811.36 grains; which would contain 12824.18 grains of oxygen. The experiments of Allen and Pepys, however, seem to show, that the oxygen, which disappears, is replaced by an equal volume of carbonic acid; and hence, it was supposed, that the whole of it must have been employed in the formation of this acid. They, consequent- ly, accord with Menzies,and Crawford; and the view is embraced byDALTON, Prout, Ellis, Henry, and otherdistinguished individu- H.3EMAT0SIS. gg als. On the other hand, the view of those who consider that the quan- tity of carbonic acid produced is less than that of the oxygen which has disappeared, is embraced by Thomson, and by Dulong and Despretz. In the carnivorous animal, they found the difference as much as one-third; in the herbivorous, on the average, only TVth. The more recent experiments of Dr. Edwards have shown, that here, again, the discordance has not depended so much upon the different methods and skill of the operators, as upon a variation in the results, arising from other causes; and he concludes, that the pro- portion of oxygen consumed, to that employed in the production of carbonic acid, varies from more than one-third of the volume of car- bonic acid to almost nothing; that the variation depends upon the particular animal species, subjected to experiment; upon its age, or on some peculiarity of constitution, and that it differs considerably in the same individual at different times. It would appear, then, that the whole of the oxygen, which res- piration abstracts from the air, is not accounted for, in all cases, by the quantity of carbonic acid formed; and that, consequently, some of it disappears altogether. It has been supposed, by some, that a part of the watery vapours, given off during expiration, is occasioned by the union of a portion of the oxygen of the air with hydrogen from the blood in the lungs; by others, that the oxygen is absorbed into the blood, and lost in its course through the system, &c; but these views are entirely conjectural. With regard to the quantity of vapour, combined with the expired air, it will be the subject of inquiry under the head of Secretion. The air likewise loses, during inspiration, certain foreign mat- ters, that may be diffused in it. In this way, indeed, medicines have been attempted to be conveyed into the system. If air, charged with odorous particles,—as with those of turpentine,—be breathed for a short time, their presence in the urine will be detected; and it is probably in this manner, that miasmata produce their effects on the frame. All these substances pass immediately through the coats of the pulmonary veins by imbibition, and, in this manner, speedily attain the most distant parts of the system. These changes, produced in the air during respiration, are easily shown, by placing an animal under a receiver, until it dies. On examining the air, it will be found to have lost largely of its oxy- gen, and to contain much carbonic acid and aqueous vapour. Let us inquire, then, whether the changes, produced in the re- spired air, are connected with those effected on the blood in the lungs. In its progress through the lungs this fluid has been changed from venous into arterial. It has become of a florid red colour; of a stronger odour; of a higher temperature by nearly two degrees; of less specific gravity, and it coagulates more speedily. That this conversion is owing to the contact of air in the lungs we have many proofs. Lower was one of the first, who clearly pointed out, that the change of colour occurs in the capillaries of the lungs. Prior to his time, the most confused notions had prevailed on the subject, 100 RESPIRATION. and the most visionary hypotheses had been indulged. On opening the thorax of a living animal, he observed the precise point of the circulation at which the change of colour takes place, and he showed, that it is not in the heart, since the blood continues to be purple, when it leaves the right ventricle. He then kept the lungs artifi- cially distended; first with a regular supply of fresh air, and after- wards with the same portion of air without renewing it. In the former case, the blood experienced the usual change of colour. In the second, it was returned to the left side of the heart unchanged. Experiments, more or less resembling those of Lower, have been performed by Goodwyn, Cigna, Bichat, Wilson Philip, and numerous others, with precisely similar results. The direct experiments of Priestley more clearly showed, that the change, effected on the blood, was to be ascribed to the air. He found, that the clot of venous blood, when confined in a small quantity of air, assumed a scarlet colour, and that the air expe- rienced the same change as by respiration. He afterwards examined the effect produced on the blood by the gaseous elements of the at- mosphere separately, as well as by the other gaseous fluids, that had been discovered. The clot was reddened more rapidly by oxygen than by the air of the atmosphere; whilst it was reduced to the dark purple by nitrogen, hydrogen, and carbonic acid. Since Priestley's time, the effect of different gases on the co- lour of venous blood has been investigated by numerous indivi- duals. The following is the result of their observations as given by Thenard. It must be remarked, however, that all experiments have been made on the blood, when out of the body; and that it by no means follows, that precisely the same changes would be accom- plished if the fluid were circulating in the vessels. Gas. Colour. Remarks. Oxygen..... Atmospheric air - - - Ammonia..... Gaseous oxyd of carbon Deutoxide of azote - - Carburetted hydrogen - Azote...... Carbonic acid - - - Hydrogen - - - - - Protoxide of azote - - Arsenuretted hydrogen Sulphuretted hydrogen Hydrochloric gas - - Sulphurous gas - - - Chlorine Rose red. Do. Cherry red. Slightly violet red Do. Do. Brown red. Do. Do. Do. {Deep violet, pass- ing gradually to a greenish brown. Maroon brown. Black brown. f Blackish brown, J passing by de- | grees to a yel- lowish white. The blood employed had been beaten, and, consequently, depriv- ed of its fibrine. These three gases coagulate the blood at the same time. hjematosis. 101 It is sufficiently manifest, then, from the disappearance of a part of the oxygen from the inspired air, and from the effects of that gas on venous blood out of the body, that it forms an essential part in the function of sanguification. But we have seen, that the expired air contains an unusual proportion of carbonic acid. Hence carbon, either in its simple state or united with oxygen, must have been given off from the blood in the vessels of the lungs. To account for these changes on chymical principles has been a great object with chymical physiologists at all times. Priestley supposed the conversion of venous into arterial blood, to be a kind of combustion; and, according to the notion of combustion then preva- lent, it was presumed to consist in the disengagement of phlogiston; in other words, the abstraction or addition of a portion of phlogis- ton made the blood, he conceived, arterial or venous; and the re- moval of phlogiston he looked upon as the principal use of respira- tion. This view was modified by Lavoisier, who conceived, that both carbon and hydrogen are given off from the lungs, and that they unite with the oxygen of the air by a kind of combustion; a part of the oxygen uniting with the carbon and forming carbonic acid, another portion uniting with the hydrogen and forming water. The presence of hydrogen was, however, found to be entirely ideal; and, subsequently, the general opinion was, that the most important change experienced by the blood in respiration, consists in the re- moval of its carbon. Two chief chymical hypotheses have been formed to explain the mode in which this carbon is given off. The first is that of Black, Priestley, Lavoisier, and Crawford ;—that the oxygen of the inspired air attracts carbon from the venous blood, and that the carbonic acid is generated by their union. The second, which has been supported by Lagrange, Hassenfratz, Edwards, Bos- tock, and others,—that the carbonic acid is generated in the course of the circulation, and is given off from the venous blood in the lungs, whilst oxygen gas is absorbed. The former of these views is still maintained by a number of physiologists. It is conceived, that the oxygen, derived from the air, unites with certain parts of the venous blood,—the carbon and the hydrogen,—the result of which union is that carbonic acid and water are found in the expired air; and the venous blood, thus depurated of its carbon and hydrogen, becomes arterialized; and, in conse- quence of these various combinations, heat enough is disengaged to keep the body always at the due temperature. According to this theory, as we have seen in the views of Priestley, Lavoisier, &c. respiration is assimilated to combustion. The resemblance, indeed, between the two processes is, at first sight, considerable. The presence of air is absolutely necessary for respiration; in every variety of respiration the air is robbed of its oxygen; and hence a fresh supply is continually needed ; and it is always arrested before the whole of the oxygen of the air is ex- 102 RESPIRATION. hausted, and this partly on account of the carbonic gas given off during expiration. Lastly, it can be continued much longer when an animal is confined in pure oxygen gas than in atmospheric air. All these circumstances likewise prevail in combustion. Every kind of combustion requires the presence of air. A part of the oxy- gen of the air is consumed; and, unless the air be renewed, com- bustion is impossible. It is arrested, too, before the whole of the oxygen is consumed,owing to the carbonic acid formed; and it can be longer maintained in pure oxygen. Moreover, when the air has been respired, it becomes unfit for combustion,—and conversely. From these analogies, respiration has been assimilated to combus- tion. Again, the oxygen of the air, in which combustion is taking place, combines with the carbon and hydrogen of the burning body; hence the formation of carbonic acid and water; and as, in this combination, the oxygen passes from the state of a very rare gas, or one containing a considerable quantity of caloric between its molecules, to the condition of a much denser gas, or even of a liquid, the whole of the caloric, which the oxygen contained in its former state, can no longer be held in the latter, and it is accord- ingly disengaged; hence the heat which is given off. In like man- ner, in respiration, the oxygen of the inspired air combines with the carbon and hydrogen of the venous blood; giving rise to the formation of carbonic acid and water; and, as in these combinations, the oxygen passes, also, from the state of a very rare to that of a denser gas, or of a liquid, there is a considerable disengagement of caloric, which becomes the source of the high temperature, main- tained by the human body. M. Thenard, admits a modification of this view,—sanguification being owing, he conceives, to the combustion of the carbonaceous parts of the venous blood, and probably of its colouring matter, by the oxygen of the air. This chymical theory, which originated chiefly with Lavoisier . and La Place, and Seguin, was adopted by Crawford, Gren, Girtanner, and others, with but little modification. Of these mo- difications it may be well to refer to one or two. Crawford was of opinion, that venous blood contains a peculiar compound of car- bon and hydrogen, called hydro-carbon, the elements of which unite in the lungs with the oxygen of the air, forming water with the one, and carbonic acid with the other; and that the blood, pu- rified in this manner, assumes the scarlet hue, and becomes adapted to the necessities of the economy. It is only necessary to say, that this supposed hydro-carbon is entirely conjectural. Mr. Ellis imagined, that the carbon is separated from the ve- nous blood by a secretory process; and that, then, coming into di- rect contact with oxygen, it is converted into carbonic acid. The circumstance that led him to this opinion, was his disbelief in the possibility of oxygen being able to act upon the blood through the H.SEMATOSIS. 103 animal membrane or coat of the vessel, in which it is confined. It is obvious, however, that if the oxygen penetrates to the blood circulating in the lungs, it must in all cases pass through the coats of the pulmonary vessels. These coats, indeed, offer little or no obstacle, and, consequently, there is no necessity for the vital or secretory action suggested by Mr. Ellis. Priestley and Hassenfratz ex- posed venous blood to atmospheric air and to oxygen in a bladder. In all cases, the parts of the blood, in contact with the gases, be- came of a florid colour. The experiments of Dr. J. K. Mitchell are, in this aspect, pregnant with interest. They prove the great facility with which the tissues are penetrated by the gases, and confirm the facts developed by the experiments of Priestley and Hassen- fratz. The second hypothesis,—that the carbonic acid is generated in the course of the circulation,—was proposed by Lagrange, in consequence of the objection he saw to the former hypothesis,— that the lung ought to be consumed by the perpetual disengage- ment of caloric taking placejwithin it; or if not so, that its tempera- ture ought, at least, to be superior to- that of other parts. He ac- cordingly suggested, that, in the lungs, the oxygen is simply ab- sorbed; passing into the venous blood, circulating with it, and uniting, in its course, with the carbon and hydrogen, so as to form carbonic acid and water, which circulate with the blood, and are finally exhaled from the lungs. The objection of Lagrange was, however, ingeniously attempted to be obviated by assuming, that arterial blood has a greater capacity for caloric than venous blood, and, consequently, that when the combustion, under the former theory, takes place in the lungs, the disengaged caloric is taken up by, and becomes latent in, the arterial blood, so that no sensible in- fluence can be exerted by it on the lungs; whilst it is disengaged in the capillary vessels, when the blood again becomes venous and acquires a less capacity for caloric; thus giving rise to the pheno- mena of animal heat, which will have to be considered hereafter. The ingenious and apparently accurate experiments of Dr. Ed- wards prove convincingly, not only that oxygen is absorbed by the pulmonary vessels, but that carbonic acid is exhaled from them. When he confined a small animal in a large quantity of air, and continued the experiment sufficiently long, he found, that the rate of absorption was greater at the commencement than towards the termination of the experiment; and, at the former period, there must have been an excess of oxygen present, and at the latter an excess of carbonic acid. This proved to him that the diminution was dependent upon the absorption of oxygen, not of carbonic acid. His experiments, in proof of the exhalation of carbonic acid, ready formed by the lungs, are very decisive. Spallanzani had asserted, that when certain of the lower animals are confined in gases, con- taining no oxygen, the production of carbonic acid is uninterrupt- ed. Upon the strength of this assertion, Edwards confined frogs 104 RESPIRATION. in pure hydrogen, for a length of timev The result indicated, that carbonic acid was produced, and, in such quantity as to show, that it could not have been derived from the residual air in the lungs, as it was, in some cases, equal to the bulk of the animal. The same results, although to a less degree, were obtained with fishes and snails,—the animals on which Spallanzani's observations were made. The experiments of Edwards were extended to the mammalia. Kittens, two or three days old, were immersed in hydrogen. They remained in this situation for nearly twenty minutes, without dying. On examining the air of the vessel after death, it was found that they had given off a quantity of carbonic acid greater than could possibly have been contained in their lungs at the commencement of the experiment. The conclusion, deduced by Dr. Edwards, from his experiments, is, "that the carbonic acid expired is an ex- halation proceeding wholly or in part from the carbonic acid con- tained in the mass of blood." Several experiments have been re- cently made by M. Collard de Marthgny, who substituted azote for hydrogen; and in all cases, carbonic acid gas was given out in considerable quantity. These experiments, then, would seem to show, that carbonic acid is exhaled in the lungs, and that oxygen is absorbed; but it is by no means proved, that the latter goes to the formation of the former in the lungs or elsewhere. They would, also, prove the existence of carbonic acid in the venous blood, respecting which so much dissi- dence has existed amongst chymists; and certain experiments by Girtanner are cited as proofs, that free oxygen is contained in arterial blood. He placed the arterial blood of the sheep under a bell-glass filled with azote. In thirty hours, enough oxygen was disengaged to admit a candle to burn for two minutes under the glass. Chaussier and Adelon, again, regard the whole process of hae- matosis as essentially organic and vital. They think, that an ac- tion of selection and elaboration is demanded, both as regards the reception of the oxygen and the elimination of the carbonic acid. But their arguments on this point are unsatisfactory, and are nega- tived by the facility with which oxygen can be imbibed, and with which carbonic acid transudes through animal membranes. In their view, the whole process is effected in the lungs, as soon as the air comes in contact with the vessel containing the venous blood. The imbibition of oxygen they look upon as a case of ordinary absorp- tion ; the transudation of carbonic acid as one of exhalation; both of which they conceive to be, in all cases, vital actions, and not to be likened to any physical or chymical operation. Admitting, that the oxygen and a portion of nitrogen absolutely enter the pulmonary vessels, of which we appear to have the most direct proof, are they, it has been asked, separated from the air in the air-cells, and then absorbed; or does the air enter, undecomposed, into the vessels, and then furnish the proportion of each of its con- HiEMATOSIS. 105 stituents, which is necessary for the wants of the system, the excess being rejected ? Could it be shown that such a decomposition is ac- tually effected at the point of contact between the pulmonary vessels and the air in the lungs, it would go far to prove the notion of Ellis, and of Chaussier and Adelon, that an action of selection, or of vitality is exerted; but we have no evidence in favour of this. Sir Humphry Davy, indeed, is of opinion, that the whole of the air is absorbed, and that the surplus quantity of each of the constituents is subsequently discharged. In favour of this view, he remarks, that air has the power of acting upon blood through a stratum of serum; and he thinks, that the undecomposed air must be absorbed before it can arrive at the blood in the vessels. This is extremely probable; for we have already seen, that air disappears during respiration, and consequently, it must have been taken into the system. It has been remarked, that when oxygen is applied to venous blood it changes it to a florid colour. On what part of the blood, then, does the oxygen act ? The general belief is, upon the red glo- bules. The facts we have stated in the description of venous blood, have shown, that these globules appear to consist of a colourless nucleus, surrounded by a coloured envelope; that both of these are devoid of colour, whilst they exist as chyle and lymph ; but that, in the lungs, the contact of air changes the envelope to a florid red. Some, indeed, have believed, that both the envelope and its colour are added in the lungs. The coloration of the blood, consequently, seems to be effected m the lungs; but whether this change is of any importance in haematosis is doubtful. In many animals, the red co- lour does not exist; and, in all, it can perhaps only be esteemed an evidence, that the other important changes have been accomplished in the lungs. Recently, the opinion has been revived, that the oxy- gen of the air acts upon the iron which Engelhart and Rose have detected in the colouring matter, but how we know not. It is as- serted, that if the iron be separated, the rest of the colouring mat- ter, which is of a venous red colour, loses the property of becoming scarlet by the contact of oxygen. The slight diminution, if it exist, in the specific gravity of arterial blood, is considered, but we know not on what grounds, to be owing to the transpiration which takes place in the air-cells, and which was formerly thought to be owing to the combustion of oxygen and hydrogen. This will engage us in another place, as well as the changes produced in its capacity for heat, and on which several in- genious speculations have been founded, to account for animal temperature. The other changes are at present inexplicable, and can only be understood hereafter by minute chymical analysis, and by an accurate comparison of the two kinds of blood,—venous and arterial. It is manifest, from the preceding detail, that our knowledge re- garding the precise changes, effected upon the air and the blood by respiration, are by no means definite. In the first place:—the air Vol. II. H 106 RESPIRATION. loses a part of its oxygen, but this loss varies according to numerous circumstances. 2dly, It is found to have acquired carbonic acid, the quantity of which is also variable; but as a general principle it is less than the oxygen consumed. 3dly, The bulk of the air is dimi- nished; but the quantity of this likewise differs. 4thly, Azote is both absorbed and exhaled by the lungs, to a variable amount. 5thly, The blood, when it attains the left side of the heart, has a more florid colour. 6thly, This change appears to be caused by the contact of oxygen. 7thly, The blood in the lungs gets rid of a quantity of car- bon, united with oxygen in the form of carbonic acid. 8thly, It ab- sorbs oxygen, and more than is necessary for the carbonic acid form- ed. 9thly, The blood, as it passes through the lungs, probably both absorbs and exhales azote;—the proportion which these processes bear to each other being extremely variable. lOthly, The air passes directly through the coats of the pulmonary vessels, and certain portions of each of its constituents are discharged or retained, ac- cording to circumstances; and, lastly, a quantity of aqueous vapour, containing albumen, is discharged from the lungs; but this is a true secretion, and not a consequence of respiration. A question, again, has arisen, whetherany absorption and exhalation of air and conversion of blood from venous to arterial takes place in any other part of the body than the lungs. The reasons urged in favour of the affirmative of this view, are:—that, in the lower classes of ani- mals, the skin is manifestly the organ for the reception of the air; that the mucous membrane of the lungs evidently absorbs air, and is simply a prolongation of the skin, and resembles it in texture; and, lastly, that when a limited quantity of air has been placed in con- tact with the skin of a living animal, it has been absorbed and expe- rienced the same changes, as are effected in the lungs. Mr. Cruik- shank and Mr. Abernethy analyzed the air, in which the hand or foot had been confined for a certain length of time, and detected in it a considerable quantity of carbonic acid. Jurine, having placed his arm in a cylinder hermetrically closed, found, after it had re- mained there two hours, that oxygen had disappeared, and that 0.08 of carbonic acid had been formed. These results were con- firmed by Gattoni. On the other hand, Drs. Priestley, Klapp, and Gordon could never perceive the least change in the air under such circumstances. Perhaps in these, as in all cases, where the res- pectability of testimony is equal, the positive, should be adopted rather than the negative evidence. It is probable, however, that, in all cases, the absorption must be effected with difficulty: and that the cuticle is placed on the outer surface to obviate the bad effects, which would be induced by heterogeneous, gaseous, mias- matic, or other absorption. We have seen, that some of the dele- terious gases, as the sulphuretted hydrogen, are most powerfully penetrant, and, if they could enter the absorbents of the surface of the body with readiness, unfortunate results might supervene. It is probable, however, that in those parts, where the cuticle is ex- effects of the section of the eighth pair of nerves. 107 tremely delicate, as in the lips, some conversion of the venous blood into arterial may be effected, and be a great cause of their florid colour. According to this view, the arterialization of the blood occurs in the lungs chiefly, owing to their formation being so admirably adapted to the purpose, and it is not effected in other parts, owing to their arrangement being unfavourable for such result. It remains for us to inquire into the effect, produced on the lungs by the cerebral nerves distributed to them,—or rather into what is the effect of depriving the respiratory organs of their nervous in- fluence from the brain. The only cerebral or encephalic nerves, dis- tributed to them, are the pneumogastric or eighth pair of Willis, which we have seen are sent, as their name imports, to both the lungs and the stomach. The section of these nerves early suggest- ed itself to physiologists, but it is only in recent times that the phe- nomena resulting from it have been clearly comprehended. The operation appears to have been performed as long ago as the time of Rufus of Ephesus, and was afterwards repeated by Chirac, Bohn, Duverney, Vieussens, Schrader, Valsalva, Morgagni, Haller, and numerous other distinguished physiologists. It is chiefly, however, in very recent times, and especially by the labours of Dupuytren, Dumas, De Blainville, Provencal, Legallois, Magendie, Breschet, Hastings, Broughton, Brodie, and Wil- son Philip, that the precise effects upon the respiratory and diges- tive function have been appreciated. When these nerves are divided in a living animal, on both sides at once, the animal dies more or less promptly; at times, imme- diately after their division; but sometimes it lives for a few days; Magendie says never beyond three or four. The effects produced upon the voice, by the division of the pneu- mogastric nerves above the origin of the recurrents, have been re- ferred to, under another head. Such division, however, does not simply implicate the larynx, but necessarily affects the lungs, as well as the stomach. As regards the larynx, precisely the same re- sult would be produced by dividing the trunk of the pneumogastric above the origin of the recurrents, as by the division of the recur- rents themselves: the muscles, whose function it is to dilate the glottis, are paralyzed; and, consequently, during inspiration, no dila- tation takes place; whilst the constrictors, which receive their nerves from the superior laryngeal, preserve all their action, and close the glottis, at times so completely, that the«nimal dies imme- diately from suffocation. But if the division of these nerves should not induce instant death in this manner, a series of symptoms fol- lows, considerably alike in all cases, which go on, until the death of the animal. These phenomena, according to Magendie, are the following:—the respiration is, at first, difficult; the inspiratory movements are more extensive and rapid; and the animal's attention appears to be particularly directed to it; the locomotive movements KkS * RESPIRATION. are less frequent, and evidently fatigue; frequently the animal re- mains entirely at rest: the formation of arterial blood is not pre- vented at first; but soon, in the second day for instance, the diffi- culty of breathing augments, and the inspiratory effects become gradually greater. The arterial blood has now no longer the Ver- million hue, which is proper to it. It is darker than it ought to be. Its temperature falls. Respiration requires the exertion of all the respiratory powers. At length, the arterial blood is almost like the venous, and the arteries contain but little of it; the body gradually becomes cold, and the animal dies. On opening the chest, the air- cells, the bronchi, and, frequently, even the trachea, are found filled by a frothy fluid, which is sometimes bloody; the substance of the lung is tumid; the divisions and even the trunk of the pulmo- nary artery are greatly distended with dark, almost black, blood; and extensive effusions of serum and even of blood are found in the parenchyma of the lungs. Experiments have, likewise, shown, that, in proportion as these symptoms appeared, the animals consumed less and less oxygen, and gave off a progressively diminishing amount of carbonic acid. From the phenomena that occur after the section of these nerves on both sides, it would seem to follow, that the first effect is exert- ed upon the tissue of the lungs, which, being deprived of the nervous influence they receive from the brain, are no longer capable of exerting their ordinary elasticity or muscularity, whichsoever it may be. Respiration, consequently, becomes difficult; the blood no longer circulates freely through the capillary vessels of the lungs; the consequence of this is, that transudation of its serous portions, and occasionally effusion of blood, owing to rupture of small ves- sels, takes place, filling the air-cells more or less; until, ultimately, all communication is prevented between the inspired air and the blood-vessels of the lungs, and the conversion of the venous into arterial blood is completely precluded. Death is, then, the inevitable and immediate consequence. The division of the nerve of one side affects merely the lung of the corresponding side; life can be continued by the action of one only. It is, indeed, a matter of astonishment how long some individuals have lived, when the lungs have been almost wholly obstructed. Every morbid anatomist must have had repeated opportunities for observing, that, in cases of pulmonary consumption, for a length of time prior to dissolution, the process of respiration must have been wholly effected by a very small portion of lung. The experiments of Dr. Wilson Philip and others moreover show, —what has been more than once inculcated,—the great similarity between the nervous and galvanic fluids. When the state of dys- pnoea was induced by the division of the pneumogastric nerves, the galvanic current was passed from one divided extremity to :the other, and, in numerous cases, the dyspnoea entirely ceased. RESPIRATION OF GASES. 109 The results of these experiments induced him to try the effect of galvanism in cases of asthma. By transmitting its influence from the nape of the neck to the pit of the stomach, he gave decided relief in every one of twenty-two cases, four of which occurred in private practice, and eighteen in the Worcester Infirmary. There is one other topic, which, although not directly belonging to physiology, has been so much the subject of experiment with physiologists, that it is worthy of observation. We allude to the Respiration of different Gases. Experience has sufficiently proved, that no combination of gases, except that which exists in the atmosphere, is adapted for the pro- longed existence of animals, or even of plants. Of the other gases, there are some, which are entirely irrespirable,producing a spasmodic closure of the glottis, and thus inducing suffocation; others that are negatively deleterious, by depriving the animal of its due supply of oxygen; and others, again, which acton the body in a positively noxious manner. Soon after the gases were discovered, their effects upon the respi- ration of animals were tested; but the most accurate and extensive information, which we possess on the subject, was afforded by the labours of Beddoes, and his distinguished pupil Sir Humphry Davy. The gases, which have been chiefly subjected to experiment, are:— oxygen, protoxide of azote, hydrogen, azote, carburetted hydro- gen, carbonic acid, carbonic oxide, sulphuretted hydrogen, arse- nuretted hydrogen, ammoniacal gas, muriatic acid gas, nitrous acid gas, nitric oxide, and chlorine. Oxygen.—This gas, which we have seen to be so essential to res- piration, and which has hence acquired the name vital air, has been subjected to numerous experiments, and the general result appears to be, a belief, that it acts in a positively deleterious man- ner; and that, although an animal may live in a limited portion of it a considerable time longer than in the same quantity of atmos- pheric air, its respiration becomes hurried and laborious before the whole is consumed, and it dies, although a fresh animal of the same kind is capable of sustaining life for some time in the residuary air. The belief is not perhaps legitimate. A part, if not the whole, of the dyspnoea and death may be produced by the evolution of carbonic acid, which is unfavourable to animal life; whilst a fresh animal may be enabled to resist its action for a time and take up some of the residuary oxygen. Oxygen is one of the gases, which has been regarded, on very insufficient evidence however, to exert a stimulant effect upon the blood, by which the left side of the heart, to which the blood is returned from the lungs, and the arterial sys- tem are excited to action; and it was accordingly respired, at one 110 respiration. time, in diseases of chronic debility—in chlorosis, asthma, paralysis, &c; but its use has been long abandoned. Protoxide of Azote.—This gas, which consists of the same con- stituents as atmosphericair,—oxygen and azote,—but in different pro- portions, is possessed of very singular properties. It is the dephlo- gisticated nitrous air of its discoverer Priestley, the nitrous oxide, protoxide of nitrogen, or laughing gas; the last name hav- ing been assigned to it by reason of its properties. Sir Humphry Davy first showed, that, by breathing a few quarts of this gas from a silken bag, for two or three minutes, effects, resem- bling those produced by drinking intoxicating liquors, are excited; yet it does not produce the same effect on all individuals, as might, indeed, have been expected. It is strange, however, that although the evidence in Sir Humphry Davy's "Researches" was most overwhelming; and although it is annually breathed in the chymical rooms of this country and Great Britain, by hundreds of students, and even made the subject of itinerant exhibition, the French chy- mists assert, that, in all cases in which they have tried it, it has sim- ply produced indisposition. In the very last edition of his Chy- mistry, Thenard affirms, " tous ceux a quije Vaivu respirer s'en sont irouvis mal," and professor Pelletan, in his" Bictionnaire de Chimie," remarks—that "In England several persons have exhibited a kind of delirious gaiety, to such an extent, that it was necessary to snatch away the bladder, that contained the gas; debi- lity and syncope soon, however, succeeded this primary state of excitement (!!) In France, in the experiments of Vauquelin and Thenard, vertigo, head-ache and protracted lassitude were alone experienced; and in no case could it be respired more than a few minutes." The only way of accounting for these results is by the supposi- tion, that these distinguished chymists must have had idiosyncrasies, which caused them to be affected differently from most other indi- viduals; or that the gas was impure; and that the promulgation of the fact of indisposition having succeeded the respiration of the gas in a few cases has deterred others from having recourse to it. In his " Researches" on this subject, Sir Humphry Davy has given the autographies of several eminent individuals relative to the effects produced upon them. Sir Humphry himself breathed four quarts of nitrous oxide from, and into, a silk bag. His first feelings were those of giddiness; but, in less than half a minute, the respiration being continued, they diminished gradually and were succeeded by a sensation, analogous to gentle pressure on all the muscles, attended by a highly pleasurable thrilling, particularly in the chest and extremities. The objects, around him, became daz- zling, and his hearing more acute. Towards the last inspiration, the thrilling increased, the sense of muscular power became greater; and, at last, an irresistible propensity to action was indulged. What followed after this he recollected but indistinctly; but his motions RESPIRATION of gases. Ill were various and violent. The effects soon ceased after respiration; and, in ten minutes, he had recovered his natural state of mind. The thrilling in the extremities continued longer than the other sen- sations. Dr. Robert Southey, the distinguished laureate of England, could not discriminate between the first effects and an apprehension of which he was unable to divest himself. His first definite sensa- tions were, a fullness and dizziness in the head, such as to induce a fear of falling. This was succeeded by an involuntary laugh, but one of a highly pleasurable character, accompanied with a peculiar thrilling in the extremities;—a sensation perfectly new and delight- ful. For many hours after this experiment, he imagined, that his taste and smell were more acute, and he felt unusually strong and cheerful. In a second experiment, he felt still superior pleasure; and has poetically remarked, that he supposes the atmosphere of the highest of all possible heavens to be composed of this gas. Mr. Wedgewood breathed atmospheric air first without knowing it was so. He declared it to have no effect, which confirmed him in his disbelief of the power of the gas. After breathing the nitrous oxide, however, for some time, he threw the bag from him, kept breathing on laboriously with an open mouth, holding his nose with his left hand, without power to take it away, though aware of the ludicrousness of his situation. All his muscles seemed to be thrown into vibratory movement. He had a violent inclination to make antic gestures; seemed lighter than the atmosphere, and as if about to ascend. Before the experiment he was a good deal fatigued after a long ride ; but the feeling left him during the respiration of the gas. All these and analogous effects are daily produced by the exhi- bited of this singular compound; and we have seen it annually given to a class for the last seven years without any of the indispo- sition resulting, which has been referred to by the French chymists. There are some, however, in whom its effects are always painful. The gas, according to the experiments of Dr. Mitchell, is pos- sessed of considerable penetrative power. By means of this, it can readily pass through the coats of the pulmonary vessels, get into the venous blood, and produce its effects directly upon the brain, in the same manner as other intoxicating substances. Although capable of being respired, nitrous oxide is unfit to support life. Priestley found that this was the fact, and it has been confirm- ed by other chymists. Mice, introduced into ajar of it, die almost immediately, whilst in azote, hydrogen, and carbonic acid, they struggle for a short time. Hydrogen.—This gas does not appear, from the experiments of Lavoisier, Sir H. Davy, and others, to exert any positively dele- terious power, when respired; and seems to destroy by excluding oxygen; hence, its effects are of a negative character. In a pure state, if the lungs have been previously emptied, as far as possible, 112 RESPIRATION. of atmospheric air, it can be breathed for a very short time only j quickly occasioning giddiness and a sense of suffocation; the coun- tenance becoming livid, and the pulse sinking rapidly, followed by a state of insensibility. When the gases were employed medicinally, hydrogen was used to diminish muscular power and sensibility, and a reduction of the force of the circulation; in catarrh, spitting of blood, consump- tion, &c. Nitrogen or azote, when respired, exerts, like hydrogen, a nega- tive influence, and proves fatal simply by excluding oxygen; an opinion, which as Bostock properly remarks, might naturally be formed respecting a substance, that enters so largely into the con- stitution of the atmosphere, and which, if it were possessed of any positively hostile properties, would be unfitted for its office, seeing that it is at all times received so largely into the lungs of animals. Carburetted hydrogen gas.—This is the most active of the gases that are conceived to operate by depressing the vital func- tions. Even when largely diluted with atmospheric air, it occa- sions vertigo, sickness, diminution in the force and velocity of the pulse, reduction of muscular vigour, and every symptom of dimi- nished power. In an undiluted state, it can scarcely be respired. Sir Humphry Davy found, that, at the third inspiration, total in- sensibility was induced, and symptoms of excessive debility con- tinued for a considerable period; effects which sufficiently exhibit its positively deleterious agency. At one time, in a properly di- luted condition, it was conceived to exert a beneficial effect in dis- eases of increased action; but it is now entirely laid aside. Carbonic acid.—The experiments of Pilatre de Rozier and of Sir H. Davy have shown, that this gas proves more speedily fatal than either nitrogen or hydrogen ; and there is every reason for believing, that it excites spasmodic contraction of the epiglottis and suffocation. Sir H. Davy found, that air was still irrespirable when it contained three-fifths of its volume of carbonic acid, but that when the proportion was diminished to three parts in ten, it might be received into the lungs. The effect, which it occasioned, after being breathed for a minute, was slight giddiness and tendency to sleep. In pneumatic medicine, it was employed as a sedative in phthisis, being diluted with atmospheric air. Carbonic oxide or oxide of carbon appears to act i n a similar man- ner. Sir Humphry Davy took three inspirations of this gas, mixed with about one-fourth of common air; the effect was a temporary loss of sensation, succeeded by giddiness, nausea, acute pains in different parts of the body, and excessive debility. Some days elapsed before he entirely recovered. Mr. Witter, of Dublin, was struck with symptoms of apoplexy, by breathing it, but was speedily re- stored by the inhalation of oxygen. It is probable, that both this gas and carbonic acid, in their pure state, occasion the closure of the glottis, and, consequently, do not enter the lungs; but, when respiration of gasesj 113 breathed in a more dilute condition, that they pass through the coats of the blood-vessel, and exert their action on the brain whilst circu- lating through it. Sulphuretted hydrogen.—This gas is extremely deleterious. When respired in a pure state, it kills instantly, and its deadly agency is rapidly exerted when put in contact with any of the tis- sues, through which it penetrates with astonishing rapidity. Even when mixed with a portion of air, it has proved immediately de- structive. Dr. Paris refers to the case of a chymist of his acquaint- ance, who was suddenly deprived of sense, as he stood over a pneu- matic trough, in which he was collecting the gas. From the experiments of Dupuytren and Thenard, air that contains a thousandth part of sulphuretted hydrogen kills birds im- mediately. A dog perished in air, containing ^th part; and a horse in air, containing ^oth. It is the deleterious agent exhaled from privies, which has been so fatal, at times, to nightmen, who have been employed to remove or to cleanse them. When this gas is breathed in a more dilute state, it produces powerful sedative effects, the pulse being rendered extremely small and weak, the contractility of the muscular organs considerably en- feebled, with stupor and more or less suspension of the cerebral functions; and if the person recovers, he regains his strength very tardily. Arsenuretted hydrogen also instantly destroys small animals, and is extremely deleterious, having proved fatal to a German chy- mist, M. Gehlen. With regard to the other gases, the ammoniacal gas, muriatic acid gas, nitrous acid gas, nitric oxide or deutoxide of azote, and chlorine, they are completely irrespirable, producing spasmodic closure of the glottis, and asphyxia or suffocation. According to the division already established, we may consider, then, that all these gases, when breathed in an undiluted condition, admit of being classed as follows:— Carbonic acid, carbonic oxide, ammo- niacal gas, muriatic acid gas, deu- toxide of azote, nitrous acid gas, and chlorine. 2. Negatively deleterious! H dr0 azote< gases. 3 J ° „ „ .,. 7 7 , ^ . } Oxygenf?), protoxide of azote, carbu- 3. Positively deleterious f /eJted^y^rogenj suiphuretted hy- 8ases- ^ drogen, and arsenuretted hydrogen. Irrespirable gases. Vol. II. 15 114 RESPIRATION. In concluding the subject of respiration, we may briefly ad- vert to the different modes in which the process is effected in the classes of animals, and espe- cially in birds, the respiratory organs of which constitute one of the most singular structures of i e._ the animal economy. The lungs themselves,—as in the mar- ginal figure of the lungs, &c. of the ostrich,—are comparatively small, and are adherent to the chest,—where they seem to be placed in the intervals of the ribs. They are covered by the pleura only on their under sur- face, so that they are, in fact, on the outside of the cavity of the chest. A great part of the thorax, as well as of the abdomen, is oc- cupied by membranous air-cells, into which the lungs open by considerable apertures. Besides o. Heart,'lodged in one^ataiwieii.-ft. The sto-these cells, a considerable por- mach — c. The intestines, surrounded by large air-f:nn nf *Up clrAlptrm forms rpppn. cells.-d. The trachea dividing into bronchiT-e, e. UOn OI lne SKeieiOn IOrmS recep- Theiungs.^,2,3.^.oAergieatair-ceiis,communi.tacles for air, in many birds; and eating with other cells and with the lungs.—g,g. The . - , 17. t J r !_• j openings by which such communication is made. n we break a long bone Of a bird of flight, and blow into it, the body of the bird being immersed in water, bubbles of air will escape from the bill. The object, of course, of all this, is to render the body light, and thus to facilitate its mo- tions. Hence the largest and most numerous bony cells are found in such birds as have the highest and most rapid flight, as the eagle. The barrels of the quills are likewise hollow, and can be filled with air, or emptied at pleasure. In addition to the uses just mentioned, these receptacles of air diminish the necessity of breathing so frequently, in the rapid and long-continued motions of several birds, and in the great vocal ex- ertions of singing birds. In fishes, in the place of lungs we find branchiae or gills, which are placed behind the head on each side, and have a movable gill- cover. By means of the throat, which is connected with these or- gans, the water is conveyed to the gills, and distributed through them; by which means, the air, contained in the water, comes in contact with the blood circulating through the gills. The water is afterwards discharged through the branchial openings,—aperturse branchiales,—and, consequently, they do not expire along the same channel as they inspire. RESPIRATION OF ANIMALS. 115 Lastly, in the insect tribe,—in the white-blooded animal,—we find the function of respiration effected altogether by the surface of the body; at least, so far as regards the reception of air, which passes into the body through apertures termed stigmata, the ex- ternal terminations of trachese or air-tubes, whose office it is to con- vey the air to different parts of the system. In all these cases we find precisely the same changes effected upon the inspired air, and especially, that oxygen has disappeared, and that carbonic acid is contained in nearly equal bulk in the resi- duary air. 116 CIRCULATION. CIRCULATION. The next function to be considered is that by which the products of the various absorptions, converted into arterial blood in the lungs, are distributed to every part of the body,—a function of the most important character to the physiologist and the pathologist, and without a knowledge of which, it is impossible for the latter to comprehend the doctrine of disease. Assuming the heart as the great central organ of the function, every particle of the circulatory fluid must set out from it, be dis- tributed through the lungs, undergo aeration there, be sent to the opposite side of the heart, whence it is distributed to every part of the system, and be thence returned, by the veins, to the right side, whence it set out,—thus performing a complete circuit. It is not easy to ascertain the total quantity of blood, circulating * in both arteries and veins. Many attempts have been instituted for this purpose, but the statements are most diversified, partly owing to the erroneous direction followed by the experimenters, but, still more, to the variation that must be perpetually occurring in the amount of fluid, according to age, sex, temperament, activity of se- cretion, &c. Harvey and the earlier experimenters formed their estimates, by opening the veins and arteries freely on a living animal, collect- ing the blood that flowed, and comparing this with the weight of the body. This method is, however, extremely objectionable, as the whole of the blood can never be obtained in this manner, and the proportion discharged varies in different animals and circum- stances. By this method, Moulins found the proportion in a sheep to be.^d; King, in a lamb, ^Vh* m a duck, ^n'f an^ m a rabbit, ^o-th. From these and other observations Harvey concluded, that the weight of the blood of an animal is to that of the whole animal as 1 to 20. Drelincourt, however, found the proportion in a dog to be nearly TVth; and Moor, fVth. An animal, according to Sir Astley Cooper, generally ex- pires, as soon as blood, equal to about TVth of the weight of the body, is abstracted. Thus, if it weighs sixteen ounces, the loss of an ounce of blood will be sufficient to destroy it: ten pounds will destroy a man weighing one hundred and sixty pounds; and, on examining the body, blood will still be found—in the small vessels especially, even although every facility has been afforded for drain- ing them. weight op the circulating fluid. 117 The following table exhibits the computations of different phy- siologists, regarding the weight of the circulating fluid—arterial and venous. Harvey, Lister, Mullen, lbs. > - 8 F. Hofmann, Haller, lbs. 28 28 to 30 Abildguard, Blumenbach,^ LOBB, > Lower, 5 Sprengel, -Quesnai, 10 10 to 15 27 Young, Hamberger, Keill, 40 80 - 100 Although the absolute estimate of Hofmann is below the truth, his proportion is probably nearly accurate. He conceives, that the weight of the blood is to that of the whole body as 1 to 5. Ac- cordingly, an individual weighing one hundred and fifty pounds, will have about thirty pounds of blood; one of two hundred pounds, forty; and so on. Of this, one-third is supposed to be contained in the arteries, and two-thirds in the veins. The estimate of Haller is, perhaps, near the truth; the arterial blood being, he conceives, to the venous as 4 to 9. If we assume, therefore, that the whole quantity of the blood is thirty pounds in a man weighing one hundred and fifty pounds,—which is perhaps allowing too much,—nine pounds, at least, may be contained in the arteries, and the remainder in the veins. The lower classes of animals differ essentially, as we shall find hereafter, in their organs of circulation: whilst, in some, the apparatus appears to be confounded with the digestive; in others,the blood is propelled without any great central organs; and in others, again, the heart is but a single organ. In man, however, and in the upper classes of animals, the heart is double;—consisting of two sides, or really of two hearts, separated from each other by a septum. As all the blood of the body has to be emptied into this organ, and to be subsequently sent from it; and as its flow is continuous, two ca- vities are necessarily required in each heart,—the one to receive the blood, and the other to propel it,—which contract and dilate alter- nately. The cavity or chamber of each heart, which receives the blood, is called auricle, and the vessels that transport it thither, are the veins; the cavity by which the blood is projected forwards, is called ventricle, and the vessels, along which the blood is sent, are called arteries. One of these hearts is entirely appropriated to the circulation of venous blood, and has hence been called the venous heart, also the right or anterior heart, from its situation, and the pulmonary from the pulmonary artery arising from it. The other is for the cir- culation of arterial blood, and is hence called the arterial heart, 118 circulation. also the left or posterior, from its situation, and the aortic heart, from the aorta rising from it. In the figure 109, the two hearts are separated from each other, and shown to be Fig. 109. distinct organs in the adult, although in the subject they seem to form but one organ. Be- tween the two, after birth, there is not the slightest communication; and, consequently, every portion of blood, which has to attain the left side of the heart, must make the circuit through the lungs. The whole of the ves- sels, communicating with the right heart, contain venous blood; whilst those of the left side contain only arterial. If we consider the o, a. Venae cavse, ascendens, and descendens.—b. Right auricle. neart tO be tne Centre, -c, c. Right ventricle.-d. Pulmonary artery.—e. Pulmonary t\VO circulations are aC- vtxo.s.—J. Left auricle.—g. Left ventricle.—A, h. Aorta. , » The arrows indicate the course of the blood. COmpllshed, before the blood, setting out from one side of the heart, performs the whole cir- cuit to the other. One of these consists in the transmission of the blood from the right side of the heart, through the lungs, to the left; the other in its transmission from the left side, along the arteries, and by means of the veins, back to the right side. The former of these is called the lesser or pulmonic, the latter the greater or systemic, circulation. The organs, by which these are accomplished, will require a more detailed examination. Anatomy of the Circulatory Organs. The circulatory apparatus is composed of the organs, by which the blood is put in motion, and along which it passes during its circuit. To simplify the consideration of the subject, we shall consider the heart double; and that each system of circulation is composed of a heart; of arteries, through which the blood is sent from the heart; and of veins, by which the blood is conveyed to it. At the minute terminations of each of these, small vessels are situated, con- stituting the capillary system. circulatory apparatus. 119 We shall first describe the central organ, as forming two distinct hearts; and afterwards regard these as united. The pulmonic, right, or anterior heart,—called also the heart of black blood,—is composed of an auricle and a ventricle. The auricle, so termed from some resemblance to an ear, is situated at the base of the organ, and receives the whole of the blood returning from various parts of the body by three veins;— the two vense cavae, and the coronary vein; the vena cava descendens,term i- nates in the auricle in the direction of the aperture by which the auricle communicates with the ventricle. The vena cava ascendens, the termination of which is directed more backwards, has the remains of a valve, which is much larger in the foetus, called the valve of Eusta- chius. The third vein is the car- diac or coronary, which returns the blood from the heart, that has been Pulmonic heart. A. The right auricle with its venae cavae.— J. The right ventricle.—C carried thither by the coronary ar- artery. The pulmonary Fig. 111. tery. In the septum, between the right and left auricle, there is a superficial depression, about the size of the point of the finger, which is the vestige of the foramen ovale, an important part of the circu- latory apparatus of the foetus, as we shall see hereafter. The opening, through which the auricle projects its blood into the ventricle, is situated down- wards and forwards, and is seen in figure 111. The inner surface of the proper auricle, or that which more par- ticularly resembles the ear of a quadruped,—the remainder being sometimes called the sinus ve- nosus, or sinus venarum cava- rum,—is distinguished by having a number of fleshy pillars in it, which, from their supposed re- semblance to the teeth of a comb, are called musculi pectinati. They are mere varieties, how- ever, of the columnse carnese of the ventricles. The right ventricle or pulmo- nary ventricle is situated in the m NUTRITION. i supplies the loss, which it has sustained by the previous action of decomposition. The former of these actions obviously belongs to the function of absorption; but its physiology, it will be recollected, was de- ferred, in consequence of its close application teethe function we are now considering. It comprises what is meant by interstitial, organic, or decom- posing absorption, and does not require many comments, after the long investigation of the phenomena of absorption, into which we have entered. The conclusion, at which we then arrived, was, —that the chyliferous and lymphatic vessels form only chyle and lymph respectively, refusing the admission of all other substances; that the veins admit every liquid which possesses the necessary tenuity; and that, whilst all the absorptions,—which require the substance acted upon to be decomposed and transformed,—are effected by the chyliferous and lymphatic vessels, those that de- mand no alteration are accomplished through the coats of the veins directly by imbibition. It is easy, then, to deduce the agents to which we refer the ab- sorption of decomposition. As it is exerted on solids, and as these cannot pass through the coats of the vessels in their solid condition1, it follows, that other agents than the veins must accomplish the process; and, again, as we never find in the lymphatic vessels any thing but lymph, and as we have every reason to believe, that an action of selection is exerted at their extremities, similar to thatof the chyliferous vessels on the heterogeneous substances exposed to them, we naturally look to the lymphatics as the sole organs con- cerned in the absorption of solids. In making this affirmation, we leave unexplained the mysterious operation by which these vessels are enabled to reduce to their elements, bone, muscle, tendon, &c, and to recqmpose them into the form of lymph. Dr. Bostock fancifully suggests, that the first step in this series of operations, is the death of the part, by which expression he means, that it is no longer under the influence of ar- terial action. " It therefore ceases to receive the supply of matter which is essential to the support of all vital parts, and the process of decomposition necessarily commences." The whole of his re- marks on this subject are eminently gratuitous, and are manifestly luggested by his extreme unwillingness to ascribe the process to any thing but physical causes. If there is, however, any one phe- nomenon of the animal economy, which is more manifestly refer- able to vital action than another, it is the whole function of nutri- tion, both as regards the absorption of parts already deposited, and the exhalation of new; and it is wise to confess our utter ignorance of the mode in which it is accomplished. We know that the blood contains most of the principles that are necessary for the nutrition of organs, and that it must contain the elements of all. Fibrine, albumen, fat, osmazome, salts, &c. exist in it, and these are depo- GROWTH OP PARTS. 167 sited, as the blood traverses the tissues; but why one should be selected by one set of vessels, as by the exhalants of bone, and another by another set, and in what manner the elements of those, not ready formed in the blood, are brought together, is totally un- known to us. Blood has been designated as "liquid flesh,"— chair coulante,—but something more than simple transudation through vessels is necessary to form it into flesh, and to give it the "compound organization of fibrine, gelatine, osmazome, &c. in the form of muscular fibre and cellular membrane, which we ob- serve in the muscle. Nothing perhaps more clearly exhibits our want of knowledge on the subject than the following vague attempt at solving^the mystery by one of the most distinguished physiologists of the age: —" Some immediate principles, that enter into the composition of the organs or of the fluids, are not found in the blood,-^such as gelatine, uric acid, &c. They are consequently formed at the ex- pense of other principles, in the parenchyma of the organs, and by a chymical action, the nature of which is unknown to us, but which is not the less real, and must necessarily have the effect of develop- ing heat and electricity." It is the action of nutrition, that occasions the constant fluc- tuations in the weight and size of the body, from the earliest embryo condition till advanced life. The cause of the' develop- ment or growth of organs and of the body generally, as well as of the limit, accurately assigned to such development, accord- ing to the animal or vegetable species, is dependent upon vital laws that are unfathomable, and which the endosmose of Dutro- chet is little calculated to explain. Nor are we able to detect the precise mode in which the growth of parts is effected. It cannot be simply extension, for the obvious reason that the body and its various compartments augment in weight as well as in dimension. In the large trees of our forests, we find a fresh layer or ring add- ed each year to the stem, until the full period of development; and it has been supposed that the growth of the animal body may be effected in a similar manner, both as regards its soft and harder materials, that is, by layers deposited externally. That the long bones lengthen at their extremities is proved by an experiment of Mr. Hunter. Having exposed the tibia of a pig, he bored a hole into each extremity of the shaft, and inserted a shot. The distance between the shot was then accurately taken. Some months after- wards, the same bone was examined, and the shots were found at precisely their original distance from each other; but the extremi- ties of the bone had extended much beyond their first distance from the shot. The flat bones also increase by a deposition at their margins, and the long bones by a similar deposition at their periphery,—circum- stances strongly exhibiting the analogy between the successive de- velopment of animals and vegetables. 168 NUTRITION. Exercise or rest, freedom from or presence of pressure, pro- duce augmentation of the size of organs or the contrary; and there are certain medicines, as iodine, which occasion the emaciation, of particular organs only—as of the female mammae. The effect of disease is likewise, in this respect, familiar and striking. The ancients had noticed the changes effected upon the body by the function we are considering, and attempted to estimate the pe- riod at which a thorough conversion must be accomplished, so that not one of its quondam constituents shall be present. By some, this was supposed to be seven years; butBERNouiLLi reduced it to three. It is hardly necessary to say, that, in such a calculation, we have nothing but conjecture to guide us. The nutrition of the body and of its parts varies, indeed, according to numerous circumstances. It is not the same during the period of growth as subsequently, when the absorption and deposition are balanced, so far at least as con- cerns the augmentation of the body in one direction. Particular organs have, likewise, their period of development, at which time the nutrition of such parts must necessarily be more active,—the organs of generation, for example, at the period of puberty; the enlargement of the mammae in the female; the appearance of the beard and the amplification of the larynx in the male, &c,—and all these changes occur after a determinate plan. The activity of nutrition appears to be increased by exercise, at least in the muscular organs; hence the well-marked muscles of the arm in the prize-fighter, of the legs in the dancer, &c. The mus- cles of the male are, in general, much more clearly defined; but the difference between those of the hard-working female and of the inactive male may not be very apparent. There are several textures of the body that do not experience nutrition, but, when once deposited, appear to remain permanent- ly, such as the epidermis, the nails, the teeth, the colouring matter of the skin, and, it is presumed, the cartilages,—especially the inter- articular. The most active in their nutrition are the glands, mus- cles, and skin, which alter their character—as to size, colobr and consistence—with great rapidity; whilst the tendons, fibrous mem- branes, bones, &c. are much less so, and are altered more slowly by the effect of disease. A practice which prevails amongst certain professions and people, would seem at first sight to show, that the nutrition of the skin cannot be energetic. Sailors are frequently in the habit of forcing gunpowder through the cuticle with a pointed instrument, and of figuring the initials of their names upon the arm in this manner; the particles of the gunpowder are thus driven into the cutis vera and remain for life. The operation of tattooing, or of puncturing and staining the skin, prevails in many parts of the globe and especially in Polynesia, where it is looked upon as greatly ornamental. The art is said to be carried to its greatest perfection in the Washington or New Marquesas Islands; where the wealthy are often covered TATTOOING. 169 with various designs from head to foot; subjecting themselves to a most painful operation for this strange kind of personal deco- Fig. 119. ration. The operation consists in puncturing the skin with some rude instrument, ac- cording to figures previously traced upon it, and then rub- bing into the punctures a thick dye, frequently composed of the ashes of the plant that furnishes the colouring mat- ter. The marks, thus made, are indelible. Magendie asks:—"How can we reconcile this phenomenon with the re- novation, which, according to authors," (and, he might have added, according to himself,) " happens to the skin?" It does not seem to us to be in any manner connected with the nutrition of the skin. The colouring matter is an extra- neous substance, which takes no part in the changes, constantly going on in the tissue in which it is imbedded; and the circum- stance seems to afford a powerful negative argument in favour of venous absorption. Had the substance possessed the necessary tenuity it would have entered the veins like other colouring mat- ters; but the particles are too gross for this, and hence they remain free from all absorbent influence. Tattooed head of a New Zealand Chief. Vol. II. 22 170 CALORIFICATION. CALORIFICATION, OR ANIMAL TEMPERATURE. The function, we have now to consider, is one of the most im- portant to organic existence, and one of the most curious in its causes and results. It has, consequently, been an object of inte- resting examination with the physiologist, both in animals and plants, and as it has been presumed by a large class of speculatists, to be greatly owing to respiration, it has been a favourite topic with the chymist also. Most of the hypotheses devised for its explanation have, indeed, been of a chymical character; and hence it will be advisable to premise a few observations regarding the physical rela- tions of caloric or the matter of heat,—an imponderable body, according to common belief, which is generally distributed through- out nature. It is this, which constitutes the temperature of bodies, by which is meant, the sensation of heat or cold which we expe- rience, when bodies are touched by us; or the height at which the mercury is raised or depressed by them, in the instrument called the thermometer;—the elevation of the mercury being caused by the caloric entering between its particles, and thus adding to its bulk; and the depression being produced by the abstraction.of caloric. Caloric exists in bodies in two states;—in the free, uncombined or sensible, and in the latent or combined. In the former case, it is intimately united with the other constituent elements of bodies, and is neither indicated by the feeling nor by the thermometer. It has, consequently, no agency in the temperature of bodies; but, by its proportion to the force of cohesion, it determines their con- dition;—whether they shall be solid, liquid or gaseous. In the latter case, caloric is simply interposed between the molecules, and is incessantly disengaged, or abstracted from surrounding bodies; and, by impressing the surface of the body or by acting upon the thermometer, it indicates to us their temperature. Equal weights of the same body, at the same temperature, con- tain the same quantities of caloric; but equal weights of different bodies, at the same temperature, have by no means the same quan- tities. The quantity, which one body contains, compared with that in another is called its specific caloric, or specific heat; and the power or property, which enables bodies to retain different quantities of caloric, is called capacity for caloric. If a pound of water, heated to 156°, be mixed with a pound of quicksilver at 40°, the resulting temperature is 152°,—instead of 98°, the exact mean. The water, consequently, must have lost four degrees of temperature, and the quicksilver gained 112°; from which we de- LAWS OF CALORIC. 171 duce, that the quantity of caloric, capable of raising one pound of mercury from 40° to 152° is the same as that required to raise one pound of water from 152° to 156°; or, in other words, that the same quantity of heat, which raises the temperature of a pound of water four degrees, raises the same weight of mercury one hun- dred and twelve degrees. Accordingly, it is said, that the capacity of water for heat is to that of mercury, as 28 to 1; and that the specific heat is twenty-eight times greater. All bodies are capable of giving and taking free caloric, and, con- sequently, all have a temperature. If the quantity given off be great, the temperature of the body is elevated. If it take heat from the thermometer, it is cooler than the instrument. In inorganic bodies the disengagement of caloric is induced by various causes; such as electricity, friction, percussion, compres- sion, the change of condition from a fluid to a solid state; and by various chymical changes, giving rise to new compounds, so that the caloric, which was previously latent, becomes free. If, for example, two substances, each containing a certain amount of spe- cific heat, unite, so as to form a compound whose specific heat is less, a portion of caloric must be set free, and this will be indicated by a rise in the temperature. It is this principle which is chiefly concerned in some of the theories of calorification that have been proposed. The subject of the equilibrium and conduction of calo- ric has already been treated of, under the sense of touch; where several other topics are discussed, that bear more or less upon the present inquiry. It is there stated, that inorganic bodies speedily attain the same temperature, either by radiation or conduction; so that the different objects, in an apartment, will exhibit the same degree of heat by the thermometer. The temperature of animals, however, being a vital operation they retain the degree of heat peculiar to them, with but little modification from external tempe- rature. There is a difference, however, in this respect, sufficient to cause the partition of animals into two great divisions—the warm- blooded and the cold-blooded; the former comprising those animals, whose temperature is high, and but little influenced by that of ex- ternal objects;—the latter those whose temperature is greatly mo- dified by external influences. The range of the temperature of the warm-blooded—amongst which are all the higher animals—is limit- ed; but of the cold-blooded extensive. The following Table exhibits the peculiar temperature of various animals in round numbers;—that of man being 98° or 100°. 172 CALORIFICATION. Animals. Observers. Temperature. Arctic fox,..... Arctic wolf, } Squirrel, $ Hare,.....} Whale,.....5 Arctomys citillus, zizil,—in summer, Do. when torpid, ... Bat, in summer, .... Musk,...... Marmotabobac—Bobac, - House mouse, .... Arctomys marmota, marmot,—in summer, - Do. when torpid Rabbit,..... Dog,..... Cat,..... Swine,..... Sheep,..... Ox, ..... Guinea-pig, .... Arctomys glis, ... Shrew,..... Young wolf, - Fringilla arctica, Arctic finch, Rubecola, redbreast Fringilla linaria, lesser red poll, Falco palumbarius, goshawk, - Caprimulgus Europaeus, European goat-sucker, ... Emberiza nivalis, snow bunting Falco lanarius, lanner, - Fringilla carduelis, goldfinch, Tetrao perdrix, partridge, Anas clypeata, shoveler, Tringa pugnax, ruffe, Scolopax limosa, lesser godwit, Tetrao tetrix, grouse, Fringilla brumalis, winter finch, Loxia pyrrhula, ... Falco nisus, sparrowhawk, Vultur barbatus, Anser pulchricollis, Colymbus auritus, dusky grebe, Tringa vanellus, lapwing, (wounded) I Tetrao lagopus, ptarmigan, { Fringilla domestica, house sparrow Capt. Lyon. Do. Pallas. Do. ScORESBY. Pallas. Do. Do. Do. Do. Do. Do. Do. De la Roche. Martine. Do. Do. Do. Do. De la Roche. Pallas. Do. Do. Braun. Pallas. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. 107 105 104 103 80 to 84 102 102 101 or 102 101 101 or 102 43 100 to 104 100 to 103 100 to 102 99 98 96 111 111 110 or 111 110 109 or 110 109 108 107 107 to 111 TEMPERATURE OF ANIMALS. 173 (Table Continued.) Animais. Observers. Temperature. Strix passerina, little owl, Pallas. Haematopus ostralegus, sea pie Do. Anas penelope, wigeon, > Do. 106 Anas strepera, gadwall, - Do. Pelecanus carbo, - Do. Falco ossifragus, sea eagle, «• Do. Fulica atra, coot, - Do. 105 Anas acuta, pintail duck, i Do. Falco milvus, kite, (wounded) \ Merops apiaster, bee eater, - \ Do. 104 Do. Goose,..... Martine. Hen,..... Dove,..... > Do. Do. 103 to 107 Duck,..... Do. Ardea stellaris, 1 Pallas. Fulco albicollis, Do. 103 Picus major, - 1 Do. Cossus ligniperda, - - - - SCHULTZE. 89 to 91 Shark, ...... Davy. 83 Torpedo marmorata, - - RUDOLPHI. 74 According to the table, it will be observed, that the inhabitants of the Arctic regions, whether belonging to the class of mammalia or birds, are amongst those whose temperature is highest. That of the Arctic fox is, indeed, probably higher than the amount given in the table, being taken after death, when the temperature of the air was as low as — 14° of Fahrenheit, and when loss of heat may be supposed to have taken place rapidly. The temperature of the smaller insects it is, of course, impractica- ble to indicate; but we can arrive at an approximation in those that congregate in masses, as the bee and the ant; for it is impossible to suppose with Maraldi, that the augmented temperature is depen- dent upon the motion and friction of the wings and bodies of the busy multitudes. Juch found that, when the temperature of the atmosphere was — 18° of Fahrenheit, that of a hive of bees was 44°; and, in an ant-hill, the thermometer stood at 68° or 70°, when the tempera- ture of the air was 55°; and at 75°, when that of the air was 66°. The power of preserving their temperature within certain limits is not, however, possessed exclusively by animals. The heat of a tree, examined by Mr. Hunter, was found to be always seve- ral degrees higher than that of the atmosphere, when the tem- perature of the air was below 56° of Fahrenheit ; but it was always several degrees below it when the weather was warmer. Some plants develope a considerable degree of heat, during the pe- 174 CALORIFICATION. riod of blooming. This was first noticed by Lamarck in the Arum italicum. In the Arum cordifolium of the Isle of Bourbon, Ilu- rert found, when the temperature of the air was 80°, that of the spathe or sheath as high as 134°; and Bory De St. Vincent ob- served a similar elevation, although to a less degree, in the Arum esculentum, esculent arum or Indian kale. The animal body is so far influenced by external heat, as to rise or fall with it; but the range, as we have already remarked, is limited in the warm-blooded animal; more extensive in the cold- blooded. Dr. Currie found the temperature of a man, plunged into sea-water at 44°, sink in the course of a minute and a half after im- mersion, from 9S° to 87°; and, in other experiments, it descended as low as 85°, and even as 83°. It was always found, however, that, in a few minutes, the heat approached its previous elevation; and, in no instance, could it be depressed lower than 81i°, or 15° below the temperature at the commencement of the operation. Si- milar experiments have been performed on other warm-blooded animals. Hunter found the temperature of a common mouse to be 99°, when that of the atmosphere was 60°; but when the same animal was exposed for an hour to an atmosphere of 15°, its heat had sunk to 83°; but the depression could be carried no farther. He found, also, that a dormouse, whose heat in an atmosphere at 64° was 81£°, when pu£ into air, at 20°, had its temperature raised, in the course of half an hour, to 93°; an hour after, the air being at 30°, it was still 93° ; another hour after, the air being at 19°, the heat of the pelvis was as low as 83°,—an experiment, which strongly proves the great counteracting influence exerted, when animals are exposed to an unusually low temperature. In this experiment, the dormouse had maintained its temperature about 70° higher than that of the surrounding medium, and for the space of two hours and a half. In the hybernating torpid quadrupeds the reduction of tempe- rature, during their torpidity, is considerable. Jenner found the temperature of a hedge-hog, in the cavity of the abdomen, towards the pelvis, to be 95°, and that of the diaphragm 97° of Fahren- heit, in summer, when the thermometer in the shade stood at 78°; whilst in winter, the temperature of the air being 44°, and the animal torpid, the heat in the pelvis was 45°,and of the dia- phragm 48£°. When the temperature of the atmosphere was at 26°, the heat of the animal, in the cavity of the abdomen, where an incision was made, was reduced as low as 30°; but, what singularly exhibits the power possessed by the system of regulating its tem- perature, when the same animal was exposed to the cold atmos- phere of 26°, for two days, its heat, in the rectum, was raised to 93°, or 67° above that of the atmosphere. At this time, however, it was lively and active, and the bed, on which it lay, felt warm. In the cold-blooded animal, we have equal evidence of the gene- ration of heat. Hunter found, that the heat of a viper, placed in EFFECTS OF DEPRESSED TEMPERATURE. 175 a vessel, at 10°, was reduced in ten minutes to 37°; in the next ten minutes, the temperature of the vessel being 13°, it fell to 35°; and in the next ten minutes, the vessel being at 20°, to 31°. In frogs, he was able to lower the temperature to 31°; but beyond this point it was not possible to lessen the heat, without destroying the animal. In the Arctic regions, the animal temperature appears to be steadily maintained, notwithstanding the intense cold that prevails; and we have already seen, that the animals of those hyperborean latitudes possess a more elevated temperature than those of more genial climes. In theenterprizing voyages, undertaken by the Bri- tish government for the discovery of a north-west passage, the crews of the ships were frequently exposed to a temperature of — 40° or —50° of Fahrenheit's scale; and the same thing hap- pened during the disastrous campaign of Russia in 1812, in which so many of the French army perished from cold. During the se- cond voyage of Captain Parry, the following temperatures of ani- mals, just after death, were taken principally by Captain Lyon. An Arctic fox Temperature of the 1821. Nov. 15. r" """ Animal. - 106|° Atmosphere. - - —14° Dec. 3. Do. - - 101$ - - — 5 Do. - - 100 - - — 3 11. Do. - - 10H - - — 21 15. Do. - - 993 - - — 15 17. Do. - - 98 - - — 10 19. Do. . - 991 - - — 14 1822. Jan. 3. Do. - - 1042 . — 23 9. A white hare - - 101 . — 21 10. An Arctic fox - - 100 - — 15 17. Do. - - 106 - - — 32 24. Do. - - 103 - - — 27 Do. - - 103 - — 27 Do. - - 102 - - — 25 27. Do. - - 101 - - — 32 Feb. 2. A wolf - - 105 - - — 27 These animals must have to disengage a quantity of caloric, at least 100° higher than the temperature of the atmosphere, through- out the whole of winter; and it would appear as if the counteract- ing influence becomes proportionately greater as the temperature is more depressed. It is, however, a part of the nature of those ani- mals to be constantly eliciting this unusual quantity of caloric, and therefore they do not suffer. Where animals, not so accus- tomed, are placed in an unusually cold medium, the efforts of the system rapidly exhaust the nervous energy; and when this be- 176 CALORIFICATION. comes so far depressed as to interfere materially with the function of calorification, which we shall find is to a certain extent under the nervous influence, the temperature sinks and the individual dies lethargic—or as if struck with apoplexy. The ship Endeavour, being on the coast of Terra del Fuego, on the 21st of December, 1769, Messrs. Banks, Solander, and others were desirous of making a botanical excursion upon the hills on the coast, which did not appear to be far distant. The party, consisting of eleven persons, were overtaken by night, on the hills during ex- treme cold. Dr. Solander, who had crossed the mountains which divide Sweden from Norway, knowing the almost irresistible de- sire for sleep produced by exposure to great cold, more especially when united with fatigue, enjoined his companions to keep moving, whatever pains it might cost them, and whatever might be the re- lief promised by an indulgence in rest. " Whoever sits down," said he, "will sleep, and whoever sleeps will wake no more." Thus admonished, they set forward, but whilst still upon the bare rock, and before they had got among the bushes, the cold suddenly became so severe, as to produce the effects that had been dreaded. Dr. Solander himself was the first who found the desire irre- sistible, and insisted on being suffered to lie down. Mr. Banks, (afterwards Sir Joseph,) entreated and remonstrated in vain. He lay down upon the ground, although it was covered with snow; and it was with the greatest difficulty, that his friend could keep him from sleeping. Richmond, also, one of the black servants, began to linger and to suffer from the cold, in the same manner as Dr. Solander. Mr. Banks, therefore, sent five of the company forward to get a fire ready at the first convenient place they came to; and himself, with four others, remained with the doctor and Richmond, whom, partly by persuasion and partly by force, they carried forward; but when they had got through the birch and swamp, they both declared they could go no farther. Mr. Banks had again recourse to entreaty and expostulation, but without ef- fect. When Richmond was told, that if he did not go on, he would, in a short time, be frozen to death, he answered, that he desired nothing but to lie down and die. Dr. Solander was not so obstinate, but was willing to go on, if they would first allow him to take some sleep, although he had before observed, that to sleep was to perish. Mr. Banks and the rest of the party found it impossible to carry them, and they were consequently suffered to sit down, being partly supported by the bushes, and, in a few mi- nutes, they fell into a profound sleep. Soon after, some of the people, who had been sent forward, returned with the welcome in- telligence, that a fire had been kindled about a quarter of a mile farther on the way. Mr. Banks then endeavoured to rouse Dr. Solander, and happily succeeded, but, although he had not slept five minutes, he had almost lost the use of his limbs; and the mus- cles were so shrunk, that his shoes fell from his feet. He con- EFFECTS OF ELEVATED TEMPERATURE. 177 sented to go forward with such assistance as could be given him, but no attempts to relieve Richmond were successful. He, with another black left with him, died. Several others began to lose their sensibility, having been exposed to the cold near an hour and a half, but the fire recovered them. The preceding history is interesting in another point of view be- sides the one for which it was more especially adduced. Both the individuals that perished were blacks, and it has been a common observation that they bear exposure to great heat with more impu- nity, and suffer more from intense cold, than the white variety of the species. As regards inorganic bodies, it has been satisfactorily shown, that the phenomena of the radiation of caloric are connect- ed with the nature of the radiating surface; and that those surfaces which radiate most, possess, in the highest degree, the absorbing power; in other words, bodies that have their temperatures most readily raised by radiant heat are those that are most easily cooled by their own radiation. In the experiments of Professor Leslie it was found, that a clean metallic surface produced an effect upon the thermometer equal to 12 ; but when covered with a thin coat of glue its radiating power was so far increased as to produce an effect equal to 80; and, on covering it with lamp-black, it became equal to 100. We can thus understand wThy, in the negro, there should be a greater expense of caloric than in the white, owing to the greater radiation; not because as much caloric may not have been elicited as in the white. In the same manner we can understand that, owing to the greater absorbing power of his skin, he may suffer less from excessive heat than the white; and this is perhaps the great use of the dark rete mucosum. To ascertain whether such be the fact, the following experiments were instituted by Sir Everard Home. He exposed the back of his hand to the sun at twelve o'clock, with a thermometer attached to it, another thermo- meter being placed upon a table with the same exposure. The temperature, indicated by that on his hand, was 90°; by the other, 102°. In forty-five minutes, blisters arose, and coagulable lymph was thrown out The pain was very severe. In a second experiment, he exposed his face, eyelids, and the back of his hand to water heated to 120°; in a few minutes, they became painful; and, when the heat was farther increased, he was unable to bear it; but no blisters were produced. In a third experiment, he exposed the backs of both hands, with a thermometer upon each, to the sun's rays. The one hand was uncovered; the other had a covering of black cloth, under which the ball of the thermometer was placed. After ten minutes, the degree of heat of each thermometer was marked, and the ap- pearance of the skin examined. This was repeated at three different times. The first time, the thermometer under the cloth stood at 91°, the other thermometer at 85°; the second time, they indicated re- spectively 94° and 91°; and the third time, 106° and 98°. In every Vol. II. 23 178 CALORIFICATION. one of these trials, the skin, that was uncovered, was scorched, whilst the other had not suffered in the slightest degree. From all his experiments, Sir Everard concludes, that the power of the sun's rays to scorch the skin of animals is destroyed, when applied to a black surface; although the absolute heat, in consequence of the absorption of the rays, is greater. When cold is applied to particular parts of the body, the heat of those parts sinks lower than the minimum of depressed tempera- ture. Although Hunter was unable to heat the urethra one degree above the maximum of elevated temperature of the body, he suc- ceeded in cooling it 29° lower than the minimum of depressed temperature, or to 58°. He succeeded in cooling down the ears of rabbits until they froze; and, when thawed, they recovered their natural heat and circulation. The same experiment was performed on the comb and wattles of a cock. He found, however, that re- suscitation occurred in no instance where the whole body had been frozen. Hunter found, that the power of generating heat, when ex- posed to a cooling influence, was possessed even by the egg. An egg, which had been frozen and thawed, was put into a cold mixture along with one newly laid. The latter was seven minutes and a half longer in freezing than the other. In another experiment, a fresh laid egg, and one which had been frozen and thawed, were put into a cold mixture at 15° ; the thaw- ed one soon rose to 32°, and began to swell and congeal; the fresh one sunk to 29i, and, in twenty-five minutes after the dead one, it rose to 32°, and began to swell and freeze. All these facts prove, that when the body is exposed to a lower temperature than usual, a counteracting power of calorification exists; but that, in the hu- man species, such exposure to cold is incapable of depressing the temperature of the system lower than about 15° beneath the natu- ral standard. On the other hand, when the human body is exposed to a tem- perature greatly beyond the natural standard, an action of refrige- ration is exerted; so that animal heat does not rise heyond a cer- tain number of degrees;—to a much smaller extent in fact than it is capable of being depressed by the opposite influence. Boerhaave 'maintained the strange opinion, that no warm- blooded animal could exist in a temperature higher than that of its own body. In the part of Virginia in which we are now situated, there are some days in every summer in which the thermometer reaches 98° of Fahrenheit ; whilst in other parts of this country it is occasionally much higher. The meteorological registers show it to be at times as high as 108° at Council Bluffs in Missouri; at 104° in New York; and at 100° in Michigan; whilst in most of the states on some day of summer it reaches 96° or 98°. At Sierra Leone, Messrs. Watt and Winterbottom saw the thermometer frequently at 100°, and even as high as 102° and 103° at some dis- EFFECTS OF ELEVATED TEMPERATURE. 179 tance from the coast. Adanson saw it at Senegal as high as 108§°. Brydone affirms, that when the scirocco blows in Sicily, the heat rises to 112°. Dr. Chalmers observed a heat of 115° in South Carolina; Humboldt of 110° to 115° in the Llanos or Plains near the Orinoco ; and Captain Tuckey asserts, that on the Red Sea he never observed the thermometer at midnight under 94°; at sunrise under 104°; or at midday under 112°. So long ago as 1758, Governor Ellis of Georgia had noticed how little the heat of the body is influenced by the external atmos- phere. "I have frequently," he remarks, "walked an hundred yards under an umbrella with a thermometer suspended from it by a thread, to the height of my nostrils, when the mercury has rose to 105°, which is prodigious. At the same time I have confined this instrument close to the hottest part of my body, and have been astonished to observe, that it has subsided several degrees. Indeed I never could raise the mercury above 97° with the heat of my body." Two years afterthedate of this communication, the powerof resist- ing a much higher atmospheric temperature was discovered by acci- dent. MM. Duhamel and Tillet,—in some experiments for de- stroying an insect that infested the grain of the neighbourhood,— having occasion to use a large public oven on the same day in which bread had been baked in it,weredesirous of ascertaining its tempera- ture. This they endeavoured to accomplish by introducing a thermo- meter into the oven at the end of a shovel. On being withdrawn, the thermometer indicated a degree of heat considerably above that of boiling water; but M. Tillet, feeling satisfied that the thermo- meter had fallen several degrees in approaching the mouth of the oven, and seeming to be at a loss how to rectify the error, a girl, —one of the servants of the baker, and an attendant on the oven,— offered to enter, and mark with a pencil the height at which the thermometer stood within the oven. The girl smiled at M. Til- let's hesitation at her proposition, entered the oven, and noted the thermometer to be at 260° of Fahrenheit. M. Tillet, anxious for her safety, called upon her to come out; but she assured him she felt no inconvenience from her situation, and remained ten minutes longer, when the thermometer had risen to 280° and upwards. She then came out of the oven, with her face considera- bly flushed, but her respiration by no means quick or laborious. These facts excited considerable interest, but no farther experi- ments appear to have been instituted, until, in the year 1774, Dr. Geo. Fordyce and Sir Charles Blagden made their celebrated trials with heated air. The rooms, in which these were made, were heated by flues in the floor. Having taken off his coat, waistcoat, and shirt, and being provided with wooden shoes tied on with list, Dr. Fordyce went into one of the rooms, as soon as the thermo- meter indicated a degree of heat above that of boiling water. The first impression of this heated air upon his body was exceedingly 180 calorification. disagreeable; but, in a few minutes, all uneasiness was removed by copious perspiration. At the end of twelve minutes he left the room very much fatigued, but not otherwise disordered. The thermometer had risen to 220°. In other experiments, it was found, that a heat of even 260° could be borne with tolerable ease. At this temperature, every piece of metal was intolerably hot; small quantities of water, in metallic vessels, quickly boiled; and streams of moisture poured down over the whole surface of the body. That this was merely the vapour of the room, condensed by the cooler skin, was proved by the fact, that when a Florence flask, filled with water of the same temperature as the body, was placed in the room, the vapour condensed in like manner upon its surface, and ran down in streams. Whenever they breathed upon the thermometer the mercury sank several degrees. Every expi- ration, especially if made with any degree of violence, communi- cated a pleasant impression of coolness to the nostrils, scorched immediately before by the hot air rushing against them when they inspired. In the same manner, their comparatively cool breath cooled their fingers, whenever it reached them. "To prove," says Sir Charles Blagden, " that there was no fallacy in the degree of heat, shown by the thermometer, but that the air, which we breathed, was capable of producing all the well-known effects of such an heat on inanimate matter, we put some eggs and a beef- steak upon a tin frame, placed near the standard thermometer, and farther distant from the cockle than from the wall of the room. In about twenty minutes, the eggs were taken out, roasted quite hard; and in forty-seven minutes the steak was not only dressed, but almost dry. Another beef-steak was rather over done in thirty- three minutes. In the evening, when the heat was still greater, we laid a third beef-steak in the same place; and as it had now been observed, that the effect of the heated air was much increased by putting it in motion, we blew upon the steak with a pair of bel- lows, which produced a visible change on its surface and seemed to hasten the dressing; the greatest part of it was found pretty well done in thirteen minutes." In all these experiments, and similar ones were made in the fol- lowing year by Dobson of Liverpool, the heat of the body, in a high temperature, speedily reached 100°, but exposure to 212° and more did not carry it higher. These results are not, however, exactly in accordance with those of MM. Berger and De La Roche, deduced from experiments, performed in 1806. Having exposed them- selves for some time to a stove,—the temperature of which was 39° of Reaumur, or 120° of Fahrenheit,—their temperature was ele- vated 3° of Reaumur, or 6^° of Fahrenheit; and M. De La Roche found, that his rose 4° of Reaumur, or 9° of Fahrenheit, when he had remained sixteen minutes in a stove, heated to 176° of Fahrenheit. In some experiments of Chabert, who has been exhibiting his powers as a " Fire-king," in this country as EFFECTS OF ELEVATED TEMPERATURE. 181 well as in Europe, he is said to have entered an oven with impu- nity, the heat of which was from 400 to 600° of Fahrenheit. Experiments have shown, that the same power of resisting ex- cessive heat is possessed by other animals. Drs. Fordyce and Blagden shut up a dog in a room, the temperature of which was between 220° and 236° for half an hour; at the end of this time, a thermometer was applied between the thigh and flank of the ani- mal; and in about a minute, the mercury sank down to 110°; but the real heat of the body was certainly less than this, as the ball of the thermometer could not be kept a sufficient time in pro- per contact, and the hair, which felt sensibly hotter than the bare skin, could not be prevented from touching the instrument. The temperature of this animal, in the natural state, was 101°. Wejind, in the case of aquatic animals, some astonishing cases of adaptation of beings to the medium in which they live. Al- though man is capable of breathing air, heated to above the boil- ing point of water with impunity, we have seen that he cannot bear the contact of water much below that temperature. Yet we find fishes living in water at a temperature, which would be entirely sufficient to boil them if dead. In the thermal springs of Bahia, in Brazil, many small fishes are seen swimming in a rivulet, that raises the thermometer to 88°, when the temperature of the air is only 77s0. Sonnerat, again, found fishes existing in a hot spring at the Manillas,at 158° Fah.; and MM. Humboldt and Bonpland, in travelling through the province of Quito in South America, perceived fishes thrown up alive and apparently in health, from the bottom of a volcano, in the course of its explosions, along with water and heated vapour that raised the thermometer to 210°, or only two degrees short of the boiling point. When the heating influence is applied to a part of the body only, as to the urethra, the temperature of the part is not increased beyond the degree to which the whole body may be raised. From all these facts, then, we may conclude, that when the body is exposed to a temperature, greatly above the ordinary standard of the animal, a frigorific influence is exerted; but this is effected at a considerable expense of the vital energy; and hence is followed by considerable exhaustion, if the effort be prolonged. In the cold-blooded animal, the power of resisting heat is not great; so that it expires in water not hotter than the human blood occasionally is. Dr. Edwards found, that a frog, which can live for eight hours in water at 32°, is destroyed in a few seconds, in water at 105°; which appears to be the highest temperature, that cold-blooded animals can bear. Observation has shown, that although the average temperature of an animal is such as we have stated in the table, yet that parti- cular circumstances give occasion to some fluctuation. A slight difference exists, according to sex, temperament, idiosyncrasy, &c. MM. Edwards and Gentil found the temperature of a young 1S2 calorification. female half a degree less than that of two boys of the same age. Edwards tried the temperature of twenty sexagenarians, thirty- seven septuagenarians, fifteen octogenarians, and five centenarians, at the large establishment of Bicetre, and he observed a slight dif- ference in each class. John Davy found, that the temperature of a lamb was a degree higher than that of its mother; in five new- born children, the heat was about half a degree higher than that of the mother, and it rose half a degree higher in the first twelve hours after birth. Edwards, on the other hand, found, that, in the cold-blooded animal, the faculty of producing heat was less, the nearer to birth; and that in many cases, as soon as the young dropped from the mother, the temperature fell to within a degree or two of that of the circumambient air; and he moreover affirms, that the faculty of producing heat is at its minimum at birth; and that it increases successively to the adult age. His trials on chil- dren, at the large Hopital des Enfans of Paris; and on the aged, at Bicetre, showed, that the temperature of infants, one or two days old, was 94° or 95° of Fahrenheit; thatof the sexagenarian from 95° to 97°; of the octogenarian 94° or 95°; and that, as a ge- neral principle, it varied according to the age. . The state of the system, as to health or disease, also influences the evolution of heat. Dr. Francis Home, of Edinburgh, took the heat of various patients, at different periods of their indisposi- tions. He found that of two persons, labouring under the cold stage of an intermittent, to be 104° ; whilst, during the sweat and afterwards, it fell to 101° and to 99°. The highest degree, which he noticed in fever, was 107°. We have often witnessed the ther- mometer at 106° in scarlatina and in typhus, but it probably rarely exceeds this, although it is stated to have been seen as high as 112°. Hunter found the interior of a hydrocele, on the day of opera- tion, to raise the mereury to 92° ; on the following day, when in- flammation had commenced, it rose to 99°. The fluid, obtained from the abdomen of an individual, tapped for the seventh time for dropsy of the lower belly, indicated a temperature of 101°. Twelve days thereafter, when the operation was repeated for the eighth time, the temperature was 104°. Dr. James Currie had himself bled; and during the operation, the mercury of a thermometer, which he held in his hand, sank, at first slowly and afterwards rapidly, nearly 10° ; and when he fainted, the assistant found, that it had sank 8° farther. MM. Edwards and Gentil also assert, that they have ob- served diurnal variations in the temperature of individuals, and these produced, apparently, by the particular succession in the ex- ercise of the different organs; as where intellectual meditation was followed by digestion. These variations, they affirm, frequently amounted to two or three degrees, between morning and evening. Such are the prominent facts, connected with the subject of ani- SEAT OF CALORIFICATION. 183 mal heat. It is obvious, that it is altogether disengaged by an ac- tion of the system, which enables it to counteract, within certain limits, the extremes of atmospheric heat and cold. The animal body, like all other substances, is subjected to the laws regarding the equilibrium, the conduction, and the radiation of caloric ; but, by virtue of the important function we are now considering, its own temperature is neither elevated nor depressed by those influ- ences to any great amount. Into the seat and nature of this mys- terious process, and the various ingenious theories, that have been indulged, we will now inquire. Physiologists have been by no means agreed, regarding the or- gans or apparatus of calorification. Some, indeed, have affirmed that there is not, strictly speaking, any such apparatus; and that animal heat results from all the other vital operations. Amongst those, too, who admit the existence of such an apparatus, a differ- ence of sentiment prevails ; some esteeming, that it is local, or ef- fected in some particular part of the body ; others, that it is gene- ral, or disseminated through the whole of the economy. Under the name caloriciti Chaussier admits a primary vital property, by virtue of which living beings disengage the caloric on which their proper temperature is dependent, in the same manner as they accomplish their other vital operations, by other vital pro- perties ; and, in support of this doctrine, he adduces the circum- stance, that each living body has its own proper temperature; which is coexistent only with the living state ; is common to every living part; ceases at death; and augments by every cause, that excites the vital activity. It has been properly, however, objected to this view, that the same arguments would apply equally to many other vital opera- tions ; to nutrition for example; and that it would be obviously improper to admit, for each of these functions, a special vital prin- ciple. The notion has not experienced favour from the physiolo- gist, and is, we believe, confined to the individual from whom it emanated. • BoNi,again,according to Adelon, considers that no particular or- gan is specially charged with the disengagement of caloric; but that it is the common resultant of all the vital actions, nervous or muscu- lar, of digestion, respiration, circulation, nutrition, secretion, &c. The arguments, that he adduces, in favour of his position, are,—that the exercise of any of these functions actually modifies the tempera- ture of the body; thab mental labour heats the head,—hence the ex- citement witnessed in the maniac, and the great resistance to cold for which he is distinguished; and that, during emotion, we are hot or cold, whatever may be the condition of the atmosphere. The action of the various organs of the body, and especially of the nervous system, we shall see, have considerable influence in modifying the disengagement of heat; and it is probable, that it 184 CALORIFICATION. occurs in the different organs, referred to by Boni, but not directly in consequence of the functions they accomplish. Amongst those, who admit that calorification is a local action, some have believed that the caloric is disengaged in a particu- lar organ, whence it is distributed to every part of the body; whilst others conceive, that every part disengages its own caloric and has its special temperature. So striking a phenomenon as animal temperature could not fail to attract early attention; and, accordingly, we find, amongst the ancients, various speculations on the subject. The most prevalent was, that its seat is in the heart; that it is communicated to the blood in that viscus, and is afterwards sent to every part of the system; and that the great use of respiration is to cool the heart; but this hypothesis is liable to all the objections, that apply to the no- tion of any organ of the body acting as a furnace,—that such organ ought to be calcined ; and it has the additional objection, which applies to all the speculations regarding the ebullition and efferves- cence of the blood as a cause of heat, that it is purely conjectural, without the slightest fact or argument in its favour. It was not, indeed, until the chymrcal doctrines prevailed, that any thing like argument was adduced in favour of the local disengagement of heat: the opinions of physiologists then settled almost universally upon the lungs ; and this chiefly in consequence of the observation, that animals, which do not breathe, have a temperature but little superior to the medium in which they live; whilst man and ani- mals that breathe have a temperature considerably higher than the medium heat of the climate in which they exist, and one which is but little affected by changes in the thermal condition of that medium ; and, moreover, that birds, which breathe, in proportion, a greater quantity of air than man, have a still higher temperature than he. Mayow, whose theory of animal heat was, in other respects, sufficiently unmeaning, affirmed, that the effect of respiration is not to cool the blood, as had been previously maintained, but to gene- rate heat, which it did by an operation analogous to combustion. It was not, however, until the publication of Dr. Black's doc- trine on latent heat, that any plausible explanation of the pheno- menon appeared. According to that distinguished philosopher, a part of the latent heat of the inspired air becomes sensible; conse- quently, the temperature of the lungs and of the blood passing through them must be elevated; and as the blood is distributed to the whole system, it communicates its heat to the parts as it proceeds in its course. But this view was liable to an obvious objection, which was, indeed, fatal to it, and so Black himself appears to have thought, from his silence on the subject. If the whole of the caloric is disengaged in the lungs, as in a furnace, and is distributed through the blood-vessels, as heated air is trans- THEORIES OF CALORIFICATION. 1S5 mitted along conducting pipes, the temperature of the lungs ought to be much greater than that of the parts more distant from the heart; so great, indeed, as to consume that important organ in a short space of time. The doctrine, maintained by Lavoisier and Seguin, was:— that the oxygen of the inspired air combines with the carbon and hydrogen of the venous blood and produces combustion. The calo- ric, given off, is then taken up by the blood-vessels, and is distri- buted over the body. The arguments they adduced in favour of this view, were:—the great resemblance between respiration and combustion; so that if the latter gives off heat, the former ought to do so likewise;—the fact that arterial blood is somewhat warmer than venous;—certain experiments of Lavoisier and La Place, which consisted in placing animals in the calorimeter, and com- paring the quantity of ice, which they melted, and, consequently, the quantity of heat they gave off, with the quantity of carbonic acid produced; and finding that the quantity of caloric, that would result from the carbonic acid formed, was exactly that disengaged by those animals. Independently, however, of other objections, this hypothesis is liable to those already urged against that of Black, which it closely resembles. The objection, that the lungs ought to be much hotter than they really are—both absolutely and relatively—was attempt- ed to be obviated by Dr. Crawford, in a most ingenious and apparently logical manner. The oxygen of the inspired air, accord- ing to him, combines with the carbon given out by the blood, so as to form carbonic acid. But the specific heat of this is less than that of oxygen; and, accordingly, a quantity of latent calo«- ric is set free; and this caloric is not only sufficient to support the temperature of the body, but also to carry off the water—which was supposed to be formed by the union of the hydrogen and the oxygen—in the state of vapour, and to raise the temperature of the inspired air considerably. So far the theory of Crawford was liable to the same objections as those of Black, and Lavoisier and Seguin. He affirmed, however, that the same process, by which the oxygen of the inspired air is converted into carbonic acid, converts likewise the venous into arterial blood; and as he assumed from his experiments, that the capacity for caloric of arte- rial blood is greater than that of venous, in the proportion of 1.0300 to 0.8928; he conceived, that the caloric, set free in the formation of the carbonic acid, in place of raising the temperature of the arterial blood, is employed in saturating its increased capa- city, and in maintaining its temperature at the same degree with the venous. According to this view, therefore, the heat is not absolutely set free in the lungs, although arterial blood contains a greater quan- tity of caloric than venous; but when, in the capillaries, the arte- rial becomes converted into venous blood, or into blood of a less Vol. II. 24 186 CALORIFICATION. capacity for caloric, the heat is set free, and occasions the tempe- rature of the body. If the facts, which have served as a foundation for this theory of animal heat, were not false, the deductions would be irresistible; and, accordingly, it was, at one time, almost universally received, especially by those who consider that all vital operations can be assimilated to chymical processes. But numerous objections arise against it. In the first place, we have elsewhere endeavoured to show, that respiration is not a combustion; and that our know- ledge is limited to the fact, that oxygen is taken into the pulmo- nary vessels and carbonic acid given off, but we have no means of knowing whether the one goes immediately to the formation of the other. Dr. Crawford had inferred from his experiments, that the specific heat of oxygen is 1.7490; of carbonic acid, 1.0454; of azote, 0.7936; and of atmospheric air, 0.2669; but the more re- cent experiments of De La Roche and Berard, make that of oxygen, 0.2361;of carbonic acid, 0.2210; of azote, 0.2754; and of atmospheric air, 0.2669; a difference of such a trifling amount, that it has been conceived the quantity of caloric, given out by oxygen during its conversion into carbonic acid, would be insuffi- cient to heat the residual air, that is expelled in breathing, to its ordinary elevation. Secondly. The one or two degrees of eleva- tion of temperature, which appears to occur in the conversion of venous into arterial blood, although generally believed in, is not assented to by all. The experiments instituted on this point have been few and imprecise. Thirdly. M. Dulong,—on repeating the experiments of Lavoisier and La Place, for comparing the quan- tities of caloric given off by animals, in the calorimeter, with those that would result from the carbonic acid formed during the same time in their respiration,—did not attain a similar result. The quan- tity of caloric, disengaged by the animals, was always superior to that which would result from the quantity of carbonic acid formed. Fourthly. The estimate of Crawford, regarding the specific heat of venous and arterial blood, has been contested. He made that of the former, we have seen, to be 0.8928; of the latter 1.0300. The result of the experiments of Dr. John Davy give 0.903 to the former, and 0.913 to the latter; and in another case, which has been adopted by Magendie, the specific heat of the venous was greater than that of the arterial blood, in the proportion of .852 to .839. Granting, however, that the case is as stated by Crawford, it is insufficient to explain the phenomena. Legallois has, indeed, attempted to show that if the whole of the caloric, set free in the manner mentioned, were immediately absorbed, it would be insuf- ficient for the constitution of the arterial blood; and that, instead of the-lung running the risk of being calcined, it would be threat- ened with congelation. But the theory of Crawford was most seriously assailed by other experiments, tending to show that the function of calorifi- theories of calorification. 187 cation is derived from the great nervous centres. When an animal is decapitated, or when the spinal marrow, or the brain, or both, are destroyed, we have seen that the action of the heart may be still kept up, provided the lungs be artificially inflated. In such cases, it is found, that the usual change in the blood, from the venous to the arterial state, is produced; oxygen is absorbed and carbonic acid exhaled as usual. Mr. Brodie, in performing this experiment, directed his attention to the point, whether animal heat is, under such circumstances, evolved, and the temperature maintained, as where the brain and spinal marrow are entire; and he found, that although the blood appeared to undergo its ordinary changes, the generation of animal heat seemed to be suspended; and conse- quently, if the inspired air happened to be colder than the body, the effect of respiration was to cool the animal; so that an animal, on which artificial respiration was kept up, became sooner cold than one killed at the same time and left undisturbed. The inference, deduced from these experiments, was, that in- stead of circulation and respiration maintaining the heat, they dissipate it; and that as the heat is diminished by the destruction of the nervous centres, its disengagement must be ascribed to the action of those centres, and particularly to that of the encephalon. M. Chossat has endeavoured to discover the precise part of the nervous system engaged in calorification; but the results of his ex- periments have not been such as to induce him to refer it with Brodie to the encephalon. He divided the brain, anterior to the pons varolii, in a living animal, so that the eighth pair of nerves were uninjured. Respira- tion, consequently, continued, and inflation of the lungs was un- necessary. Notwithstanding this serious mutilation, the circulation also went on; and Chossat observed distinctly, that arterial blood circulated in the arteries. Yet the temperature of the animal gra- dually sank, from 104° Fahr.,—its elevation at the commence- ment of the experiment,—to 76°, in twelve hours, when the ani- mal died. It seemed manifest to M. Chossat, that from the time that the brain was divided, heat was no longer given off, and the body gradually cooled as it would have done after death. Farther than this, he noticed, that the time at which the refrigeration oc- curred most rapidly was that in which the circulation was most active,—at the commencement of the experiment. In other expe- riments, M. Chossat paralyzed the action of the brain by a violent concussion, and by injecting a strong decoction of opium into the jugular vein,—keeping up respiration at the same time artificially. The results were the same. From these experiments he drew the conclusion that the brain has a direct influence over the production of heat. His next experiments were directed to the discovery of the medium through which the brain acts,—the eighth pair of nerves, or spinal marrow. He divided the eighth pair of nerves in 188 CALORIFICATION. a dog, and kept up artificial respiration. The temperature of the animal sank gradually, and at the expiration of sixty hours when the animal died, it was reduced to 68° of Fahrenheit. Yet the animal did not die of asphyxia or of suspension of the pheno- mena of respiration, as the lungs crepitated, exhibited no signs of infiltration, and were partly filled with arterial blood. It appeared to M. Chossat to expire from cold. As, however, the mean de- pression of heat was less than in the preceding experiments, he in- ferred, that a slight degree of heat is still disengaged after the sec- tion of the eighth pair, whilst after injury done to the brain directly it is no longer given off. Again, he divided the spinal marrow beneath the occiput, and although artificial respiration was maintained, as in the experiments of Brodie, the temperature gradually fell, and the animal died ten hours afterwards, at a heat of 79°; and as death occurred in this case so much more speedily than in the last, he inferred, that the influence of the brain over the production of heat is transmitted rather by the spinal marrow than by the eighth pair of nerves. In his farther experiments, Chossat found, that when the spinal marrow was divided between each of the twelve dorsal vertebra?, the depression of temperature occurred less and less rapidly, the lower the intervertebral section, and it was imperceptible at the lowest; he therefore concluded, that the spinal marrow did not act directly in the function, but indirectly through the trisplanchnic nerve. To satisfy himself on this point, he opened a living animal on the left side, beneath the twelfth rib, and removed the supra- renal capsule of that side, dividing the trisplanchnic, where it joins the semilunar plexus. The animal gradually lost its heat, and died ten hours afterwards in the same state as regarded temperature as when the spinal marrow was divided beneath the occiput. Desiring to obtain more satisfactory results,—the last experiment applying to only one of the trisplanchnic nerves,—he tied the aorta, which supplies both with the materials on which they operate, be- neath the place where it passes through the arch of the diaphragm, at the same time preventing asphyxia by inflation of the lungs. The animal lost its heat much more rapidly, and died in five hours. In all these cases, the animal, according to Chossat, died of cold; the func- tion, by which the caloric, constantly abstracted from the system by the surrounding medium,isgenerated,having been rendered imprac- ticable. To have a medium of comparison, he killed several ani- mals by protracted immersion in cold water, when he found, that the lowest degree, to which the warm-blooded could be reduced and life yet exist, was 79° of Fahrenheit. M. Chossat also alludes to cases of natural death by congelation, which he conceives to de- stroy, in the manner we have before suggested, by diminution of the nervous energy, as indicated by the progressive stupor, and debility of the chief functions of the animal economy. Lastly,—On killing animals suddenly, and attending to the pro- THEORIES OF CALORIFICATION. 189 gress of refrigeration after death, he found it to be identical with that which follows direct injury of the brain, or division of the spinal marrow beneath the occiput. A view, somewhat analogous to this of M. Chossat, has been indulged by Sir Everard Home. He conceives, that the phe- nomenon is restricted to the ganglionic part of the nervous sys- tem, and he rests the opinion chiefly upon the position, that there are certain animals which have a brain, or some part equivalent to it, but whose temperature is not higher than that of the surround- ing medium; whilst, on the other hand, all the animals that evolve heat are provided with ganglia. The doctrines of Brodie and Chossat have been considered by the generality of the chymists,—by Brande, Thomson, and Pa- ris,—as completely subversive of the chymical doctrines, which re- fer the production of animal heat to the respiratory function. Their position,—that it is a nervous function,—has,likewise,been confirmed by the facts attendant upon injury done to the nerves of parts; and by what is witnessed in paralytic limbs, the heat of which is generally and manifestly inferior to that of the sound parts. But there are many difficulties in the way of admitting, that the nervous system is the special organ for the production of animal temperature. Dr. Wilson Philip, from a repetition of the experiments of Mr. Brodie, was led to conclude, that the cause why the temperature of the animal body diminished more rapidly, where artificial inflation was practised, than where the animal was left undisturbed, was owing to too large a quantity of air having been sent into the lungs; and he found, that when a less quantity was used, the cooling process was sensibly retarded by the infla- tion. The experiments of Legallois, Hastings, and Williams, although differing from each other in certain particulars, corrobo- rate the conclusion of Dr. Philip, and what is singular, would ap- pear to show, that the temperature occasionally rises during the ex- periment. Many of the facts, detailed by Chossat, are curious, and exhibit the indirect agency of the nervous system, but his conclusion, that the trisplanchnic is the special organ for its development is liable to the objections we have urged regarding the theory, which looks upon the heart, or the lungs as furnaces for the disengagement of ca- loric, viz. that they ought to be consumed in a short space of time by the operation. All these facts exhibit, that, in the upper classes of animals, the three great acts of innervation, respiration and circulation are indi- rectly concerned in this function ; not that any one is the special apparatus. M. Edwards has attempted to show, that it is more connected with the second of these than with either of the others. Thus, animals, whose temperature is highest, bear privation of air the least, whilst cold-blooded animals suffer comparatively little from it; and young animals are less affected than the adult. 190 calorification. The greater the temperature of the animal, and the nearer to the adult age, the greater is the consumption of oxygen; and he far- ther observed, that whilst the seasons modify calorification, they affect also respiration ; and that if, in summer, less heat is elicit- ed, and in winter more, respiration consumes less oxygen in the former season than in the latter. That innervation is indirectly concerned in the phenomenon is proved by the various facts that have been referred to ; and Le- gallois, although he does not accord with Mr. Brodie, conceives that the temperature is greatly under the influence of the nervous system, and that whatever weakens the nervous power, proportion- ally diminishes the capability of producing heat. Dr. Philip, too, concluded from his experiments, that the nervous influence is so intimately connected with the power of evolving heat, that it must be looked upon as a necessary medium between the different steps of the operation. He found, that if the galvanic influence be ap- plied to fresh drawn arterial blood, an evolution of heat, amounting to three or four degrees takes place, whilst the blood assumes the venous hue and becomes partly coagulated. He regards the pro- cess of calorification as a secretion; and explains it upon his gene- ral principle of the identity of the nervous and galvanic influences, and of the necessity for the exercise of such influence in the func- tion of secretion. Of the fact of the circulation being necessary to calorification we have evidence in the circumstance, that if the vessels, proceeding to a part, be tied, animal heat is no longer disengaged from it. It is manifest then, that in animals, and especially in the warm- blooded, the three great vital operations are necessary for the dis* engagement of the due temperature, but we have no sufficient evi- dence of the direct agency of any one, whilst we see heat elicited in the vegetable, in which these functions are at all events rudi- mental; and the existence of one of them—innervation—more than doubtful. The view of those, who consider, that the disengagement of ca-" loric occurs in the capillary system of the whole of the body, ap- pears to us the most consistent with observed phenomena. These views have varied according to the physical circumstances, that have been looked upon as producing heat. By some, it has been regarded as the product of an effervescence of the blood and hu- mours; by others, as owing to the disengagement of an igneous matter, or spirit from the blood ; by others to an agitation of the sulphureous parts of the blood ; whilst Boerhaave and Douglas ascribed it to the friction of the blood against the parietes of the vessels, and of the globules against each other. In favour of the last hypothesis, it was urged, that animal heat is in a direct ratio with the velocity of the circulation, the circumference of the vessels, and the extent of their surface; and that thus we are able to explain, why the heat of parts decreases in a direct ratio with their distance THEORIES OF CALORIFICATION. 191 from the heart; and they accounted for the greater heat of the arte- rial blood, in the lungs, by the supposition, that the pulmonary cir- culation is far more rapid. Most of these notions are entirely hypothetical. The data are generally incorrect, and the deductions characteristic of the faulty physics of the period in which they were indulged. The correct view, it appears to us, is that embraced by, perhaps, the generality of physiologists, who admit the caloric to be disen- gaged in every part, by a special action, under the nervous influ- ence, and the presence of arterial blood ; the latter either furnish- ing the materials, or merely acting as a stimulus. In this manner, calorification becomes, like nutrition, a function executed in the capillary system, and therefore appropriately considered in this place. It is by this theory alone, that we are capable of accounting for the increased heat that occurs in certain local diseases, in which the temperature exceeds, by several degrees, that of the blood in the large vessels. By some, it has been doubted whether, in cases of local inflam- mation, any such augmentation of temperature exists, but the error seems to have arisen from the temperature of the part, in health, having generally been ranked at blood heat; whereas, we shall find, that it differs essentially in different parts. Dr. Thomson found, that a small inflamed spot, in his right groin, gave out, in the course of four days, a quantity of heat, sufficient to have heated seven wine-pints of water from 40° to 212°; yet the temperature was not sensibly less than that of the rest of the body at the end of the experiment, when the inflammation had ceased. Of the mode, in which heat is evolved in the capillaries, it is impossible for us to arrive at any satisfactory information. The result alone indicates, that the process has been accomplished. In the present state of our knowledge, we are compelled to refer it to some vital action, of the nature of which we are ignorant; but which seems to be possessed by all organized bodies,*—vegetable as well as animal. By supposing, that calorification is effected in every part of the body, we can understand why different portions should have dif- ferent temperatures; as the activity of the function may vary, in this respect, according to the organ. Chopart and Dessault found the heat of the rectum to be 100°; of the axilla and groin, when covered with clothes, 96°; and of the chest, 92°. Davy found the temperature of a naked man, just risen from bed, to be 90° in the middle of the 2ble of the foot; 93° between the inner ancle and tendo Achilles; 91.5° in the middle of the skin; 93° in the calf; 95° in the ham; 91° in the middle of the thigh; 96.5° in the fold of the groin; 95° at three lines beneath the umbilicus; 94° on the sixth rib of the left side; 93° on the same rib of the right side; and 98° in the axilla. MM. Edwards and Gentil found 192 calorification. the temperature of a strong adult male, to be, in the rectum and mouth, 102°; in the hands, 100°; in the axillae and groins, 98°; in the cheeks, 97°; in the prepuce and the feet, 96°, and in the chest and abdomen, 95°. ✓ All these experiments, it is obvious, concern only the tempera- ture of parts which can be readily modified by the circumambient medium. To judge of the comparative temperature of the inter- nal organs, Davy killed a calf, and noted the temperature of dif- ferent parts, both external and internal. The blood of the jugular vein raised the thermometer to 105°. 5; that of the carotid artery to 107°; of the rectum to 105°.5; of the metatarsus to 97°; of the* tarsus to 90°; of the knee to 102°; of the head of the femur to 103°; of the groin to 104°; of the under part of the liver to 106°; of the substance of that organ to 106°; of the lung to 106°.5; of the left ventricle to 107°; of the right to 106°; and of the substance of the brain to 104°. It is not easy to account for these differences without supposing, that each part has the power of disengaging its own heat; and that the communication of caloric is not suffici- ently ready to prevent the difference from being perceptible. We have stated, early in this section, that man possesses the power of resisting cold as well as heat within certain limits; and of preserving his own temperature greatly unmodified. Let us inquire into the direct and indirect agents of these counteracting influences. As the mean temperature of the warmest regions does not ex- ceed 85° of Fahrenheit, it is obvious that he must be constantly disengaging caloric to the surrounding medium:—still his tempera-. ture remains the same. This is effected by the mysterious agency, which we have been considering, materially aided, however, by several circumstances both intrinsic and extrinsic to the system. The external envelope of the body is a bad conductor of caloric, and therefore protects the internal organs, to a certain extent, from the sudden influence of excessive heat or cold. The cutaneous sys- tem of man is, however, a much less efficient-protection than that of animals. In the warm-blooded animals, in general, the bo-fc, dies are covered with hair or feathers. The whale is destitute of hair; but besides the protection, which is afforded by the ex- traordinary thickness of its skin, and the stratum of fat,—a bad conductor of caloric,—with which the skin is lined, as the animal constantly resides in the water, it is not subjected to the same vicissitudes of temperature as the land animals. The seals, bears and walruses, which seek their food in the same seas, sleep on land. They have a coating of hair to protect Uiem. In the case of some of the birds of the genus Anas, of northern regions, we meet with a singular anomaly,—the whole of the circumference of the anus be- ing devoid of feathers; but to make amends for this deficiency, the animal has the power of secreting an oleaginous substance, with which the surface is kept constantly smeared. It may be remarked calorification. 193 that we do not find the quantity of feathers on the bodies of birds to be proportionate to the cold of the climates in which they re- side, as is pretty universally the case regarding the quantity of h»jj on the mammaliatfMan is compelled to have recourse to cloth- ing, for the impose ofpreventing the sudden abstraction or.recep- tion oTjigji&Ey J*This he does by ein»ering himself with subslaj|ces, that arebad conductors of caloric, and retain an atmosphere next to the suM§pS|' wfrift is warmed by the caloric of the body, T^Hkis compelled, j^gj infhe colder seasons, to have recourse to artifi- cial temperature. It will be^ibvious, from what has already been said, that the greater thefMBe of activity of any organ or set of organs, the greater willQ^the^s^jdeveloped1^ and, in this way, muscular ex- "efjion, and digestion jgpuence its production. '"' By an attention to all these points, and by his acquaintance with the physical laws relative to the development ahdjpsopagation of caloric, man is enabled to live amongst the arctic snj^wSy .and to exist in climates, where the j^^^rta^eis frequently,, for a length of time, upwards of 140° lower than that of his pwpii,.body. The ingenious contrivances, adopted in the polar voyages, under the direction*^Captain Parry, are monumentssfij&enuity, directed to obviate*one of the greatest obstacles to pljee^fged exisier|ce*ih those inhospitable regions, for which., man is naturally incapaci- tated, and attains the capab^^jsojely, by the exercise of that supe- ]fior intellect, wfth wtach n&lwir&been vested b$Uhe author of his In periods of intense cold, the Jptrerne psWLs of the body do not possess the necessary degree?*™'£rit*K*».-tn rpsfst r>nnorp.la. to resist congela* tion, unlessj&fogsftare carefully Ijfotected. • In the disastrous expe- ditions of ^RT^^^n to Russia, me loss of the nji^angPears was a common casualty;ti8fii£in arctic voyages j&$^bit69^ occur in spite of every^|je!"j^^fen the temperature of the whole body sinks to about 78° or 79°, death takes place, preceded by the symp- toms of nervous depression, ;fhat have been already depicted. The counteracting influence, which is exerted, when the body is exposed to a temperature greatly above the ord^^j^tandard of Hie animal, is as difficult of appreciation as that bjlwhich calorifi- cation is-effected. The probability is, that, in such case, thei^s- engagement of animal heat is ftgliftided; and that the body recejfes heat from without by direct, ^ut not by rapid, communication, owing to its being an imperfect conductor of caloric. Through the agency of this extraneous heat the temperature rises a limited num- ber of degrees; but its elevation is checked by the evaporation, constantly taking place through the cutaneous and pulmonary trans- pirations. For this last idea, we are indebted to Franklin, and its truth has been confirmed by others. B MM. Bergx?r and De LARocHE,for example,put into an oven,-— heated to from 120° to 140°,—a frog, one of those porous vessels, Vol. II. *5 »- 194 i ALORTFICATION- called alcarazas,—which permit the transudation of the fluid, within them, through their sides,—filled with water at the animal heat, and two sponges, imbibed with the same water. The tem- perature of the frog at the expiration of two hours, was 99°; and the other bodies continued at the same. Having substituted a rab- bit for the frog, the result was identical. On the other hand, having placed animals in a warm atmosphere, so saturated with humidity that no evaporation could occur, they received the caloric by com- munication, and their temperature rose; whilst inert evaporahlc bodies, put into a dry stove, became but slightly warmed ;—much less so, indeed, than the warm-blooded animals in the moist stove.' Hence they concluded, that evaporation is one of the great refri- gerative agents, when the body is exposed to excessive heat; and, this conclusion is confirmed by the loss in weight, which animals sustain by the experiment. Dr. Edwards, in his experiments on the influence of physical agents on life, found, that warm-blooded animals have less power of producing heat, after they have been exposed for some time to an elevated temperature, as.in summer,—whilst the opposite effect occurs in winter. He instituted a series of experiments, which consisted in exposing birds to the influence of a freezing mixture, first in February^ and afterwards in July and August, and observ- ing in what degree they were cooled by remaining in this situation for equal lengths of time ; the result of which was, that the same kind of animal was cooled six or eight times as much in the sum- mer as in the winter months. This principle he presumes to be of great importance in maintaining the regularity-of the temperature at the different seasons; even more so than evaporation, the effect, of which, in this respect, he thinks has been greatly exaggerated. When exposed to high atmospheric temperature, the ingenuity of man has to be as much exerted as in the opposite condition. The clothing must be duly regulated according to physical princi- ples, and perfect quietude be observed, so that undue activity of any of the organs that materially influence the disengagement of animal heat, may be prevented. It is only within limits, that this refrigeratory action is sufficient. At a certain degree, the transpiration is inadequate^ the tempera- ture of the animal rises, and death supervenes. secretion 195 SECRETION. We have yet to describe an important and multiple function, which takes place in the very tissue of our organs—in the capillary system,—and which separates from the blood the various humours of the body. This is the function of secretion,—a term which has been applied-both to the operation and "• the product. Thus, the liver is said to separate the bile from the blood by an action of se- cretion, and The' bile is said to be a secretion. The organs that execute the various secretory operations, differ greatly from each other. They have, however, been grouped by anatomists in three classes, each of which will require a general notice. Anatomy of the Secretory Apparatus. The secretory organs have been divided into exhalant, follicu- lar, and glandular. The remarks made respecting the exhalant vessels, under the head of nutrition, will render it unnecessary to allude, in this place, to any of the apochryphal descriptions of them, especially as their very existence is supposititious. Many, indeed, imagine them to be nothing more than the minute radicles of ordinary ar- teries. The follicle or crypt has the form of an ampulla or vesicle, and is situated in the substance of the skin and mucous membranes; se- creting a fluid forthe purpose of lubricating those parts. In the exhalant vessel, the secreted fluid passes immediately from the blood-vessel, without being received into any excretory duct; and in the follicle there is essentially no duct specially destined for the excretion of the humour. The follicle is membranous and vascular, having an internal ca- vity in which the secretion is accomplished; and the product is poured upon the surface, beneath which it is situated, either by a central aperture, or by a very short duct—if duct it can be called— termed a lacuna. The gland is of a more complex structure than the last. It con- sists of an artery, which conveys blood to it; of an intermediate body,—the gland, properly so called,—and of an excretory duct to carry off the secreted fluid, and pour it on the surface of the skin or mucous membranes. The blood-vessel, which conveys to the gland the material from which the secretion has to be operated, enters the organ at times by various branches; at others, by a 196 SECRETION. single trunk, and ramifies in the tissue of the gland; communi- cating at its extremities with the origins of the veins and of the ex- cretory ducts. These ducts arise by fine radicles at the part where the arterial ramifications terminate; and they unite to form larger and less numerous canals, until they terminate in one large duct, as in the pancreas; or in several, as in the lachrymal gland ; the duct generality leaving the gland at the part where the blood-ves- sel enters. Of this we have a good exemplification in the kidney, (see Fig. 123.) Besides these vessels, veins exist, which communicate with the vessels that convey blood to the gland, both for the formation of the humour and the nutrition of the organ, and return the resi- duary blood to the heart. Lymphatic vessels likewise exist; and nerves, which proceed from the ganglionic system, form a net- work around the secreting arteries, as in Fig. 120, accompany them into the interior of the organ, and terminate, like them, invisibly: Fig. 120. a a. A portion of intestine.—b b. Part of the aorta.—c c. Nerves following the branches of the aorta, to supply the intestine. Bordeu was of opinion, that the glands, judging from the paro- tid, are largely supplied with nerves. The nerves, however, do not all belong to it, merely crossing it in their course to other parts. Bichat, from the small number sent to the liver, was induced? to draw opposite conclusions to those of Bordeu. These may be looked upon as the great components of the glan- dular structure, along with cellular membrane, to bind them toge- ther, and, at times, an outer envelope. SECRETORY APPARATUS. 197 The intimate texture of these organs has been a topic of much speculation. It is generally considered, that the final ramifications of the arterial vessels, with the radicles of the veins and excretory ducts, and the final ramifications of the lymphatic vessels and nerves, form so many small lobules, composed of minute, granular masses. Such, indeed, is the appearance the texture presents, when exa- mined by the naked eye. Each lobule is conceived to contain a final ramification of the vessel or vessels conveying blood to the organ, a nerve, a vein, a lymphatic, and an excretory duct,—with cellular tissue binding them together. When the organ has an ex- ternal membrane, it usually forms a sheath to the various ves- sels. The lobated structure is not, however, equally apparent in all the glands. It is well seen in the pancreas, and in the salivary and lachrymal. The precise mode in which the blood-vessel, from the blood of which the secretion is effected, communicates with the excre- tory duct, does not admit of detection. Some have supposed, that between the termination of the blood-vessel and the commence- ment of the duct, a secretory vessel, specially charged with the function, exists, which conveys the secreted humour into the ex- cretory duct. Of this, however, we have no evidence; and the existence of any, except the minute capillary vessel, appears need- less. Malpiohi maintained, that such glands as the liver are com- posed of very minute bodies, called acini, from their resemblance to the stones of grapes; that these acini are hollow internally, and are covered externally by a net-work of blood-vessels; and that these minute blood-vessels pour into the cavities of the acini the secreted fluid, from which it is subsequently taken up by the ex- cretory ducts. Ruysch, however, satisfied himself, that the acini of Malpighi are merely convoluted vessels, and that they are continuous with the excretory ducts. In Malpighi's view, the secretory organ is a mere collection of follicles: in Ruysch's, simply an exhalant membrane variously convoluted. The latter is the view almost universally embraced by the anatomist and physiologist. " The 'chief, if not the only difference," says Sir Charles Bell, " be- tween the secreting structure of glands and that of simple surfaces, appears to consist in the different number and the different arrange- ment of their capillary vessels. The actual secreting organ is in both cases the same,—capillary blood-vessel; and it is uncertain whether either its peculiar arrangement, or greater extent in glan- dular texture, be productive of any other effect than that of fur- nishing the largest quantity of blood-vessels within the smallest space. Thus convoluted and packed up, secreting organ may be procured to any amount that may be required, without the incon- veniences of bulk and weight." It is manifest, then, that the three classes of secretory organs. tot >ECRET(ON. however different they may appear to be, are essentially varieties of the same structure; that the capillary vessel is the important agent of the secretion; that the simplest form of the secretory ap- paratus is this simple capillary vessel; and that the follicles and glands are structures of a more complex organization. Physiology of Secretion. The uncertainty which rests upon the intimate structure of se- creting organs, and upon the mode in which the different blood- vessels communicate with the commencement of the excretory duct, envelopes the function, executed by those parts, in obscurity. We see the pancreatic artery pass to the pancreas, ramify in its tissue, become capillary, and escape detection; and we see other vessels becoming larger and larger, and emptying themselves into vessels of greater magnitude, until, ultimately, all the secreted hu- mour is contained in one large duct, which passes onwards and discharges its fluid into the small intestine. Yet if we follow the pancreatic artery as far as the eye can carry us, even when aided by glasses of considerable magnifying powTer, or if we trace back the pancreatic duct as far as is practicable, we find, in the former vessel, always arterial blood, and, in the latter, always pancreatic juice. It must, consequently, be between the part at which the artery ceases to be visible, and the pancreatic duct becomes so, that secretion is effected f and we cut.the knot by asserting, that it oc- curs in the very tissue, parenchyma, or in the capillary system of the secretory organ. Conjecture, in the absence of positive knowledge, has been busy, at all times, in attempting the explanation of the mysterious agency by which we find such various humours separated from the same fluid; and, according as chymical, or mechanical, or vital doctrines have prevailed in physiology, the function has been referred to one or other of those agencies. The general belief, amongst the physiologists of the sixteenth and seventeenth centuries, was, that each gland possesses a pecu- liar kind of fermentation, .which assimilates to its own nature the blood passing through it. The notion of fermentation was, indeed, applied to most of the vital phenomena. It is now totally abandon- ed, owing to its being purely imaginary, and inconsistent with all our ideas of the vital operations. When this notion passed away, and the fashion of accounting for physiological phenomena on me- chanical principles usurped its place, the opinion prevailed, that the secretions are operated through the glands as through filters. To admit of this mechanical result, it was maintained, that all the secreted fluids exist ready formed in the blood, and that when they respectively arrive at the different secretory organs, they pass through, and are received by the excretory ducts. Descartes and Leibnitz were warm supporters of this mecha- physiology op secretion. 199 nical doctrine, although their views differed materially with regard to the precise nature of the operation. Descartes supposed, that the particles of the various humours are of different shapes, and that the pores of the glands have respectively' a corresponding figure; so that each gland permits those particles only to pass through it, which have the shape of its pores. Leibnitz, on the other hand, likened the glands to filters, which had their pores saturated with their own peculiar substance, so that they admitted this substance alone to pass through them, and excluded all others,__ as paper, saturated with oil, will prevent the filtration of water, and vice versa. The mechanical doctrine of secretion was taught by Malpigiii and by Boerhaave and continued to prevail even till the time of Haller. All the secretions were conceived to be ready form- ed in the blood, and the glands were looked upon as sieves or strainers to convey off the appropriate fluids or humours. In this view of the subject, all secretion was a transudation through the coats of the vessels,—the blood globules of various sizes passing through pores adapted to them. The mechanical doctrine of transudation, in this shape, is founded upon supposititious data; and the whole facts and arguments are so manifestly defective, that no refutation is necessary. It is now, indeed, wholly abandoned. MM. Magendie and Fodera have, however, revived the mechanical doctrine of late years, but under an essentially different form; and one applicable especially to the exhalations. The former gentleman, believing that many of the exhalations exist ready formed in the blood, thinks that the character of the exhaled fluid is dependent upon the physical arrangement of the small vessels, and his views repose upon the following experi- ments. If, in the dead body, we inject warm water into an artery pass- ing to a serous membrane, as soon as the current is established from the artery to the vein, a multitude of minute drops are observed oozing through the membrane, which speedily evaporate. If, again, a solution of gelatine, coloured with vermilion, be in- j^ftted into all the vessels, it will often happen, that the gelatine is deposited around the cerebral convolutions, and in the anfractuosi- ties, without the colouring matter escaping from the vessels, whilst the latter is spread over the external and internal surface of the choroid. If again, linseed oil, also coloured with v^rwiilion, form the matter of the injection, the oil, devoid of colouring matter is deposited in the articulations furnished with large synovial cap- sules, whilst no transudation takes place at the surface of the brain, or in the interior of the eye. Magendie asks, if these are not instances of true secretion taking place post mortem, and evidently dependent upon the phy- sical arrangemenl of the small vewls; and whether it is not ex- 200 SECRETION. trem|0|probable, thatjifcsame arrangement must, in part at least, presuf^over exhalation^d&ring life? Fodera, to whosejjpKJments on the imbibition of tissues we had occasion to allude under the head of ^sorption, eni|^ thf views of Magendie. If the vessels of a dead body, he remarks, be injected, the substance of the injection is seen oozing through the vessels ;'anfi if an artery and a vein be ex^Pwjin a living ani- mal, a similar oozing through theJ^Se^Ris f$tfi|g|able. This is more manifest if the trunk, whencetl^^terv originates, be tied; the fluid being occasionally bloodg^Tf the iftail^j^eins be tied, not only cedema occurs in the SjP&^above the jigatures, but there is an increase of the sai&$r^secretion. It is not necessary to dppceJtfieJWous ex|as^j*n-ts of Fode- ra, relating to this topic, or those of LawrenCe, Coates and Harlan, or of Dutrochet, Togno, MitjO^ell and others. They are of pjiettisely the same character as those; tjrat we Aa$|ii pre- viously -described, regarding the imbibition of tissues ; and transu- dation is only imbibition or soaking from without to within; Ma- gendie and Fodera, indeed, conclude, that one ^pjijf^ "~ sical cause of exhalation is the same as thatof absorption,/* imbibition. 4fa »«*, - ._. ^ Another physical causeT^dduceWby Magendij;, experienced by the blood in thejpra ory syste conceives, ^bntributgs powerfully Toeausethe i_ to pass through the:«joats of the, vessels. If watei^f jected, by means of a syringe )£&»«. an artery, all tfye, surfaces, to which the ves^^jis £itribute^{as.well as the larger tranches and the trunk itself, exhibit the injected fluid oozing in greater abun- dance, according to thejfbrcg exertedvjji the injection. **, . <.- He farther remarks,l{pwa|er be injected into the veihj£bf..a$:ani- mal, in sufficiebtjfeMJBotii'Kio.double or treble the natural amount of blood, a consjd^fi^^^^^^on of the circulatory organs is pro- duced; and, consequently, the pressure, exj^lenced^ by the^circu- lating fluid, is largely augumented. If any serous membrane be now examined,—as the peritoneum,—a serous fluid is observed issuing.rapidly from its surface,»,t$»ich accumulates in the cavity, and pi$jj|jp<$©5 a true dropsy under the eyes of the experimenter, and, ocjeaaionally, the colouring part of the blood transudes at the surface of certain organs, as the liver, spleen, &c. Hamberger, again, br^jMjfjjed the untenable physical hypothesis, that each secreted humour is deposited in its proper secretory or- gan, by jgirtue of its specificjp;avity. It is obvious, lhakall ^^Lapeculations proceed upon the belief, that the exhalations existgfrqliij^formed in the blood; and that, consequently, the act of secretion, so far as concerns them, is one of sepaty$iftiji or of secerning,—not of fresh formation. That this is the case with the n^pre aqueous secretions is proba- ble, and not impossible with regard to the rest. Organic chymistry THEORIES OF SECRETION. 201 is, however, subject to more difficulties in the way of analysis than inorganic ; and it can be readily understood, that in a fluid so he- terogeneous as the blood, the discovery of any distinct humour may be impracticable. Of course, the elements of every fluid, as well as solid, must be contained in it; and we have already seen, that not merely^the inorganic elements, but the organic or compounds of organization, have been detected by the labours of Chevreul and others. There are, however, some singular facts connected with this sub- ject. MM. Prevost and Dumas having removed the kidneys in cats and dogs, and afterwards analyzed the blood, found urea in it— the characteristic element of urine. This principle was contained in greater quantity, the longer the period that had elapsed after the operation; whilst it cannot be detected in the blood, where the kidneys exist. The experiment was afterwards repeated by Segalas with the same results. He also introduced urea into the veins of an animal, whose kidneys were left untouched, and was unable to detect the principle in the blood; but the urinary secretion was largely aug- mented after the injection. Whence he concludes that urea is an excellent diuretic. Adelon, too, asserts, that since their experiments on urea, MM. Prevost and Dumas are said to have found the principles of other secreted humours in the blood, after the secretory organs of the re- spective humours had been removed in the living animal; and it has been asserted, that after having extirpated the testicles of a frog, artificial fecundation has been effected with the blood of the animal; and that after the removal of the mammae in animals, sugar of milk has been detected in the blood. These are singular facts, entirely inexplicable in the existing state of our knowledge, under the doctrines of simple mechanical filtration or transudation, and unlike any physical process, which can be imagined. The doctrines of filtration and transudation can apply only to those exhalations, in which the humour has undergone no apparent change; and it is obviously impossible to specify these, in the im- perfect state of our means of analysis. In the ordinary aqueous se- cretions, simple transudation may embrace the whole process; and, therefore, it is unnecessary to have recourse to any other explana- tion; especially after the experiments instituted by Magendie, supported by the pathological observations of Bouillaud of Pa- ris, Dr. D. Davis of the London University, Ribes, Velpeau, and others. Bouillaud found, that partial oedema of the legs was con- stantly accompanied by more or less complete obliteration of the veins of the infiltrated part,—the vessels being obstructed by fibrin- ous coagula, or compressed by circumjacent tumours; and he sug- gests, that ascites or dropsy of the lower belly is frequently occa- Vol. II. 26 202 SECRETION. sioned by obstruction of the portal circulation in the liver. In this way, we can account for the numerous cases in which we find a union of hydropic and hepatic affections in the same individual. The same pathological doctrine, founded on direct observation, has been extended to phlegmatia dolens, or swelled leg; an affec- tion occurring in the puerperal state, and which has jpeen found connected with obstruction in the great veins that convey the blood back from the lower extremity. The generality of physiologists have regarded the more complex secretions—the follicular and the glandular—as the results of chy- mical operations; and under the view, that they do not exist ready formed in the blood, and that the elements alone are contained in that fluid, it is impossible not to admit that chymical agency must be exerted. In support of the chymical hypothesis, which has appeared un- der various forms,—some, as Keill, presuming that the secretions are formed in the blood, before they arrive at the place appointed for secretion, others, that the change is effected in the glands them- selves,—the fact of the formation of a number of substances from a very few elements, provided these are united in different propor- tions, has been invoked. For example, take the elementary bodies, oxygen and azote. These, in one proportion, compose atmos- pheric air; in another, nitrous oxide; in another, nitric oxide; in a fourth, hyponitrous acid; in a fifth, nitrous acid, and in a sixth, ni- tric acid; substances which differ as much as the various secretions differ from each other and from the blood. Many of the compounds of organization likewise exhibit by their elementary composition, that but a slight change is necessary,in order that they shall be converted into each other. Dr. Prout has exhi- bited this close alliance between three substances—urea, lithic acid and sugar—and has shown how they may be converted into each other, by the addition or subtraction of single elements of their constituents. Urea is composed of two atoms of hydrogen, and one of carbon, oxygen and azote respectively: by removing one of the atoms of hydrogen and the atom of nitrogen, it is converted into sugar; or, by adding to it an additional atom of carbon, into lithic acid. Bostock,—who is disposed to push the application of chymistry to the explanation of the functions as far as possible,—to aid us in con- ceiving how a variety of substances may be produced from a single compound, by the intervention of physical causes alone, supposes the case of a quantity of the materials adapted for the vinous fer- mentation, being allowed to flow from a reservoir, through tubes of various diameters, and with various degrees of velocity. " If we were to draw off portions of this fluid in different parts of its course or from tubes, which differed in their capacity, we should, in the first instance, obtain a portion of unfermented syrup; in the next, we should have a fluid in a state of incipient fermentation; in a theories of secretion. J03 third, the complete vinous liquor; while, in a fourth, we might have acetous acid." Any explanation, however, founded upon this loose analogy, is manifestly too physical: this Bostock admits, for he subsequently remarks, that " if we adopt the chymical theory of secretion, we must conceive of it as originating in the vital action of the vessels, which enables them to transmit the blood, or certain parts of it, to the various organs or structures of the body, where it is subjected to the action of those reagents, which are necessary to the production of these changes." The admission of such vital agency, in some shape, seems to be indispensable. Attempts have, indeed, been made to establish it as a nervous action; and numerous arguments and experiments have been brought forward in support of the position. That many of the secretions are affected by the condition of the mind is known to all. The act of crying, in evidence of joy or sor- row; the augmented action of the salivary glands at the sight of pleasant food; the increased secretion of the kidneys during fear or anxiety, sufficiently indicate, that the organs of secretion can be in- fluenced through the nervous system in the same manner as the functions of nutrition and calorification. The discovery of galvanism naturally suggested it as an im- portant agent in the process,—or rather, that the nervous fluid strongly resembled it. This conjecture seems to have been first ha- zarded by Berzelius, and by Sir Everard Home; and, about the same time, an experiment was made by Dr. Wollaston, which he conceived to throw light upon the process. He took a glass tube, two inches high and three-quarters of an inch in diameter; and closed it at one extremity with a piece of bladder. He then poured into the tube, a little water, containing 5|7th of its weight of muriate of soda, moistened the bladder on the outside, and placed it upon a piece of silver. On curving a zinc wire so that one of its extremi- ties touched the piece of metal, and the other dipped into the liquid to the depth of an inch, the outer surface of the bladder immediate- ly indicated the presence of pure soda; so that, under this feeble electric influence, the muriate of soda was decomposed, and the soda, separated from the acid, passed through the bladder. M. Fodera performed a similar experiment, and found, that whilst ordinary transudation frequently required an hour before it was evidenced, it was instantaneously exhibited under the galvanic influence. On putting a solution of prussiate of potassa into the bladder of a rabbit; forming a communication with the solution by means of a copper wire; and placing on the outside a cloth, soaked in a solution of sulphate of iron, to which an iron wire was attach- ed; he found, by bringing these wires into communication with the galvanic pile, that the bladder or the cloth was suddenly coloured blue, according as the galvanic current, set from without to within, or from within to without; that is, according as the iron wire was 204 secretion. made to communicate with the positive pole, and the copper wire with the negative, or vice versa. The effects of the section of the pneumogastric nerves on the func- tions of digestion and respiration have been given elsewhere at some length. It was there stated, that when digestion was suspended by their division, Dr. Wilson Philip was led to ascribe it to the se- cretion of the gastric juice having been arrested; an opinion, which Mr. Brodie had been induced to form previously, from the results of experiments, which showed that the secretion of urine is suspend- v ed by the removal or destruction of the brain; and that when an animal is destroyed by arsenic, after the division of the pneumogas- tric nerves, all the usual symptoms are produced, except the pecu- liar secretion from the stomach. Mr. Brodie did not draw the conclusion, that the nervous influence is absolutely necessary to secretion, but that it is a step in the process. We have, indeed, numerous evidences, that the nervous system cannot be indispen- sably necessary to this function. In all animals, this power must exist, yet there are many animals in which no nervous system is apparent. Bostock has given references, in a note, to many cases of monstrous or deformed foetuses, born with many of their organs fully developed, yet where there was no nervous system. Setting aside, however, the cases of animals, we have the most indisputable testimony of the existence of secretion in the vegetable, in which there is no nervous system, or, at the most, a rudimental one only; yet the function is accomplished as perfectly, although not in as multiple a manner, as in man. It is manifest, therefore, that this is one of the vital actions oc- curring in the very tissue of organs, of which we have no more knowledge than we have of the capillary actions in general. All that we know is, that in particular organs various humours are se- creted from the blood, some of which can be detected in that fluid, others not, but that we are ignorant of the precise agency, by which this mysterious process is effected. In describing the physiology of the different secretions, one of three arrangements has usually been adopted; either according to the nature of the secreting organ, the functions of the secreted fluid, or its chymical character. " The first of these has been followed by Bichat and by Magen- die, who have adopted the division into exhaled, follicular and glandular secretions. According to the second, embraced by Boyer, Sabatier, and Adelon, they are divided into recrementi- tial secretions or such as are taken up by internal absorption and reenter the circulation, and into excrementitial, or such as are eva- cuated from the body and constitute the excretions. Some physi- ologists add a third division—the recremento-excrementitial,—in which a part of the humour is absorbed and the remainder is ejected. Lastly, the division, according to chymical character has been fol- SEROUS EXHALATION. 205 ** lowed with more or less modification, by Plenck, Richerand, Blumenbach, Young, and Bostock: the last of whom, the most re- cent writer, has eight classes:—the aqueous, albuminous, mucous, gelatinous, fibrinous, oleaginous, resinous, and saline. To all of these classifications, cogent objections may be made. The one we shall follow is the anatomical, not because it is the most perfect, but because it is the course, that has been usually adopted through- out this work.* Sect. I.—Of the Exhalations. All the exhalations occur in the areolae or internal cavities of the body, or from the skin and mucous membranes:—hence their di- vision into internal and external. The former are all recremen- titial; the latter recremento-excrementitial. To the class of in- ternal exhalations belong; 1. The serous exhalation. 2. The serous exhalation of the cellular membrane. 3. The adipous exhalation of the cellular membrane. 4. The exhalation of the marrow. 5. The synovial exhalation. 6. The exhalation of the colouring matter of the skin, and of other parts; and 7. The areolar exhalation. To the class of external exhalations belong; 1, that of the skin, or cuta- neous transpiration. 2. The exhalation of the mucous membranes. 1. The Serous Exhalation. This is the fluid secreted by the serous membranes that line the various cavities of the body; as the pleura, pericardium, peritoneum, arachnoid coat of the brain, and tunica vaginalis testis. From these membranes a fluid is exhaled, which is of an albumi- nous character, considerably resembling the serum of the blood ex- cept in containing less albumen. In the healthy condition, this fluid never accumulates in the ca- vities; the absorbents taking it up in proportion as it is deposited; but if, from any cause, the exhalants should pour out a larger quan- tity than usual, whilst the absorbents are not proportionably ex- cited, accumulation takes place; or the same effect ensues if the ex- halants pour out no more than their usual quantity, whilst the ab- sorbents do not possess their due activity. Under either circum- stance, we have accumulation or dropsy; and, accordingly, dropsy may be either active or passive. The exhaled fluid probably transudes through the parietes of the ar- teries, and reenters the circulation by imbibition through the coats of the veins. If we kill an animal and open it immediately afterwards, this exhalation appears in the form of a halitus or vapour, and the fluid is seen lubricating the free surface of the membrane. • For an enumeration of the different fluids or humours of the body, see Vol. I. 20G slXKETlOX This, indeed, appears lobe its principal office; by which it favour the motion of the organs upon each other. The serous exhalations probably differ somewhat in each cavity, or according to the precise structure of the membrane. The differ- ence betv/een the chymical character of the fluid of the dropsy of different-cavities would lead to this belief. As a general rule, ac- cording to Dr. Bostock, the fluid from the cavity of the abdomen contains the greatest proportion of albumen, and that from the brain the least; but many exceptions occur to this. 2. Serous Exhalation of the Cellular Membrane. The cellular membrane, wherever existing, is kept moist by a serous fluid, analogous to that exhaled from serous membranes, and which appears to have the same uses,—that of facilitating the motion of the lamellae or plates on each other, and consequently of the or- gans, between which the cellular tissue is placed. When this secretion collects, from the causes mentioned in the last section, the disease, called oedema or anasarca, is induced. 3. Adipous Exhalation of the Cellular Membrane. Considerable diversity of opinion has prevailed regarding the pre- cise organ of the secretion oifat. Haller supposed that the sub- stance exists ready formed in the blood, and that it simply transudes through the pores of the arteries; and Chevreul has given some countenance to this opinion, by the circumstance of his having met with a fatty matter in that fluid. Anatomists have, likewise, been divided upon the subject of the precise tissue into which the fat is deposited; some believing it to be the ordinary cellular tissue, into which it is dropt by the agency of appropriate vessels; others, as Malpighi and William Hunter, believing in the existence of a peculiar adipous tissue, consisting, ac- cording to Beclard, of small bursae or membranous vesicles, which inclose the fat, and are found situated in the areolae of the cellular tissue. These vesicles are said to vary greatly in size: generally, they are round and globular; and, in certain subjects, receive ves- sels, that are very apparent. These vesicles form so many small sacs without apertures, in the interior of which are filaments ar- ranged like septa. In fatty subjects, these adipous vesicles are very perceptible, being attached to the cellular tissue and neighbouring parts by a vascular pedicle. The arrangement of this tissue, as well as the quantity of fat, varies in different parts of the body. It is always found in the or- bit, on the sole of the foot, and at the pulps of the fingers and toes. The subcutaneous cellular tissue, and that covering the heart, kid- neys, &c. also generally contain it; but it is never met with in the eyelids, scrotum, or within the cranium. adipous exhalation. 207 Fat is exhaled by the secretory vessels, in a fluid state; but, after it is deposited, it becomes more or less solid. According to the researches of Chevreul, human fat is almost always of a yellow colour; inodorous, and composed of two portions;—the one fluid, and the other concrete, which are themselves composed, but in dif- ferent proportions, of two new immediate principles, to which that chymist gave the names elaine and stearine respectively. It is probable, that chymical analysis would exhibit the fat to vary in different parts of the body, as its sensible properties are manifestly different. Sir Everard Home, on loose analogies and inconclusive arguments, has advanced the opinion, that it is more than probable, that fat is formed in the lower portion of the intes- tines, and from thence is carried, through the medium of the cir- culating blood, to be deposited in almost every part of the body. " When there is a great demand for it, as in youth, for carrying on growth, it is laid immediately under the skin, or in the neighbour- hood of the abdomen. When not likely to be wanted, as in old age, it is deposited in the interstices of muscular fibres, to make up in bulk for the wasting of these organs." The uses of the fat are both general and local. The great gene- ral use is, by some physiologists, conceived to be,—to serve as a provision in cases of wasting indisposition; when the digestive func- tion is incapacitated for performing its due office, and emaciation is the consequence. In favour of this view, the rapidity with which fat disappears after slight abstinence has been urged, as well as the facts, connected with the torpidity of animals, which are always found to diminish in weight during this state. Professor Mangili of Pavia, procured two marmots from the Alps, on the first of December. The larger weighed 25 Milanese ounces; the smaller only 22-|th; on the third of January, the larger had lost iths of an ounce, and the smaller i|ths. On the fifth of Febru- ary, the larger weighed only 22|ths; the smaller 21. Dr. Monro kept a hedge-hog from the month of November to the month of the March following, which lost, in the meanwhile, a considerable portion of its weight. On the 25th of December, it weighed 13 ounces and 3 drachms; on the 6th of February, 11 ounces and 7 drachms; and on the eighth of March, 11 ounces and 3 drachms. The loss was 13 grains daily. The local uses of the fat are chiefly of a physical character. On the sole of the foot it diminishes the effects of pressure, and its use is the same on the nates: in the orbit, it forms a kind of cushion,on which the eyeball moves with facility; and when in certain limits, it gives that rotundity to the frame, which we are accustomed to regard as symmetry. In another place, it was observed, that fatty substances are bad conductors of caloric; and hence that it may tend to preserve the temperature of the body in cold seasons;—a view, which is favoured by the fact, that many of the arctic animals are largely supplied with fat beneath the common integuments; and it 208 SECRETION. has been affirmed, that fat people generally suffer less than lean from the cold of winter. It is obviously impracticable to estimate, accurately, the total quantity of fat in the body. It has been supposed, that, in an adult male of moderate size, it fjrms ^th of the whole weight; but it is doubtful whether we ought to regard this as even an approximation; the data being so inadequate. In some cases of polysarcia or obesity, the bulk of the body has been enormous. In the Philosophical Transactions, No. 185, the case of a girl is detailed, who weighed 256 pounds, when only four years old. A man of the name of BRiGHT,atMaldon, England, weigh- ed 728 pounds; and the celebrated Daniel Lambert, of Leicester, England, weighed 739 pounds a little before his death, which occur- red in the fortieth year of his age. The circumference of his body was three yards and four inches; of his leg one yard and one inch. His coffin was six feet four inches long; four feet four inches wide; and two feet four inches deep. In some of the varieties of the human family we meet with sin- gular adipous deposits. In the Bosjesman female vast masses of fat accumulate on the buttocks, which give them the most extrava- gant appearance. The projection of the posterior part of the body, in one subject, according to Barrow, measured five inches and a half from a line touching the spine. " This protuberance," he re- marks, " consisted of fat, and when the woman walked, had the most ridiculous appearance imaginable, every step being accom- panied with a quivering and tremulous motion, as if two masses of jelly were attached behind." The " Hottentot Venus," who had several projections, measured more than nineteen inches across the haunches; and the projection of the hips exceeded 6§ inches. Dr. Somerville found, on dissec- tion, that the size of the buttocks arose from a vast mass of fat, in- terposed between the integuments and muscles, which equalled four fingers breadth in thickness. It is singular, that, according to the statement of this female, which is corroborated by the testimony of Mr. Barrow, this deposition does not take place till the first pregnancy. Pallas has described a variety of sheep—the ovis steatopyga or" fat-buttocked,"—which is reared in immense flocks by the pas- toral tribes of Asia. In it, a large mass of fat covers the nates and occupies the place of the tail. The protuberance is smooth beneath, and resembles a double hemisphere, when viewed behind; the os coc- cygis or rump-bone being perceptible to the touch in the notch be- tween the two. They consist merely of fat; and when very large, shake in walking like the buttocks of the female Bosjesman. Mr. Lawrence remarks, that there are herds of sheep in Persia, Syria, Palestine and some parts of Africa, in which the tail is not want- ing as in the ovis steatopyga, but retains its usual length and be- comes loaded with fat. EXHALATION OF THE MARROW. 209 The circumstances, which favour obesity, are absence of activity and of excitement of all kinds; hence, for the purpose of fattening ani- mals in rural economy, they are kept in entire darkness,—to deprive them of the stimulus of light, and to favour sleep and muscular inacti- vity. Castration—by abolishing one kind of excitability—and the time of life at which the generative functions cease to be exerted, especially in the female, are favourable to the same result. 4. Exhalation of the Marrow. A fluid, essentially resembling fat, is found in the cavity of long bones, in the spongy tissue of short bones, and in the areolae of bones of every kind. This is the marrow. The secretory organ is the very delicate membrane, which is perceptible in the interior of the long bones, lining the medullary cavity, and sending prolonga- tions into the compact substance, and others internally, which form septa and spaces for the reception of the marrow. The cells, thus formed, are distinct from each other; and, from the observations of Howship, it would seem probable, that the oil of bones is deposited in longitudinal canals, that pass through the solid substance of the bone, and through which its vessels are transmitted. This oil of bones is the marrow of the compact structure, the latter term being generally restricted to this secretion, when contained in the cavities of long bones; that which exists in the spongy substance being term- ed by some writers, the medullary juice. The medullary membrane, called also the internal periosteum, consists chiefly of blood-vessels ramifying on an extremely delicate cellular tissue, in which nerves may likewise be traced. Berzelius examined marrow obtained from the thigh-bone of an ox, and found it to consist of the following constituents:—pure adipous matter, 96; skins and blood-vessels, 1; albumen, gelatine, extractive, peculiar matter and water, 3. The marrow is one of the corporeal components, of whose use we can scarcely offer a plausible conjecture. It has been supposed to render the bones less brittle; but this is not correct, as those of the foetus, which contain little or no marrow, are less brittle than those of the adult; and the bones of old persons, in which the me- dullary cavity is extremely large, are more hrittle than those of the adult. It is possible that it may be placed in the cavities of the bones,—which would otherwise be so many vacant spaces,—to serve the general purposes of the fat, when it is required by the system. The other hypotheses, that have been entertained on the subject, are not deserving of notice. 5. Synovial Exhalation. Within the articular capsules, and the bursae mucosae,—which have been described under the head of muscular motion,—a fluid is Vol. II. 27 210 secretion. secreted, which is spread over the articular surfaces of the bones, and facilitates their movements. Havers considered this fluid to be secreted by synovial glands, for such he conceived the reddish cellular masses to be, that are found in certain articulations. Haller, again, strangely regarded the syno- via as the marrow, that had transuded through the spongy extremi- ties of the bones; but, since the time of Bichat, every anatomist and physiologist has ascribed it to the exhalant action of the syno- vial membrane, which strongly resembles the serous membranes in form, structure and functions, and whose folds constitute the pro- jections, which Havers mistook for glands. This membrane exists in all the movable articulations, and in the channels and sheaths in which the tendons play. The gene- rality of anatomists regard the articular capsules as shut sacs; the membrane being reflected over the incrusting cartilages. Magen- die, however, affirms, that he has several times satisfied himself, that the membranes do not pass beyond the circumference of the cartilages. From the inner surface of these membranes, the synovia is ex- haled, precisely in the same manner as in other serous cavities. Margueron analyzed the synovia, obtained from the lower ex- tremity of the ox, and found it to consist of fibrous matter, 11.86; albumen, 4.52; muriate of soda, 1.75; soda, 0.71; phosphate of lime, 0.70; and water, 80.46. 6. Exhalation of the Colouring Matter of the Skin and of other parts. The nature of the exhalation, which constitutes the colouring matter of the rete mucosum, has already engaged our attention, when treating of the skin under the sense of touch. It is presumed to be exhaled by the vessels of the skin, and to be deposited beneath the cuticle, so as to communicate the colours that characterize the different races. Such are regarded as the secretory organs by most anatomists and physiologists; but Gautier, whose researches into the intimate constitution of the skin have gained him much cele- brity, is of opinion, that it is furnished by the bulbs of the hair; and he assigns, as reasons for this belief, that the negro, in whom it is abundant, has short hair; that the female, whose hair is more beau- tiful and abundant than that of the male, has the fairest skin; and that when he applied blisters to the skin of the negro, he saw the colouring matter oozing from the bulbs of the hair, and deposited at the surface of the rete mucosum. The composition of this pigment cannot be determined with pre- cision, owing to its quantity being too small to admit of examina- tion. Chlorine deprives it of its black hue, and renders it yellow. A negro, by keeping his foot for some time in water, impregnated with this gas, deprived it of its colour, and rendered it nearly white; AREOLAR EXHALATION. 211 but, in a few days, the black colour returned with its former inten- sity. This experiment was made with similar results on the fingers of a negro. Blumenbach, as is noticed elsewhere, thought, that the mucous pigment was formed chiefly of carbon ; and his notion has received favour with many. The uses of this pigment, as well as of that which lines the cho- roid coat of the eye, the posterior surfaces of the iris, and of the ciliary processes, are detailed in another place. 7. Areolar Exhalation. Under this term, Adelon has included different recrementitial secretions effected within the organs of sense, or in parenchymatous structures,—as the aqueous, crystalline, and vitreous humours of the eye, and the liquor of Cotugno, all of which have already engaged attention, the exhalation of a kind of albuminous, reddish, or whitish lymph into the interior of the lymphatic ganglions, and into the or- gans, called, by Chaussier, glandiform ganglions, and by Be- clard, sanguineous ganglions;—viz: the thymus, thyroid, supra- renal capsules, and spleen. We know but little, however, of the fluids, formed in these various parts. They have never been ana- lyzed, and their uses are inappreciable. By some physiologists, a fluid is supposed to be exhaled from the inner coat of the arterial, venous, and lymphatic vessels. Not only, however, are we unaware of the nature of this fluid, but its very existence is doubted. Its use is presumed to be, to lubricate the in- terior of the vessel, and to prevent adhesion between it and the fluid circulating within it. The following belong to the external exhalations. 8. Cutaneous Exhalation or Transpiration. A transparent fluid is constantly exhaled from the skin, which is generally invisible, in consequence of its being converted into vapour as soon as it reaches the surface; but, at other times, owing to augmen- tation of the secretion, or to the air being loaded with humidity, it is apparent on the surface of the body. When invisible, it is called the insensible transpiration or per- spiration; when perceptible, sweat. In the state of health, according to Thenard, this fluid reddens litmus paper; yet the taste is rather saline,—resembling that of com- mon salt,—than acid. Its smell is peculiar, and becomes almost insupportable when concentrated, and especially when subjected to distillation. It is composed, according to Thenard, of much water, a small quantity oi acetic acid, muriate of soda, and perhaps of potassa, a very little 212 SECRETION. earthy phosphate, a trace of oxide of iron, and an inappreciable quantity of animal matter. Berzelius regards it as water, holding in solution the muriates of potassa and soda, lactic acid, lactate of soda, and a little animal matter. Numerous experiments have been instituted for the purpose of discovering the quantity of transpiration that takes place in a given time. Of these, the earliest were by Sanctorius, for which he is more celebrated than for any other of his labours. For thirty years, this indefatigable experimentalist weighed daily, with the greatest care, his solid and liquid ingesta and egesta, and his own body, with the view of deducing the loss sustained by the cutaneous and pulmonary exhalations. He found, that every twenty-four hours, his body returned sensibly to the same weight, and that he lost the whole of the ingesta;—five-eighths by transpiration, and three-eighths by the ordinary excretions. For eight pounds of ingesta, there were only three pounds of sensible egesta, which con- sisted of forty-four ounces of urine, and four of faeces. It is lamentable to reflect, that so much time was occupied in the attainment of such insignificant results. The self-devotion of Sanc- torius, gave occasion, however, to the institution of numerous ex- periments of the same kind; as well as to discover the variations in the exhalation, according to age, climate, &c. The results of these have been collected by Haller, but they afford little instruction; especially as they were directed to the transpiration in general, without affording us any data to calculate the proportion exhaled from the lungs to that constantly taking place by the cutaneous surface. Rye, who dwelt in Cork, lat. 51° 54', found, in the three winter months,—December, January, and February—that the quantity of urine was 3937 ounces; of the perspiration, 4797: in the spring months—March, April, and May—the urine amounted to 3558; the perspiration to 5405: in the summer months of June, July, and August, the urine amounted to 3352; the perspiration to 5719: and in the three autumnal months—September, October, and November —the quantity of urine was 3369: that of the perspiration 4471. The daily average estimate in ounces was as follows:— Urine. Perspiration. Winter,.....42T7T - - 53 Spring,.....40 -, - - 60 Summer,.....37 ---63 Autumn,.....37--- 50 thus, making the average daily excretion of urine, throughout the year, to be a little more than 39 ounces; and of the transpiration, 56 ounces. Keill, on the other hand, makes the average daily perspiration, 31 ounces; and that of the urine 38; the weight of the faeces being CUTANEOUS EXHALATION. 213 5 ounces, and that of the solid and liquid ingesta, 75 ounces. His experiments were made at Northampton, England, lat. 52° 11'. Bryan Robinson found, as the result of his observations in Ire- land, that the ratio of the perspiration to the urine was, in summer, as 5 to 3; in the winter as 2 to 3; whilst in April, May, October, November, and December, they were nearly equal. In youth, the ratio of the perspiration to the urine, was as 1340 to 1000; in the aged, as 967 to 1000. Hartmann, when the solid and liquid ingesta amounted to 80 ounces, found the urine discharged 28 ounces; the faeces 6 or 7 ounces; and the perspirable matter, 45 or 46 ounces. Von Gorter, in Holland, when the ingesta were 91 ounces, found the perspiration to amount to 49 ounces; the urine to 36; and the faeces to S. Dodart asserts, that in France, the ratio of the perspiration to the faeces, is as 7 to 1; and to the whole egesta as 15 to 12 or 10. The average perspiration, in the twenty-four hours, he estimates at 33 ounces and 2 drachms; and Sauvages, in the south of France, found, that when the ingesta were 60 ounces in the day, the trans- piration amounted to 33 ounces; the urine to 22; and the faeces to 5. Most of these estimates were made in the cooler climates,—the " regiones boreales,"—as Haller has, not very happily, termed them. According to Lining, whose experiments were made in South Carolina, lat. 32° 47', the perspiration exceeded the urine in the warm months; but in the cold, the latter had the preponderance. The following table gives the average daily proportion of the urine and perspiration, for each month of the year, in ounces,—as quoted by Haller. December, Urine. 70.81 - Perspiration. - 42.55 January, February, March, - 72.43 -77.86 -70.59 - - 39.97 - 37.45 - 43.23 April, ... May, June, - 59.17 -56.15 -52.90 - - 47.72 - 5S.11 - 71.39 July, August, September, October, 43.77 -55.41 -40.60 -47.67 - - 86.41 - 70.91 - 77.09 - 40.78 November, 63.16 - - 40.97 After the period at which Haller wrote, no experiments of any moment were adopted for appreciating the transpiration. When- ever trials were instituted, the exhalation from both the skin and the lungs was included in the result, and no satisfactory means were adopted for separating them, until Lavoisier and Seguin made their celebrated experiments. 214 SECRETION. Seguin inclosed himself in a bag of gummed taffeta, which was tied above the head, and had an aperture, the edges of which were fixed around the mouth by a mixture of turpentine and pitch. By means of this arrangement, the pulmonary transpiration alone es- caped into the air. To estimate its quantity, it was merely ne- cessary for M. Seguin to weigh himself in the sack, in a very delicate balance, at the commencement and termination of the experiment. By repeating the experiment out of the sack, he de- termined the total quantity of the transpired fluid; so that, by de- ducting from this the quantity of fluid exhaled from the lungs, he obtained the amount of the cutaneous transpiration. He, moreover, kept an account of the food, which he took; of the solid and liquid egesta; and, as far as he was able, of every circumstance that could influence the transpiration. The results, at which Lavoisier and Seguin arrived by a series of well-devised and well-conducted experiments were the following:— First. Whatever may be the quantity of food taken, or the variations in the state of the atmosphere, the same individual, after having increased in weight by the whole quantity of nourishment taken, returns daily, after the lapse of twenty-four hours, to nearly the same weight as the day before; provided he be in good health; his digestion perfect; that he is not fattening, or growing; and that he avoids all kinds of excess. Secondly. If, when all other circumstances are identical, the quantity of food varies; or if—the quantity of food being the same —the effects of transpiration differ; the quantity of the excrements augments or diminishes, so that every day, at the same hour, we return nearly to the same weight;—proving that when digestion goes on well, the causes, that concur in the loss or excretion of the food taken in, afford each other mutual assistance;—in the state of health one charging itself with what the other is unable to accom- plish. Thirdly. Defective digestion is one of the most direct causes of the diminution of transpiration. Fourthly. When digestion goes on well, and the other causes are alike, the quantity of food has but little effect on the transpiration. Seguin affirms, that he has very frequently taken, at dinner, two pounds and a half of solid and liquid food; and, at other times, four pounds, yet the results, in the two cases, differed but little from each other; provided only, that the quantity of fluid did not vary materi- ally in the two cases. Fifthly. Immediately after dinner, the transpiration is at its mi- nimum. Sixthly. When all other circumstances are equal, the loss of weight, induced by insensible transpiration, is at its maximum dur- ing digestion. The increase of transpiration, during digestion, com- pared with the loss sustained when fasting is, at an average, 2 ,\ grains per minute. CUTANEOUS EXHALATION. 215 Seventhly. When circumstances are most favourable, the greatest loss of weight, caused by insensible transpiration, was, according to their observations, 32 grains per minute; consequently 3 ounces, 2 drachms and 4S grains, poids de marc, per hour; and 5 pounds in twenty-four hours; under the calculation that the loss is alike at all hours of the day, which is not the fact. Eighthly. When all the accessory circumstances are least favour- able, provided only that digestion is properly accomplished, the smallest loss of weight is 11 grains per minute; consequently, 1 ounce, 1 drachm and 12 grains per hour; and 1 pound, 11 ounces and 4 drachms in the twenty-four hours. Ninthly. Immediately after eating, the loss of weight, caused by the insensible perspiration, is 10£ grains per minute, during the time at which all the extraneous causes are most unfavourable to transpiration; and 19T^ grains per minute, when these causes are most favourable and the internal causes are alike. " These differ- ences," says M. Seguin, " in the transpiration after a meal, accord- ing as the causes, influencing it, are more or less favourable, are not in the same ratio with the differences, observed at any other time, when the other circumstances are equal; but we know not how to account for the phenomenon." Tenthly. The cutaneous transpiration is immediately dependent both on the solvent virtue of the circumambient air, and on the power possessed by the exhalants of conveying the perspirable fluid as far as the surface of the skin. Eleventhly. From the average of all the experiments it seems, that the loss of weight caused by the insensible transpiration is IS grains per minute; and that of these 18 grains, 11, on the average, belong to the cutaneous transpiration, and 7 to the pulmonary. Twelfthly. The pulmonary transpiration, compared with the volume of the lungs, is much more considerable than the cutaneous, compared with the surface of the skin. Thirteenthly. When every other circumstance is equal, the pul- monary transpiration is nearly the same before and immediately after a meal; and if, as an average, the pulmonary transpiration be 17-j grains per minute before dinner, it is 17T7ff grains after dinner. Lastly. Every other intrinsic circumstance being equal, the weight of the solid excrements is least during winter. Although these results are probably fairly deduced from the ex- periments; and the experiments themselves were as well conceived as the subject admits of, we cannot regard the estimates as more than approximations. Independently of the fact, that the envelope of taffeta must necessarily have retarded the exhalation, and caused more to pass off by pulmonary transpiration; the perspiration must incessantly vary according to circumstances within and without the system; some individuals, too, perspire more readily than others; and its extent is dependent, as we have seen, upon climate and sea- son,—and likewise upon the quantity of fluid received into the 216 SECRETION. digestive organs. From all these and other causes, Bichat is led to observe, that the attempt to determine the quantity of the cuta- neous transpiration is as vain as to endeavour to specify what quan- tity of water is evaporated every hour, by a fire, the intensity of which is varying every instant. Since the time of Lavoisier and Seguin, Dr. Edwards has made some experiments, for the purpose of illustrating the effect produced upon cutaneous transpiration by various circumstances, to which the body is subjected. His first trials were made on cold- blooded animals, in which the cutaneous transpiration can be rea- dily separated from the pulmonary, owing to the length of time, that they are capable of living without respiring. All that is neces- sary is to weigh the animal before and after the experiment, and to make allowance for the ingesta and egesta. In this way he discovered, that the body loses successively less and less in equal portions of time; that the transpiration proceeds more rapidly in dry than in moist air; in the extreme states nearly in the proportion of 10 to 1; that temperature has, also, considera- ble influence,—the transpiration, at 68° of Fahrenheit, being twice as much; and, at 104°, seven times as much as at 32°. He likewise found, that frogs transpire, whilst they are in water, as is shown by the diminution, which they experience while immersed in that fluid, and by the appearance of the water itself, which becomes perceptibly impregnated by the matter excreted by the skin. In warm-blooded animals, he found, as in the cold-blooded, the transpiration become less and less in proportion to the quantity of fluid evaporated from the body; and he observed the same difference between the effects of moist and dry air, and between a high and a low temperature. The effects of these agents were essentially the same on man as on other animals. He found, that the transpiration was more copious during the early than the latter part of the day; that it is greater after taking food; and, on the whole, appeared to be increased during sleep. Whenever the fluid, which constitutes the insensible transpira- tion, does not evaporate, owing to the causes referred to at the com- mencement of this article, it appears on the surface in the form of insensible perspiration or sweat. It has been supposed by some physiologists, that the insensible and sensible perspiration are two distinct functions. Such appears to be the opinion of Haller and of Edwards, but no sufficient reason seems to exist why we should not regard them as different degrees of the same function. It is, in- deed, affirmed, that the sweat is generally less charged with carbonic acid than the vapour of transpiration, but that it is richer in salts, which are deposited on the skin, and are sometimes seen in the form of white flocculi; but our knowledge on this matter is extremely vague. Particular parts of the body perspire more freely, and sweat more CUTANEOUS EXHALATION. 217 readily, than others. The forehead, armpits, groins, hands, feet, &c. exhibit the evidences most frequently; some of these, perhaps, ow- ing to the fluid, when exhaled, not evaporating readily,—the con- tact of air being impeded. It is presumed, likewise, that the sweat has not every where the same composition. Its odour certainly varies in different parts of the body. In the armpits and feet it is more acid; in the violent sweats, accompanying acute rheumatism, this acidity always attracts attention; in the groins, its odour is strong and rank. It differs too greatly in individuals, and especially in the races. In the red-haired, it is said to be unusually strong; and in the negro, during the heat of summer, it is alliaceous and overwhelming. By cleanliness, the red-haired can obviate the unpleasant effects, in a great measure, by preventing undue accumulation in the axillae, groins, &c; but no ablution can remove the odour of the negro, al- though cleanliness can detract from its intensity. Each race appears to have its characteristic scent; and, according to Humboldt, the Peruvian Indian, whose smell is highly developed by education, can distinguish the European, the American Indian, and the negro, in the middle of the night, by the sole evidence of this sense. Some physiologists have doubted whether the odorous matter of the skin belongs properly to the perspiration, and have presumed it to be the product of specific organs. This is, however, conjec- tural; and the experiments of Thenard, as well as the facts we have just mentioned, would rather seem to show, that the matter of sweat itself has, within it, the peculiar odour. The fact of the dog tracing its master to an immense distance, and discovering him, perhaps, in a crowd, has induced a belief, that the scent may be distinct from the matter of sweat; but the supposition is not neces- sary, if we admit the matter of perspiration to be itself odorous. Besides the causes before referred to, the quantity of perspiration is greatly augmented by running or by violent exertion of any kind; especially if the temperature of the air be elevated. Warm fluids favour it greatly, and hence their use, alone or combined with sudo- rifics, where this class of medicines is indicated. Magendie con- ceives, that being readily absorbed, they are also readily exhaled. This is true; but, in hot climates, ice-cold drinks are as rapidly fol- lowed by sensible perspiration, owing, probably, to the copious ex- halation which is constantly going on diminishing the quantity of fluid circulating in the vessels; and, we know that, under such cir- cumstances, the activity of absorption is largely augmented. With regard to the uses of the insensible transpiration, it has been supposed to preserve the surface supple, and thus to favour the ex- ercise of touch; and, also, by undergoing evaporation, to aid in the refrigeration of the body. It is probable, however, that these are quite secondary uses, under ordinary circumstances and that the great office, performed by it, is to remove a certain quantity of fluid from the blood: hence it has been termed by Broussais the cutaneous depuration. In this respect, consequently, it bears a Vol. II. 28 218 secretion. striking analogy to the urine, which is the only other depuratory secretion, with the exception of the pulmonary transpiration, which, we shall find, essentially resembles the cutaneous. It can, therefore, be readily conceived, that any interruption to this necessary exhalation should be attended with equally serious effects as in the case of the urinary depuration. Most diseases are, indeed, produced probably by irregularly impeded cutaneous transr piration. By exposure to currents of air, or to the irregular action of cold in any manner to the surface, the depuration of the part is morbidly modified; and, owing to the extensive sympathy exist- ing, as we have elsewhere seen, between every part of the capillary surface, any organ, which may be at the time particularly predis- posed to irritation, is affected with disease. Sudden atmospheric vicissitudes are not so liable to excite such partial disease, as when the check to perspiration is more local and irregular; the exhalation from the lungs taking place in greater abundance, so as in some measure to compensate for the diminished cutaneous exhalation. As the sensible transpiration or sweat is merely the insensible perspiration in increased quantity, its uses demand no special no- tice. The pulmonary transpiration, to which we have so often al- luded, bears a striking analogy to the cutaneous. At one time, it was universally believed to be owing to the combustion of the air with the hydrogen and carbon given off from the lungs; but we have elsewhere shown, that no such combustion occurs; and besides the exhalation occurs when gases,, containing no oxygen, have been respired by animals. It is now universally admitted to be exhaled into the air-cells of the lungs from the pulmonary artery chiefly, but partly from the bronchial arteries, distributed to the mucous membrane of the air- passages. Several interesting experiments have been made on this exhala- tion, by Magendie, Milne Edwards, Breschet, and others. If water be injected into the pulmonary artery, it passes into the air- cells, in an innumerable quantity of almost imperceptible drops, and mixes with the air contained in them. Magendie found, that its quantity might be augmented at plea- sure on living animals, by injecting distilled water, at a tempera- ture approaching that of the body, into the venous system. He injected into the veins of a small dog, a considerable amount of water. The animal was at first in a state of real plethora, the vessels being so much distended that it could scarcely move; but, in a few minutes, the respiration became manifestly hurried, and a large quantity of fluid was discharged from the mOuth, the source of which appeared evidently to be in the pulmonary transpiration considera- bly augmented. Not only, however, is the aqueous portion of the blood exhaled pulmonary exhalation. 219 in this manner. Experiment shows that many substances, when in- troduced into the veins by absorption, or by direct injection, issue by the lungs. Weak alcohol, a solution of camphor, ether and other odorous substances, when thrown into the cavity of the perito- neum or elsewhere, were found, by Magendie, to be speedily ab- sorbed by the veins and conveyed to the lungs, where they trans- uded into the bronchial cells, and were recognised by the smell in the expired air. Phosphorus, when injected, exhibited this transmission in a sin- gular and evident manner. Magendie, on the suggestion of M. Armand de Montgarny, " a young physician," he remarks, " of much merit," now no more, injected into the crural vein of a dog, half an ounce of oil, in which phosphorus had been dissolved; and, scarcely had he finished the injection, before the animal sent through the nostrils clouds of a thick, white vapour, which was phosphorous acid. When the expe- riment was made in the dark, these clouds were luminous. More lately, MM. Breschet and Milne Edwards have made several experiments, for the purpose of discovering why the pul- monary transpiration expels so promptly the different gaseous and liquid substances received into the blood. Considering properly, that exhalation differs only from absorp- tion in taking place in an inverse direction, these gentlemen con- jectured, that it ought to be accelerated by every force that would attract the fluids from within to without; and such a force they con- ceive inspiration to be, which, in their view, solicits the fluids of the economy to the lungs, in the same mechanical manner as it occasions the entrance of the air into the air-cells. In support of this view, they adduce the following experiments. 1. To the trachea of a dog, a pipe, communicating with a bel- lows, was adapted, and the thorax was largely opened. Natural respiration was immediately suspended; but artificial respiration was kept up by means of the bellows. The surface of the air-cells was, in this way, constantly subjected to the same pressure; there being no longer diminished pressure during expiration, as when the thorax is sound, and the animal breathing naturally. Six grains of camphorated spirit were now injected into the pe- ritoneum of the animal; and, at the same time, a similar quantity was injected into another dog, whose respiration was natural. In the course of from three to six minutes, the odorous substance was detected in the pulmonary transpiration of the latter; but in the other it was never manifested. In the first animal, they now exposed a part of the muscles of the abdomen, and applied a cupping-glass to it; when the smell of the camphor speedily appeared at the cupped surface. The conclu- sion was obvious, that the pulmonary surface, having ceased to be subjected to the suction force of the chest, during inspiration, the exhalation was arrested, whilst that of the skin was developed as 220 SECRETION. soon as an action of aspiration was exerted upon it by the cupping- glass. 2. Into the crural veins of two dogs;—one of which breathed naturally, and the other was circumstanced as in the last experi- ment,—they injected the essential oil of turpentine. In the first of these, the substance was soon apparent in the pulmonary transpira- tion ; and, on opening the body, it was discovered, that the turpen- tine had impregnated the lung and the pleura much more strongly than the other tissues. In the other animal, on the contrary, the odour of the turpentine was scarcely apparent in the vapour of the lungs; and, on dissection, it was not found in greater quantity in the lungs, than in the other tissues;—in the pleura than in the peritoneum. From the results of these experiments, MM. Breschet and Edwards conclude, that each inspiratory movement constitutes a kind of suction, which attracts the blood to the lungs; and which causes the ejection, through the pulmonary surface, of the liquid and gaseous substances that are mingled with that fluid, more than through the other exhalant surfaces of the body. In their experiments, these gentlemen did not find that the ex- halation was effected with equal readiness in every part of the sur- face, when the cupping-glass was applied in the manner that has been mentioned. The skin of the thigh, for example, did not indi- cate the odour of camphorated alcohol, as that of the region of the stomach. The chymical composition of the pulmonary transpiration is pro- bably nearly identical with that of the sweat; appearing to consist of water, holding in solution, perhaps, some saline and albuminous matter; but our information, on this matter, derived from the chy- mist, is not precise, Chaussier found, that by keeping a portion of it in a close vessel, exposed to an elevated temperature, a very evi- dent putrid odour was exhaled on opening the vessel. This could only have arisen from the existence of animal matter in it. The pulmonary transpiration being liable to all the modifications that apply to the cutaneous, it is not surprising that we should meet with so much discordance in the estimates of different individuals, regarding its quantity in a given time. Hales valued it at 20 ounces in the twenty-four hours; Menzies at 6 ounces; Abernethy at 9 ounces; Lavoisier and Seguin at 17£ ounces, poids de marc; Thomson at 19 ounces, and Dalton at 1 pound Si ounces. The uses it serves, in the animal economy, are identical with those of the cutaneous depuration. 9. Exhalation of the Mucous Membranes. The mucous membranes, like the skin, which they so strongly resemble in their structure, functions and diseases, exhale a similar transpiratory fluid; which has not, however, been subjected to chy- mical examination. It is, indeed, almost impracticable to separate it follicular secretions. 221 from the follicular secretions, poured out from the same membrane; and from the extraneous substances, almost always in contact with it. It is probably, however, similar to the fluid of the cutaneous and pulmonary depurations, both in character and use. Sect. II.—Follicular Secretions. The follicular secretions must, of necessity, be effected from the skin or the mucous membranes; as the follicles or crypts are met with there only. They may, therefore, be divided into two classes:— 1st, the mucous follicular secretion; and 2d, the cutaneous follicu- lar secretion. 1. Mucous Follicular Secretion. The whole extent of the great mucous membranes, lining the ali- mentary canal, the air-passages and the urinary and genital organs, is the seat of a secretion, the product of which has received, in the abstract, the name of mucus; although it differs somewhat accord- ing to the situation and character of the particular follicles, whence it proceeds. Still, essentially, the structure, functions and product are the same. In the history of the different functions, in which some of the mu- cous membranes are concerned, the uses of this secretion have been detailed; and in those that will hereafter have to engage attention, in which other mucous membranes are concerned, their uses will fall more conveniently under notice then. But few points will, therefore, require explanation at present. The mucus, secreted by the nasal follicles, seems alone to have been subjected to chymical analysis. Fourcroy and Vauquelin found it composed of precisely the same ingredients as the tears. According to the analysis of Berzelius, its constituents are as fol- lows:—water, 933.7; mucus, 53.3; muriates of potassa and soda, 5.6; lactate of soda, with animal matter, 3.0; soda, 0.9; albumen and animal matter, soluble in water, but insoluble in alcohol, with a trace of phosphate of soda, 3.5. The great use of mucus, wherever met with, is to lubricate the surface on which it is poured. 2. Follicular Secretion of the Skin. This is the sebaceous and micaceous humour, observed in the skin of the cranium, and in that of the pavilion of the ear. It is also the humour, which occasionally gives the appearance of small worms beneath the skin of the face, when it is forced through the external aperture of the follicle; and which causes, when exposed to the air, the black spots sometimes observable on the face. The cerumen is, likewise, a follicular secretion, as well as the whit- 222 secretion. ish, odorous and fatty matter, which forms under the prepuce of the male, and in the external parts of the female, where cleanli- ness is disregarded. The humour of Meibomius is also follicu- lar, as well as that of the caruncula lachrymalis. The use of this secretion is,—to favour the functions of the part over which it is distributed. That which is secreted from the skin, is spread over the epidermis, hair, &c, giving suppleness and elasticity to the parts, rendering the surface smooth and polished, and thus obviat- ing the evils of abrasion that might otherwise arise. It is also con- ceived, that its unctuous nature may render the parts less permeable to humidity. Sect. III.—Glandular Secretions. The glandular secretions are seven in number;—those of the tears, saliva, pancreatic juice, bile, urine, sperm, and milk. 1. Secretion of the Tears. The lachrymal apparatus, being a part of that accessory to vision, was described under that head. As we meet with the tears, they are not simply the secretion of the lachrymal gland, but of the conjunctiva, and occasionally of the caruncula lachrymalis and folli- cles of Meibomius. They have a saline taste; mix freely with water; and, owing to the presence of free soda, communicate a green tint to the blue infusion of violets. Their chief salts are the muriate, and phosphate of soda. According to Fourcroy and Vauquelin, the animal matter of the tears is mucus; but it is presumed by some to be albumen or an analogous principle. This secretion is more influenced by the emotions than any other; and hence it is concernedjn the expressions of lively joy and sor- row, especially of the latter. 2. Secretion of the Saliva. The salivary apparatus has, likewise, engaged attention else- where. It consists of a parotid gland on each side, situated in front of the ear and behind the neck and ramus of the jaw; a sub- maxillary, beneath the body of the bone; and a sublingual, situ- ated immediately beneath the tongue,—the parotids and submaxil- lary glands having each but one excretory duct, the sublingual se- veral. All these ducts pour the fluids of their respective glands into the mouth, where it collects, and becomes mixed with the exhalation from the mucous membrane of the mouth, and the secretion from its follicles. It is this mixed fluid, that has been generally ana- lyzed by the chymist. According to Berzelius, its constituents arc,—water, 992.2; pc- pancreatic secretion. 223 culiar animal matter, 2.9; mucus, 1.4; muriates of potassa and soda, 1.7; lactate of soda, and animal matter, 0.9 ; soda, 0.2. Drs. Bos- tock and Thomas Thomson think, that the " mucus" of Berzelius resembles coagulated albumen in its properties. MM. Leuret and Lassaigne analyzed pure saliva, obtained from an individual labouring under salivary fistula, and found it to contain,—water, mucus, traces of albumen, soda, chloride of potas- sium, chloride of sodium, carbonate and phosphate of lime ;—and lastly, Messrs. Tiedemann and Gmelin affirm, that the saliva con- tains only one or two-hundredths of solid matter, which are com- posed of a peculiar substance, called salivary matter; osmazome; mucus; perhaps albumen; a little fat, containing phosphorus; and the insoluble salts—phosphate and carbonate of lime. Besides these, they detected the following soluble salts;—acetate, carbonate, phos- phate, sulphate, and muriate of potassa, and the sulpho-cyanate of potassa. As the salivary secretion forms an important part in the processes preparatory to stomachal digestion, its uses have been detailed in the first volume of this work. 3. Secretion of the Pancreatic Juice. The pancreas or sweatbread, Fig. 122, G., secretes a juice or humour, called succus pancreaticus or pancreatic juice. Its tex- ture resembles that of the salivary glands ; and hence it has been called, by some, the abdominal salivary gland. It is situated transversely in the abdomen, behind the stomach, towards the con- cavity of the duodenum; is about six inches Jong; of a reddish- white colour, and firm consist- ence. Its excretory ducts ter- Fig. 121. minate in one,—called the duct of Wirsung,—which opens into the duodenum, at times separately from the duc- tus communis choledochus, but close to it; at other times, being confounded with, or opening into, it. The quantity of fluid, se- creted by the pancreas, does not seem to be considerable. Magendie, in his experi- ments, was struck with the ", ' ,., ,. , , a. The hepatic duct, formed by a branch from the right, Small quantity discharged, and one from the left lobe of the liver.-6. Fundusof gall- -r, -i l j bladder.—c. d. Body and neck of gall-bladder.—e. Cystic r requently, Scarcely a drop duct.-/. Ductus communis choledochus.—£#. Trunkand ■ Pllni • u~]C nn V,mir. onrl branches of the pancreatic duct.—A. Termination of the ISSUea in Iidll dli nuui , dim, ductuS communis choledochus and the ductus pancreati" occasionally, a much longer cus~i-Theduodenum* time elapsed. Nor did he find that the flow, according to the com- 224 secretion. mon opinion and to probability, was more rapid whilst digestion was going on. It will be easily understood, therefore, that it cannot be an easy task to collect it. De Graaf, a Dutch anatomist affirms, that he succeeded by introducing, into the intestinal end of the excretory duct, a small quill, terminating in a phial fixed under the belly of the animal. Magendie, however, states, that he tried this plan several times but without success; and he believes it to be imprac- ticable. The plan he adopts is to expose the intestinal orifice of the duct; to wipe, with a fine cloth, the surrounding mucous mem- brane; and, as soon as a drop of the fluid oozes, to suck it up by means of a pipette or small glass tube. In this way he collected a few drops, but never sufficient to undertake a satisfactory analysis. Messrs. Tiedemann and Gmelin make an incision into the ab- domen ; draw out the duodenum, and a part of the pancreas; and, opening the excretory duct, insert a tube into it; and a similar plan was adopted successfully on a horse by MM. Leuret and Lass aigne. The difficulty experienced in collecting a due quantity, is a pro- bable cause of some of the discrepancy amongst observers, regarding its sensible and chymical properties. Some of the older physiologists affirm it to be acidulous and sa- line; others assert that it is alkaline. The majority of those of the present day compare it to the sa- liva, and affirm it to be inodorous, insipid, viscid, limpid, and of a bluish white colour. The latest experimenters by no means ac- cord with each other. According to Magendie, it is of a slightly yellowish hue, saline taste, devoid of smell, occasionally alkaline, and partly coagulable by heat. MM. Leuret and Lassaigne found that of the horse, of which they obtained three ounces, to be alkaline, and composed of 991 parts of water in 1000; of an animal matter, soluble in alcohol; another, soluble in water; traces of albumen and mucus; free soda; chloride of sodium; chloride of potassium, and phosphate of lime. In their view, consequently, the pancreatic juice strongly resem- bles the saliva. MM. Tiedemann and Gmelin succeeded in obtaining upwards of two drachms of the juice in four hours; and, in 100 parts, they found from five to eight solid. These solid parts consisted of osmazome; a matter which became red by chlorine; another analo- gous to caseine, and probably associated with salivary matter; much albumen; a little free acid, probably the acetic; the acetate, phos- phate, and sulphate of soda, with a little potassa; chloride of potas- sium, and carbonate and phosphate of lime: so that, according to these gentlemen, the pancreatic juice differs from the saliva in containing; —a little free acid, whilst the saliva is alkaline; much albumen, and matter resembling caseine; but little mucus and salivary mat- ter, and no sulpho-cyanate of potassa. OF THE BILE. 225 The precise use of the pancreatic juice in digestion is not deter- mined. 4. Secretion of the Bile. The biliary secretion is, also, a digestive fluid, of which we have spoken in the appropriate place. The mode, however, in which the process is effected, has not yet been investigated. The apparatus consists of the liver, which accomplishes the for- mation of the fluid; the hepatic duct,—the excretory channel, by which the bile is discharged; the gall-bladder, in which a portion of the bile is retained for a time; the cystic duct—the excretory channel of the gall-bladder; and the ductus communis choledochus, or choledoch duct, formed by the union of the hepatic and cystic ducts, and which conveys the bile immediately into the duodenum. The liver, A, A, Fig. 92, and A, A, Fig. 122, is the largest gland in the body; situated in the abdo- men, beneath the diaphragm, above the stomach, the arch of the colon, and the duodenum; filling the whole of the right hypochondrium, and more or less of the epigas- trium, and fixed in its situation by duplicatures of the peritoneum, called ligaments of the liver.. The weight of the human liver is generally, in the adult, about three or four pounds. In disease, however, it sometimes weighs twenty or twenty-five pounds; and, at other times, not as many ounces. Its shape is irregular, and it is divided into three chief lobes, the right, the left, and the lobulus spigelii. Its upper convex surface touches every where the arch of the diaphragm. The lower concave surface corresponds to the stomach, colon, and right kidney. At the COncave surface, tWO A»,A- Concave surface of liver turned up- j. , iii wards, andtothenphtside.—B. Lobulus spigelii. JlSSUreS are Observable;---the One— Between B and C, the porta of the liver.—D. • _ p___if . i i • i j Ligamentum rotundum.—E, F. Gall-bladder.— passing from before to behind, and g. The Pancreas.-H. The Bpieen.-i The lodging the umbilical vein in the *ST& ,^3^E^Bft2£ foetus—called the horizontal sulcus £SEf.'xtoESSSZSZStfbSZ or fissure, great fissure, or fossa mon aiac v«n;--v. End of coion.-x. com- ■L'f v a.\ *l ,*• i meneement of the rectum.-V, y. Urinary umbuicalis; the other, cutting the bladder. last at right angles, and running from right to left, by which the Vol. II. 29 226 SECRETION. different nerves and vessels proceed to and from the liver, and called the principal fissure, or sulcus transversus. The liver itself is composed of the following anatomical elements: —1. The hepatic artery, a branch of the coeliac, which ramifies minutely through the substance of the organ. The minuter branches of this artery are arranged somewhat like the hairs in a painter's brush, and have hence been called the penicilli of the liver. 2. The vena porta, which we have elsewhere seen to be the common trunk of all the veins of the digestive organs and of the spleen. It divides like an artery, its branches accompanying those of the hepatic artery. Where the vein lies in the transverse fissure, it is of great size, and has hence been called sinus venae portae. The possession of two vascular systems, containing blood, is peculiar to the liver, and has been the cause of some difference of opinion, with regard to the precise material—arterial or venous—from which the bile is derived. 3. The excretory ducts or biliary ducts. These are presumed to arise from acini, communicating, according to some, with the extremities of the vena portae; according to others, with the radicles of the he- patic artery. At their commencement, they are termed pori biliarii. These ultimately form two or three large trunks, which issue from the liver by the transverse fissure, and end in the hepatic duct. 4. Lymphatic vessels. 5. Nerves, in small number, compared with the size of the liver, some proceeding from the eighth pair; but the majority from the solar plexus, and following the course and divi- sions of the hepatic artery. 6. The supra-hepatic veins, or venae cavae hepaticse, which arise in the liver by imperceptible radicles, communicating with the final ramifications of both the hepatic artery and vena porta?. They return the superfluous blood, carried to the liver by these vessels, by means of two or three trunks, and six or seven branches, which open into the vena cava inferior. These veins generally pass, in a convergent manner, towards the posterior margin of the liver, and cross the divisions of the vena porta? at right angles. 7. The remains of the umbilical vein, which, in the foetus, enters at the horizontal fissure. This vein, after respiration is established, becomes converted into a ligamentous substance, called, from its shape, ligamentum rotundum, or round ligament. The parenchyma, formed by these anatomical elements, it is dif- ficult to describe; and although the term liver-coloured is used in common parlance, it is not easy to say what are the ideas attached to it. The organ has two coats;—the outer, derived from the perito- neum, which is very thin, transparent, easily lacerable, and vascular, and is the seat of the secretion, operated by serous membranes in general. It does not cover the posterior part, nor the excava- tion for the gall-bladder, the vena cava, nor the fissures in the con- cave surface of the liver. The inner coat is the proper mem- brane of the liver. It is thin, but not easily torn, and it covers not only every part of the surface of the liver, but also the large vessels OF THE BILE. 227 that are proper to the organ. The condensed cellular substance,— which unites the sinus of the vena portae and its two great branches, the hepatic artery, the common biliary duct, lymphatic glands, lymphatic vessels, and nerves in the transverse fossa or fissure of the liver,—was described by Glisson as a capsule; and hence has been called the capsule of Glisson. The gall-bladder, (Figs. 92,121, and 122,) is a small membranous pouch, of a pyriform shape, situated at the inferior and concave sur- face of the liver, to which it is attached, and above the colon and duodenum. A quantity of bile is usually found in it. The gall-bladder is not found in all animals. It is wanting in the elephant, horse, stag, camel, rhinoceros, and goat; in certain of the cetacea; and in some birds, as the ostrich, pigeon, and parrot; and is occasionally deficient in man. Its largest part or fundus,Figs. 121 and 122, is turned forwards; and, when filled, frequently projects beyond the anterior margin of the liver. Its narrowest portion, cervix or neck is turned backwards, and terminates in the cystic duct. Externally, it is partly covered by the peritoneum which attaches it to the liver, and to which it is, moreover, adherent by cellular tissue and vessels. Internally, it is rugous; the folds being reticulated, and appearing somewhat like the cells of a honey-comb. Anatomists have differed with regard to the number of coats pro- per to the gall-bladder. Some have described two only;—the peri- toneal and mucous; others have added an intermediate cellular coat; whilst others have reckoned four;—a peritoneal coat;—a thin stra- tum of muscular fibres, passing in different directions, and of a pale colour; a cellular coat, in which a number of blood-vessels is situ- ated; and an internal mucous coat. The existence of the muscular coat has been denied by perhaps the generality of anatomists; but there is reason for believing in its existence. Amussat saw mus- cular fibres distinctly in a gall-bladder dilated by calculi; and Dr. Monro, the present Professor of anatomy in the University of Edinburgh, asserts, that he has seen it contract, in a living animal, for half an hour, under mechanical irritation, and assume the shape of an hour-glass. The mucous coat forms the ruga? to which we have already al- luded. In the neck, and in the beginning of the cystic duct, there are from three to seven,—sometimes twelve,—semilunar duplicatures, which retard the flow of any fluid inwards or outwards. These are sometimes arranged spirally, so as to form a kind of valve, accord- ing to Amussat. On the inner surface of the gall-bladder, especially near its neck, numerous follicles exist; the secretion from which is said to fill the gall-bladder, when that of the bile has been interrupted by disease, as in yellow fever, scirrhus of the liver, &c. The hepatic duct, Fig. 121, a, is the common trunk of all the excretory vessels of the liver; and makes its exit from that organ 228 SECRETION. by the transverse fissure. It is an inch and a half in length, and about the diameter of an ordinary writing quill. It is joined, at a very acute angle, by the duct from the gall-bladder—the cystic duct, Fig. 121, e, to form the ductus communis choledochus. The cystic duct is about the same length as the hepatic. The ductus communis choledochus is about three or three and a half inches long. It descends behind the right extremity of the pancreas, through its substance; passes for an inch obliquely between the coats of the duodenum, diminishing in diameter; and ultimately terminates by a yet more contracted orifice, on the inner surface of the intestine, at the distance of three or four inches from the sto- mach. The structure of all these ducts is the same. The external coat is thick, dense, strong, and generally supposed to be of a cellular character; the inner is a mucous membrane, like that, which lines the gall-bladder. The secretion of the bile is probably effected like the other glan- dular secretions; modified, of course, by the peculiar structure of the liver. We have seen that the organ differs from every other secre- tory apparatus, in having two kinds of blood distributed to it:—ar- terial blood by the hepatic artery; and venous blood by the vena portse. A question has consequently arisen—from which of these is the bile formed? Anatomical inspection throws no light on the subject; and, ac- cordingly, argument is all that can be adduced on one side or the other. The most common and the oldest opinion is, that the bile is se- parated from the blood of the vena porta?; and the chief reasons, ad- duced in favour of this belief, are the following. First. The blood of the portal system is better adapted than arterial blood for the for- mation of bile, on account of its having, like all venous blood, more carbon and hydrogen, which are necessary for the production of a humour as fat and oily as the bile; and it has been imagined, by some, that the blood, in crossing the omentum, becomes loaded with fat. Secondly. The vena porta? ramifies in the liver, after the manner of an artery, and evidently communicates with the secretory ves- sels of the bile. Thirdly. It is larger than the hepatic artery; and more in proportion to the size of the liver; the hepatic artery seeming to be merely for the nutrition of the liver, as the bronchial artery is for that of the lung. In answer to these positions it has been argued; that there' seems to be no more reason why the bile should be formed from venous blood than the other fatty and oleaginous humours—the mar- row and fat, for example,—which are derived from arterial blood. It is asked, again, whether, in fact, the blood of the vena porta is really more rich in carbon and hydrogen? and whether there is a closer chymical relation between the bile and the blood of the vena OF THE BILE. 229 porta?, than between the fat and arterial blood? The notion of the absorption of fat from the omentum, it is properly urged, is totally gratuitous. Secondly. Admitting that the vena porta? is distributed to the liver after the manner of an artery; is it clear, it has been asked, that it is inservient to the biliary secretion? Thirdly. If the .vena porta? be more in proportion to the size of the liver than the hepatic artery, the latter appears to bear a better ratio to the quan- tity of bile secreted; and, moreover, it is probable, as has been shown in another place, that the liver has other functions connect- ed with the portal system, in the admixture of heterogeneous liquids absorbed from the intestinal canal. In the absence of direct experiment, however, physiologists have usually embraced one or other of these exclusive views. The gene- rality, as we have remarked, assign the function to the vena portae. Bichat, on the other hand, ascribes it to the hepatic artery. Broussais thinks it probable, that the blood of the vena porta? is not foreign to the formation of the bile, since it is confounded with that of the hepatic artery in the parenchyma of the liver; " but to say with the older writers, that thebile cannot be formed but by venous blood, is, in our opinion" he remarks " to advance too bold a position, since the hepatic artery sends branches to each of the glandular aci- ni, that compose the liver." Magendie likewise concludes, that nothing militates against the idea of both kinds of blood serving in the secretion; and that it is supported by anatomy: as injections prove, that all the vessels of the liver,—arterial, venous, lymphatic, and excretory,—communicate with each other. The view, that ascribes the bile to the hepatic artery, appears to us the most probable. It has all analogy in its favour. We have no disputed origin as regards the other secretions. They all pro- ceed from arterial blood; and function sufficient, we think, can be assigned to the portal system, without conceiving it to be concerned in the formation of bile. We have, moreover, pathological cases, which prove that the bile can be formed from the blood of the he- patic artery. Mr. Abernethy met with an instance, in which the trunk of the vena porta? terminated in the vena cava; yet bile was found in the biliary ducts, which could have been derived only from the hepatic artery. A similar case is given by Mr.Lawrence; and the present Professor Monro, in his "Elements of Anatomy" details a case communicated to him by the late Mr. Wilson, of the Windmill street school, in which there was reason to suppose, that the greater part of the bile had been derived from the hepatic ar- tery. The patient, a female, thirteen years old, died from the ef- fects of an injury of the head. On dissection, Mr. Wilson found a large swelling at the root of the mesentery, consisting of several ab- sorbent glands in a scrofulous state. Upon cutting into the mass, he accidentally observed a large vein passing directly from it into the vena cava inferior, which, on dissection, proved to be the vena portae; and on tracing the vessels entering into it, one was found to 230 secretion. be the inferior mesenteric vein; and another, which came directly to meet it from behind the stomach, proved to be a branch of the splenic vein, but somewhat larger, which ran upwards by the side of the vena cava inferior, and entered that vein immediately before it passes behind the liver. Mr. Wilson then traced the branches of the trunk of the vessel corresponding to the vena porta? suffi- ciently far in the mesentery and mesocolon, to be convinced, that it was the only vessel that returned the blood from the small in- testines, and from the caecum and colon of the large. He could trace no vein passing into the liver at the cavity of the porta; but a small vein descended from the little epiploon, and soon joined one of the larger branches of the splenic vein. The hepatic artery came off in a distinct trunk from the aorta, and ran directly to the liver. It was much larger than usual. The greater size of the hepatic artery, in this case, would favour the idea, that the arterial blood had to execute some office, that ordina- rily belongs to the vena porta?. Was this the formation of bile? The case shows positively, too, that bile can be formed from the blood of the hepatic artery. When bile is once secreted in the tissue of the liver, it is re- ceived into the minute excretory radicles, whence it proceeds along the ducts, until it arrives, from all quarters, at the hepatic duct. A difference of sentiment exists regarding the flow of the bile from the liver and gall-bladder into the duodenum. According to some, it is constantly passing along the choledoch duct; but the quantity is not the same during digestion as at other times. In the intervals, a part only of the secreted bile attains the duodenum; the remainder ascends along the cystic duct, and is deposited in the gall-bladder. During digestion, however, not only the whole of the secretion arrives at the duodenum, but all that which has been collected in the interval is evacuated into the intestine. In sup- port of this view it is affirmed, that bile is always met with in the duodenum; that the gall-bladder always contains more bile when abstinence is prolonged, whilst it is empty immediately after di- gestion. The great difficulties have been, to explain how the bile gets into the gall-bladder, and how it is expelled from that reservoir. In many birds, reptiles, and fishes, the hepatic duct and the cystic duct open separately into the duodenum; whilst ducts, called hepato- cystic, pass directly from the liver to the gall-bladder. In man, however, the only visible route by which it can reach that reservoir, is by the cystic duct, the direction of which is retrograde; and, con- sequently, the bile has to ascend against gravity. The spiral valve of Amussat has been presumed to act like the screw of Archi- medes, and to facilitate the entrance of the refluent bile, but this appears to be imaginary. It is, indeed, impossible to see any analogy between the corporeal and the hydraulic instrument. The arrange- ment of the termination of the choledoch duct in the duodenum has OF THE BILE. 231 probably a more positive influence. The embouchure is the narrowest part of the duct, the ratio of its calibre to that of the hepatic duct having been estimated at not more than one to six, and to the calibre of its own duct as one to fifteen. This would render it impracticable for the bile to flow into the duodenum as promptly as it arrives at the embouchure; and, in this way, collecting in the duct, it might reflow into the gall-bladder. Amussat, indeed, affirms, that this can be demonstrated on the dead body. By injecting water or mer- cury into the upper part of the hepatic duct, the injected liquid was found to issue both by the aperture into the duodenum, and by the upper aperture of the cystic duct into the gall-bladder. With regard to the mode in which the gall-bladder empties itself during digestion, it is probably by a contractile action. We have seen, that it has not usually been admitted to possess a muscular coat, but that it is manifestly contractile. The chyme, as it passes into the duodenum, excites the orifice of the choledoch duct; this excitement is propagated along the ducts to the gall-bladder, which contracts; but, according to Amussat, does not evacuate its con- tents suddenly, for the different planes of the spiral valve are ap- plied against each other, and only permit the flow to take place slowly. This he found was the case, in the subject, when water was injected into the gall-bladder, and pressed out through the cys- tic duct. Other physiologists have presumed, that although the bile is se- creted in a continuous manner, it only flows into the duodenum at the time of chylification; at other times, the choledoch duct is con- tracted, so that the bile is compelled to reflow through the cystic duct into the gall-bladder; and it is only when the gall-bladder is filled, that it passes freely into the duodenum. Independently, however, of other objections to this view, vivisections have shown, that if the orifice of the choledoch duct be exposed, whatever may be the circumstances in which the animal is placed, the bile is seen issuing guttatim at the surface of the intestine. The biliary secretion, which proceeds immediately from the liver,—hence called hepatic bile,—differs from that obtained from the gall-bladder, which is termed cystic bile. The latter possesses greater bitterness, is thicker, of a deeper colour, and is that which has been usually analyzed. It is of a yellowish-green colour, viscid, and slightly bitter. Its chymical properties have been frequently examined; yet much is still needed, before we can consider the analysis satisfactory. It has been examined by Boerhaave, Ver- heyen, Baglivi, Hartmann, Macbride, Ramsay, Gaubius, Cadet, Van Bochante, Poulletier de la Salle, Fourcroy, Macclurg, Thenard, Berzelius, Chevreul, Leuret find Las- saigne, Tiedemann and Gmelin, &c. &c. Thenard's analysis of 1100 parts of human bile is as follows:— Water, 1000; albumen, 42; resinous matter, 41; yellow matter, 2 to 10; free soda, 5 or 6; phosphate, muriate, and sulphate of soda, 232 secretion. phosphate of lime, and oxide of iron, 4 or 5. According to Cheval- lier, it contains also a quantity of picromel. Berzelius calls in question the correctness of Thenard's ana- lysis, and gives the following:—Water, 90S.4; picromel, SO; albu- men, 3.0; soda, 4.1; phosphate of lime, 0.1; common salt, 3.4; phos- phate of soda, with some lime, 1.0. The results of Dr. Davy's analysis of healthy bile were as fol- lows:—Water, 86.0; resin of bile, 12.5; albumen, 1.5. Lastly, the few experiments, that were performed by Tiedemann and Gmelin on human bile, indicated the existence of cholesterine, resin, picro- mel, &c, and accorded greatly with the analysis of Thenard. Hepatic and cystic bile do not appear to differ materially from each other, except in the greater concentration of the different ele- ments in the latter. Leuret and Lassaigne found them to be alike in the dog. Orfila, however, affirms, that human hepatic bile does not contain picromel. The great uses of the bile have been detailed under the head of digestion. It has, likewise, been conceived to be a necessary depu- rative excretion; separating from the blood matters that would be injurious if retained. This last idea is probable; but our knowledge of the precise changes, produced in the mass of blood by it, are ex- tremely limited. If its excretion be prevented from any cause, we know that derangement is induced; but it is probable, that its agency in the production of disease is much overrated; and that, as Brous- sais has suggested, the source of many of the affections, termed bilious,\s in the mucous membrane liningthe stomach and intestines; which, owing to the heterogeneous matters constantly brought into contact with it, must be peculiarly liable to be morbidly affected. When irritation exists there, we can easily understand how the secretion from the liver may be consecutively modified; the excite- ment spreading directly along the biliary ducts to the secretory organ. 5. Secretion of Urine. This is the most extensive secretion, accomplished by any of the glandular structures of the body, and is essentially depurative; its suppression giving rise to formidable evils. The apparatus consists of the kidneys, which secrete the fluid; the ureters, which convey the urine to the bladder; the bladder itself, which serves as a.reser- voir for the urine; and the urethra, which conveys the urine exter- nally. These will require a distinct consideration. The kidneys are two glands situated in the abdomen; one on each side of the spine, (Fig. 122, K, K,) in the posterior part of the lumbar region. They are without the cavity of the peritoneum, which covers them at the anterior part only, and are situated in the midst of a considerable mass of adipous cellular tissue. The right kidney is nearly an inch lower down than the left, owing OF THE URINE. 233 Fig. 123. to the thick posterior margin of the right lobe of the liver pressing it downwards. Occasionally, there is but one kidney; at other times, three have been met with. They have the form of the haricot or kidney-bean, which has indeed been called after them; and are situated vertically—the fis- sure being turned inwards. If we compare them with the liver, their size is by no means in proportion with the extensive secretion effected by them. Their united weight does not amount to more than six or eight ounces. They are hard, solid bodies, of a brown colour. The sangui- ferous vessels, which convey and return the blood to them, as well as the excretory duct, communicate with the kidney at the fissure. The anatomical constituents of these organs are:—1. The renal ar- tery, which arises from the abdominal aorta at a right angle, and, after a short course, enters the kidney, ramify- ing in its substance. 2. The excretory ducts, which arise from every part of the tissue, in which the ramifications of the renal artery terminate, and end in the pelvis of the kidney. (Fig.123.) 3. The renal veins, which receive the superfluous blood, after the urine has been separated from it, and ter- minate in the renal or emulgent vein, which issues at the fissure, and opens into the abdominal vena ca- va. 4. Of lymphatic vessels, arrang- ed in two planes—a superficial and deep-seated, which terminate in the lumbar glands. 5. Of nerves, which proceed from the semilunar gan- glion, solar plexus, &c, and which surround the renal artery as with a «,a,Thecortical substance.-6, a, Thetubu- ■i r>n • •-• ii -a __-lar portion.—c, c, c, c, The papillse.—d, The net-WOrk, following it in all ltS rami-pelvw; and e, The ureter. fications. 6. Of cellular membrane, which, as in every other organ, binds the parts together. These anatomical elements, by their union, constitute the organ as we find it. When the kidney is divided longitudinally, it is seen to consist of two substances; which differ in their situation, colour, consist- ence and texture. The one of these and the more external is called the cortical or glandular substance. It forms the whole circum- ference of the kidney; is about two lines in thickness; of less con- sistence than the other: of a pale red colour; and receives almost entirely the ramifications of the renal artery. The other and inner- most is the tubular, medullary, uriniferous,conoidalor radiated Vol. II. 30 234 SECRETION. substance. It is more dense than the other; less red; and seems to be formed of numerous minute tubes, which unite in conical bun- dles of unequal size, and the base of which is turned towards the cortical portion; the apices forming the papillae or mammillary processes, and facing the pelvis of the kidney. The papilla? vary in number, from five to eighteen; are of a florid colour; and upon their points or apices are the terminations of the uriniferous tubes, large enough to be distinguished by the naked eye. Around the root of each papilla a membranous tube arises, called calix or in- fundibulum: this receives the urine from the papilla and con- veys it into the pelvis of the kidney, which may be regarded as the commencement of the ureter. Similar ideas, with regard to the precise termination of the blood- vessel, and the commencement of the excretory duct, have prevailed as in the case of the liver and other glands; their intimate structure, however, escapes detection. In the quadruped, each kidney is made up of numerous lobes, which are more or less intimately united, according to the species. In birds, the kidneys consist of a double row of distinct, but connected, glandular bodies, placed on both sides the lumbar ver- tebra?. The ureter is a membranous duct, which extends from the kid- ney to the bladder. It is about the size of a goose-quill; descends through the lumbar region; dips into the pelvis by crossing in front of the primitive iliac vessels and the internal iliac; crosses the vas deferens at the back of the bladder, and, penetrating that viscus ob- liquely, terminates in an orifice, ten or twelve lines behind that of the neck of the bladder. At first, it penetrates two of the coats only of that viscus; running for the space of an inch between the mucous and muscular coats, and then entering the cavity. The ureters have two coats. The outermost is a dense fibrous membrane; the innermost Fig. 124. a thin mucous layer, con- tinuous at its lower ex- tremity with the inner coat of the bladder; and, at the upper end,supposed, by some, to be reflected over the papilla?, and even to pass for some distance into the tubuli uriniferi. The bladder is a mus- culo-membranous sac, si- tuated in the pelvis; ante- rior to the rectum, and behind the pubis. Its supe- A. Crus penis.—B. Bulb of the urethra.—C'Membranous n / , , partoftheuiethra.—D. Prostate gland.—E. Vesicute seminales. Upper JUnaUS; and the -FF.Vasa deferentia.-G. Ureter.-H. Upper part of thc blad- 1',,,,„ „„j «u • r • der, covered by peritoneum. lower end, the lUjertOr OF THE URINE. 235 fundus or bas-fond; the body being situated between the two. The part where it joins the urethra is the neck. The shape and situation of the organ is influenced by age and by sex. In very young in- fants, it is cylindroid, and rises up almost wholly into the abdomen. In the adult female, who has borne many children, it is nearly sphe- rical; has its greatest diameter transverse, and is more capacious than in the male. Like the other hollow viscera, the bladder consists of several coats. 1. The peritoneal coat which covers only the fundus and back part. Towards the lower portion the organ is invested by cellular membrane, which takes the place of the peritoneal coat of the fun- dus. This tissue is very loose and permits the distention and con- traction of the bladder. 2. The muscular coat is very strong; so much 60, that it has been classed amongst the distinct muscles, un- der the name detrusor urinae. The fibres are pale, and pass in vari- ous directions. Towards the lower part of the bladder, they are particularly strong; arranged in fasciculi, and form a kind of net of muscles inclosing the bladder. In cases of stricture of the urethra, where much effort is necessary to expel the urine, these fasciculi acquire considerable thickness and strength. 3. The mucous or villous coat is the lining membrane, which is continuous with those of the ureters and urethra, and is generally rugous, in consequence, of its being more extensive than the muscular coat without. It is furnished with numerous follicles, which secrete a fluid to lubricate it. Towards the neck of the organ, it is thin and white, though reddish in the rest of its extent. A fourth coat, called the cellular, has been reckoned by most anatomists, but it is nothing more than cellular tissue uniting the mucous and muscular coats. The part of the internal surface of the bladder, situated immedi- ately behind and below its neck, and occupying the space between it and the orifices of the ureters, is called the vesical triangle, tri- gonus Lieutaudi, or trigone vesical. The anterior angle of the tri- angle looks into the orifice of the urethra, and is generally so pro- minent, that it has obtained the name of uvula vesicas. It is merely a projection of the mucous membrane, dependent upon the subja- cent third lobe of the prostate gland, which, in old people, is fre- quently enlarged, and occasions difficulty in passing the catheter. The neck of the bladder penetrates the prostate gland, but, at its commencement, is surrounded by loose cellular tissue, containing a very large and abundant plexus of veins. The internal layer of muscular fibres is here transverse; and they cross and intermix with each other, in different directions, forming a close, compact tissue, which has the effect of a particular apparatus for retaining the urine, and has been called the sphincter. Anatomists have not usually esteemed this structure to be distinct from the muscular coat at large; but Sir Charles Bell asserts, that if we begin the dissection by taking off the inner membrane of the bladder from 236 SECRETION. around the orifice of the urethra, a set of fibres will be discovered, on the lower half of the orifice, which, being carefully dissected, will be found to run in a semicircular form around the urethra. These fibres make a band of about half an inch in breadth, particu- larly strong on the lower part of the opening; and having ascended a little above the orifice, on each side, they dispose of a portion of their fibres in the substance of the bladder. A smaller and some- what weaker set of fibres will be seen to complete their course, sur- rounding the orifice on the upper part. The arteries of the bladder proceed from various sources, but chiefly from the umbilical and common pudic. The veins return the blood into the internal iliacs. They form a plexus of considera- ble size upon each side of the bladder, particularly about its neck. The lymphatics accompany the principal veins of the bladder, and, at the under part and sides, pass into the iliac glands. The nerves are from the great sympathetic and sacral. The urethra is the excretory duct of the bladder. It extends, in the male, from the neck of the bladder to the extremity of the glans; and is from seven to ten inches in length. In the female it is much shorter. The male urethra has several curvatures in the state of flaccidity of the penis; but. is straight or nearly so, if the penis be drawn forwards and upwards, and if the rectum be empty. The first portion of this canal, which traverses the prostate gland, is called the prostatic portion. Into it open,—on each side of a caruncle, called the verumontanum, caput gallinaginis or crista urethralis,—the two ejaculatory ducts, those of the prostate, and, a little lower, the orifice of Cowper's glands. Between the prostate and the bulb is the membranous part of the urethra, which is eight or ten lines long. The remainder of the canal is called the corpus spongiosum or spongy portion, be- cause surrounded by an erectile spongy tissue. It is situated beneath the corpora cavernosa, and passes forward to terminate in the glans; the structure of which will be considered under generation. At the commencement of this portion of the urethra is the bulb of the urethra, Fig. 124, B.; the structure of which resembles that of the corpora cavernosa of the penis—to be described hereafter. The dimensions of the canal are various. At the neck of the bladder, it is considerable; behind the caput gallinaginis it contracts, and immediately enlarges in the forepart of the prostate. The membranous portion is narrower; and, in the bulb, the channel en- larges. In the body of the penis, it diminishes successively, till it nearly attains the glans, when it is so much increased in size as to have acquired the name fossa navicularis. At the apex of the glans it terminates by a short vertical slit. Mr. Shaw has described a set of vessels, immediately on the outside of the internal membrane of the urethra; which, when empty, are very similar, in appearance, to muscular fibres. These Vessels, he remarks, form an internal spongy body, which passes OF THE URINE. 237 down to the membranous part of the urethra, and forms even a small bulb there. Dr. Horner, however, says, that this appeared to him to be rather the cellular membrane connecting the canal of the urethra with the corpus spongiosum. The whole of the urethra is lined by a very vascular and sensible mucous membrane, which is continued from the inner coat of the bladder. It has, apparently, a certain degree of contractility, and therefore, by some anatomists, is conceived to possess muscular fibres. Sir Everard Home, from the results of his microscopical observations, is disposed to be of this opinion. This is, however, so contrary to analogy, that it is probable the fibres may be seated in the tissue surrounding it. The membrane contains numerous follicles, and several lacuna?, one or two of which, near the extremity of the penis, are so large as occasionally to obstruct the catheter, and to convey the impres- sion that a stricture exists. The prostate and the glands of Cowper,being more concerned in generation, will be described hereafter. There are certain muscles of the perineum, that are engaged in the expulsion of the urine from the urethra; and some of them in defe- cation and in the evacuation of the sperm likewise; as the accelera- tores urinas, or bulbo-urethrales, which propel the urine or semen forward; the transversus perinei, or ischio-perinealis, which dilates the bulb for the reception of the urine or semen; the sphinc- ter ani, which draws down the bulb, and thus aids in the ejection of the urine or sperm; and the levator ani which surrounds the extremity of the rectum, the neck of the bladder, the membranous portion of the urethra, the prostate gland, and a part of the vesicula? seminales, and assists in the evacuation of the bladder, vesicula? se- minales, and prostate. A part of the levator, which arises from the pubis and assists in indosing the prostate gland, is called by Soem- mering, compressor prostatas. Between the membranous part of the urethra and that portion of the levator ani which arises from the inner side of the symphysis pubis, a reddish, cellular, and very vascular substance exists, which closely surrounds the canal, has been described by Mr. Wilson under the name compressor urethras, and is termed, by some of the French anatomists, muscle de Wilson. By many, however, it is considered to be a part of the levator ani. Amussat asserts, that the membranous part of the urethra is formed, externally, of muscu- lar fibres, which are susceptible of energetic contraction, and Ma- gendie confirms his assertion. With regard to the urinary organs of the female,—the kidneys and ureters have the same situation and structure as those of the male. The bladder, also, holds the same place behind the pubis, but rises higher when distended. It is proportionally larger than the bladder of the male, and is broader from side to side, thus al- lowing the greater retention to which females are often necessitated. 238 SECRETION. The urethra is much shorter, being only about an inch and a half, or two inches long, and it is straighter than in the male, having only a slight curve downwards between its extremities, and passing almost horizontally under the symphysis of the pubis. It has no prostate gland, but is furnished, as in the male, with follicles and lacunae, which provide a mucus to lubricate it. In birds in general, and in many reptiles and fishes, the urine, prior to expulsion, is mixed with the excrement in the cloaca. No- thing analogous to urinary organs has been detected in the lowest classes of animals, although in the dung of the caterpillars of certain insects, traces of urea have been met with. The urine is separated from the blood in the kidneys. The proofs of this are easy and satisfactory; but with regard to the mode in which the operation is effected, we are in the same darkness that hangs over the glandular secretions in general. The transformation must, however, occur in the cortical part of the organ; for the tubu- lar portion seems to consist only of a collection of excretory ducts, and if we cut into it urine oozes out. The urinary secretion takes place continuously. If a catheter be left in the bladder, the urine drops constantly; and in cases of ex- strophia of the bladder—a faulty conformation, in which the organ opens above the pubes, so that a red mucous surface, formed by the inner coat of the bladder is seen in the hypogastric region, in which two prominences are visible, corresponding to the openings of the ureters—the urine is seen to be constantly passing out at these openings. After the secretion has been effected in the cortical substance, it flows through the tubular portion, and issues guttatim through the apices of the papilla? into the pelvis of the kidney, whence it pro- ceeds along the ureter to the bladder. When the uriniferous cones are slightly compressed, the urine issues in greater quantity, but, instead of being limpid, as when it flows naturally, it is thick and troubled. Hence a conclusion has been drawn, that it is really fil- tered through the hollow fibres of the medullary or tubular portion. If this were the case, what must become of the separated thick por- tion? Ought not the tubes to become clogged up with it? And is it not more probable, that compression, in this case, forces out with the urine some of the blood that is connected with the nutrition of the organ? The fresh secretion constantly taking place in the kidney causes the urine to flow along the tubuli uriniferi to the pelvis of the or- gan, whence it proceeds along the ureter, if we are in the erect attitude, by virtue of its gravity; the fresh fluid too, continually secreted from the kidney, pushes on that which is before it; and moreover, there is not improbably some degree of contractile ac- tion exerted by the ureters themselves; although, like the excre- tory ducts in general, such a power has been denied them. These OF THE URINE. 239 Fig. 125. are the chief causes of the progression of the urine into the bladder, which is aided by the pressure of the abdominal contents and mus- cles, and, it is supposed, by the pulsation of the renal and iliac arteries; but the agency of these must be trivial. The orifices of the ureters form the posterior angles of the tri- gone visical, and are contracted somewhat below the size of the ducts themselves. They are said, by Sir Charles Bell, to be fur- nished with a small fasciculus of muscular fibres, which runs back- wards from the orifice of the urethra, immediately beneath the la- teral margins of the triangle, and when it contracts, stretches the orifice of the ureter so as to permit the urine to enter the bladder with facility. As the urine enters, it gradually distends the organ until the quan- tity has attained a certain amount. It cannot reflow by the ureters, on account of the smallness of their orifices and their obliquity; and as the bladder becomes filled,—owing to the duct passing forsomedis- tance between the muscular and mucous coats,—the sides are pressed against each other, so that the cavity is obliterated. (Fig. 125.) Besides, when we are in the erect attitude, the urine would have to enter the ureters against gravity. These ob- stacles are so effective, that if an in- jection be thrown forcibly and co- piously through the urethra into the bladder, it does not enter the ureters. On the other hand, equally powerful impediments exist to its being dis- charged through the urethra. The inferior fundus of the bladder is situ- ated lower than the neck; and the sphincter presents a degree of re- sistance, which requires the bladder to contract forcibly on its contents, aided by the abdominal muscles to overcome it. Magendie considers the contraction of the levatores ani to be the most efficient cause of the retention of the urine; the fibres which pass around the urethra press- siMlorificeofthTu"reter.c' ing its sides against each other and thus closing it. The urine accumulates in the bladder until the desire arises to expel it During its stay in this reservoir, it is believed to be de- prived of some of its more aqueous portions by absorption, and to become of greater specific gravity, and more coloured: it is here that those depositions are apt to take place which constiiute ureteSso ^ "^ WUh them in b°th the kidne-vs and As in every excretion, a sensation first arises, in consequence of A. Cavity of the bladder.—B. Ureter.—C. Ve- 240 SECRETION. which the muscles required for the ejection of the secreted matter are called into action. This sensation arises whenever the urine has accumulated to the necessary extent, or when it possesses irritating qualities, owing to extraneous substances being contained in, or de- posited from, it; or if the bladder be unusually irritable from any morbid cause, the sensation may be repeatedly, nay, almost inces- santly experienced. The remarks, that have been made on the sen- sations accompanying the other excretions, are equally applicable here. The impression takes place in the bladder; such impression is conveyed to the brain, which accomplishes the sensation ; and, con- secutively, the muscles concerned in the excretion, are called into action by volition. Physiologists have differed regarding the power of volition over the bladder. Some have affirmed, that it is as much under cerebral control as the muscles of locomotion ; and they have adduced, in support of this view, that the bladder receives spinal nerves, which are voluntary; that it is paralyzed in affections of the spinal mar- row, like the muscles of the limbs; and that a sensation which seems destined to arouse the will is always the precursor of its action. Others, again, have denied, that the muscular fibres of the blad- der are contractile under the will; and they adduce the cases of other reservoirs,—the stomach and the rectum, for example,—whose influence in excretion we have seen to be involuntary; as well as the fact, that we no more feel the contraction of the bladder than we do that of the stomach or intestines; and they affirm, that the action of the bladder itself has been confounded with that of the accessory muscles, which are manifestly under the influence of the will, and are important agents in the expulsion of the fluid from the bladder. The views, last expressed, appear to be most accurate, and the catenation of phenomena seems to be as follows:—the sensation to expel the urine arises; the abdominal muscles are thrown into con- traction by volition; the viscera are thus pressed down upon the pelvis; the muscular coat of the bladder is, at the same time, stimu- lated to contraction; the levatores ani and the sphincter fibres are relaxed, so that the resistance of the neck of the organ is diminished, and the urine is forced out through the whole extent of the urethra, being aided in its course, especially towards the termination, by the contractile action of the urethra itself, as well as by the levatores ani and acceleratores urina? muscles. These expel the last drops by giving a slight succussion to the organ, and directing it upwards and forwards; an effect which is aided by shaking the organ to free it from the drops that may exist in the part of the canal near its extremity. The gradually diminishing jet, which we notice, as the bladder is becoming empty, indicates the contraction of the mus- cular coat of the bladder; whilst the kind of intermittent jet, coinci- dent with voluntary muscular exertion, indicates the contraction OF THE URINE. 241 of the urethral muscles. When we feel the inclination to evacuate the bladder, and do not wish to obey it, the same muscles,—the levatores ani, the acceleratores urina?, and the fibres around the membranous portion* of the urethra and the neck of the bladder— are thrown into contraction, and resist thatof the bladder. Such is the ordinary mechanism of the excretion of urine. The contraction of the bladder is, however, of itself sufficient to expel its contents. Magendie affirms, that he has frequently seen dogs pass the urine when the abdomen was opened, and the bladder re- moved from the influence of the abdominal muscles; and he farther states, that if, in a male dog, the bladder, with the prostate and a small portion of the membranous part of the urethra, be removed from the body, the bladder will contract after a few moments, and project the urine, with an evident jet, until it is entirely expelled. Urine,—voided in the morning by a person who has eaten heartily, and taken no more fluid than sufficient to allay thirst,—is a transpa- rent, limpid fluid, of an amber colour, saline taste, and a peculiar odour. Its specific gravity is a little above that of water, or 1.030. It is slightly acid, for it reddens vegetable blues. Although at first quite transparent, it deposits an insoluble matter on standing; so that urine, passed at bed-time, is found to have a light cloud floating in it by the following morning. This substance consists, in part, of mucus from the urinary passages; and, in part, of the super-urate of ammonia, which is much more soluble in warm than in cold water. The urine is extremely prone to decomposition. When kept for a few days, it acquires a strong smell, which, being sui generis, has been called urinous; and as the decomposition proceeds, the odour becomes extremely disagreeable. The urine, as soon as these changes commence, ceases to have an acid reaction, and the earthy phosphates are deposited. In a short time, a free alkali makes its appearance; and a large quantity of the carbonate of ammonia is generated. These phenomena are owing to the decomposition of urea, which is almost wholly resolved into carbonate of ammonia. Dr. Henry affirms, that the following substances have been satis- factorily proved to exist in healthy urine,—water, free phosphoric acid, phosphate of lime, phosphate of magnesia, fluoric acid, uric acid,* benzoic acid, lactic acid, urea, gelatine, albumen, lactate of ammonia, sulphate of potash, sulphate of soda, fluate of lime, mu- riate of soda, phosphate of soda, phosphate of ammonia, sulphur^ and silex. The most recent and elaborate analysis of the urine has been given by Berzelius. He states it to consist in 1000 parts, of wa- ter, 933.00; urea, 30.10; sulphate of potassa, 3.71; sulphate of soda, 3.16; phosphate of soda, 2.94; muriate of soda, 4.45; phosphate of * In Vol. I. p.17, this acid is accidentally said to be "found in the urine of man, birds, serpents, &c. and silk worms," instead of, " and in the excrements of silk worms." Vol. II. 31 242 SECRETION. ammonia, 1.65: muriate of ammonia, 1.50; free lactic acid, lactate of ammonia, animal matter soluble in alcohol, and urea not sepa- rable from the preceding, 17.14; earthy phosphates, with a trace of fluate of lime, 1.00; lithic acid, 1.00; mucus of the bladder, 0.32; silex, 0.03. The yellowish-red incrustation, deposited on the sides of chamber utensils, is the uric acid. This is the basis of one of the varieties of calculi. The quantity of urine, passed in the twenty-four hours, is very variable. On the average, it is estimated at two pounds, or two pounds and a half; hence the cause of the great size of the renal ar- tery, which, according to the estimate of Haller, conveys to the kidney a sixth or eighth part of the whole blood. Its quantity and character vary according to age, and, to a certain extent, according to sex. We have already seen, under the head of cutaneous exha- lation, how its quantity varies, according to climate and season; and it is influenced by the serous, pulmonary, and cellular exhalations likewise: one of the invariable concomitants of dropsy is diminution in the renal secretion. Its character, too, is modified by the nature of the substances received into the blood. Rhubarb, turpentine, and asparagus materially alter its physical properties; whilst certain articles stimulate the kidney to augmented secretion, or are diure- tics. The urine does not appear to be intended for any local function. Its use seems to be restricted to the removal of the elements of the substances, of which it is composed, from the blood; hence it is solely depuratory and decomposing. How this decomposition is accomplished, we know not. We have already referred to the experiments, performed by MM. Prevost and Dumas, and by Segalas, in which urea was found in the blood of animals whose kidneys had been extirpated: an in- quiry has consequently arisen,—how it exists there. Prior to these experiments, it was universally believed, that its formation is one of the mysterious functions executed in the intimate tissue of the kidney. The peculiarity of urea is, that it contains a very large proportion of azote, so that it has been imagined, the kidney may possibly be the outlet for any excess of nitrogen, or for preventing its accumu- lation in the system. The quantity of azote discharged in the form of urea, is so great, even in those animals, whose food does not essentially contain this element, that it has been conceived a necessary ingredient in the nutrition of parts, and especially in the formation of fibrine, which, we have seen to be a chief constituent of the blood, and of every muscular organ. The remarks, made on the absorption of azote during respiration, indicate how it is received into the system; and it has been presumed, that the superfluous portion is thrown off in the form of urea. OF THE URINE. 243 The experiments of MM. Prevost and Dumas, and of Segalas, would certainly favour the conclusion, that urea may exist ready formed in the blood, and that the great function of the kidney may be to separate it along with the other constituents of the urine. Adelon ascribes the source of the urea to the products of inter- stitial decomposition. He conceives, that, in this shape, they are received into the blood, and that the office of the kidneys is to se- parate them. All this is necessarily conjectural, and it must be ad- mitted, that our knowledge of the subject is by no means ample, and that we must wait for farther developments. Certain it is, that the removal of the constituents of the urinary secretion from the blood is all important. Experiments on animals have shown, that if it be suppressed by any cause for about three days, death supervenes, and the dangers to man are equally im- minent. In consequence of the rapidity with which fluids, received into the stomach, are sometimes voided by the urinary organs, it has been imagined, either that vessels exist which communicate directly between the stomach and bladder, or that the fluid passes through the intermediate cellular tissue, or by means of the anastomoses of the lymphatics. In support of the opinion that a more direct passage exists, the assertion of Chirac,—that he saw the urinary bladder become filled with urine, when the ureters were tied, and that he excited urinous vomiting, by tying the renal arteries, is adduced. It has been farther affirmed, that the oil, composing a glyster, has been found in the bladder. Darwin, having administered to a friend a few^ grains of nitrate of potassa, collected his urine at the expiration of half an hour, and had him bled. The salt was detected in the urine, but not in the blood. Brande made similar experiments with the prussiate of potassa, from which he inferred, that the circulation is not the only medium of communication between the stomach and the urinary organs, without, however, indicating the nature of the supposed medium; and this view is embraced by Sir Everard Home, Wollaston, Marcet, and others. Very recently, Lippi, of Florence, thinks he has found an anatomical explanation of the fact. According to him, the chyliferous vessels have not only nu- merous inosculations with the mesenteric veins, either before their entrance into the mesenteric glands, or whilst they traverse the glands, but, when they attain the last of those glands, some of them proceed to open directly into the renal veins, and into the pelves of the kidneys. At this place, according to him, the chyliferous ves- sels divide into two sets; the one, ascending and conveying the chyle into the thoracic duct; the other, descending and carrying the drinks into the renal veins and pelves of the kidneys. He affirms, that the distinction between these two sets is so marked, that an in- jection, sent into the former, goes exclusively into the thoracic duct, 244 SECRETION. whilst if it be thrown into the latter it passes exclusively to the kid neys. These direct vessels Lippi calls vasa chylopoietica urinifera. If the assertions of Lippi were anatomical facts, it would be ob- viously impossible to doubt some of the deductions; other anato- mists have not, however, been so fortunate as he; and, consequently, it may be well to make a few comments. Some of these chylopoietica urinifera, he affirms, open into the renal veins. This arrangement, it is obvious, cannot be invoked to account for the shorter route,—the royal road to the kidney: the renal vesSel is conveying the blood back from the kidney, and every thing, that reaches it from the intestines, must necessarily pass into the vena cava, and ultimately attain the kidney through the renal artery. The vessels, therefore, that end in the renal veins, must be put entirely out of the question, so far as regards the topic of dispute; and our attention be concentrated upon those that termi- nate in the pelvis of the kidney. Were this termination proved, we should be compelled, as we have remarked, to bow to authority; but not having been so, it may be stated as seemingly improbable, that the ducts in question should take the circuitous course to the pelvis of the kidney, instead of proceeding directly to the bladder. We know, then, anatomically, nothing of any canal existing be- tween the stomach and the bladder; and we have not the slightest evidence,—positive or relative,—in favour of the opinion, that there is any transmission of fluid through the intermediate cellular tissue. We have, indeed, absolute testimony against it. MM. Tiedemann and Gmelin, having examined the lymphatics and cellular tissue of the abdomen in cases where they had administered indigo and essence of turpentine to animals, discovered no traces whatever of them, whilst they could be detected in the kidney. The facts, again, referred to by Chirac, are extremely doubtful. If the renal arteries be tied, the secretion cannot be effected by the kidney; consequently, no urine ought to be found in the economy, and urinous vomitings would be impossible. On the other hand, if the ureters be tied, the secretion being practicable, death will oc- eur if the suppression be protracted; and, in such case, the secreted •fluid may pass into the vessels and give a urinous character to the perspiration, vomited matters, &c. &c. Again, the experiments of Darwin, Brande, Wollaston, and others only demonstrate, that these gentlemen were unable to de- tect that in the blood which they found in the urine. Against the negative results attained by these gentlemen, we may adduce the positive testimony of Fodera, an experimentalist of weight, espe- cially on those matters. He introduced into the bladder of a rabbit a plugged catheter, and tied the penis upon the instrument to pre- vent the urine from flowing along its sides. He then injected into the stomach a solution of the ferrocyanate of potassa. This being done, he frequently removed the plug of the catheter, and received the drops of urine on filtering paper: as soon as indications of OF THE SPLEEN. 245 the presence of the salt appeared in the urine by the appropriate tests,—which usually required from five to ten minutes after its re- ception into the stomach,—the animal was killed; and, on examin- ing the blood, the salt was found in the serum taken from the tho- racic portion of the vena cava inferior, in the right and left cavities of the heart, in the aorta, the thoracic duct, the mesenteric glands, the kidneys, the joints, and in the mucous membrane of the bronchi. Magendie, too, states, as the result of his experiments,—First. That whenever prussiate of potassa is injected into the veins, or is exposed to absorption in the intestinal canal, or in a serous cavity, it speedily passes into the bladder, where it can be readily recog- nised in the urine. Secondly. That if the quantity of prussiate in- jected be considerable, it can be detected in the blood by reagents; but if the quantity be small, it is impossible to discover it by the ordinary means. Thirdly. That the same thing happens if the prus- siate of potassa be mixed with the blood out of the body. Fourthly. That the salt can be detected, in every proportion, in the urine. The existence, consequently, of any more direct route from the stomach to the bladder than through the venous system is disproved, and the absorption of fluids must be considered to be effected through the vessels described under the absorption of drinks. Such are the glandular secretions that we shall consider in this place. There are still two important fluids, whose uses will have to be detailed in the next class of functions—the sperm and the milk. There are several organs likewise, as the spleen, thyroid, thymus and supra-renal capsules, which are termed glands by many anatomists; but which Chaussier has termed glandiform gan- glions. Of the uses of these we know little or nothing. Yet it is necessary, that the nature of the organs, and the fancied functions should meet with notice. The offices of the thyroid, thymus, and supra-renal capsules, being apparently confined to fcetal existence, will not require consideration here. OP THE FUNCTIONS OF THE SPLEEN. The spleen is a viscus of considerable size, situated in the left hypochondriac region, (Fig. 122, H,) beneath the diaphragm, above the left kidney, and to the left of the stomach. Its medium length is about four and a half inches; its thickness two and a half inches; and its weight about eight ounces. It is of a soft texture, somewhat spongy to the feel, and easily torn. In a very recent subject, it is of a grayish-blue colour; which, in a few hours, changes to a pur- ple, so that it resembles a mass of clotted blood. At its inner surface, or that which faces the stomach and kidney, a fissure exists, by which the vessels, nerves, &c. enter or issue from the organ. 246 OF THE SPLEEN. The anatomical elements of the spleen are:—1. The splenio ar- tery, which arises from thc coeliac, and after having given off branches to the pancreas and thc left gastro-epiploic artery, divides into several branches, which enter the spleen at the fissure, and ramify in the tissue of the organ, so that it seems to be exclusively formed by them. (Fig. 101.) Whilst the branches of the artery are still in the duplicature of the gastro-splenic omentum, and before they ramify in the spleen, they furnish the vasa brevia to the sto- mach. The precise mode of termination of the arteries in the spleen is unknown. The communication of the arteries with the veins does not, however, appear to be as free as in other parts of the body, or the anastomoses between the minute arteries as numerous. If, according to Assolant, one of the branches of the splenic artery be tied, the portion of the spleen to which it is distributed dies; and if air be injected into one of these branches, it does not pass into the others; so that the spleen would appear to be a con- geries of several distinct lobes; and in certain animals the lobes are so separated as to constitute several spleens. A similar appearance is occasionally seen in the human subject. 2. The splenic vein arises by numerous radicles in the tissue of the spleen; these be- come gradually larger and less numerous, and leave the fissure of the spleen by three or four trunks, which ultimately, with veins from the stomach and pancreas, unite to form one, that opens into the vena porta?. It is without valves, and its parietes are thin. These are the chief constituents. 3. Lymphatic vessels, which are large and numerous. 4. Nerves, proceeding from the coeliac plexus: they creep along the coats of the splenic artery,—upon which they form an intricate plexus,—into the substance of the spleen. 5. Cellular tissue, which serves as a bond of union be- tween these various parts; but is in extremely small quantity. 6. A proper membrane, which envelopes the organ externally; ad- heres closely to it, and furnishes fibrous sheaths to the ramifications of the artery and vein; keeping the ramifications separated from the tissue of the organ, and sending prolongations into the parenchyma, which give it more of a reticulated than spongy aspect. 7. Of blood, according to many anatomists, but blood differing from thatof both the splenic artery and vein; containing, according to Vauquelin, less colouring matter and fibrine, and more albumen and gelatine, than any other kind of blood. This, by stagnating in the organ, is conceived to form an integrant part of it. Malpighi believed it to be contained in cells; but others have supposed it to be situated in a capillary system intermediate to the splenic artery and vein. Assolant and Meckel believe, that the blood is in a peculiar state of combination and of intimate union with the other organic elements of the viscus, and with a large quantity of albumen; and that this combination of the blood forms the dark brown pulpy sub- stance, contained in the cells formed by the proper coat, and which can be easily demonstrated by tearing or cutting the spleen, and OF THE SPLEEN. 247 scraping it with the handle of a knife. These cells and the cha racter of the tissue of the spleen are exhibited in the marginal figure. Fig. 126. In addition to the pulp, many ana- tomists assert, that they have met with an abundance of rounded cor- puscles, varying in size from an almost imperceptible magnitude to a line or more in diameter. By Malpighi these were conceived to be granular corpuscles, and by Ruyscii simply convoluted vessels. Besides the proper membrane, the spleen also receives a peritoneal coat; and between the stomach and the organ, the peritoneum forms the gastro-splenic epiploon or gastro- splenic ligament, in the duplica- ture of which are situated the vasa brevia. Lastly, the spleen is capable of distention and contraction; and is possessed of little sensibility in the healthy state. It has no excretory duct. The hypotheses, that have been indulged on the nature of the spleen, are beyond measure numerous and visionary; and after all, we are in the greatest obscurity as to its real uses. Many of these hypotheses are too idle to merit notice; such are those, that consider it to be the seat of the soul,—the organ of dreaming,—of melancholy and of laughter,—of sleep and the vene- real appetite—the organ that secretes the mucilaginous fluids of the joints,—that serves as a warm fomentation to the stomach, and so on. It was long regarded as a secretory apparatus, for the formation of the atrabilis,—of a fluid intended to nourish the nerves,—of the gastric juice,—of a humour intended to temper the alkaline cha- racter of the chyle or bile, &c. The absence of an excretory duct would be a sufficient answer to all these speculations, if the non-existence of these supposititious humours were insufficient to exhibit their absurdity. MM. Tiedemann and Gmelin consider its function to be iden- tical with that of the mesenteric glands. They regard it as a gan- glion of the absorbent system, which prepares a fluid to be mixed with the chyle and effect its animalization. In favour of the view, that it is a part of the lymphatic system, they remark, that it exists only in those animals that have a distinct absorbent system; that its bulk, in animals is in a ratio with the development of the absor- bent system; that the lymphatics predominate in the structure of 248 OF THE SPLEEN. the organ; that its texture is like that of the lymphatic ganglions; and lastly, that, on dissecting a turtle, they distinctly saw all the lymphatics of the abdomen passing first to the spleen, then leaving that organ of larger size, and proceeding to the thoracic duct. In support of their second position, that it furnishes some mate- rial towards the animalization of the chyle, they adduce;—the large size of the splenic artery, which manifestly, they conceive, carries more blood to the spleen than is needed for its nutrition; and they affirm, that, in their experiments, they have frequently found, whilst digestion and chylosis were going on, the lymphatic ves- sels of the spleen gorged with a reddish fluid, which was carried by them into the thoracic duct, where the chyle always has the most rosy hue; and they add, that a substance injected into the splenic artery,'passes readily into the lymphatics of the spleen. Lastly, after extirpating the spleen in animals, the chyle appeared to them to be more transparent; no longer depositing coagula; and the lymphatic ganglions of the abdomen seemed to have augmented in size. Chaussier, as we have seen, classes thc spleen amongst the glan- diform ganglions, and affirms, that a fluid is exhaled into its inte- rior of a serous or sanguineous character, which, when absorbed, assists in lymphosis. Many, again, have believed, that the spleen is a sanguineous, not a lymphatic ganglion, but they have differed regarding the blood on which it exerts its action; some maintaining, that it prepares the blood for the secretion of the gastric juice; others for that of the bile. The former of these views is at once repelled by the fact, that the vessels, which pass from the splenic artery to the stomach, leave that vessel before it enters the spleen. The latter view also rests on very uncertain data and deductions. Since the period of Haller, the blood of the splenic vein has been presumed to differ essentially from that of other veins, which has led to the belief that some elaboration is effected in the spleen so as to fit the blood for the secretion of the bile. It has been described as more aqueous, more albuminous, more unctuous, and blacker than other venous blood; to be less coagulable, less rich in fibrine, and the fibrine it does contain to be less animalized. Yet these affirma- tions have been denied; and even were they admitted, we have no positive knowledge that such changes better adapt it for the forma- tion of bile by the liver. The ideas that have existed regarding its acting as a diver- ticulum for the blood have been mentioned, under the head of Circulation By some, it has been supposed to act as such in the intervals of digestion; or, in other words, to be a diver- ticulum to the stomach; by others, its agency in this way is believed to apply to the whole circulatory system, so that when the flow of blood is impeded or arrested in other parts, it may be received into the spleen. It is hard to [say which of these OF THE SPLEEN. 249 speculations is the most ingenious. None can satisfy the judicious physiologist, especially when he considers the comparative impu- nity consequent on extirpation of the organ. This was an operation performed at an early period. Pliny affirms that it was practised on runners to render them more swift. On animals the spleen has been repeatedly removed, and although many of these have died in consequence of the operation, several have recovered. Adelon refers to the case of a man who was wounded by a knife under the last false rib of the left side. Surgical attendance was not had until twelve hours afterwards; and, as the spleen had issued at the wound, and was much altered, it was considered necessary to extirpate it. The vessels were tied ; the man got well in less than two months, and has ever since enjoyed good health. Sir Charles Bell asserts, in his "Anatomy and Physiology," that an old pupil had recently given him an account of his having cut off the spleen in a native of South America. The spleen had escaped through a wound, and had become gangrenous. He could observe no effect to result from the extirpation. Dr. O'Brien, in an inaugural dissertation, published at Edin- burgh in 1818, refers to a case which fell under his own ma- nagement. The man was a native of Mexico; the spleen lay out, owing to a wound of the abdomen, for two days before the surgeon was applied to. The bleeding was profuse; the vessels and other connexions were secured by ligature, and the spleen separated com- pletely on the twentieth day of the wound. On the forty-fifth day, the man was discharged from the hospital, cured; and he remarked to some one about this time, that " he felt as well as he ever did in his life." Dulaurens, Kerckring, Baillie, and others, refer, also, to cases, in which the spleen has been found wanting in man, with- out any apparent impediment to the functions. The experiments, that have been made on animals by removing the spleen, have led to discordant results. Malpighi says, that the operation was followed by increased secretion of urine; Dumas, that the animals had afterwards a voracious appetite; Mead, and Mayer, that digestion was impaired, that the evacuations were more liquid,and the bile more watery; Tiedemann and Gmelin, that the chyle appeared more transparent and devoid of clot; Professor Cole- man, that the dogs,—the subjects of the experiment,—were fat and indolent. Dupuytren extirpated the spleens of forty dogs on the same day, without tying any vessel, but merely stitching up the wound of the abdomen,—yet no hemorrhage supervened. In the first eight days, half the dogs, operated on, died of inflammation of the abdominal viscera induced by the operation, as was proved by dissection. The other twenty got well without any accident at the end of three weeks at the farthest. At first, they manifested a voracious appetite, Vol. II. 32 250 OF the spleen. but it soon resumed its natural standard. They fed on the same ali- ment, the same drinks, took the same quantity of food, and diges- tion seemed to be accomplished in the same time. The fa?ces had the same consistence, the same appearance, and the chyle appeared to have the same character. Nor did the other functions offer any modification. Dupuytren opened several of these dogs some time afterwards, and found no apparent change in the abdominal circulation,—in that of the stomach, epiploon, or liver. The last organ, which appear- ed to some of the experimenters to be enlarged, did not seem to him to be at all so. The bile alone appeared a little thicker, and deposited a slight sediment. These circumstances render it extremely difficult to arrive at any theory regarding the offices of this anomalous organ. It is mani- festly not essential to life, and therefore not probably inservient to the purposes assigned to it by Tiedemann and Gmelin. Bostock properly remarks, that its office must be something of a supple- mentary or vicarious nature; and this would accord best, perhaps, with the notion of its serving as a diverticulum; the blood speedily passing, after the organ has been extirpated, into other channels. It must be admitted, however, that our knowledge of the function is of a singularly negative and unsatisfactory character. generation. ■251 CLASS III. FUNCTIONS OF REPRODUCTION, OR GENERATION. The functions, which we have been hitherto considering, relate exclusively to the individual. We have now to investigate those, that refer to the preservation of the species; and without which living beings would soon cease to exist. Although these are really multiple, it has been the custom with physiologists to refer them to one head—generation—of which they are made to form the sub- ordinate divisions. The function of generation, much as it varies amongst orga- nized bodies, is possessed by them exclusively. When a mineral gives rise to another of a similar character, it is at the expense of its own existence; whilst the animal and the vegetable, produce being after being, without any curtailment of theirs. The writers of antiquity considered that all organized bodies are produced in one of two ways. Amongst the upper classes of both animals and vegetables they believed the work of reproduc- tion to be effected by a process, which is termed univocal or regu- lar generation; but in the very lowest classes, as the mush- room, the worm, the frog, &c. they conceived that the putrefaction of different bodies, aided by the influence of the sun, might gene- rate life. This has been termed equivocal or spontaneous gene- ration; and is supposed to have been devised by the Egyptians, to account for the swarms of frogs and flies, which appeared on the banks of the Nile after its periodical inundations. Amongst the ancients the latter hypothesis was almost univer- sally credited. Pliny unhesitatingly expresses his belief, that the rat and the frog are produced in this manner; and, at his time, it was generally thought, that the bee, for example, was derived at times from a parent; but at others from putrid beef.* The passage of Virgil,—in which he describes how the shepherd Aristjeus succeeded in producing swarms of bees from the entrails of a steer, exposed for nine days to putrefaction,—is probably fami- liar to most readers:— " First in a place, by nature close, they build A narrow flooring, gutter'd, wall'd and til'd. In this, four windows are contriv'd, that strike To the four winds oppos'd, their beams oblique. • A steer of two years' old they take, whose head Now first with burnish'd horns begins to spread. * "Apes nascuntur partim ex apibus, partim ex bubulo corpore putrefacto."— Varro. 252 generation. They stop his nostrils, while he strives in vain To breathe free air, and struggles with his pain. Knock'd down he dies; his bowels, bruised within, Betray no wound on his unbroken skin. Extended thus, in this obscene abode They leave the beast; but first sweet flow'rs are strew'd Beneath his body, broken boughs and thyme, And pleasing cassia, just renew'd in prime. » * * * * The tainted blood, in this close prison pent, Begins to boil, and through the bones ferment. Then (wond'rous to behold) new creatures rise, A moving mass, at first, and short of thighs; Till, shooting out with legs, and imp'd with wings, The grubs proceed to bees with pointed stings-, And, more and more affecting air, they try Their tender pinions, and begin to fly. At length, like summer storms, from spreading clouds That burst at once and pour impetuous floods— Or flights of arrows from the Parthian bows, When from afar they gall embattled foes: — With such a tempest through the skies they steer, And such a form the winged squadrons bear." Georgic. Lib. iv. The hypothesis of equivocal generation having been conceived, in consequence of the impracticability of tracing ocularly the function in the minute tribes of animals, it naturally maintained its ground, as regarded those animals, until better means of observa- tion were invented. The difficulty, too, of admitting regular gene- ration as applicable to all animals, was augmented by the fact, not at first known to naturalists, that many of the lower tribes conceal their eggs, in order that their nascent larva? may find suitable food. The existence, however, of evident sexual organs in many of those small species, induced physiologists, at an early period, to believe, that they also might be reproduced by sexual intercourse; but direct proofs were not obtained until the discovery of the mi- croscope; after which the investigations of Redi, Vallisneri, Swammerdam, Hooke, Reaumur, Bonnet and others clearly demonstrated, that the smallest insects have eggs and sexes, and that they reproduce like other animals. In the case of plants, it has been supposed that the growth of the fungi amongst dung, and of the various parasitical plants that appear on putrid flesh, fruit, &c. furnishes facts in support of the equivocal theory; but the microscope, exhibits the seeds of many of these plants, and experiments show that they are pro- lific. The characters, by which the different species and varieties are distinguished, although astonishingly minute, are fixed; exhi- biting no fluctuation, such as might be anticipated, did these plants arise by spontaneous generation, or by the fortuitous concourse of atoms. The animalcules, that make their appearance in water, in which GENERATION. 253 vegetable or animal substances have been infused or are contained, would seem, at first sight, to favour the ancient doctrine. In these cases, however, the species, again, have determinate characters; presenting always the same proportion of parts; and appearing to transmit their vitalit)' to their descendants in a manner not unlike that of animals higher in the scale. The explanation offered by the supporters of the univocal theory for those obscure cases, in which direct observation fails us, is, that their seeds and eggs are so ex- tremely minute, that they can be borne about by the winds; be readily deposited in every situation, and when they find a soil or nidus, favourable to their growth, can undergo development. Thus, the soil, in which alone the monilia glauca flourishes, is pu- trid fruit; whilst the small infusory animal—the vibrio aceti or vinegar eel,—requires, for its growth, vinegar that has been for some time exposed to the air. " That the atmosphere," says Dr. Good, " is freighted with myriads of insect eggs, that elude our senses; and that such eggs, when they meet with a proper bed, are hatched in a few hours, into a perfect form, is clear to any one who has attended to the rapid and wonderful effects of what, in common lan- guage, is called a blight, upon plantations and gardens. I have seen, as probably many, who may read this work, have also, a hop- ground completely overrun and desolated by the aphis humuli or hopgreen-louse, within twelve hours after a honey-dew, (which is a peculiar haze or mist, loaded with a poisonous miasm,) has slowly swept through the plantation, and stimulated the leaves of the hop to the morbid secretion of a saccharine and viscid juice, which, while it destroys the young shoots by exhaustion, renders them a favourite resort for this insect, and a cherishing nidus for the my- riads of little dots that are its eggs. The latter are hatched within eight-and-forty hours after their deposit, and succeeded by hosts of other eggs of the same kind; or, if the blight take place in an early part of the autumn, by hosts of the young insects produced vivi- parously; for in different seasons of the year, the aphis breeds both ways. "Now it is highly probable, that there are minute eggs or ovula, of innumerable kinds of animalcules floating in myriads of myriads through the atmosphere, so diminutive as to bear no larger propor- tion to the eggs of the aphis than these bear to those of the wren, or the hedge-sparrow; protected, at the same time, from destruction by the filmy integument, that surrounds them, till they can meet with a proper nest for their reception, and a proper stimulating power to quicken them into life; and which, with respect to many of them, are only found obvious to the senses in different descrip- tions of animal fluids. "The same fact occurs in the mineral kingdom; stagnant water, though putrid by distillation and confined in a marble basin, will, in a short time, become loaded on its surface or about its sides with various species of confervas; while the interior will be peopled with 254 generation. microscopic animalcules. So, while damp cellars are covered with boletuses, agarics and other funguses, the driest brick walls are often lined with lichens and mosses. We see nothing of the animal and vegetable eggs or seeds by which all this is effected; but we know, that they exist in the atmosphere, and that this is the medium of their circulation." This view of the extraneous origin of the seeds of the confervas, &c. is strongly corroborated by an experiment of Senebier. He filled a bottle with distilled water and corked it accurately; not an atom of green matter was produced, although it was exposed to the light of the sun for four years; nor did the green matter, considered as the first stage of spontaneous organization, exhibit itself in a glass of common water, covered with a stratum of oil. The subject of intestinal worms has been eagerly embraced by the supporters of the doctrine of equivocal generation, who, are of opi- nion, that the germs need not be received from without; whilst the followers of the univocal doctrine maintain, that they must always be admitted into the system. The first opinion includes amongst its supporters the names of Needham, Buffon, Patrinus, Treviranus, Rudolphi, Bremser and Himly. The latter comprises those who believe in the Har- veian maxim,—omne vivum ex ovo;—in other words, the majority of the physiologists of the present day. To support the latter opinion, it has been attempted to show, that the worms, found in the human intestines, are precisely the same as others that have been found out of the body; but the evidence in favour of this position is by no means strong or satisfactory. LiNNasus affirms, that the distoma hepaticum or fluke has been met with in fresh water: the taenia vulgaris,—of a smaller size, however,—in muddy springs; and the ascarides vermiculares in marshes and in the putrescent roots of plants. Gadd also affirms, that he met with the taenia articulata plana osculis lateralibus geminis in a chalybeate rivulet; Unzer, the taenia in a well; and Tissot, that he found a taenia, exactly like the human, in a river; whilst Leeuenhoek, Schaeffer, Palmer and others affirm, that they have found the distoma hepaticum in water; but Mueller, who took extraordinary pains in the comparative exa- mination of the entozoa, that infest the human body, with those that are met with in springs, states that he has frequently de- tected the planarias, but never saw one like the distoma hepa- ticum. On the other hand, the supporters of the equivocal theory have attempted, with a good deal of success, to show, that a difference is always discoverable between the worms, that are found without and those within the body; but were it demonstrated to a mathematical certainty, that such difference exists, it would not be an invincible ar- gument against the accuracy of the univocal theory; as difference of locality, food, &c. might induce important changes in their corpo- generation. 255 real development, and give occasion to the diversity which is occa- sionally perceptible amongst them. If we admit, however, that the germs of the entozoa are al- ways received from without, their occurrence, in different stages of development, in the foetus in utero is a circumstance some- what difficult of explanation under that theory. Small, indeed, must be the germ, which, when received into the digestive organs of the mother, can pass into her circulation, be transmitted into the vessels of the foetus, be deposited in some viscus and there undergo its full development; yet such cases have occurred, if the theory be correct. Certain it is, that, however the fact may be ac- counted for, worms have been'found in the foetus by individuals whose testimony cannot be doubted. Frommann saw the distoma hepaticum in the liver of the foetal lamb; Kerckring, ascarides lumbricoides in the stomach of a foetus six and a half months old; Brendel, taeniae in the human foetus in utero; Heim, taeniae in the new-born infant; Blumenbach, taeniae, in the intestine of the new- born puppy; and Goeze, Bloch, and Rudolphi, the same parasite in sucking lambs. Perhaps the conclusion of Cuvier is the soundest and most con- sistent with analogy, that these parasites "propagate by germs so minute as to be capable of transmission through the narrowest passages; so that the germs may exist in the infant at birth." We have seen, that not simply the germs, but the animals them- selves have been found at this early period of existence. Still there are many distinguished naturalists, who conceive it probable, that spontaneous generation may occur in the lowest di- visions of the living scale. Amongst these Lamarck and Geoffroy are perhaps the greatest names; and Adelon seems to accord with them; but the facts, which he adduces in support of the position are singularly inapposite, and feeble. The views of Lamarck, regarding the formation of living bodies, are strange in the extreme; and exhibit to us, what we so frequently witness, that in order to get rid of a subject, which is difficult to the comprehension, the philosopher will frequently explain facts, or adopt suppositions, that require a much greater stretch of the ima- gination to invent, and present stronger obstacles to belief than those for which they are substituted. M. De Lamarck maintains, that the first organized beings were formed throughout by a true spontaneous generation; owing their existence to an excitative cause of life, probably furnished by the circumambient medium, and con- sisting of light and the electric fluid. When this cause met with a substance of a gelatinous consistence and dense enough to retain fluids, it organized the substance into cellular tissue, and a living being re- sulted. This process, according to Lamarck, is occurring daily at the extremity of the vegetable and animal kingdoms. The being, thus formed, manifested three faculties of life;— nutrition, growth, and reproduction,—but only in the most simple 256 GENERATION. manner. The organization soon, however, became more complica- ted, for it is, he remarks, a property of the vital movement to tend always to a greater degree of development of organization, to create particular organs, and to divide and multiply the different centres of activity; and, as reproduction constantly preserved all that had been acquired, numerous and diversified species were, in this man- ner, formed, possessing more and more extensive faculties. So that, according to this system, nature was directly concerned only in the first draughts of life; participating indirectly in the existence of living bodies of a more complex character; and these last pro- ceeded from the former after the lapse of an enormous time, and an infinity of changes in the incessantly increasing complication of organization;—reproduction continuing to preserve all the ac- quired modifications and improvements. The simplest kind of generation does not require sexual organs. The animal, at a certain period of existence, separates into several fragments, which form so many new individuals. This is called fissiparous generation, or generation by spontaneous division. We have examples of it in the infusory animalcules—as the vine- gar eel or vibrio aceti. A somewhat more elevated kind of reproduction is the gemmi- parous, which consists in the formation of buds or germs on some part of the body. These, at a particular period, drop off, and form as many new individuals. According as the germs are developed at the surface of the body, or internally, the gemmiparous generation is said to be external or internal. In these two varieties the whole function is executed by a single individual. Higher up in the scale we find special organs for the accomplish- ment of generation—male and female. In those animals, however, that possess special reproductive organs, some have both sexes in the same individual, or are hermaphrodite or androgynous, as is the case in almost all plants, and in some of the lower tribes of animals. In these, again, we notice a difference. Some are capable of re- production without the concourse of a second individual; others, again, although possessing both attributes, require the concourse of another; the male parts of the one uniting with the female parts of the other, and vice versa. Both, in this way, become impregnated. The helix hortensis or garden snail affords us an instance of this kind of reproduction. They meet in pairs, according to Shaw, and stationing themselves an inch or two apart, launch several small darts, not quite half an inch long, at each other. These are of a horny substance, and sharply pointed at one end. The animals, during the breeding season, are provided with a little reservoir for them, situated within the neck, and opening on the right side. On the discharge of the first dart, the wounded snail immediately re- taliates on its aggressor; by throwing a similar dart; the other re- GENERATION/ 257 news the battle, and in turn, is again wounded. When the darts are ex- pended, the war of love is completed, and its consummation succeeds. In the superior animals each sexual characteristic is possessed by a separate individual,—the species being composed of two indivi- duals, male and female, and the concourse of these individuals, or of matters proceeding from both sexes, being absolutely necessary for reproduction. But here, again, two great differences are met with in the pro- cess. Sometimes the fecundating fluid of the male sex is not ap- plied to the ovum of the female, until after its ejection by the latter, as in fishes. In other cases, the ovum cannot be fecundated after its ejection, and the fluid of the male sex is applied to it whilst still within the female, as in birds and the mammalia. In such case, the male individual is furnished with an organ for penetrating the parts of the female^ and in this kind of generation there must be copulation. Again, where there is copulation, the following varieties may exist. First. The ovum, when once fecundated, may be imme- diately laid by the female, and may be hatched out of the body, con- stituting oviparous generation. Secondly. Although the process of laying may commence immediately, the fecundated ovum may pass so slowly through the excretory passages, that it may be hatched there, and the new individual may issue from the womb of the parent possessing the proper formation. This constitutes ovo- viviparous generation, of which we have an example in the viper. Lastly. The fecundated ovum may be detached from the ovary soon after copulation, but, in place of being ejected, it may be de- posited in a reservoir, termed a womb or uterus; be fixed there; attract fluids from the organ adapted for its development, and thus increasing at the expense of the mother, be hatched, as it were, in this reservoir, so that the new individual may be born under its appropriate form. In such case, moreover, the new being, after birth, may be for a time supported on a secretion of the mother— the milk. These circumstances constitute viviparous generation; in which there are copulation, fecundation, gestation or pregnancy, and lactation or suckling. There is a very considerable difference in animals as regards the nurturing care afforded by the parents to their young. Amongst the oviparous animals, many are satisfied with instinctively de- positing their ova in situations, and under circumstances favour- able to their hatching, and then abandoning them, so that they can never know their progeny. This is the case with insects. Others again, as birds, subject their ova to incubation, and, after they have been hatched, administer nourishment to their young during the early period of existence. In the viviparous animal, these cares are still more extensive; the mother drawing from her own bosom the nutriment needed by the infant, or suckling her young. There are some other varieties in the generation of animals. In Vol. II. 33 258 GENERATION. some, it can be performed but once during the life of the individual; in others, we knbw it can be effected repeatedly. Sometimes one copulation fecundates but a single individual; at others, several ge- nerations are fecundated. A familiar example of this fecundity occurs in the common fowl, in which a single access will be suffi- cient to fecundate the eggs for the season. In the insect tribe this is still more strikingly exemplified. In the aphis puceron or green-plant louse, through all its divisions, and in the monoculus pulex, according to naturalists, a single impregnation suffices for at least six or seven generations. There is in this case another strange deviation from the ordinary laws of propagation, viz. that in the warmer summer months the young are produced viviparously, and in the cooler autumnal months oviparously. A single impregnation of the queen bee will serve to fecundate all the eggs she may lay for two years at least. Huber believes for the whole of her life, but he has had numerous proofs of the former. She begins to lay her eggs forty-six hours after impregnation, and will commonly lay about three thousand in two months, or at the rate of fifty eggs daily. Lastly, the young are sometimes born with the shape which they have always to maintain; at others, under forms, which are, subsequently, materially modified, as in the papi- lio or butterfly genus. The reproduction of the human species requires the concourse of both sexes; these sexes being separate, and each possessed by a dis- tinct individual—male and female. All the acts comprising it may be referred to five great heads. 1. Copulation, the object of which is to apply the fecundating principle, furnished by the male, to the germ of the female. 2. Conception or fecundation, the prolific result of copulation. 3. Gestation or pregnancy, com- prising the sojourn of the fecundated ovum in the uterus, and the development it undergoes there. 4. Belivery or accouchement, which consists in the detachment of the ovum; its excretion and the birth of the new individual; and lastly, lactation, or the nou- rishing of the infant on the maternal milk. Of the Generative Apparatus. The part, taken by the two sexes in the process of generation, is not equally extensive. Man has merely to furnish the fluid, neces- sary for effecting fecundation, and to convey it within the female. He consequently participates only in copulation and fecundation; whilst, in addition, the acts of gestation and lactation are accom- plished by the female. Her generative apparatus is therefore more complicated, and consists of a greater number of organs. 1. Of the Genital Organs of the Male. The generative apparatus of the male comprises two orders of parts:—those which secrete and preserve the fecundating fluid, and GENERATIVE APPARATUS. 259 those which accomplish copulation. The first consist of two simi- lar glands—the testes—which secrete the sperm or fecundating fluid from the blood. 2. The excretory ducts of those glands—the vasa deferentia. 3. The vesiculae seminales, which communicate with the vasa deferentia and urethra ; and 4. Two canals, called ejacu- latory, which convey the sperm from the vesicula? seminales into the canal of the urethra, whence it is afterwards projected exter- nally. The second consists of the penis, an organ essentially com- posed of erectile tissue, and capable of acquiring considerable ri- gidity. These parts will require a more detailed notice. Testes.—The testicles are two glands situated in a bag, suspend- ed beneath the pubes, called the scrotum; the right being a little higher than the left. They are of an ovoid shape, compressed late- rally, their size being usually that of a pigeon's egg, and their weight about seven and a half, or eight drachms. Like other glands, they receive arterial blood by an appropriate < vessel, which communicates with the excretory duct. The sper- matic artery conveys the blood, from which the secretion has to be operated, to the testicle. It arises from the abdominal aorta at a very acute angle, is small, extremely tortuous, and passes down to the abdominal ring, through which it proceeds to the testicle. When it reaches this organ, it divides into two sets of branches, some of which are distributed to the epididymis, others enter the testicle at its upper margin, and assist in constituting its tissue. The excretory ducts form, in the testicle, what are called the seminiferous vessels or tubuli seminiferi. These terminate in a white cord or nucleus, situated at the upper and inner part of the organ, where the excretory duct commences, and which is called the corpus highmorianum or sinus of the seminiferous vessels. Besides these anatomical elements of the testes, there are also—1. Veins, termed spermatic, which return the superfluous blood back to the heart. These arise in the very tissue of the organ, and form the spermatic plexus, the divisions of which collect in several branches, that pass through the abdominal ring, and unite into a single trunk, which subsequently divides again into another plexus, termed corpus pampinifor me. This has been described as pecu- liar to the human species, and as a diverticulum for the blood of the testicle, whose functions are intermittent. These veins ulti- mately terminate on the right side in the vena cava, and on the left in the renal vein. 2. Lymphatic vessels, in considerable number, the trunks of which, after having passed through the abdominal ring, open into the lumbar glands. 3. Nerves, partly furnished by the renal and mesenteric plexuses and by the great sympathetic, partly by the lumbar nerves, and which are so minute as not to be traceable as far as the tissue of the testicle. 4. An outer membrane or envelope to the whole organ, called tunica albuginea or peri- testis. This is of an opaque white colour, of an evidently fibrous and close texture, and envelopes and gives shape to the organ. It also sends into the interior of the testicle numerous filiform, flat- 260 GENERATION. tened prolongations, which constitute incomplete septa or parti- tions. These form triangular spaces, filled with seminiferous ves- sels, that pass, with considerable regularity, towards the superior margin and the corpus highmorianum. These elements united constitute the testicle, the substance of which.is soft, of a yellowish-gray colour, and divided by prolonga- tions of the tunica albuginea, into a considerable number of lobes and lobules. It seems to be formed of an immensity of very deli- cate, tortuous filaments, interlaced and convoluted in all directions, loosely united, and between which are ramifications of the sper- matic arteries and veins. According to Monro Secundus, the seminiferous tubes of the testicle do not exceed the -^oth part of an inch in diameter, and, when filled with mercury, the -j-^th Par^ °f an incn« He calcu- lated, that the testis consists of 62,500 tubes, supposing each to be one inch long; and that if the tubes were united, they would be 5208 feet and 4 inches long. The tubuli seminiferi finally termi- nate in straight tubes, called vasa recta, which unite near the cen- tre of the testis, in a complicated arrangement bearing the name rete testis or rete vasculosum testis; from this from 12 to 18 ducts proceed upwards and backwards to penetrate the corpus highmorianum and the tunica albuginea. These ducts are called vasa efferentia. Each of them is afterwards convoluted upon itself, so as to form a conical body, called conus vasculosus, having its base backwards; and at its base the tube of each cone enters the tube of which the epididymis is formed. The epididymis is the prismatic arch, B, C. 127. Fig. 127, which rests vertically on the back of the testicle and ad- heres to it by the re- flection of the tunica vaginalis, so as to ap- pear a distinct part from the body of the testis. It is enlarged at both ends; the upper enlargement being formed. by the coni vasculosi, and called the globus major; the lower the globus minor. The epidi- dymis is formed by a single convoluted tube, the fourth of a line in diameter.When Left hand Fig. The testicle covered by its membranes, and seeming the tube attains the like one body .—Rig ht lumd F;>.The testicle! freed from its outer coat, i 1 f .1 1 —A. Body of the testicle.— B. Commencementof the epididymis, or lOWer CnU 01 tne glO- ft.m°/0''"C'Thesmallhcador*r'o6"f minor'"D" Th'vasdc' bus minor, it becomes GENERATIVE APPARATUS. 261 less convoluted, enlarges, turns upwards, and obtains the name of vas deferens. The testes of most animals, that procreate but once a year, are comparatively small during the months when they are not excited. In man, the Organ before birth, or rather during the greater part of gestation, is an abdominal viscus; but, about the seventh month of foetal existence, it gradually descends through the abdominal ring into the scrotum, which it reaches in the eighth month, by a mechanism to be described hereafter. In some cases, it never de- scends, but remains in the cavity of the abdomen, giving rise to considerable mental distress in many instances, and exciting the idea, that there may be a total absence of the organs, or that, if they exist, they cannot effect the work of reproduction. The uneasiness is needless, the descent appearing to be by no means essential. It has been sufficiently demonstrated, that indivi- duals, so circumstanced, are capable of procreation. In many animals, the testicles are always internal; whilst, in some, they appear only in the scrotum during the season of amorous excite- ment. Foder6 has indeed asserted, that the crypsorchides, or those whose testes have not descended, are occasionally remarked for the possession of unusual prolific powers and sexual vigour.* It appears, that there is a set of barbarians at the back of the Cape of Good Hope, who are generally possessed of but one testi- cle, or are monorchides; and Linn.eus, under the belief that this is a natural defect, has made them a distinct variety of the human species. Mr. Barrow has noticed the same singularity; but Dr. Good thinks it doubtful, whether, like the want of beard amongst the American savages, the destitution may not be owing to a bar- barous custom of extirpation in early life. The deviation is not, however, more singular than the unusual formation of the nates and of the. genital organs of the female in certain people of these regions, to which we shall have to refer. The testicle is connected with the abdominal ring by means of the spermatic cord, a fasciculus of about half an inch in diameter, which can be readily felt through the skin of the scrotum. It is formed, essentially, of the vessels and nerves that pass to or from the testicle;—the spermatic artery, spermatic veins, lymphatics and nerves of the organ, and the vas deferens, or excretory duct. These are bound together by means of cellular tissue; and, exter- nally, a membranous sheath of a fibrous character envelopes the cord, and keeps it distinct from the surrounding parts, and espe- cially from the scrotum. When the cord has passed through the abdominal ring, its various elements are no longer held together, but each passes to its particular destination. * " Ces organes paraissant tirer du bain chaud ou its se trouvent plong^s plus d'aptitude a. la secretion que Iorsqu'ils sout descendus au dehors dans leurs en- veloppes ordinaires"!—Truite de Medecint legale, t. 1, p. 370. 262 GENERATION. The scrotum or purse is a continuation of the skin, of the Inner side of the thighs, the perineum, and the penis. It is sym- metrical, the two halves being separated by a median line or raphe. The skin is of a darker colour here than elsewhere; is rugous, studded with follicles, and sparingly furnished with hair. This may be considered its outermost coat. Beneath this is the dartos, —a reddish, cellular membrane, which forms a distinct sac for each testicle, and a septum—the septum scroti—between them. Much discussion has taken place regarding the nature of this en- velope; some supposing it to be muscular, others cellular. Bres- chet and Lobstein affirm,^hat it does not exist in the scrotum before the descent of the testes, and they consider it to be formed by the expansion of the gubernaculum testis. Meckel, however, suggests, that it constitutes the transition between the cellular and muscular tissues, and that there exists between it and other mus- cles the same relation that there is between the muscles of the su- perior and inferior animals. It consists of long fibres considerably matted together, and passing in every direction, but which are easily separable by distention with air or water, and by slight ma- ceration. The generality of anatomists conceive it to be of a cellular cha- racter, yet it is manifestly contractile, corrugates the scrotum, and probably consists of muscular tissue also. Dr. Horner, in- deed, affirms that he dissected a subject in January, 1830, in which the fibres were evidently muscular, although interwoven. Beneath the dartos a third coat exists, which is manifestly mus- cular:—it is called the cremaster or tunica erythroides. It arises from the lesser oblique muscle of the abdomen, passes through the abdominal ring, aids in the formation of the spermatic cord, and terminates insensibly on the inner surface of the scrotum. It draws the testicle upwards. The cellular substance, that connects the dartos and cremaster with the tunica vaginalis, has been considered by some as an ad- ditional coat, and termed tunica vaginalis communis. The tunica vaginalis or tunica elytroides is a true serous membrane, enveloping the testicle and lining the scrotum; having, consequently, a scrotal and a testicular portion. We shall see, hereafter, that it is a dependence of the peritoneum, pushed down by the testicle in its descent, and afterwards becoming separated from any direct communication with the abdomen. The vas deferens or excretory duct of the testicle commences at the globus minor of the epididymis, (C, Fig. 127,) which is itself, we have seen, formed of a convoluted tube. This, when unfolded, according to Monro, measures as much as thirty-two feet. As soon as the vas deferens quits the testicle, it joins the spermatic cord, passes upwards to the abdominal ring, separates from the blood-vessels on entering the abdomen, and descends downwards and inwards to the posterior and inferior part of the bladder, pass- GENERATIVE APPARATUS. 263 Fig. 128. ing between the bas-fond of the latter and the ureter. It then converges towards its fellow along the under extremity of the bladder, at the inner margin of the vesicula seminalis of the same side, and ultimately opens into the urethra near the neck of the bladder. (Fig. 124.) At the base of the prostate it receives a ca- nal from the vesicula, and continues its course to the urethra un- der the name of ejaculatory duct. The vas deferens has two coats, the outermost of which is very firm and almost cartilaginous; but its structure is not manifest. The inner coat is thin, and belongs to the class of mucous mem- branes. The vesiculae seminales, E, Fig. 124, are considered to be two convoluted tubes,—one on each side,—which are two inches or two inches and a half long, and six or seven lines broad at the fun- dus, are situated on the lower fundus of the bladder, between it and the rectum and behind the prostate gland. At their anterior extremities they approach each other very closely, being separated only by the vasa de*ferentia. When in- flated and dried, they present the appearance of cells; but are gene- rally conceived to be tubes, which, being convoluted, are brought with- in the compass of the vesicula?. When dissected and stretched out, they are four or five inches long by about one-fourth of an inch in dia- meter. Amussat, however, denies this arrangement of the vesicula?; and he affirms, that he has disco- , „ „ . , , , c ac • V. Section of vas deferens.—S. Section of ve- Vered them tO be formed Ol a mi-siculaseminalis.—E. Section of ejaculatory duct. nute canal of considerable length, variously convoluted, the folds of which are united to each other by cellular filaments, like those of the spermatic vessels. At the anterior part, termed the neck, a short canal passes off, which unites at an acute angle with the vas deferens, to form the ductus ejaculatorius. The vesicula? are formed of two membranes; the more external like that of the vas deferens, and capable of contracting in the act of ejaculation; and an internal lining, of a white, delicate charac- ter, a little like that which lines the interior of the gall-bladder, and supposed to be mucous. Although the vesicula? are manifestly contractile, no muscular fibres have been detected in them. They are found filled, in the dead body, with an opaque, thick, yellow- ish fluid, very different, in appearance, from the sperm ejaculated during life. The prostate gland, Fig. 124, D, is an organ of a very dense tissue, embracing the neck of the bladder, and penetrated by the 264 GENERATION. urethra, which traverses it much nearer its upper than its lower surface. The base is directed backwards, the point forwards, and its inferior surface rests upon the rectum, so that, by passing the finger into the rectum, enlargements of the organ may be de- tected. The prostate was once universally esteemed glandular, and it is still so termed. It is, now, generally and correctly regarded, as an agglomeration of several small follicles, filled by a viscid, whitish fluid. These follicles have numerous minute excretory ducts, which open on each side of the caput gallinaginis. The glands of Cowper are two small, oblong bodies; of the size of a pea; of a reddish colour, and of a somewhat firm tissue. They are situated anterior to the prostate, parallel to each other, and at the sides of the urethra. Each has an excretory duct, which creeps obliquely in the spongy tissue of the bulb, and opens before the verumontanum. The male organ or penis consists of the corpus cavernosum and corpus spongiosum; parts essentially formed of an erectile tissue, and surrounded by a very firm elastic covering, which pre- vents over-distention, and gives form to the organ. The corpora cavernosa constitute the great body of the penis. They are two tubes which are united and separated by an imper- fect partition. Within them a kind of cellular tissue exists, into which blood is poured, so as to cause erection. The posterior extremities of these cavernous tubes are called crura penis. These separate in the perineum, each taking hold of a ramus of the pubis; and, at the other extremity, the cavernous bodies terminate in rounded points under the glans penis. The anatomical elements of the internal tissue of the corpora cavernosa, are,—the ramifica- tions of the cavernous artery, which proceeds from the internal pudic; those of a vein bearing the same name; and, probably, nerves, although they have not been traced so far. All these ele- ments are supported by filamentous prolongations from the outer dense envelope. A difference of opinion prevails amongst anato- mists, with regard to the precise arrangement of these prolonga- tions. Some consider them to form cells, or a kind of spongy structure, on the plates of which the ramifications of the cavernous artery and vein and of the nerves terminate, and into which the blood is extravasated. Others conceive, that the internal arrangement consists of a plexus of minute arteries and veins, supported by the plates of the outer membrane, interlacing like the capillary vessels, but with this addition, that, in place of the minute veins becoming capillary in the plexus, they are of greater size, forming very extpnsible dila- tations and net-works, and anastomosing freely with each other. If the cavernous artery be injected, the matter first fills the ramifica- tions of the artery, then the venous plexus of the cavernous bodies, and it ultimately returns by the cavernous vein, having produced GENERATIVE APPARATUS. 265 erection. The same effect is caused still more readily by injecting the cavernous vein. Attached to the corpora cavernosa of the penis, and running in the groove beneath them, is a spongy body, of a similar structure,—the cor- pus spongiosum urethras,—through which the urethra passes. It commences, posteriorly, at the bulb of the urethra, already described under the Secretion of Urine, and terminates, anteriorly, in the glans, which is, in no wise, a de- pendency of the corpora cavernosa, but is separated from them by a portion of E their outer membrane; so that erection may take place in one and not simulta- neously in the other; and injections into the corpora cavernosa of the one do not pass into those of the other. The glans appears tO be the final expansion of the A. External membrane or sheath of the ,.i ,. i-i i i penis.—B. Corpus cavernosum.—D. Cor- erectile tissue which surrounds the ure- pus spongiosum urethra. thra. The posterior circular margin of the glans is called the corona glandis, and behind this is a depression called the cervix, collum or neck. Several follicles exist here, called the glandulas odoriferas Tysoni, which secrete an unctuous humour, called the smegma praeputii, which often accumulates largely, where clean- liness is not attended to. The penis is covered by the skin, which forms, towards the glans, the prepuce or foreskin. The cellular tissue that unites it to the organ is lax, and never contains fat. The inner lamina of the prepuce being inserted circularly into the penis, some distance back from the point, the glans can generally be denuded, when the prepuce is drawn back. The under and middle part of the prepuce is attached to the extremity of the glans by a duplicature, called the frasnum praeputii, which extends to the orifice of the urethra. The skin is continued over the glans, but it is greatly modified in its structure, being smooth and velvety, highly delicate, sensi- ble, and vascular. Lastly.—In addition to the acceleratores urinse, the transversus perinei, the sphincter ani, and the levator ani muscles, which we have described as equally concerned in the excretion of urine and semen, the erector penis or ischio-cavernosus muscle is largely connected with the function of generation. The genital organs of man are, in reality, merely an apparatus for a glandular secretion, of which the testicle is the gland; the vesiculae seminales are supposed to be the reservoir; and the vas deferens and urethra the excretory ducts;—the arrangement which we observe in the penis being for the purpose of conveying the secreted fluid into the parts of the female. Vol. II. 34 266 GENERATION. The sperm or semen is secreted by the testicles from the blood of the spermatic artery, by a mechanism, which is no more under- stood than that of secretion in general. When formed it is re- ceived into the tubuli seminiferi, and passes along them to the epididymis, the vas deferens, and the vesiculae seminales, where it is generally conceived to be deposited, until it is projected into the urethra, under the venereal excitement. That this is its course is sufficiently evidenced by the arrangement of the excretory ducts, and by the function which the sperm has to fulfil. De Graaf, however, adduces an additional proof. On tying the vas deferens of a dog, the testicle became swollen, and ultimately the vas deferens gave way between the testicle and the ligature. The causes of the progression of the sperm through the ducts are, the continuity of the secretion by the testicle, and a contrac- tion of the excretory ducts themselves. These are the efficient agents. It has been a question with physiologists, whether the secretion of the sperm is constantly taking place, or whether, as the func- tion of generation is accomplished at uncertain intervals, the secre- tion may not likewise be intermittent. It is impossible to arrive at any positive conclusion on this point. It would seem, however, unnecessary for the secretion to be operated at all times; and it is more probable, that when the vesicula? seminales are emptied of their contents, during coition, a stimulus is given to the testes by the excitement, and they are soon replenished. This, how- ever, is more and more difficult in proportion to the number of re- petitions of the venereal act, the excretory ducts becoming more and more emptied, whilst the secretion takes place at best but slowly. By some, the spermatic and pampiniform plexuses have been regarded ao diverticula to the testes during this intermission of action. The sperm passes slowly along the excretory ducts of the testi- cle, owing partly to the slowness of the secretion, and partly to the arrangement of the ducts, which, as we have seen, are remarkably convoluted, long, and minute. The use of the vesicula? seminales has been disputed. The ma- jority of physiologists regard them to be reservoirs for the sperm, and to serve the same purpose as the gall-bladder in the case of the bile. Others, however, have supposed, that they secrete a fluid of a peculiar nature, the use of which may probably be to dilute the sperm. They are manifestly not essential to the function, as they do not exist in all animals. The dog and cat kind, the bears, opossums, sea-otter, seals, &c, possess them not; and there are several in which there is no direct communication between the duct and the vas deferens, which open separately into the urethra. This cir- cumstance, however, with the fact, that they generally contain, after death, a fluid of different appearance and properties from those of the sperm, with the glandular structure which their coats seem SECRETION OF SPERM. 267 to possess in many instances, is opposed to the views that they are simple reservoirs for the semen, and favours that which ascribes to them a peculiar secretion. Where this communication between the duct of the vesicles and the vas deferens does exist, a reflux of the semen may take place, and an admixture between the sperm and the fluid secreted by them. It is not improbable, however, as Adelon suggests, that all the excretory ducts of the testicle may act as a reservoir; and in the case of animals, in which the vesi- cula? are wanting, they must possess this office exclusively. If we are to adopt the description of Amussat as an anatomical fact, the vesicula? themselves are constituted of a convoluted tube, hav- ing an arrangement somewhat resembling that which prevails in the excretory ducts of the testis. But how, it has been asked, does it happen, that the sperm, in its progress along the vas deferens, does not pass directly on into the urethra by the ejaculatory duct, instead of reflowing into the- spermatic vesicles? This, it has been imagined, is owing to the ex- istence of an arrangement at the opening of the ejaculatory duct into the urethra similar to that which prevails at the termination of the choledoch duct in the duodenum. It is affirmed, by some, that the prostate exerts a pressure on the ductus ejaculatorius, and that the opening of the duct into the urethra is smaller than any other part of it; by others, that the ejaculatory ducts are embraced, along with the neck of the bladder, by the levator ani, and consequently, that the sperm finds a readier access into the duct of the vesicula? seminales. The sperm is of a white colour, and of a faint smell, which,. owing to its peculiar character, has been termed spermatic. It is of a viscid consistence, of a saline, irritating taste, and appears com- posed of two parts, the one more liquid and transparent, and the other more grumous. In a short time after emission, these two parts unite and the whole becomes more fluid. When examined chymically, the sperm appears to be of an alkaline, and albuminous character. Vauquelin analyzed it and found it to be composed,— in 1000 parts,—of water, 900; animal mucilage, 60; soda, 10; cal- careous phosphate, 30. Berzelius affirms that it contains the same salts as the blood along with a peculiar animal matter. No analysis however, has been made of the sperm as secreted by the testicle. The fluid examined has been the compound of the pure sperm and the secretions of the prostate gland and of those of Cow- per. The thicker, whitish portion, is considered to be the secre- tion of the testicles;—the more liquid and transparent consisting of the fluids of the accessory glands or follicles. Some authors have imagined, that a sort of halitus or aura is given off from the sperm, which they have called the aura semi- nis, and have considered to be sufficient for fecundation. The fallacy of this view will be exhibited hereafter. Others have dis- covered, by the microscope, numerous minute bodies in the sperm, 268 GENERATION. which they have conceived to be important agents in generation. These animalcules, however, have been denied to be peculiar to this fluid, and have been regarded as infusory animalcules, similar to those met with in all animal infusions; by others, they have been esteemed organic molecules of the sperm; whilst Virey,—a phy- siologist, strangely fantastic in his speculations,—conceives, that, as the pollen of vegetables is a collection of small capsules, containing wTithin them the true fecundating principle, which is of extreme subtlety, the pretended spermatic animalcules are tubes containing the true sperm, and the motion we observe in them is owing to the rupture of the tubes. The agency of the sperm in fecundation will be considered here- after. It may be observed, however, that in all examinations of it, whether by the microscope or otherwise, we must bear in mind the caution to which we have adverted more than once as applica- ble to the examination of animal fluids in general,—that we ought not to conclude,'positively, from the results of our observations of the fluids when out of the body, that they possess precisely the same characteristics when in it; and this remark is especially ap- plicable to the sperm, which varies manifestly in its sensible pro- perties in a short time after it has been excreted. The sperm being the great vivifying agent,—the medium by which life is communicated from generation to generation,—it has been looked upon as one of the most important if not the most im- portant of animal fluids; and hence it is regarded, by some physi- ologists, as formed of the most animalized materials, or of those that constitute the most elevated part of the new being—the ner- vous system. The quantity of sperm secreted cannot be estimated. It varies according to the individual, and to his extent of voluptuous excite- ment, as well as to the degree of previous indulgence in venereal pleasures. Where the demand is frequent, the supply is larger; although, when the act is repeatedly performed, the absolute quan- tity at each copulation may be less. 2. Genital Organs of the Female. The genital organs of the male effect fewer functions than those of the female. They are inservient to copulation and fecundation only. Those of the female, in addition to parts which fulfil these offices, comprise others for gestation, and lactation. The soft and prominent covering to the symphysis pubis—which is formed by the common integuments, elevated by fat, and, at the age of puberty, covered by hair,—is called the mons veneris. Be- low this, are the labia pudendi or labia majora, which are two large soft lips, formed by a duplicature of the common integuments, with adipous matter interposed. The inner surface is smooth, and studded with sebaceous follicles. The labia commence at the sym- GENERATIVE APPARATUS. 269 physis pubis, and descend to the perineum, which is the portion of integument, about an inch and a half in length, between the pos- terior commissure of the labia and the anus'. This commissure is called the frasnum labiorum or fourchette. The opening be- tween the labia is the vulva. At the upper junction of the labia, and within them, a small organ exists, called the clitoris, which greatly resembles the penis. It is formed of corpora cavernosa, and is terminated, anteriorly, by the glans, which is covered by a prepuce, consisting of a prolonga- tion of the mucous membrane of the vagina. Unlike the penis, however, it has no corpus spongiosum, or urethra attached to it; but is capable of being made erect by a mechanism similar to that which applies to the penis, and has two erector muscles—the erectores clitoridis,—similar to the erectores penis. From the prepuce of the clitoris, and within the labia majora, are the labia minora or nymphas, the organization of which is simi- lar to that of the labia majora. They gradually enlarge as they pass downwards, and disappear when they reach the orifice of the vagina. A singular variety is observed in the organization of those parts amongst the Bosjesmen or Bushmen, the tribe to whose peculiari- ties of organization we have already had occasion to refer. Dis- cordance has, however, prevailed regarding the precise nature of this peculiarity, some describing it as existing in the labia, others in the nympha?, and others, again, in a peculiar organization; some deeming it natural, others artificial. Dr. Somerville, who had numerous opportunities for observation and dissection, asserts, that the mons veneris is less prominent than in the European, and is either destitute of hair, or thinly covered by a small quantity of a soft, woolly nature; that the labia are very small, so that they seem at times to be almost wanting; that the loose, pendulous, and ru- gous growth, which hangs from the pudendum, is a double fold; and that it is proved to be the nympha?, by the situation of the cli- toris at the commissure of the folds, as well as by all other circum- stances ; and that they sometimes reach five inches below the mar- gin of the labia; Le Vaillant says nine inches. Cuvier examined the Hottentot Venus, and found her to agree well with the account of Dr. Somerville. The labia were very small; and a single prominence descended between them from the upper part. It divided into two lateral portions, which passed along the sides of the vagina to the inferior angle of the labia. The whole length was about four inches. When she was examined, naked, by the French Savans, this formation was not observed. She kept the tablier, ventrale cutaneum, or, as it is termed by the Germans, schurze, carefully concealed, either between her thighs, or yet more deeply; and it was not known, until after her death, that she possessed it. 270 GENERATION. the the Its has Both Mr. Barrow- and Dr. Somerville deny that the pecu- liarity is artificially excited. In warm climates, the nympha? are often greatly and inconve- niently elongated, and amongst the Egyptians and other African tribes, it has been the eustom to extirpate them, or to diminish their size. This is wnat is meant by circumcision in the female. The vagina is a canal, which extends between the vulva and the uterus, the neck of which it embraces. It is sometimes called the vulvo-uterine canal, and is from four to six inches long, and an inch and a half, or two inches in diameter. It is situated in the pelvis, between the bladder before, and the rectum behind; is F£g. 130. slightly curved, with the concavity forwards, and is narrower at middle than at extremities. inner surface numerous—chiefly transverse---ruga?, which become less in the progress of age, after repeated acts of copulation, and especially after accouchement. The vagina is A. Section of os pubis.—B. Section of spine and sacrum.—C. Urinary Composed of an in- bladder, moderately distended, and rising; behind the pubis.—D. The fOT,nol miinriMa mom urethra.—E. The uterus.—G. The vagina, embracing the neck of the lemal mUCOUS mem- womb, with the os uteri projecting into it. , brane, suppl ied with numerous mucous follicles, of a dense cellular membrane, and be- tween these a layer of erectile tissue, which is thicker near the vulva, but is, by some, said to extend even as far as the uterus. It is termed the corpus spongiosum vaginae. It is chiefly situated around the anterior extremity of the vagina, below the clitoris, and at the base of the nympha?: the veins of which it is constituted are called plexus reteformis. The upper portion of the vagina, to a small extent, is covered by the peritoneum. The sphincter or constrictor vaginae muscle surrounds the orifice of the vagina, and covers the plexus reteformis. It is about an inch and a quarter wide; arises from the body of the clitoris, and passes backwards and downwards, to be inserted into the dense, white substance in the centre of the perineum, which is common tothe transversi perinei muscles, and the anterior point of the sphincter ani. Near the external aperture of the vagina, is the hymen, or vir- ginal, or vaginal valve, which is a more or less extensive, mem- GENERATIVE APPARATUS. 271 branous duplicative, of variable shape, and formed by the mucous membrane of the vulva where it enters the vagina, so that it closes the canal, more or less completely. It is generally very thin, and easily lacerable; but is sometimes-extremely firm, and prevents penetration. It is usually of a semilunar shape, but is sometimes oval from right to left, or almost circular, with an aperture in the middle, whilst, occasionally, it is entirely imperforate, and of course prevents the issue of the menstrual flux. It is easily de- stroyed by mechanical violence of any kind, as by strongly rubbing the sexual organs of infants by coarse cloths, and by ulcerations of the part; hence its absence is not an absolute proof of the loss of virginity, as it was of old regarded by the Hebrews. Nor is its presence a positive evidence of continence. Individuals have conceived in whom the aperture of the hymen has been so small as to prevent penetration. Around the part of the vagina, where the hymen was situated, small, reddish, flattened, or rounded tubercles afterwards exist, which are of various sizes, and are formed, according to the general opinion, by the remains of the hymen; but Beclard considers them to be folds of the mucous membrane. Their number varies from two to five, or six. Fig. 131. The uterus is a hollow organ, for the reception of the foetus, and its retention during gestation. It is situated in the pelvis, be- tween the bladder, which is before, and the rectum behind, and be- low the convolutions of the small intestines. Fig. 130 gives a la- teral view of their relative situation, and Fig. 131, of their posi- tion, when regarded from before. It is of a conoidal shape, flat- 272 GENERATION. tened on the anterior and posterior surfaces; rounded at the base, which is above, and truncated at its apex, which is beneath. It is of small size; its length being only about two and a half inches; its breadth one and a half inch at the base, and ten lines at the neck; its thickness about an inch. It is divided into the fundus, body, and cervix or neck. The fundus is the upper part of the organ, which is above the insertion of the Fallopian tubes. The body is the part between the insertion of the tubes and the neck; and the neck is the lowest and narrow- est portion, which projects and opens into the vagina. Fig. 132. a. Fundus uteri.—b. Body of the uterus.—c. Neck of the uterus.—d. Os uteri.—e. Vagina.—/",/. Fal- lopian tubes.—g,g. Broad liguments of the uterus.—h, h. Round lig-aments.-^i, p. Fimbriated extremi- ties of the Fallopian tube.—o, o. Ovaries.—I, I. Ligaments of the ovary. At each of the two superior angles are—the opening of the Fal- lopian tube, the attachment of the ligament of the ovary, and that of the round ligament. The inferior angle is formed by the neck, which projects into the vagina to the distance of four or five lines, and terminates by a cleft, situated crosswise, called os tineas, os uteri, or vaginal orifice of the uterus. The aperture is bounded by two lips, which are smooth and rounded in those that have not had children; jagged and rugous in those who are mothers,— the anterior lip being somewhat thicker than the posterior. It is from three to five lines long, and is gene- rally more or less open, especially in those who have had children. " The internal 4javity of the uterus is very small in proportion to the bulk of the organ, owing to the thickness of the parietes, which almost touch internally. It is divided into the cavity of the body, and that of the neck, (Fig. 133.) The former is triangular. The GENERATIVE APPARATUS. 273 tubes open into its upper angles. The second cavity is more long than broad; is broader at the middle than at either end, and at the upper part where it Fig. 134. communicates with the cavity of the body of the uterus, an opening exists, called the in- ternal orifice of the uterus: the external orifice being the os uteri. The inner surface has several transverse ruga?, which are not very prominent. It is covered by very fine villi, and the orifices of several mucous follicles are visible. The marginal figure exhibits the cavity of the uterus, as seen by a vertical antero-poste- rior section. The precise organization of the uterus has been a topic of interesting inquiry amongst anatomists. It is usually considered to be formed of two parts, a mucous membrane in- ternally, and the proper tissue of the uterus, which constitutes the principal part of the substance. The mucous membrane has been esteemed a prolongation of that which lines the vagina. It is very thin; of a red hue in the cavity of the body of the organ; white in that of the neek. Chaus- sier, Ribes and Madame Boivin, however, deny its existence. Chaussier asserts, that having macerated the uterus and a part of the vagina in water, in vinegar, and in alkaline solutions; and having subjected them to continued ebullition, he always observed the mucous membrane of the vagina stop at the edge of the os uteri; and Madame Boivin,—a well-known French authoress on ob- stetrics, who has attended carefully to the anatomy of those organs during pregnancy,—says, that the mucous membrane of the vagina terminates by small expansible folds, and by a kind of prepuce, un- der the anterior lip of the os uteri. In their view, the inner surface of the uterus is formed of the same tissue as the rest of it. The proper tissue of the organ is dense, compact, not easily cut, and somewhat resembles cartilage in colour, resistance, and elasticity. It is a whitish, homogeneous substance, penetrated by numerous minute vessels. In the unimpregnated state, the fibres, which seem to enter into the composition of the tissue, appear ligamentous and pass in every direction, but so as to permit the uterus to be more readily lacerated from the circumference to the centre than in any other direction. The precise character of the tissue is a matter of contention amongst anatomists. To judge from the changes it ex- periences during gestation, and by its energetic contraction in deli- very, it would seem to be decidedly muscular? or at least capable of assuming that character; but, on this point, we shall have occa- sion to dwell hereafter. The uterus has, besides the usual organic constituents,—arte- Vol. II. 35 274 GENERATION. ries, veins, lymphatics, and nerves. The arteries proceed from two sources:—from the spermatic, which are chiefly distributed to the fundus of the organ, and towards'the part where the Fallo- pian tubes terminate; and from the hypogastric, which are sent especially to the body and neck. Their principal branches are readily seen under the peritoneum, which covers the organ: they are very tortuous; frequently anastomose, and their ramifications are lost in the tissue of the viscus, and on its inner surface. The veins empty themselves partly in the spermatic, and partly in the hypo- gastric. They are even more tortuous than the arteries; and, dur- ing pregnancy, they dilate and form what have been termed the uterine sinuses. The nerves are derived partly from the great sympathetic, and partly from the sacral pairs. The appendages of the uterus are:—1. The ligamenta lata or broad ligaments, which are formed by the peritoneum. This membrane is reflected over the anterior and posterior surfaces and over the fundus of the uterus, and the lateral duplicatures of it form a broad expansion, and envelope the Fallopian tubes and ovaria. These expansions are the broad ligaments. (See Fig. 132, g,g, and Fig. 131.) 2. The anterior and posterior ligaments, which are four in number and are formed by the peritoneum. Two of these pass from the uterus to the bladder,—the anterior; and two be- tween the rectum and uterus,—the posterior. 3. The ligamenta rotunda or round ligaments, which are about the size of a goose- quill, arise from the superior angles of the fundus uteri, and, proceeding obliquely downwards and outwards, pass out through the abdominal rings to be lost in the cellular tissue of the groins. They are whitish, somewhat dense, cords, formed by a collection of tortuous veins and lymphatics, of nerves, and of longitudinal fibres which were, at one time, believed to be muscular, but are now generally considered to consist of condensed cellular tissue. Meckel thinks, that these different ligaments contain, between the layers composing them, muscular fibres, which are more or less marked, and which proceed from the lateral margin of the uterus. 4. The Fallopian or uterine tubes; two conical, tor- tuous canals, four or five Fig. 135. inches in length; situated in the same broad liga- ments, which contain the ovaries, and extending from the superior angles of the uterus as far as the lateral parts of the brim of the pelvis. (Figs. 131, 132, and 135.) The ute- ri ne extremity of the tube (Figs. 133 and 135,) is ex- tremely small, and opens into the uterus by an aperture so minute, GENERATIVE APPARATUS. 375 as to scarcely admit a hog's bristle. The other extremity is called the pavilion. It is trumpet-shaped, fringed, and commonly inclined towards the ovary, to which it is attached by one of its longest fimbria?. This fringed portion is called corpus fimbriatum or morsus diaboli. The Fallopian tubes, consequently, open at one end into the cavity of the uterus, and at the other through the peri- toneum into the cavity of the abdomen. They are covered exter- nally by the broad ligament, or peritoneum; are lined internally by a mucous membrane, which is soft, villous, and has many longi- tudinal folds; and between these coats is a thick, dense, whitish membrane, which is possessed of contractility; although muscular fibres cannot be detected in it. Santorini asserts, that in robust females the middle membrane of the tubes has two muscular lay- ers; an externa], the fibres of which are longitudinal, and an in- ternal, whose fibres are circular. The ovaries, (Figs. 132 and 136,) are two ovoid bodies, of a pale red colour, ru- a Fig. 126. b. gous, and near- ly of the size of the testes of the male. They are situated in the Cavity of Ovary. Section of ovary. the pelvis, and are contained in the posterior fold of the broad liga- ments of the uterus. At one time they were conceived to be glan- dular, and were called the female testes; but as soon as the notion prevailed, that they contained ova, the term ovary or egg-vessel was given to them. The external extremity of the ovary has at- tached to it one of the principal fimbria? of the Fallopian tube. The inner extremity has a small fibro-vascular cord inserted into it: this passes to the uterus to which it is attached behind the insertion of the Fallopian tube, and a little lower. It is called the ligament of the ovary, and is in the posterior ala of the broad ligament. It is solid, and has no canal. The surface of the ovary has many round prominences, and the peritoneum envelopes the whole of it, except at the part where the ovary adheres to the broad ligament. The precise nature of its parenchyma is not determined. When torn or divided longitu- dinally, as in Fig. 136, 6, it appears to be constituted of a cellulo- vascular tissue. In this, there are from fifteen to twenty spheri- cal vesicles—ovula Graafiana—varying in size from half a line to three lines in diameter. These are rilled with an albuminous fluid, which is colourless or yellowish, and may be readily seen by dividing the vesicles carefully with the point of a pair of fine scissors. The arteries and veins of the ovaries belong to the spermatics. Their nerves, which are extremely delicate, are from the renal plex- uses; and their lymphatics communicate with those of the kidneys. 276 GENERATION. Such is the anatomy of the chief organs, concerned in the func- tion of generation. Those of lactation we shall describe hereafter. It is obvious, that the sexual characteristics in man are widely separate; and the two sexes are never perhaps, united in the same individual. Yet such an unnatural union has been supposed to exist; from the fabulous son of 'Effmsand a^o^tjj,—Mercury and Venus,—to his less dignified representatives of modern times:— "Nee foemina dici, Nee puer ut possent, neutrumque et utrumque videntur."—Ovid.* We have already remarked, that in the lower animals and in plants such hermaphrodism is common; but in the upper classes, and especially in man, a formation, which gives to an individual the attributes of both sexes, has never, perhaps, been witnessed. Mon- strous formations are occasionally met with; but, if careful examina- tion be made, it can usually be determined to what sex the being be- longs. The generality of cases are produced by unusual develop- ment of the clitoris in the female, or by a cleft scrotum in the male. Only two instances of the kind have fallen under the observation of the author, one of which has been described by the late Profes- sor Beclard of Paris, whose details we borrow. Marie-Madeleine Lefort, aged sixteen years, seemed to belong to the male sex, if attention were paid merely to the pro- portions of the trunk, limbs, shoulders, and pelvis; to the confor- mation and dimensions of the pelvis; to the size of the larynx; the tone of the voice, the development of the hair; and to the form of the urethra, which extended beyond the symphysis pubis. An attentive examination, however, of the genital organs showed, that she* belonged to the female sex. The mons veneris was round and covered with hair. Below the symphysis pubis was a clitoris, re- sembling the penis in shape, twenty-seven millimetres, or about an inch long in the state of flaccidity; and susceptible of slight elon- gation during erection; having an imperforate glans, hollowed be- neath by a duct or channel, at the inferior part of which were five small holes, situated regularly on the median line. Beneath and behind the clitoris a vulva existed, with two nar- row, short and thin labia, furnished with hair, devoid of any thing like testicles, and extending to within ten lines of the anus. Be- tween the labia was a very superficial cleft, pressure upon which communicated a vague sensation of a void space in front of the anus. At the root of the clitoris was a round aperture, through which a catheter could not be passed into the bladder. It could be readily directed, however, towards the anus, in a direction pa- rallel to the perineum. * " Bath bodies in a single body mix, A single body with a double sex."—AnDiso>.. hermaphrodism. 277 When the catheter was passed a little backwards and upwards to the depth of eight or ten centimetres it was arrested by a sensible obstacle, but no urine flowed through it. It seemed to be in the vagina. At the part where the vagina stopped, a substance could be distinguished through the parietes of the rectum, which appeared to be the body of the uterus. No where could testicles be dis- covered. She had menstruated from the age of eight years; the blood issuing in a half coagulated state through the aperture at the root of the clitoris. She experienced, too, manifest inclination for commerce with the male, and a slight operation only would probably have been necessary to divide the apron, closing the vul- va from the clitoris to the posterior commissure of the labia. The urethra extended in this case for some distance beneath the cli- toris, as in the penis, which is unusual. From all the circum- stances M. Beclard concluded, that the person, subjected to the examination of the Sociiti de Mtdecine of Paris, was a female; and that she possessed several of the essential organs of the female;— the uterus, and vagina—whilst she had only the secondary charac- ters of the male;—as the proportions of the trunk and limbs; that of the shoulders and pelvis; the conformation and dimensions of the pelvis; the size of the larynx; the tone of the voice; the develop- ment of the hair; the urethra extending beyond the symphysis pubis, &c. In the year 1818, an individual was exhibited in London, who had a singular union of the apparent characteristics of the two sexes. The countenance resembled that of the male, and she had a beard, but it was scanty. The shape, however, of the body and limbs was that of the female. The students of the Anatomical Theatre of Great Blenheim street, London, of whom the author was one, of- fered her a certain sum, provided she would permit the sexual or- gans to be inspected by the veteran head of the school—Mr. Brookes: to this she consented. She was, accordingly, exposed before the class; and her most striking peculiarities exhibited. The clitoris was large, but not perforate. Mr. Brookes, desirous of trying the experimentum crucis, passed one catheter into the vagina, and attempted to introduce another into the urethra; but fearing discovery, and finding that the mystery of her condition was on the point of being unveiled, she started up and defeated the experiment. No doubt existed in the mind of Mr. Brookes, that there were two distinct canals,—one forming the vagina; the other the urethra,—and that she was consequently female. One of the most complete cases of admixture of the sexes is con- tained in the recent journals, the particulars of which were present- ed by Rudolphi to the Academy of Sciences of Berlin. It was met with in the body of a child, which died, it was said, seven days after birth, but the development of parts led to the supposition, that it was three months old. The penis was divided inferiorly; ^78 GENERATION. the right side of the scrotum contained a testicle; the left side was small and empty. There was a uterus, which communicated at its superior and left portion with a Fallopian tube, behind which was an ovary destitute of its ligament. On the right side, there was neither Fallopian tube, nor ovary, nor ligament, but a true testicle, from the epididymis of which arose a vas deferens. Below the uterus was a hard, flattened, ovoid body, which, when divided, ex- hibited a cavity with thick parietes. The uterus terminated above, in the parietes of this body, but without penetrating its cavity. At its inferior part was a true vagina, which terminated in a cul-de- sac. The urethra opened into the bladder, which was perfect; and the anus, rectum and other organs were naturally formed. Rudolphi considered the ovoid body, situated beneath the uterus, to be the prostate, and vesiculae seminales in a rudimental state. The varieties of these sexual vagaries are extremely numerous; and form occasionally the subject of medico-legal inquiry. Instances of animals being brought forth, whose organs of gene- ration are preternaturally formed, sometimes occur, and they have been commonly called hermaphrodites; but such examples have been rarely investigated. Monstrous productions, having a mixture of the male and fe- male organs, seem to arise most frequently in neat cattle, and have been called free-martins. When a cow brings forth twin calves, one a male and the other apparently a female, the former always grows up to be a perfect bull, but the latter appears destitute of all sexual functions and propensities, and never propagates. This is the free-martin. From Mr. Hunter's observations it would seem, that in all the instances of free-martins, which he examined, no one had the com- plete organs of the male and female, but partly the one and partly the other; and, in all, the ovaria and testicles were too imperfect to perform their functions. In noticing this phenomenon, Sir Everard Home remarks, that it may account for twins being most commonly of the same sex; "and when they are of different sexes," he adds, "it leads us to inquire whether the female, when grown up, has not less of the true female character than other women, and is incapable of having children." "It is curious," says Sir Everard, " and in some mea- sure to the purpose, that, in some countries, nurses and midwives have a prejudice, that such twins seldom breed." The remark of Sir Everard is signally unfortunate, and ought not to have been hastily hazarded, seeing that a slight examination, would have ex- hibited, that there is no analogy between the free-martin and the females in question; and, more especially, as the suggestion accords with a popular prejudice, highly injurious to the pros- pects and painful to the feelings of all who are thus situated. In the London Medical Repository, for September, 1823, Mr. Cribb, of Cambridge, England, has properly observed, that the MENSTRUATION. 279 external characters and anatomical conformation of the free-martin are totally unlike those of the human female. In external appear- ance, the free-martin differs considerably from the perfectly formed cow, the head and neck in particular, bearing a striking resem- blance to those of the bull. Mr. Cribb has, however, brought forward the most decisive evidence in favour of the fallacy of the popular prejudice, by the history of seven cases, which are of themselves sufficient to put the matter for ever at rest. Of these seven cases,—which are all that he had ever known, of women, born under the circumstances in question, having been married,— six had children. Before proceeding to the physiology of generation there is one function, peculiar to the female, which will require consideration. This consists in a periodical discharge of blood from the vulva, oc- curring from three to six days in every month, during the whole time that the female is capable of conceiving, or from the period of puberty to what has been termed the critical age. This discharge is called the catamenia, menses, flowers, &c., and the process menstruation. It seems to be possessed by the human species alone. F. Cuvier, however, asserts that he has discovered indica- tions of it in the females of certain animals. In some females, menstruation is established suddenly, and with- out any premonitory symptoms; but, in the greater number, it is preceded and accompanied by some inconvenience. The female complains of signs of plethora, or general excitement, indicated by redness and heat of skin, heaviness in the head, oppression, quick pulse, and pains in the back or abdomen; whilst the discharge commences drop by drop, but continuously. During the first twenty-four hours the flow is not as great as af- terwards, and is more of a serous character, but on the following day it becomes more abundant and sanguineous, and gradually sub- sides, leaving, in many females, a whitish, mucous discharge, tech- nically termed leucorrhasa, and, in popular language, the whites. The quantity of fluid, lost during each menstruation, varies greatly, according to the individual and to the climate. Its ave- rage is supposed to be from six to eight ounces in temperate climes. By some, it has been estimated as high as twenty, but this is an exaggeration. The menstrual fluid proceeds from the interior of the uterus, and not from the vagina. At one time, it was believed, that in the in- tervals between the flow of the menses, the blood gradually accu- mulates in some parts of the uterus, and when these parts attain a certain degree of fulness, they give way and the blood flows. This office was ascribed to the cells,—which were conceived to exist in the substance of the uterus between the uterine arteries and veins,—and, by some, to the veins themselves, which, owing 280 GENERATION. to their great size, were presumed to be reservoirs, and hence were called uterine sinuses. The objection to these views is,—that we have no evidence of the existence of any such accumulation; and that when the interior of the uterus of one, who has died during menstruation, is examined, there are no signs of any such rupture as that described; whilst the enlarged vessels exist only during pregnancy or during thc expand- ed state of the uterus; the veins, in the unimpregnated uterus, being extremely small, and totally inadequate to such a purpose. The menstrual fluid is a true exhalation, effected from the inner surface of the uterus. This is evident from the change in the lining of the organ during the period of its flow. It is rendered softer and more villous, and exhibits bloody spots, with numerous pores from which the fluid may be expressed. An injection, sent into the arteries of the uterus, also readily transudes through the lining membrane. The appearance of the menstrual fluid in the cavity of the uterus, during the period of its flow; its suppression in va- rious morbid conditions of the organ; and the direct evidence, fur- nished in cases of prolapsus uteri, where the fluid has been seen distilling from the os uteri, likewise show that it is a uterine exha- lation. It has been a question, whether the fluid proceeds from the ar- teries or veins; and this has arisen from the circumstance of its being regarded as mere blood, which it is not. It is in truth but little like blood except in its colour; and it may be distinguished from blood by the smell, which is sui generis, and also by its not being, in general, coagulable. "It is," says Mr. Hunter, " neither similar to blood taken from a vein of the same person, nor to that which is extravasated by accident in any other part of the body ; but is a species of blood, changed, separated, or thrown off from the common mass by an action of the vessels of the uterus, similar to that of secretion, by which action the blood loses the principle of coagulation and, I suppose, life." The fact of the injection, sent into the arteries, transuding through the inner lining of the uterus is in favour of the exhalation taking place from the arteries, and the analogy of all the other exhalations, is confirmatory of the position. The efficient cause of menstruation has afforded ample scope for speculation and hypothesis. As its recurrence corresponds to a revolution of the moon around the earth, lunar influence has been invoked ; but before this solution can be admitted it must be shown, that the effect of lunar attraction is different in the various relative positions of thc moon and earth. There is no day of the month, in which numerous females do not commence their menstrual flux, and whilst the discharge is beginning with some, it is at its acme or decline with others. The hypothesis of lunar influence must therefore be rejected. MENSTRUATION. 281 In the time of Van Helmont, it was believed that a ferment exists in the uterus, which gives occasion to a periodical, intestine motion in the vessels, and a recurrence of the discharge; but inde- pendently of the want of evidence of the existence of such a fer- ment, the difficulty remains of accounting for its regular renova- tion every month. Local, and general plethora have been assigned as causes, and many of the circumstances, that modify the flow, favour the opinion. The fact of, what has been called, vicarious men- struation, has been urged in favour of this view. In these cases, instead of the menstrual flux taking place from the uterus, hemor- rhages occur from various other parts of the body, as the breasts, lungs, ears, eyes, nose, &c. It does not seem, however, that in any of these cases, the term menstruation is appropriate; inasmuch as the fluid is not men- strual, but consists of blood periodically extravasated. Still they would appear to indicate, that there is a necessity for the monthly evacuation, or purgations, as the French term it; and that if this be obstructed, a vicarious hemorrhage may be established; yet the loss of several times the quantity of blood from the arm, previous to, or in the very act of, menstruation does not always prevent or interrupt the flow of the catamenia; and in those maladies, that are caused by their obstruction, greater relief is afforded by the flow of a few drops from the uterus itself, than by ten times the quan- tity from any other part. Some of the believers in local plethora of the uterus have main- tained, that the arteries of the pelvis are more relaxed in the female than in the male; whilst the veins are more unyielding; and hence, .that the first of these vessels convey more blood than the second return. It has been also affirmed, that whilst the arteries of the head predominate in man, by reason of his being more disposed for intellectual meditation; the pelvic and uterine arteries predominate in the female, owing to her destination being more especially for reproduction. Setting aside all these gratuitous assumptions, it is obvious that a state, if not of plethora, at least of irritation, must occur in the uterus every month, which gives occasion to the menstrual secre- tion; but, as Adelon has properly remarked, it is not possible to say why this irritation is renewed monthly, any more than to ex- plain why the predominance of one organ succeeds that of another in the succession of ages. The function is as natural, as instinctive, to the female, as the development of the whole sexuak system at the period of puberty. That it is connected most materially with the capability of reproduction is shown by the fact, that it does not make its appearance until puberty,—the period at which the young female is capable of conceiving,—and that it disappears at the cri- tical time of life, when conception is impracticable. It is arrested, too, as a general principle, during pregnancy, and lactation; and in Vol. II. 36 282 generation. amenorrhea or obstruction of the menses fecundation is not readily effected. In that variety, indeed, of menstruation, which is ac* complished with much pain, at every period, and is accompanied by the secretion of a membranous substance having the shape of the uterine cavity, conception may be esteemed impracticable. Pro- fessor Hamilton, of the University of Edinburgh, is, indeed, in the habit of adducing this, in his lectures, as one of two circumstances— the other being the want of a uterus—which are alone invincible ob- stacles to fecundation. Yet, in the case of dysmenorrhcea, of the kind mentioned, if the female can be made to pass one monthly period without suffering, or without the morbid secretion from the uterine cavity, she will sometimes become pregnant, and the whole of the evil will be removed: for, the effect of pregnancy being to arrest the catamenia, the morbid habit is Usually got rid of during gestation, and lactation, and does not subsequently recur. Gall strangely supposes, that some general, but extraneous cause of menstruation exists,—not the influence of the moon; and he affirms that, in all countries, females generally menstruate about the same time; that there are, consequently, periods of the month in which none are in that condition; and he affirms, that all females may, in this respect, be divided into two classes:—the one comprising those that menstruate in the first eight days of the month, and the other, those that are " unwell"—as it is termed by them, in some countries—in the last fortnight. He does not, however, attempt to divine what this cause may be. We are sa- tisfied that his positions are erroneous. Some considerable atten- tion to the matter has led us to the belief, already expressed, that there is no period of the moon, at which the catamenial discharge is not taking place in some, and we have not the slightest reason for believing, that on the average more females are menstruating at any one part of the month than at another. After these comments, it is unnecessary to notice the visionary speculations of those, who have regarded menstruation as a me- chanical consequence of the erect attitude, or the opinion of Rous- sel, that it originally did not exist, but that being produced arti- ficially by too succulent a regimen, it was afterwards propagated from generation to generation; or finally, that of Aubert, who maintained, that if the first amorous inclinations were satisfied, the resulting pregnancy would totally prevent the establishment of menstruation. The function, it need scarcely be said, is instinc- tive, and forms an essential part of the female constitution. The age, at which menstruation commences, varies in indi- viduals and in different climates. It is a general law, that the warmer the climate, the earlier the discharge takes place, and the sooner it ceases. In some climates, it begins at nine years of age, whilst in northern regions, women may not arrive at puberty until they are seventeen or eighteen years old. In the temperate zone, the most common period is from thirteen to fifteen years. Men- INSTINCT OP REPRODUCTION. 283 struation commonly ceases in the same zone at from forty to fifty years of age. In oriental climes, the menses begin soon, flow co- piously, and end early: females being old when those of the tem- perate regions would be still in their prime. In northern regions, on the contrary, they begin late, flow sparingly, and continue long. These rules are, however, liable to many exceptions. The menses, with powers of fecundity, have continued, in particular instances, much beyond the ages that have been specified; some of these protracted cases having had regular catamenia; in others, the discharge, after a long suppression, having returned. A relation of Haller had two sons after her fiftieth year; and children are said to have been born, even after the mother had attained the age of sixty. Holdefreund relates the case of a female, in whom menstruation continued till the age of seventy-one; Bourgeois till the age of eighty; and Hagendorn to ninety; but it is probable, that these were not cases of true menstruation, but perhaps of irre- gularly periodical discharges of true blood from the uterus or va- gina. During the existence of menstruation the system of the female is more irritable than at other times; so that all exposure to sud- den and irregular checks of transpiration should be avoided, as well as every kind of mental and corporeal agitation, otherwise the pro- cess may be impeded, or hysterical and other troublesome affec- tions be excited,. Physiology of Generation. In man and the superior animals, in which each sex is possessed by a distinct individual, it is necessary that there should be a union of the sexes, and that the fecundating fluid of the male should be conveyed within the appropriate organs of the female; in order that, from the concourse of the matters furnished by both sexes, a new individual may result. To this union we are incited by an imperious instinct, establish- ed within us for the preservation of the species; as the senses of hunger and thirst are placed within us for the preservation of the individual. This has been termed the desire or instinct of repro- duction; and, for wise purposes, its gratification is attended with the most pleasurable feelings which man or animals can experience. Prior to the period of puberty, or whilst the individual is inca- pable of procreation, this desire does not exist; but it suddenly makes its appearance at puberty, persists vehemently during youth and the adult age, and disappears in advanced life, when pro- creation becomes again impracticable. It is strikingly exhibited in those animals, in which generation can only be effected at particu- lar periods of the year, or whilst they are in heat: as in the deer during the rutting season. The views that have been entertained, regarding the seat of this 2S4 GENERATION. instinct—whether in the encephalon or genital organs—were con* sidered under the head of the mental and moral manifestations. It was there stated, that Cabanis and Broussais make the internal impressions to proceed from the genital organs, but to form a part of the psychology of the individual; and that Gall assigns an encephalic organ—the cerebellum—for its production, and ranks the instinct of reproduction amongst the primary facul- ties of the mind. In farther proof of the idea, which refers it to the encephalon, it may be remarked, that the instinct has been observed in those who, owing to original malformation, have wanted the principal part of the genital organs, whilst it has con- tinued in the case of eunuchs, not castrated till after the age of puberty. In opposition to this view, it has been urged, that simple titilla- tion of the organs will excite the desire. This, however, may be entirely dependent upon association, in which the brain is largely concerned. In many cases, the desire is produced through the agency of vision; when the brain must necessarily be first ex- cited, and, through its influence, the generative apparatus. The cause of the desire has, by some, been ascribed to the pre- sence of sperm, in the requisite quantity, in the vesicula? semi- nales; but, in answer to this, it is urged, that eunuchs, as under the circumstances above mentioned, and females, in whom there is no spermatic secretion, have the desire. , The fact is, we have no more precise knowledge of the na- j?l ture of this instinct, than we have of any of the internal sensations or moral faculties. We know, however, that it exhibits itself in various degrees of intensity, and occasionally assumes an opposite character—constituting anaphrodisia. In the union of the sexes, the part performed by the male is the introduction of the penis,—the organ for the conveyance of the sperm to the uterus,—and the excretion of that fluid, during its in- troduction. In the flaccid state of the organ this penetration is im- practicable; it is first of all necessary, that, under the excitement of the venereal desire, the organ should attain a necessary state of rigidity, which is termed erection. In this state, the organ be- comes enlarged, and raised towards the abdomen; its arteries beat forcibly; the veins become tumid; the skin more coloured, and the heat augmented. It becomes also of a triangular shape, and these changes are indicated by an indescribable feeling of pleasure. Erection is not dependent upon volition. At times, it manifests itself against the will; at others, it refuses to obey it; yet it re- quires, apparently, the constant excitement of the encephalic organ concerned in its production;—the slightest distraction of the mind causing its cessation. The modest and retiring spouse is, at times, unable to consummate the marriage for nights, perhaps weeks; yet, he is only temporarily impotent; for the inclination and the con- COPULATION. 285 sequent erection supervene sooner or later. Pills of the crumb of bread, and a recommendation to the individual not to apfproach his wife for a fortnight, whatever may be his desire, have in almost all cases removed the impotence. The state of erection is not long maintained, except under un- usual excitement; the organ soon returning to its ordinary flacci- dity. Its cause is evidently a congestion of blood in the erectile tissue of the corpora cavernosa, urethra, and glans. Swammerdam and De Graaf cut off the penis of a dog during erection, and found the tissue gorged with blood, and that the organ returned to its flaccid condition, as the blood flowed from it. The same fact, ac- cording to Adelon, has been observed in the human subject, where erection has continued till after death. Mr. Callaway, of Guy's Hospital, London, has described the case of an individual, who, in a state of inebriation, had communication three times with his wife the same night, without the consequent collapse succeed- ing, although emission ensued each time. This condition persisted for sixteen days, notwithstanding the use of the appropriate means: at this time, an opening was made with a lancet in the left crus of the penis, below the scrotum, and a large quantity of dark, grumous blood, with numerous small coagula, escaped. By pressing the penis, the corpora cavernosa were immediately emptied, and each side became flaccid; the communication by the pecten, or septum penis, permitting the discharge of the contents of both corpora by the incision into the left crus. After recovery, the person remain- ed quite impotent, the organ being incapable of erection, owing, as Mr. Callaway judiciously suggests, to the deposition of coa- gulable lymph in the cells of the corpora cavernosa preventing the admission of blood, and the consequent distention of the organ. Artificial erection can, likewise, be induced in the dead body by injections, so that but little doubt need exist, that the enlarge- ment and rigidity of the penis, during erection, are caused by the larger quantity of blood sent into it. The great difficulty has been, to account for this increased flow. The older writers ascribed it to the compression of the internal pudic vein against the symphysis pubis, owing to the organ being raised towards the abdomen by the ischio-cavernosi muscles; and as the cavernous vein empties its blood into the internal pudic, stagnation of blood in the corpora cavernosa ought necessarily to result from such compression, and consequent distention of the or- gan; whilst the cavernous arteries, being firmer, would not yield to the compression, and would, therefore, continue to convey the blood to the penis. It is obvious, however, that here,—as in every case, where the erectile tissue is concerned,—the congestion must be of an active kind: the beating of the arteries and the coloration of the organ in- 286 GENERATION. dicate this; and, besides, it is not possible, that any compression of the pudic vein can precede erection; it must, if it occur at all, be re- garded rather as a consequence of erection than as its cause. The case of the female nipple affords us an instance of erectility, where no compression can be invoked, and where the distention must be caused by augmented flow of blood by the arteries. If the nipple be handled, particularly whilst the female is under voluptuous ex- citement, it will be found to enlarge,and to become rigid, or to be in a true state of erection. The common opinion, amongst physiolo- gists, is, that irritation of this erectile tissue is the first link in the chain of phenomena constituting erection. The feeling of pleasure is certainly experienced there, prior to, and during, erection; and this irritation, like every other, solicits an increased flow of blood into the erectile tissue, which, by organization, is capable of con- siderable distention. The erectile tissues of the corpora cavernosa, and of the corpus spongiosum urethra?, and glans, are all concerned in the process, but in what precise manner physiologists are not entirely agreed. Some have supposed, that the blood is effused into the cells, and is consequently out of the vessels. Another view, supported by some of the most eminent anatomists and physiologists is, that the blood simply accumulates in the venous plexuses of the corpora cavernosa. Such seems to have been the inference of Cuvier, Chaussier, and Beclard, from their injections; and the rapidity, with which erection disappears, favours the notion. It has been asked, again, whether this accumulation of blood be, as we have remarked, an increased afflux by the arteries, or a diminished action of the veins; or these two states combined. The last opinion is probably the most correct. The arteries first respond to the appeal; the organ is, at the same time, raised by the appropriate muscles; its tissue becomes distended, the. plexus of veins becomes turgid, and the return of blood im- peded. In this way, the organ acquires the rigidity, necessary for penetrating the parts of the female. The friction which then occurs, keeps up the voluptuous excitement and the state of erection. This excitement is extended to the whole generative system; the secre- tion of the testicle is augmented; the sperm arrives in greater quantity in the vesicula? seminales; the testicles are drawn up to- wards the abdominal rings by the contraction of the dartos and cremaster, so that the vas deferens is rendered shorter, and, in the opinion of some, the sperm, filling the excretory ducts of the tes- ticle is, in this manner, forced mechanically forwards towards the vesicles. When these have attained a certain degree of distention they contract suddenly and powerfully, and the sperm is projected through the ejaculatory ducts into the urethra. It is at this period, that the pleasurable sensation is at its height. When the sperm reaches the urethra, the canal is thrown into the highest excitement; COPULATION. 287- the ischio-cavernosi and bulbo-cavernosi muscles, with the trans- versus perinei, and levator ani are thrown into violent contraction; the two first holding the penis straight, and assisting the others in projecting the sperm along the urethra. By the agency of these mus- cles and of the proper muscular structure of the urethra, the fluid is expelled, not continuously, but in jets, as it seems to be sent into the urethra by the alternate contractions of the vesicula? semi- nales. The quantity of sperm, discharged, varies materially according to the circumstances previously mentioned; its average is estimated at about two drachms. Along with the true sperm, the fluids of the prostate and of the glands of Cowper are discharged; so as to constitute the semen as we meet with it. When the emission is accomplished, the penis gradually returns to its ordinary state of flaccidity; and it is usually impracticable, by any effort, to repeat the act without the inter- vention of a certain interval of repose, to enable the due quantity of sperm to collect in the spermatic vessels and vesicles. In some persons, however, the excitability is so great, and the secretion of sperm so ready, that no interval is required between the first and second attempt. This comprises the whole of the agency of the male in the func- tion of generation. In man, the emission of sperm is* soon effected ; but in certain animals it is a long process. In the dog, which has no vesicula? seminales, the penis swells so much, during copulation, that it can- not be withdrawn until the emission of sperm removes the erec- tion. In the female, during copulation, the clitoris is in the same state of erection as the penis; as well as the spongy tissue, lining more especially the entrance of the vagina, and it is in these parts, particularly in the clitoris, that pleasure is experienced during sexual desire, and during copulation. This feeling persists the whole time of coition, and ultimately attains its acme, as in the case of the male, but without any spermatic ejaculation. It is not ow- ing to the contact of the male sperm,—-for it frequently occurs before or after emission by the male,—but is dependent upon some inap- preciable modification in the female organs,—in the ovaries or Fallopian tubes, it is supposed by some physiologists. In most cases, an increased discharge takes place from the mucous follicles of the vagina and vulva; but this appears to be gradual, during the progress of coition, and in nowise to resemble the ejaculation of the male. After the kind of convulsive excitement into which the female is thrown, a sensation of languor and debility is expe- rienced, as in the male, but not to the same extent,—and in conse^ quence of no spermatic emission taking place in her, she is capable of a renewal of intercourse more speedily than the male, and can better support its frequent repetition. 28S GENERATION. An admixture having, in this manner, been effected between the materials furnished by the male and those of the female, after a fecundating copulation conception or fecundation results, and the rudiments of the new being are instantaneously constituted. The well-known fact, that, after the removal of the testicles, the indi- vidual is incapable of procreation, although the rest of the genital organs may remain entire, is of itself sufficient to show, that the fecundating fluid is the secretion of those organs, and that this fluid is indispensable. Physiologists have not, however, been satisfied with this fact. Spallanzani examined frogs with great attention, whilst in the act of copulation both in and out of water; and he observed, that, at the moment when the female deposited her eggs, the male darted a transparent liquor through a tumid point which issued from its anus. This liquor moistened the eggs, and fecun- dated them. To be certain that it was the fecundating agent, he dressed the male in waxed taffeta breeches; when he found that fecundation was prevented, and that sperm enough was contained in the breeches to be collected. This he took up by means of a camel's-hair pencil, and all the eggs, which he touched with it, were fecundated. Three grains of this sperm were sufficient to render a pound of water fecundating; and a drop of this solution, which could not contain more than the 2,994,687-500th part of a grain was enough for the purpose. To diminish the objection, that the frog is too remote in orga- nization from man to admit of any analogical deduction, Spallan- zani took a spaniel bitch, which had engendered several times; shut her up some time before the period of heat, and waited until she exhibited evidences of being in that condition, which did not happen until after twenty-three days of seclusion. He then in- jected into the vagina and uterus, by means of a common syringe warmed to 100° of Fahrenheit, nineteen grains of sperm ob- tained from a dog. Two days afterwards she ceased to be in heat, and, at the ordinary period, she brought forth three young ones, which not only resembled her but the dog from which the sperm had been obtained. This experiment has been repeated by Rossi of Pisa, and byBuFFOLiNi of Cesena, with similar results. In some experiments on generation, Prevost and Dumas fe- cundated artificially the ova of the frog. Having expressed the fluid from several testicles, and diluted it with water, they placed the ova in it. These were observed to become tumid and deve- loped ; whilst other ova, placed in common water, merely swelled up, and in a few days became putrid. They observed, moreover, that the mucus, with which the ova are covered in the oviduct, —the part corresponding to the Fallopian tube in the mammalia,— assists in the absorption of the sperm, and in conducting it to the surface of the ovum; and that, in order to succeed in these arti- ficial fecundations, the sperm must be diluted. If too much con- centrated its action is less. They satisfied themselves, likewise, FECUNDATION. 289 that the chief part of the sperm penetrates as far as the ova, as ani- malcules could be detected moving in the mucus covering their surface, and these animalcules they conceive to be the active part of the sperm. It is not, however, universally admitted, that the positive con- tact of the sperm with the ovum is indispensable to fecundation. Some physiologists maintain, that the sperm proceeds no farther than the upper part of the vagina ; whence, according to some, it is absorbed by the vessels of that canal, and conveyed through the circulation to the ovary. This is, however, the most improbable of all the views that have been indulged on this topic; for if such were the fact, impregnation ought to be effected as easily by in- jecting sperm into the blood-vessels,—the female being, at the time, in a state of voluptuous excitement. Others have presumed, that when the sperm is thrown into the vagina, a halitus or aura— the aura seminis—escapes from it, makes its way to the ovary, and impregnates an ovum. Others, again, think that the sperm is projected into the uterus, and that in this cavity it undergoes admixture with the germ furnished by the female ; whilst a last class, with more probability in their favour, maintain that the sperm is thrown into the uterus, whence it passes through the Fal- lopian tube to the ovary, the fimbriated extremity of the tube, at the time, embracing the latter organ. Dr. Dewees,—the able adjunct professor of midwifery in the University of Pennsylvania,—has suggested, that after the sperm is deposited on the labia pudendi or in the vagina, it may be taken up by a set of vessels,—which, he admits, have never been seen in the human female—whose duty it is to convey the sperm to the ovary. This conjecture he conceives to have been in part con- firmed, by the discovery of ducts, leading from the ovary to the vagina, in the cow and sow, by Dr. Gartner of Copenhagen. The objections that may be urged against his hypothesis, Dr. De- wees remarks, "he must leave to others." We have no doubt, that his intimate acquaintance with the subject could have suggested many that are pertinent and cogent. It will be obvious, that if we admit the existence of the ducts, described by Gartner, it by no means follows, that they are certainly inservient to the function in question. Independently, too, of the objection, that they have not been met with in the human female, it may be urged, that if we grant their existence, there would seem to be no reason, why closure of tfye os uteri after impregnation, or division of the Fal- lopian tubes, should prevent subsequent conception, in the former case during the existence of pregnancy, in the latter, for life. These vessels ought, in both cases, to continue to convey sperm to the ovary, and extra-uterine pregnancies or superfcetation ought to be constantly occurring. MM. Prevost and Dumas are the most recent writers, who Vol. II. 37 290 generation. maintain, that fecundation takes place in the uterus, and they as- sign the following reasons for their belief. First. That in their experiments, they always found sperm in the cornua of the uterus, and they conceive it natural, that fecundation should be operated only where sperm is. Secondly. That in those animals, whose ova are not fecundated until after they have been laid, fecundation must necessarily be accomplished out of the ovary; and Thirdly, that in their experiments on artificial fecundation, they have never been able to fecundate ova taken from the ovary. In reply to the first of these positions it has been properly re- marked by Adelon, that the evidence of MM. Prevost and Du- mas, with regard to the presence of sperm elsewhere than in the uterus, is only of a negative character; and that, on the other hand; we have the positive testimony of physiologists in favour of its ex- istence in the Fallopian tubes and ovary. Haller asserts, that he found it there; and MM. Prevost and Dumas afford us evi- dence against the position they have assumed respecting the seat of fecundation. They affirm, that in the first day after copulation, the sperm was discoverable in the cornua of the uterus, and that it was not until after the lapse of twenty-four hours, that it had at- tained the summits of the cornua. Once they detected it in the Fal- lopian tubes:—a circumstance which is inexplicable under the view, that fecundation is accomplished in the uterus. Leeuenhoek and Hartsoeker also found it in some cases in the Fallopian tube. In reply to the second argument it may be remarked, that ana- logies drawn from the inferior animals are frequently very loose and unsatisfactory, and ought consequently to be received with caution. This is peculiarly one of these cases; for the fecundation, in the case adduced, is always accomplished out of the body, and analogy might with equal propriety be invoked to prove, that in the human female, fecundation is also effected out of the body. In answer to the third negative position of MM. Prevost and Dumas, the positive experiments of Spallanzani may be adduced, who succeeded in producing fecundation in ova, that had been pre- viously separated from the ovary. The evidence, that conception takes place in the ovary appears to us convincing. The cases of ovarian pregnancy offer irresistible proof. Of these Mr. Stanley of Bartholomew's Hospital has given an instructive example in the sixth volume of the Medical Trans- actions; and a still more extraordinary instance is related by Dr. Granville in the Philosophical Transactions for 1820. Other varieties of extra-uterine pregnancy are confirmative of the same position. At times, the foetus is found in the cavity of the abdo- men,—the ovum seeming to have escaped from the Fallopian tube, when its fimbriated extremity grasped the ovary to receive the ovum and convey it to the cavity of the uterus. At other times, FECUNDATION. 291 the foetus is developed in the Fallopian tube,—as in the marginal figure,—someimpedimenthav- ing existed to the passage of Fig. 137. the ovum from the ovarium to the uterus. This impedi- ment can, indeed, be excited artificially so as to give rise to tubal pregnancy. Nuck ap- plied a ligature round one of the cornua of the uterus of a bitch, three days after copula- tion; and he found, afterwards, two foetuses arrested in the Fal- Tubal pregnancy. lopian tube between the ligature and the ovary. It is obvious, then, from these facts, either that fecundation oc- curs in the ovarium, or else that the ovum, when fecundated in the uterus, travels along the Fallopian tube to the ovarium and from thence back again to the uterus, which is not probable. Moreover, that the ovaries are indispensable agents in the function of genera- tion is shown by the well-known fact, that their removal, by the operation of spaying, not only precludes reproduction but takes away all sexual desire. In the Philosophical Transactions for 1805, a case is detailed of a natural defect of this kind in an adult woman, who had never exhibited the slightest desire for commerce with the male, and had never menstruated. On dissection, the ovaria were found deficient; and the uterus was not larger than an infant's. But, to prevent impregnation, it is not even necessary that the ovaries should be removed. It is sufficient to deprive them of all immediate communication with the uterus, by simply dividing the Fallopian tubes. On this subject, Haighton instituted numerous experiments, the result of which was, that after this operation, a foetus was in no instance produced. The operation is much more simple than the ordinary method of spaying by the removal of the ovaries, and it has been for several years successfully practised, at the recommendation of the author, on the farm of his friend Mr. Jefferson Randolph, of Virginia. It does not seem that the sim- ple division of the Fallopian tubes takes away the sexual desire, like the removal of the ovaries. Dr. Blundell has proposed this division of the tubes, and even the removal of a small portion of them, so as to render them completely impervious, where the pel- vis is so contracted as not to admit of the birth of a living child in the seventh month; and he goes .so far as to affirm, that the opera- tion is much less dangerous than delivery by perforating the head, when the pelvis is greatly contracted. We have already remarked, that sperm has been found in the cavity of the uterus, and even in the Fallopian tubes. Fabricius ab Acquapendente maintained that it could not be detected there; 292 GENERATION. and Harvey contended, that, in the case of the cow, whose vagina is very long, as well as in numerous other animals, the sperm cannot possibly reach the uterus, and that there is no reason for supposing that it ever does so. In addition, however, to the facts already cited, we may remark, that Mr. John Hunter killed a bitch in the act of copulation, and found the semen in the cavity of the uterus, conveyed thither, in his opinion, per saltum. Ruysch discovered it in the uterus of a woman taken in adultery by her husband and killed by him; and Haller in the uterus of a sheep killed forty-five minutes after copulation. Blumenbach supposes, that, during the venereal orgasm, the uterus sucks in the sperm. It is impossible to explain the mode in which this is accomplish- ed, but the fact of the entrance of the fluid into the uterus seems unquestionable. Granting, then, that conception occurs in the ovarium, and that sperm is projected into the uterus, with or without the action of aspiration referred to by Blumenbach, in what manner does the sperm exert its fecundating agency on the ovarium ? It is mani- festly impossible, that the force of projection from the male can propel it, not only as far as the cornua of the uterus, but also through the narrow media of communication between the uterus and ovary by the Fallopian tubes. This difficulty suggested the idea of the aura seminis or aura seminalis, which, it was sup- posed, might readily pass into the uterus, and through the tubes to- the ovary. Haighton, indeed, embraced an opinion more obscure than this, believing that the semen penetrates no farther than the uterus, and acts upon the ovaria by sympathy; and this view has been adopted by some distinguished individuals. In opposition to the notion of the aura seminis, we have some striking facts and experiments. In all those animals, in which fecundation is accomplished out of the body, direct eontact of the sperm ap- pears necessary. Spallanzani, and MM. Prevost and Dumas found, in their experiments on artificial fecundation, that they were always unsuccessful when they simply subjected the ova to the emanation from the sperm. Spallanzani took two watch-glasses, capable of being fitted to each other, the concave surface of the one being opposed to that of the other. Into the lower he put ten or twelve grains of sperm, and into the other about twenty ova. In the course of a few hours, the sperm had evaporated, so that the ova were moistened by it; yet they were not fecundated, but fecun- dation was readily accomplished by touching them with the sperm that remained in the lower glass. A similar experiment was per- formed by MM. Prevost and Dumas. They prepared about an ounce and a half of a fecundating fluid from the expressed humour of twelve testicles, and as many vesicula? seminales. With two and a half drachms of this fluid they fecundated more than two hundred ova. The remainder of the fluid was put into a small retort to which an adopter was attached. In this, forty ova were placed, ten of which fecundation. 293 occupied the hollowest part, whilst the rest were placed near the beak of the retort. The apparatus was put under the receiver of an air-pump, and air sufficient with- Fig. 138. drawn to diminish the pressure of the atmosphere one- half. The rays of the sun were now di- rected upon the bo- dy of the retort, un- til the temperature Tl Within rose to about a. The retort containing the sperm.—B. The adopter containing the 90° • and after the ova,-c# Bodyof the retort--d- Beak of the retort- lapse of four hours the experiment was stopped, when the follow- ing were the results. The eggs, at the bottom of the adopter, were bathed in a transparent fluid, the product of distillation. They had become tumid as in pufe water, but had undergone no develop- ment. The eggs, near the beak of the retort, were similarly cir- cumstanced, but all were readily fecundated by the thick sperm, which remained at the bottom of the retort. No aura, no emana- tion from the sperm appeared consequently to be capable of im- pregnating these ova. Absolute contact was indispensable. This is probably the case with the human female, and if so, the sperm must proceed from the uterus along the Fallopian tube to the ovarium. The common opinion is, that, during the intense ex- citement at the time of copulation, the tube is raised, and its digi- tated extremity applied to the ovarium. The sperm then proceeds along it,—in what manner impelled we know not,—and attains the ovary. Haller states, that by injecting the vessels of the tube in the dead body, it has assumed this kind of action. De Graaf, too, affirms, that he has found the fimbriated extremity adhering to the ovary, twenty-seven hours after copulation; and Magendie, that he has seen the extremity of the tube applied to a vesicle. As the aura seminis appears to be insufficient for impregnation, it is obviously a matter of moment, that the sperm should be eja- culated as high up into the vagina as possible. It has been often ob- served, that where the orifice of the urethra does not open at the extremity of the glans, but beneath the penis, or at some distance from the point, the individual has been rendered less capable of procreation. In a case that fell under the care of the author, the urethra was opened opposite the corona glandis by a sloughing syphilitic sore, and the aperture continued, in spite of every effort to the contrary. The individual was married, and the father of three or four children; but after this occurrence he had no increase of his family. Many medico-legal writers have considered, that when the urethra terminates at some other than its natural situa- 294 generation. tion, impotence is the necessary result,—that although copulation may be effected, impregnation is impracticable. Zacchias, how- ever, gives a positive case to the contrary. Belloc, too, asserts, that he knew a person, in whom the orifice of the urethra termi- nated at the root of the fra?num, who had four children, that re- sembled the father, two having the same malformation; and Dr. Francis refers to the case of an inhabitant of New York, who, under similar circumstances, had two children. We cannot, there- fore, regard it as an absolute cause of impotence, but the inference is just, that if the semen be not projected far up into the vagina, and in the direction of the os uteri, impregnation is not likely to be accomplished; a fact, which it might be of moment to bear in mind, where the rapid succession of children is an evil of magni- tude. The part, then, to which the semen is applied is the ovary. Let us now inquire into the changes experienced by this body after a fecundating copulation. Fabricius ab Acquapendente, having killed hens a short time after they had been trodden, examined their ovaries, and observ- ed,—amongst the small yellow, round, granula, arranged racemi- ferously, which constitute those organs,—one having a small spot, in which vessels became developed. This increased in size, and was afterwards detached, and received by the oviduct; becoming covered, in its passage through that tortuous canal and the cloaca, by particular layers, especially by the calcareous envelope; and being ultimately extruded in the form of an egg. Harvey, in his experiments on the doe, made similar observations. He af- firms, positively, that the ovary furnishes an ovum, and that the only difference, which exists amongst animals in this respect, is, that, in some, the ovum is hatched after having been laid, whilst, in others, it is deposited in a reservoir—a womb—where it under- goes successive changes. De Graaf instituted several experiments on rabbits, for the purpose of detecting the series of changes in the organs from conception till delivery. Half an hour after copulation, no al- teration was perceptible, except that the cornua of the uterus appeared a little redder thaln usual. In six hours, the coverings of the ovarian vesicles, or vesicles of De Graaf, seemed reddish. At the expiration of a day from conception, three vesicles in one of the ovaries, and five in the other, appeared changed, having become opaque and reddish. After twenty-seven, forty, and fifty hoyrs, the cornua of the uterus and the tubes were very red, and one of the tubes had laid hold of the ovary; a vesicle was in the tube, and two in the right cornu of the uterus. These vesi- cles were as large as mustard seed. They were formed of two membranes, and were filled by a limpid fluid. On the fourth day, the ovary contained only a species of envelope, called, by De Graaf, a follicle: this appeared to be the capsule that had fecundation. 295 contained the ovum. The ovum itself was in the cavity of the uterus, had augmented in size, and its two envelopes were very distinct. Here it remained loose until the seventh day, when it formed an adhesion to the uterus. On the ninth day, De Graaf observed a small opaque point, a kind of,cloud, in the transparent fluid that filled the ovum. On the tenth day, this point had the shape of a small worm. On the eleventh, the embryo was clearly perceptible; and from this period it underwent its full develop- ment, until the thirty-first day, when delivery took place. Malpighi and Vallisnieri also observed, in their experiments, that after a fecundating copulation, a body is developed at the sur- face of the ovary, which subsequently bursts, and suffers a smaller body to escape. This is laid hold of by the tube, and conveyed by it to the uterus. It is not, however, universally admitted, that this body is the impregnated ovum; some affirming, that it is a sperm similar to that of the male; and others, that it is an amor- phous substance, which, after successive developments, becomes the new individual. Haller exposed the females of sheep and of other animals to the males, on the same day; and killed them at different periods after copulation, for the purpose of detecting the whole series of changes, by which the vesicle is detached from the ovary and con- veyed to the uterus. Half an hour after copulation, one of the vesicles of the ovary ap- peared to be prominent; to have on its convexity a red, bloody spot, and to be about to break; in an hour or more, the vesicle gave way, and its interior seemed bleeding and inflamed. What remained of the vesicle in the ovary, and appeared to be its envelope, gradu- ally became inspissated, and converted into a body of a yellowish colour, to which Haller gave the name corpus luteum. The cleft, by which the vesicle escaped, was observable for some time, but, about the eighth day, it disappeared. On the twelfth day, the cor- pus luteum became pale and began to diminish in size. This it continued to do until the end of gestation; and ultimately became a small, hard, yellowish or blackish substance, which could always be distinguished in the ovarium, by the cicatrix left by it. Its size was greater the nearer the examination was made to the period of conception. In a bitch, for example, on the tenth day, it was half the size of the ovary; yet it proceeded in that case, from one vesicle only. In multiparous animals, as many corpora lutea ex- isted as foetuses. The experiments of Haller have been frequently repeated and with similar results. Magendie, whose trials were made on bitches, observed that the largest vesicles of the ovary were greatly augment- ed in size, thirty hours after copulation; and that the tissue of the ovary, surrounding them, had acquired greater consistence, had changed colour, and become of a yellowish-gray. This part was the corpus luteum. It increased for the next three or four days 296 GENERATION. as well as the vesicles; and seemed to contain, in its areola?, a white, opaque fluid, similar to milk. The vesicles now successively rup- tured the external coat of the ovary, and passed to the surface of the organ, still adhering to it, however, by one side. Their size was sometimes that of a common hazelnut, but no germ was per- ceptible in them. The surface was smooth, and the interior filled with fluid. Whilst they were passing to the uterus, the corpus luteum remained in the ovary, and underwent the changes referred to by Haller. In similar experiments, instituted by MM. Prevost and Dumas, no change was perceptible in the ovary during the first day after fecundation; but, on the second day, several vesicles enlarged, and continued to do so for the next four or five days, so that, from be- ing two or three millimetres in diameter, they attained a diameter of eight. From the sixth to the eighth day, the vesicles burst, and allowed an ovule to emerge, which often escaped observation, owing to its not being more than half a millimetre in diameter, but was clearly seen by MM. Prevost and Dumas by the aid of the microscope. This part they term ovule, in contradistinction to that developed in the ovary, which they call vesicle. The latter has the appearance at its surface, of a bloody cleft, into which a probe may be passed; and in this way it can be shown, that the vesicle has an interior cavity, which is the void space left by the ovule after its escape from the ovarium into the Fallopian tube. On the eighth day, in the bitch, the ovule passes into the uterus. All the ovules do not, however, enter that cavity at the same time; an interval of three or four days sometimes occurring between them. When they attain the uterus, they are at first free and floating; and, if examined with a microscope magnifying twelve diameters, they seem to consist of a small vesicle, filled with an albuminous, transparent fluid. If examined in water, their up- per surface has a mammiform appearance, with a white spot on the side. This is the cicatricula. These ovules speedily aug- ment in size, and on the twelfth day foetuses can be recognised in them. From these facts, then, we may conclude, that the sperm excites the vesicles in the ovaria to development; that the ova, within them, burst their covering, are laid hold of by the Fallopian tube, and conveyed to the uterus, where they remain during the period of gestation. The exact time, required by the ovum or ova to make their way into the uterus, has not been accurately determined. Cruik- shank found, that in rabbits forty-eight hours were necessary. Haighton divided one of the Fallopian tubes in a rabbit; and, having exposed the animal to the male, he observed, that gesta- tion occurred only on the sound side. On making this section after copulation, he found, that if it were executed within the two first days, the descent of the ovule was prevented; but if it were de- FECUNDATION. 297 layed for sixty hours, the ovula had passed through' the tube and were in the cavity of the uterus. A case, too, is quoted by writers on this subject, on the authority of a surgeon named Bussieres, who observed an ovoid sac, about the size of a hazelnut and con- taining an embryo, half in the Fallopian tube and half adherent to the ovary. The minuteness of the calibre of the Fallopian tube is not as great a stumbling-block in the way of understanding how this pas- sage is effected, as might appear at first sight. The duct is, doubt- less, extremely small in the ordinary state; but it admits of con- siderable dilatation. Magendie asserts, that he once found it half an inch in diameter. The period, that elapses between a fecundating copulation and the passage of the ovum from the ovarium to the uterus, is different in different animals. In rabbits, it occurs on the third day after co- pulation; in bitches on the fifth, and in the human female, perhaps, about the same time. Maygrier refers to a case of abortion twelve days after copulation; the abortment consisting of a vesicle, shaggy on its surface and filled by a transparent fluid. But the most instructive case that we possess on this subject is given by Sir Everard Home. A servant maid, twenty-one years of age, had been courted by an officer, who had promised her mar- riage, in order that he might more easily accomplish his wishes. She was but little in the habit of leaving home, and had not done so for several days, when she requested a fellow servant to remain in the house, as she was desirous of calling upon a friend, and should be detained some time. This was on the seventh of Janu- ary, 1817. After an absence of several hours she returned with a pair of new corsets and other articles of dress which she had pur- chased. In the evening she got one of the maid servants to assist her in trying on the corsets. In the act of lacing them, she com- plained of considerable general indisposition, which disappeared on taking a little brandy. Next day she was much indisposed. This was attributed to the catamenia not having made their appearance, although the period had arrived. On the following day, there was a wildness in her manner, and she appeared to suffer great mental distress. Fever supervened, which confined her to bed. On the 13th she had an epileptic fit, followed by delirium, which conti- nued till the 15th, when she expired in the forenoon. On making inquiries of her fellow servants, many circumstances were men- tioned, which rendered it highly probable, that on the morning of the 7th, when she was immediately on the point of menstruating, her lover had succeeded in gratifying his desires; and that she had become pregnant on that day, so that, when she died, she was in the seventh or eighth day of impregnation. Dissection showed the uterus to be much larger than in the virgin state and conside- rably more vascular. On accurately observing the right ovarium, in company with Mr. Clift, Sir Everard noticed, upon the most Vol. II. 38 298 generation. prominent part of its outer surface, a small ragged orifice. This induced him to make a longitudinal incision in a line close to this orifice, when a canal was found, leading to a cavity filled with coa- gulated blood and surrounded by a narrow yellow margin, in the structure of which the lines had a zig-zag appearance. The cavity of the uterus was then opened, by making an incision through the coats from each angle; and from the point where these incisions met, a third incision was continued down through the ps uteri to the vagina., The os uteri was found completely blocked up by a plug of mucus, so that nothing could have escaped by the vagina; the orifices, leading to the Fallopian tubes, were both open, and the inner surface of the cavity of the uterus was composed of a beautiful efflorescence of coagulable lymph resembling the most delicate moss. By attentive examination, Sir Everard discovered a small, spherical, transparent body concealed in this efflorescence, which was the impregnated ovum. This was submitted to thc mi- croscopic powers of Mr. Bauer, who made various drawings of it, and detected two projecting points, which were considered to mark out, even at this early period, and before the ovum was attached to the uterus, the seat of the brain and spinal marrow. This case shows, that an ovum had left the ovarium, and that it was in the interior of the uterus, prior to the seventh or eighth day after im- pregnation. But it has been asked, is it a mere matter of chance, which of the ovarian vesicles shall be fecundated; or are there not some one or more that are riper than the rest, and that receive, by pre- ference, the vivifying influence of the sperm? MM. Prevost and Dumas have shown that such is the case with oviparous animals. They found, in their experiments, that not only were the vesicles of the ovaries of frogs of different sizes, but that the largest were always first laid, whilst the smallest were not to be deposited until subsequent years. In all the animals, whose eggs were fecundated externally, they seemed evidently prepared or maturated. We have, too, the most indubitable evidence that birds—although un- questionable virgins—will lay infecund eggs. Analogy would lead^ us to believe that something similar may happen to the viviparous animal, and direct observation has confirmed the position. Not longer ago than the year 1808 the existence of corpora lutea in the ovaria was held to be full proof of impregnation. In that year * Charles Angus, Esq. of Liverpool, England, was tried at the Lancaster Assizes, for the murder of a Miss Burns, a resident of his house. The symptoms, previous to her decease, and the ap- pearances observed on dissection, were such as to warrant the sus- picion that she had been poisoned. The uterine organs were also found to be in such a state as to induce a belief, that she had been delivered a short time before her death of a foetus, which had near- ly arrived at maturity. It was not, however, until after the trial, that the ovaria were examined, in the presence of a number of fecundation. 299 physicians, and a corpus luteum was distinctly perceived in one of them. The uterus was taken to London and shown to several of the most eminent practitioners there, all of whom appear to have considered that the presence of a corpus luteum proved the fact of pregnancy beyond a doubt. Such, indeed is the positive aver- ment of Haller, an opinion which was embraced by Haighton, who maintained that they furnish " incontestable proof" of pre- vious impregnation. It was this belief, coupled with the fact, that division of the Fallopian tubes, in his experiments, prevented im- pregnation, whilst corpora lutea were found, notwithstanding, in the ovary, which led him to the strange conclusion, that the semen penetrates no farther than the uterus, and acts upon the ovaria by sympathy. Sir Everard Home has satisfactorily shown, that corpora lutea exist independently of impregnation. " Upon examining," says he, "the ovaria of several women, who had died virgins, and in whom the hymen was too perfect to admit of the possibility of im- pregnation, there were not only distinct corpora lutea, but also small cavities round the edge of the ovarium, evidently left by ova, that had passed out at some former period;" and he affirms, that whenever a female quadruped is in heat, one or more ova pass from the ovarium to the uterus, whether she receives the male or not. This view of the subject appears to have been first propounded by Blumenbach, in the Transactions of the Royal Society of Guttingen, in which he remarks, that the state of the ovaria of females, who have died under strong sexual passion, has been found similar to that of rabbits during heat; and he affirms, that in the body of a young woman, eighteen years of age, who had been brought up in a convent, and had every appearance of being a vir- gin, Vallisnieri found five or six vesicles pushing forward in one Ovarium, and the corresponding Fallopian tube redder and larger than usual, as he had frequently observed in animals during heat. Bonet, he adds, gives the history of a young lady, who died ve- hemently in love with a man of low station, and whose ovaria were turgid with vesicles of great size. Buffon, again, maintained, that instead of the corpus luteum of Haller being the remains of the ovule it is its rudiment; and that the corpus exists prior to fecundation, as he also found it in the virgin. Lastly, Dr. Blundell states, that he has in his possession a preparation, consisting of the ovaries of a young girl, who died t>f chorea under seventeen years of age, with the hymen, which nearly closed the entrance of the vagina, unbroken. In these ova- ries the corpora lutea are no fewer than four; two of them being a little obscure, but easily perceptible by an experienced eye. The remaining two are very distinct, and differ from the corpus luteum of genuine impregnation merely by their more diminutive size and the less extensive vascularity of the contiguous parts of the ovary. 300 GENERATION. "In every other respect," says Dr. Blundell, "in colour and form, and the cavity which they contain, their appearance is per- fectly natural, indeed, so much so, that I occasionally circulate them in the class-room, as accurate specimens of the luteum upon the small scale." In a paper, published in the sixth volume of the Transactions of the College of Physicians of London, Mr. Stanley confirms the fact of the corpora lutea of virgins, being of smaller size than those, that are the consequences of impregnation. The structure of the corpus luteum is of a peculiar kind, and is not distinctly seen in small animals or in those that have nu- merous litters; but in the cow, which commonly has only one calf at a birth, it is so large, according to Sir Everard Home, that, when magnified, the structure can be made out. It is a mass of thin convolutions bearing a greater resemblance to those of the brain than of any other organ. Its shape is irregularly oval, with a central cavity, and, in some animals, its substance is of a bright orange colour, when first exposed. The corpora lutea are found to make their appearance immediately after puberty, and they con- tinue to succeed each other, as the ova are expelled, till the period arrives when impregnation can no longer be accomplished. Sir Everard's theory, regarding these bodies, is, that they are glands, formed purposely for the production of ova,—that they exist pre- vious to, and are unconnected with, sexual intercourse,—and, when they have fulfilled their office of forming ova, they are removed by absorption whether the ova be fecundated or not. Fig. 139. Figures, 139, a and b, afford an external and internal view of a human ovary, that did not contain the ovum, from which a child had been developed. It was taken immediately after the child was born. The corpus luteum is nearly of the full size. a and b, Fig. 140, afford an external and internal view of an ova- fecundation. 301 rium, in which the impregnated ovum had been formed. The latter figure exhibits how much the corpus luteum had been broken down. In it we see a new corpus luteum forming. Fig. 140. From all these facts, then, we are perhaps justified in concluding with Sir Everard Home, and Messrs. Blundell, Saumarez, Cuvier, and the generality of physiologists, that the corpus luteum may be produced independently of sexual intercourse, by the mere excitement of high carnal desire, during which it is probable, that the digitated extremity of the Fallopian tube embraces the ovary, a vesicle bursts its covering, and a corpus luteum remains; the vesicle being conveyed along the tube into the uterus, but, being infecund, undergoing no farther development there; so that un- impregnated ova may, under such circumstances^ be discharged as we observe in the oviparous animal. We have now endeavoured to demonstrate the part performed by the two sexes in fecundation. We have seen that the material furnished by the male is the sperm; that afforded by the female an ovum. The most difficult topic of inquiry yet remains,—how the new individual results from their commixture? Of the nature of this mysterious process we are, indeed, profoundly ignorant; and if we could make any comparison between the extent of our ignorance on the different vital phenomena, we should be dis- posed to decide that the function of generation is the least intelli-, gible. The new being must be stamped instantaneously, as by the die. From the very moment of the admixture of the materials, at a fecundating copulation, the embryo must have within it the powers necessary for its own formation, and under impulses, com- municated by each parent,—as regards likeness, hereditary predis- positions, &c. From this moment the father has no communication 302 generation. with it; yet we know, that it will resemble him in its features and in its predispositions to certain morbid states,—whilst the mother probably exerts but a slight and indirect control over it after- wards, her office being chiefly to furnish the homunculus with a nidus, in which it may work its own formation, and with the ne- cessary pabulum. We have seen, that even so early as the seventh or eighth day after fecundation, two projecting points arc observed in the ovum, which indicate the future situations of the heart and brain. Our want of acquaintance with the precise character of this im- penetrable mystery will not, however, excuse us from passing over some of the ingenious hypotheses, that have been entertained on the subject. These have varied according to the views that have prevailed respecting the nature of the sperm; and to the opinions indulged regarding the matter furnished by the ovary. Drelin- court, who died in 1G97, collected as many as two hundred and sixty hypotheses of generation; but they may all, perhaps, be classed under two,—the system of epigenesis and that of evo- lution. 1. Epigenesis.—According to this system, which is the most ancient of all, the new being is conceived to be wholly constituted of materials furnished by both sexes, the particles composing these materials having previously possessed the arrangement necessary for constituting it, or having suddenly received such arrangement. Still it is requisite that these particles should have some controlling agent to regulate their affinity, different from any of the ordinary forces of matter; and hence a force has been imagined to exist, which has been termed cosmic, plastic, essential, nisus formatiuus,— the Bildungstrieb of the Germans,—force of formation, &c. Hippocrates maintained, that each of the two sexes possesses two kinds of seed, formed by the superfluous nutriment, and by fluids constituted of materials proceeding from all parts of the body, and especially from the most essential,—the nervous. Of these two seeds, the stronger begets males, the weaker females. In the act of generation, these seeds become mixed in the uterus, and by the influence of the heat of that organ, they form the new in- dividual, by a kind of animal crystallization, male or female, ac- cording to the predominance of the stronger or the weaker seed. Aristotle thought that it is not by seed that the female parti- cipates in generation, but by the menstrual blood. This blood he conceived to be the basis of the new individual, and the principles /urnished by the male, to communicate to it the vital movement, and to fashion it. Empedocles, Epicurus, and various other ancient physiolo- gists, contended, that the male and female respectively contribute a seminal fluid, which equally co-operates in the generation and development of the foetus, and that it belongs to the male or fe- male sex, or resembles more closely the father or the mother, ac- theory op epigenesis. 303 cording as the orgasm of the one or the other predominates, or is accompanied by a more copious discharge:— " Semper enim partus duplici de semine constat; Atque utrique simile esfrmagis id quodcumque creatur." Lucret. lib. iv. Lactantius, in quoting the views of Aristotle on generation, fancifully affirms, that the right side of the uterus is the proper chamber of the male foetus, and the left of the female,—a belief, which appears to be still prevalent amongst the vulgar, in many parts of Great Britain. But, he adds, if the male or stronger semen should, by mistake, enter the left side of the uterus, a male child may still be conceived ; yet as it occupies the female department, its voice, face, &c. will be effeminate. On the contrary, if the weaker or female seed should flow into the right side of the uterus, and a female foetus be engendered, it wifl exhibit evidences of a masculine character. The idea of Aristotle, with regard to the menstrual blood, has met with few partisans, and is undeserving of notice. That of Hippocrates, notwithstanding the objections which we now know to apply to it,—that the female furnishes no sperm, and that the ovaria are probably in no respects analogous to the testes of the male,—has had numerous supporters amongst the moderns, being modified to suit the scientific ideas of the time, and of the indivi- dual. Descartes, for example, considered the new being to arise from a kind of fermentation of the seed, furnished by both sexes. Pascal, that the sperm of the male is acid, and that of the fe- male alkaline; and that they combine to form the embryo. Mau- pertuis maintained that, in each seed, parts exist, adapted for the formation of every organ of the body, and that, at the time of the union of the seed in a fecundating copulation, each of the parts is properly attracted and aggregated by a kind of crystallization. The celebrated hypothesis of the eloquent but too enthusiastic Buffon is but a modification of the Hippocratic doctrine of epi- genesis. According to him, there exist in nature two kinds of matter,—the living and the dead; the former perpetually changing during life, and consisting of an infinite number of small, incor- ruptible particles, or primordial monads, which he called organic molecules. These molecules, by combining in greater or less quantity with dead matter, form all organized bodies; and, with- out undergoing destruction, are incessantly passing from vegeta- bles to animals, in the nutrition of the latter, and are returned from the animal to the vegetable by the death and putrefaction of the former. These organic molecules, during the period of growth, are appropriated to the development of the individual; but, as soon as he has acquired his full size, the superfluous molecules are sent into depot in the genital organs, each molecule being invested with the shape of the part sending it. In this way he conceived 304 „ generation. the seed of both sexes to be formed of molecules obtained from every part of the system. In the commixture of the seeds, during a fecundating copula- tion, the same force that assimilates the organic molecules to the parts of the body for their nourishment and increase,—and which Needham termed vegetative force,—causes them, in this hypo- thesis, to congregate for the formation of the new individual; and according as the molecules of the male or female predomi- nate, so is the embryo male or female. The ingenuity of this doctrine was most captivating; and it appeared so well adapted for the explanation of many of the phenomena of generation, that it had numerous and respectable votaries. It accounted for the circumstance of procreation being impracticable, until the sys- tem had undergone its great development at puberty. It explain- ed why excessive indulgence in venery occasions emaciation and exhaustion; and why, on the other hand, the castrated animal is disposed to obesity,—the depot having been removed by the mutila- tion. The resemblance of the child to one parent rather than to the other was supposed to be owing to the one furnishing a greater pro- portion of organic molecules than the other; and as more males than females are born, the circumstance was ascribed to the male being usually stronger, and therefore furnishing a stronger seed, or more of it. Prior to this hypothesis, Leeuenhoek had discovered what he considered to be spermatic animalcules in the semen; but Buffon contested their animalcular nature, and regarded them as his vital particles or organic molecules; whilst he looked upon the ovarian vesicle as the capsule that contained the sperm of the female. The opinions of Buffon were slightly modified by Professor Blumen- bach of Gottingen, and by Dr. Darwin. The former, like Buf- fon, divided matter into two kinds, possessing properties essen- tially different from each other;—the inorganic, and the organized; the latter possessing a peculiar creative or formative effort, which he called Bildungstrieb or nisus formativus,—a principle in many respects resembling gravitation, and endowing every organ, as soon as it acquires structure, with a vita propria. This force he conceived to preside over the arrangement of the materials, fur- nished by the two sexes in generation. Darwin prefers to the term organic molecules that of vital germs, which he says are of two kinds, according as they are secreted or provided by male or female organs, whether animal or vegetable. In the subdivision, however, of the germs the term molecule is retained; but it is limited to those of the female; the vital germs or particles, secreted by the female organs of a bud or flower, or the female particles of the animal, being denominated by him molecules with formative propensities; whilst those secreted from the male organs are termed fibrils with formative appeten- cies. To the fibrils he assigns a higher degree of organization than THEORY OF EVOLUTION. 305 to the molecules. Both, however, he asserts, have a propensity or appetency to form or create, and " they reciprocally stimulate and embrace each other and instantly coalesce; and may thus popularly be compared to the double affinities of chymistry." Subtile as these hypotheses are, they are open to forcible objec- tions of which a few only will suffice. The notion of this occult force is identical with that, which, we shall see hereafter, has pre- vailed as regards life in general and leaves the subject in the same obscurity as ever. What do the terms plastic, cosmic, or vegeta- tive force, or Bildungstrieb express, which is not equally conveyed by vital force,—that mysterious property, on which so many unfathomable processes of the animal body are dependent— and of the nature or essence of which we know absolutely nothing? The objection, urged against the doctrine of Hippocrates,—that we have no evidence of the existence of female sperm, applies equally to the hypotheses that have been founded upon it; and even were we to grant, that the ovarium is a receptacle for female sperm, the idea, that such sperm is constituted of organic mole- cules, derived from every part of the body, is entirely gratuitous. We have no facts to demonstrate the affirmative; whilst there are many circumstances, that favour the negative. The indivi- dual, for example, who has lost some part of his person—nose, eye or ear, or has had a limb amputated, still begets perfect children; yet whence can the molecules, in such cases, have been obtained? It is true that if the mutilation affect but one parent, the organic molecules of the lost part may still exist in the seed of the other; but we ought, at least, to expect the part to be less perfectly formed in the embryo, which it is not. Where two docked horses are made to engender, the result ought, a fortiori, to be imperfect, as the organic molecules of the tail could not be furnished by either parent, yet we find the colt, in such cases, per- fect in this appendage. An elucidative case is also afforded by the foetus. If we admit the possibility of organic molecules constitut- ing those parts that exist in the parents, how can we account for the formation of such as are.peculiar to fcetal existence. Whence are the organic molecules of the navel-string, or of the umbilical vein, or of the ductus venosus, or the ductus arteriosus, or the umbi- lical arteries,—all of which have to be described hereafter,—ob- tained ? These and other objections have led to the abandonment of the theory of Buffon, which remains merely as a monument of the author's ingenuity and elevation of fancy. 2. Evolution. According to this theory the new individual pre-exists in some shape in one of the sexes, but requires to be vivified by the other, in the act of generation; after which it com- mences the series of developments or evolutions, which lead to the formation of an independent being. The great differences of sentiment, that have prevailed under Vol. II. 39 306 GENERATION. this view, have been owing to the part which each sex has been considered to play in the function. Some have considered the germ to exist in the ovary, and to require the vivifying influence of the male sperm to cause its evolution. Others have conceived the male sperm to contain the rudiments of the new being, and the female to afford it merely a nidus, and pabulum during its development. The former class of physiologists have been called ovarists;—the latter spermatists, seminists, and animalculists. The ovarists maintain, that the part furnished by the female is an ovum from the ovary; and this ovum they conceive formed of an embryo and of particular organs for the nutrition and first de- velopment of the embryo; and adapted for becoming, after a series of changes or evolutions, a being similar to the one whence it has emanated. The hypothesis was suggested by the fact, that in many animals but a single individual is necessary for reproduction; and it is easier, perhaps, to consider this individual female than male; as well as by what is noticed in many oviparous animals. In these the part, furnished by the female, is manifestly an ovum or egg; and in many, such egg is laid before the union of the sexes, and is fecundated, as we have seen, externally. By analogy, the inference was drawn, that this may happen to the viviparous ani- mal also. The notion is said, but erroneously, to have been first of all ad- vanced by Joseph de Aromatariis, in his Epistola de gene- ratione plantarum ex seminibus, published at Venice, in 1625. It was developed by Harvey, who strenuously maintained the doctrine omne vivurn ex ovo. The anatomical examinations of Sylvius, Vesalius, Fallopius, De Graaf, Malpighi, Val- lisnieri and others,—by showing, that what had been previously regarded as female testes, and had been so called, were organs containing minute vesicles or ova, and hence termed, by Steno, ovaria,—were strong confirmations of this view, and startling objections to the ancient theory of epigenesis, and the problem appeared to be demonstrated, when it was discovered, that the ve- sicle or ovum leaves the ovarium and passes through the Fallo- pian tube to the uterus. The chief arguments, that have been adduced in favour of this doctrine are:—First. The difficulty of conceiving the formation, ab origine, of an organized body, as no one part can exist without the simultaneous existenoe of others. Secondly. The existence of the germ prior to fecundation in many living beings. In plants, for example, the grain exists in a rudimental state in the flower, before the pollen, which has to fecundate it, has attained maturity. In birds, too, the egg must pre-exist, as we find that those, which have never had intercourse with the male, can yet lay. This is more strikingly manifest in many fishes, and in the batracia or frog kind; where the egg is not fecundated until after extrusion. Spallanzani, moreover, asserts, that he could distinguish the pre- THEORY OF EVOLUTION. 307 sence of the tadpole in the unfecundated ova of the frog; and Hal- ler that of the chick in the infecund egg; at least he has seen them containing the yolk, which, in his view, is but a dependence of the intestine of the foetus, and if the yolk exists the chick exists also. Thirdly. The fact, before referred to, that, in certain ani- mals, a single copulation is capable of fecundating several succes- sive generations. In these cases, it is argued, the germs of the different generations must have existed in the first. Fourthly. The fact of natural and accidental encasings or emboitements; as in the bulb of the hyacinth, in which the rudiments of the flower are distinguishable; in the buds of trees, in which the branches, leaves, and flowers, have been detected in miniature, and greatly convoluted; in the jaws of certain animals, in which the germs of different series of teeth can be detected; in the volvox, a transpa- rent animal, which exhibits several young ones encased in each other; in the common egg, which occasionally has another within it; and in the instances on record, in which human foetuses have been found in the bodies of youths, of which there is a striking example in the Museum of the Royal College of Surgeons of Lon- don; and a similar case in a boy, fourteen years of age, has been related by Dupuytren. Fifthly. The fact of the various meta- morphoses, that take place in certain animals. Of these we have the most familiar instances in the batracia and in insects. The forms they have successively to assume are evidently encased. In the chrysalis, the outlines of the form of the future butterfly are apparent; and in the larva we observe those of the chrysalis. The frog is also apparent under the skin of the tadpole. Sixthly. The fact of artificial fecundation, which has been regarded, by the ova- rists, as one of the strongest proofs of their theory; the quantity of sperm employed, as in the experiments of Spallanzani, already detailed, being too small, in their opinion, to assist in the forma- tion of the new individual, except as a vivifying material. Lastly. They invoke the circumstance of partial reproductions, of which all living bodies afford more or less manifest examples;—as the reproduction of the hair and nails in man; of the teeth in the ro- dentia;—of the tail in the lizard; of the claw in-the lobster; the head in the snail, &c. &c. All these phenomena are, according to them, owing to each part possessing within itself germs destined for its reproduction, and requiring only favourable circumstances for their development. The partisans of the doctrine of epigenesis, how- ever, consider these last facts as opposed to the views of the ovarists; and they maintain that in such cases there is throughout a fresh formation. The chief objections, that have been urged against the hypothe- sis of the ovarists, are:—First. The resemblance of the child to the father—a subject which we shall refer to presently. The ova- rists cannot of course deny that such resemblance exists; and they ascribe it to the modifying influence exerted by the male sperm, 308 GENERATION. but without being able to explain the nature of such influence. They affirm, however, that the likeness of the mother is more fre- quent and evident. Certain cases of resemblance, it must be ad- mitted, are weighty stumbling-blocks to ovism, or to the doctrine of a pre-existent germ in the female. It is a well known fact, that six-fingered men will beget six-fingered children. How can we explain this upon the principle of the pre-existence of the germ in the female, and of the part played by the male sperm being simply that of a vivificative agent; and must we suppose, in the case of monstrosities, that such germs have been originally monstrous? Secondly. The production of hybrids is one of the strongest coun- ter-arguments. They are produced by the union of the males and females of different species. Of these the mule is the most familiar instance—the product of the ass and the mare. This strikingly participates of the qualities of both parents, and, consequently, the pre-existing germ in the female must have been more than vivified by the sexual intercourse. Its structure must have been altogether changed, and all the germs of its future offspring annihilated, as the mule is seldom fertile. If a white woman marries a negro, the child is a mulatto; and if the successive generations of this woman are continually united to negroes, the progeny will ultimately become entirely black; or at least the white admixture will escape recognition. As a general principle, the offspring of different races have an intermediate tint between those of the parents; and the proportions of white and black blood, in different admixtures, have even been subjected to calculation, in those countries where negroes are common. The following table represents these proportions, according to the prin- ciples sanctioned by custom. Parents. Offspring. Begree of Mixture. Negro and white, - mulatto, - - -| white, \ black. White and mulatto, - terceron, - - 1 — % — Negro and mulatto, < ^n,, ', , ' > \ — | — ° ' I or black terceron, 3 * 4 White and terceronx quarteron, Negro and terceron, black quarteron, White and quarteron, quinteron, Negro and quarteron, black quinteron, The two last are considered to be respectively white and black; and of these the former are white by law and consequently free in the British West India Islands. All these cases exhibit the great influence, exerted by the father upon the character of the offspring, and are great difficulties in the way of supposing, that the male sperm is simply a vivifier of the germ pre-existing in the female. Thirdly. The doctrine of the ovarists does not account for the greater degree of fertility of cultivated plants and of domesticated 7 1 ■5- —~4 S 1 7 s ~~' T 1 5 1 TS ~~~ lT 1 1 5 T3- 1 6 THEORY OF EVOLUTION. 309 animals. Fourthly. The changes, induced by the succession of ages on the animal and vegetable species inhabiting the surface of the globe, have been adduced against this hypothesis. In examining the geological character of the various strata that compose the earth, it has been observed by geologists, that many of these contain imbedded the fossil remains of animals and vege- tables. Now, under the supposition, that those rocks on which others rest are the oldest, and that the successive strata above these are more and more modern, it has been found, that the organic fossil remains in the different strata differ more and more from the present inhabitants of the surface of the globe in proportion to the depth we descend ; and that the remains of those beings, that have always been the companions of man, are found only in the most recent of the alluvial deposites,—in the upper crust of the earth. In the older rocks the impressions are chiefly of the less perfect plants—as the ferns and reeds ; and of the lower animals—the re- mains of shells and corals ; whilst fish are uncommon. In the more recent strata, the remains of reptiles, birds and quadrupeds are apparent; but all of them differ essentially from the exist- ing kinds ; and in none of the formations of more ancient date has the fossil human skeleton been met with. The pretended human bones, conveyed by Spallanzani from the Island of Cerigo—the ancient Cythera—are not those of the human species any more than the bones of the Homo diluvii testis of Scheuchzer; and the skeleton of the savage Galibi, conveyed from Gaudaloupe and deposited in the British museum is imbedded in a calcareous earth of modern formation. From these facts it has been concluded, that man is of a date posterior to animals in all countries where fossil bones have been discovered. These singular facts, furnished by modern geological inquiry, have been attempted to be explained by the supposition, that the present races of animals are the descendants of those, whose re- mains are met with in the rocks, and that their difference of cha* racter may have arisen from some change in the physical consti- tution of the atmosphere, or of the surface of the earth, producing a corresponding change on the forms of organized beings. It has been properly remarked, however, by Dr. Fleming, that the ef- fect of circumstances on the appearance of living beings is circum- scribed within certain limits, so that no transmutation of species was ever ascertained to have taken place; whilst the fossil species differ as much from the recent kinds, as the last do from each other; and he adds, that it remains for the abettors of the opinion to connect the extinct with the living races by ascertaining the in- termediate links or transitions. This will probably ever be im- practicable. The difference, indeed, between the extinct and the living races is in several cases so extreme, that many naturalists 310 GENERATION. have preferred believing in the occasional formation of new orga- nized beings. Linnjeus was bold enough to affirm, that, in his time, more species of vegetables were in existence than in anti- quity, and hence, that new vegetable species must necessarily have been ushered into being; and Wildenow embraced the views of Linneus. Lamarck, one of the most distinguished naturalists of the day, openly professes his belief, that both animals and vege- tables are incessantly changing under the influence of climate, food, domestication, the crossing of breeds, &c, and he remarks, that if the species, now in existence, appear to us fixed in their charac- ters, it is because the circumstances, that modify those species, re- quire an enormous time for action; and would consequently re- quire numerous generations to establish the fact. The manifest effect of climate, food, &c. on vegetables and ani- mals, he thinks, precludes the possibility of denying those changes on theoretical considerations; and what we call lost species are, in his view, only the actual species before they experienced modifi- cation. It is proper, however, to observe, that the sculptures on the wall of one of the sepulchres in the valley of Beban el Molook, at Thebes, which is regarded by Champollion as having been exe- cuted upwards of two thousand years before the Christian era, en- able the features of the Jew and of the negro, amongst others, to be recognised as easily as the representations of their descendants of the present day ; so that, for the space of at least three thousand eight hundred years, no modification of the kind referred to by Lamarck seems to have occurred in the human species. Another explanation has been afforded for these geological facts, and for the rotation which we observe in the vegetable occupants of particular soils in successive years. It has been supposed, that as the seeds of plants and the ova of certain animals are so exces- sively minute as to penetrate wherever water or air can enter; and as they are capable of retaining the vital principle for an indefinite length of time, of which we have many proofs, and of undergoing evolution whenever circumstances are favourable, the crust of the earth may be regarded as a receptacle of germs, each of which is ready to expand into vegetable or animal forms, on the occurrence of conditions necessary for their development. This is the hypo- thesis of panspermia or dissemination of germs, according to which the germs of the ferns and reeds were first expanded, and af- terwards those of the staminiferous or more perfect vegetables; and, in the animal kingdom, first the zoophyte, and gradually the being more elevated in the scale •, the organized bodies of the first period flourishing, so long as the circumstances, favourable to their development, continued, and then making way for the evolution of their successors,—the changes effected in the soil by the growth and decay of the former probably favouring the evolution of the THEORY OF EVOLUTION. 311 latter* which, again, retained possession of the soil so long as cir- cumstances were propitious. The changes that take place in forest vegetation are favourable to this doctrine. If, in Virginia, the forest trees be removed so as to make way for other growth, and the ground be prepared for the first cultivation, the ^Phytolacca decandra or poke, which was not previously perceptible on the land, usurps the whole sur- face. When Mr. Madison went with Gen. Lafayette to the Indian treaty, they discovered, that wherever trees had been blown down by a hurricane, in the spring, the white clover had sprung up in abundance, although the spot was many miles distant from any cleared land; and it has often been remarked, that where during a drought in the spring the woods have taken fire and the surface of the ground has been torrefied, the water weed has made its appearance in immense quantities, and occupied the burnt sur- face. The late Judge Peters, having occasion to cut ditches on his land, in the western part of Pennsylvania, was surprised to find every subterraneous tree that was met with, different from those at the time occupying the surface; and Mr. Madison informs us, that in the space of sixty or seventy years he has noticed the fol- lowing spontaneous rotation of vegetebles. 1. Mayweed; 2. Blue centaury; 3. Bottle-brush-grass; 4. Broomstraw; 5. White clo- ver ; 6. Wild carrot; and the last is now giving way to the blue grass. The doctrine of panspermia is, however, totally inapplicable to the viviparous animal, in which the ovum is hatched within the body, and which, consequently, continues to live after the birth of its progeny ; whilst the facts, furnished us by geology, seem clearly to show, that the development of the animal kingdom has been successive, not simultaneous; but under what circumstances they were successively ushered into being we know not. Lastly, as regards the ovarists themselves;—they differ in es- sential points; whilst some are favourable to the doctrine of the dissemination of germs, believing, as we have seen, that ova or germs are disseminated over all space, and that they only undergo development under favourable circumstances, as when they meet with bodies capable of retaining them, and causing their grewth, or which resemble themselves; others assert, that the germs are inclosed in each other, and that they are successively aroused from their torpor, and called into life, by the influence of the seminal fluid; so that not only did the ovary of the first female contain the ova of all the children she had, but one only of these ova con- tained the whole of the human race. This was the celebrated sys- tem of embbitement des germes, or encasing of germs, of which Bonnet was the propounder, and Spallanzani the promulgator. Yet how monstrous for us to believe, that the first female had, within her, the germs of all mankind, born, and to be born; or 312 GENERATION. to conceive, that a grain of Indian corn contains within it all the seed, that may hereafter result from its culture. Many of the ovarists, again, and they alone who have any thing like probability in their favour, believe, that the female forms her own ova, as the male makes his own sperm by a secretory action; and, so far as the female is concerned in the generative process, we shall find that this is the only philosophical view; but it is imperfect in not ad- mitting of more than a vivifying action in the materials furnished by the male. About the middle of the seventeenth century, Hamme, Leeuen- hoek, and Hartsoker discovered a prodigious number of small moving bodies in the sperm of animals, which they regarded as animalcules. This gave rise to a new system of generation, di- rectly the reverse of that of Harvey,—that of generation ab ani- malculo maris. As, in the Harveian doctrine, the germ was con- ceived to be furnished by the mother and the vivifying influence to be alone exerted by the male, so, in this doctrine, the entire formation was regarded as the work of the father, the mother af- fording nothing more than a nidus, and appropriate pabulum, for the homunculus or rudimental foetus. The pre-existing germ was ac- cordingly now referred exclusively to the male; and, by some, the doctrine of emboitement or encasing was extended to it. In support of this hypothesis, the spermatists urged;—that the animalcules, they discovered, were peculiar to the semen, and that they exist in the sperm of all animals, capable of generation; that they differ in different species, but are always identical in the sperm of the same animal, and in that of individuals of the same species; that they are not perceptible in the sperm of any animal, until the age at which generation is practicable, whilst they are wanting in infancy and decrepitude; that their number is so considerable, that a drop of the sperm of a cock, scarcely equal in size to a grain of sand contains 50,000; and lastly, that their size being so minute, is no obstacle to the supposition, that ge- neration is accomplished by them; the disproportion between the trees of our forest and the seed producing them being nearly if not entirely as great as that between the animalcule and the being it has to develope.* The difficulty with the spermatists or animalculists was to de- termine the mode, in which the homunculus attains the ovary, and effects the work of reproduction. Whilst some asserted, that it was only requisite, that the sperm should attain the uterus, whither it attracted the ovum from the ovarium; others imagined, that the animalcule travelled along the Fallopian tube to the ovary; entered one of the ovarian vesicles; shut itself up there for some time, and * Lt.euenhoek estimated those of the frog at about the l-10,000th part of a human hair, and that the milt of a cod may contain 15,000,000,000,000,000 of them. THEORY of EVOLUTION. 313 then returned into the cavity of the uterus, to undergo its first de- velopment, through the medium of the nutritive substance con- tained in the vesicle; and a celebrated pupil of Leeuenhoek even affirmed, that he not only saw these animalcules under the shape of the tadpole, as they were generally described, but that he could trace one of them, bursting through the envelope that retained it, and exhibiting two arms, two legs, a human head and a heart! Although this doctrine was extremely captivating, and, for a time,, kept the minds of many eminent philosophers in a state of delusive enthusiasm;* it was, subsequently, strongly objected to by many; and the great fact on which it rested—the very existence of the spermatic animalcules—was, and is, strenuously contested. Linn.eus discredited the observations of Leeuenhoek; Ver- heyen denied the existence of the animalcules, and undertook to demonstrate that the motion, supposed to be traced in them, was a mere microscopic delusion:—whilst Needham and Buffon re- garded them as organic molecules. Of late years, MM. Prevost and Dumas have directed their at- tention to the subject; and their investigations, as on every other topic of physiological inquiry, are worthy of the deepest regard. The results of their examinations have led them to confirm the existence of these animalcules, and likewise to consider them as the direct agents of fecundation. By means of the microscope they detected them in all the animals, whose sperm they examined, and these were numerous. Whether the fluid was observed after its excretion by a living animator after its death, in the vas deferens or in the testicle, the animalcules were detected in it with equal facility. They consider these bodies to be characteristic of the sperm, as they found them only in that secretion; being wanting in every other humour of the body, even in those, that are excreted with the sperm, as the fluids of the prostate, and of the glands of Co wper, and although similar in shape, and size, and in the character of their lo- comotion in the individuals of the same species, they are of various shapes and dimensions in different species. In passing through the series of genital organs these animalcules experience no change, being as perfect in the testicle as at the time of their excretion; and MM. Prevost and Dumas controvert the remark of Leeuen- hoek, that they are met with apparently of different ages. They were manifestly endowed with spontaneous motion, which gradually ceased,—in the sperm obtained during life by ejaculation, * Dr. Thomas Morgan in a work, published in 1731, thus expresses himself regarding this doctrine:—" That all generation is from an animalculum pre-ex- isting in semine maris, is so evident in fact, and so well confirmed by experience and observation, that I know of no learned men, who in the least doubt of it. Vol. II. 40 314 GENERATION. in the course of two or three hours; in that taken from the ves- sels after death, in fifteen or twenty minutes; and in eighteen or twenty hours, when left in i|s own vessels after death. In farther proof of the position, that these animalcules are the fecundating agents, MM. Prevost and Dumas assert, that they are only met with whilst reproduction is practicable:—that in the human species they are not found in infancy or decrepitude; and, in the majority of birds, are apparent in the sperm only at the periods fixed for their copulation; facts which, in their opinion, show, that they are not mere infusory animalcules. MM. Prevost and Dumas moreover affirm, that they appeared to be connected with the physiological condition of the animal furnishing them; their motions being rapid or languishing, accord- ing as the animal, was young or old, or in a state of health or dis- ease. They state, also, that in their experiments on the ova of the mammiferous animal, they observed animalcules filling thc cornua of the uterus, and remaining there alive and moving, until the ovule descended into that organ, when the animalcules gradually disap- peared; and they argue in favour of the influence of these animal- cules;—that the positive contact of the sperm is necessary for fe- cundation, and that the aura seminis is totally insufficient;—that the sperm in twenty-four hours loses its fecundating property, and it requires about this time for the animalcules to gradually cease their movements and perish; and, lastly, that having destroyed the animalcules in the sperm, the fluid lost its fecundating pro- perty. One of these experiments consisted in killing all the ani- malcules in a spermatized fluid,—whose fecundating power had been previously tested,—by repeated discharges of a Leyden phial: another consisted in placing a spermatized fluid on a quintuple filter, and repeating this, until all the animalcules were retained on the filter; when it was found, that the fluid, which passed through, had no fecundating power, whilst the portion retained by the filter had the full faculty; a result that had been obtained by Spallan- zani, who found, besides, that he was capable of effecting fecun- dation with water in which the papers, used as filters, had been washed. Lastly, MM. Prevost and Dumas, and Rolando, conjecture that the spermatic animalcule forms the nervous system of the new be- ing, and that the ovulum furnishes only the cellular frame-work in which the organs are formed; but this is mere hypothesis. All that seems to be proved to us by the essays of these ingenious ex- perimenters is, the fact of the existence of peculiar animalcules in the sperm, and their apparent agency in the generative process; but how this agency is exerted we know not. It is scarcely necessary to remark, that all the objections which were urged against the system of the ovarists, as regards the proof in favour of an active participation of both sexes in the work of THEORY OF EVOLUTION. 315 reproduction, are equally applicable to the views of those animal- culists, who refer generation exclusively to the spermatic animal- cule. Such are the chief theories that have been propounded on the subject of generation. It has been already observed, that the par- ticular modifications are almost innumerable. They may all, how- ever, be classed with more or less consanguinity under some of the doctrines enumerated. Facts and arguments are strongly against any view that refers the whole process of formation to either sex. There must be a union of materials furnished by both, otherwise it is impossible to explain the similarity in conformation to both parents, which is often so manifest. Accordingly, this modi- fied view of epigenesis is now adopted by most physiologists;—that at a fecundating copulation, the secretion of the male is united to a material, furnished by the ovarium of the female; that from the union of these elements the embryo results, impressed, from the very instant of such union, with life, and with an impulse to a greater or less resembance of this or that parent, as the case may be; and that the material, furnished by the female, is as much a secretion resulting from the peculiar organization of the ovarium, as the sperm is from that of the testicle,—life being capable, in this manner, of communication from father to child, without the ne- cessity of invoking tHe incomprehensible and revolting doctrine of the pre-existence of germs. This admixture of the materials, furnished by both sexes, ac- counts for the likeness that the child may bear to either parent, whatever may be the difficulty in understanding the precise mode in which they act in the formation of the foetus. It has been at- tempted, however, by some, to maintain, that the influence of the maternal imagination during a fecundating copulation may be suf- ficient to impress the germ, within her, with the necessary im- pulse ; and the plea has been occasionally urged in courts of justice. Of this we have an example in a well-known case, tried in New York, five-and-twenty years ago. A mulatto woman was delivered of a female bastard child, which became chargeable to the authori- ties of the city. When interrogated, she stated that a black man of the name of Whistelo was the father, who was accordingly ap- prehended, for the purpose of assessing him with the expenses. Several physicians, who were summoned before the magistrates, gave it as their opinion that it was not his child, but the offspring of a white man. Dr. Mitchell, however, who, according to Dr. Beck, seemed to be a believer in the influence of the imagination over the foetus, thought it probable that the negro was the father. Owing to this difference of sentiment, the case was carried before the mayor, recorder, and several aldermen. It appeared in evi- dence, that the colour of the child was somewhat dark, but lighter 316 GENERATION. than the generality of mulattos, and that its hair was straight, and had none of the peculiarities of the negro race. The court very properly decided in favour of Whistelo, and of course against the testimony of Dr. Mitchell, who, moreover, maintained, that as alteration of complexion has occasionally been noticed in the human subject,—as of negroes turning partially white,—and in animals, so this might be a parallel instance. The opinion does not seem entitled to much greater estimation than that of the poor Irish woman, in a recent London police report, who ascribed the fact of her having brought forth a thick-lipped, woolly-headed urchin to her having eaten some black potatoes, during her pregnancy. It is obvious, that the effect of the maternal imagination can only be invoked—by those who believe in its agency on the future ap- pearance of the foetus—in the case of those animals in which copu- lation is a part of the process. Where the eggs are first extruded and then fecundated, all such influence must be out of the question; and even in the viviparous animal we have seen, that experiments on artificial impregnation have shown, that not only has the bitch been fecundated by sperm injected into the vagina, but that the resulting young have manifestly resembled the dog, whence the sperm had been obtained. The strongest case in favour of the influence of the maternal imagination is given by Sir Everard Home. An English mare was covered by a quaga,—a species of wild ass from Africa, which is marked somewhat like the zebra. This happened in the year 1815, in the park of Earl Morton, in Scotland. The mare was only covered once; went eleven months, four days, and nineteen hours; and the produce was a hybrid, marked like the father. The hybrid remained with the dam for four months, when it was wean- ed and removed from her sight. She probably saw it again in the early part of 1816, but never afterwards. In February, 1817, she was covered by an Arabian horse, and had her first foal—a filly. In May, 1818, she was covered again by the same horse, and had a second. In June, 1819, she was covered again, but this year missed; but in May, 1821, she was covered a fourth time, and had a third; all being marked like the quaga. Similar facts have been alluded to by other writers. Haller remarks, that the female organs of the mare seem to be cor- •rupted by the unequal copulation with the ass, as the young foal of a horse from a mare, which previously had a mule by an ass, has something asinine in the form of its mouth and hips; and Becher says, that when a mare has had a mule by an ass, and af- terwards a foal by a horse, there are evidently marks in the foal of the mother having retained some ideas of her former paramour, —the ass; whence such horses are commended on account of their tolerance and other similar qualities. FECUNDATION. 317 The mode in which the influence is exerted in this and similar cases is most unfathomable; and the fact itself, although indisputa- ble is astounding. Sir Everard Home thinks that it is one of the strongest proofs of the effect of the mind of the mother upon her young that has ever been recorded. Although we are totally inca- pable of suggesting any satisfactory solution, it appears to us more probable, that the impression must have been made in these cases on the genital system, rather than upon the mind of the animal. Conception usually occurs without the slightest consciousness on the part of the female; and hence the difficulty of reckoning the precise period of gestation. Certain signs, as shivering pain about the umbilicus, &c. are said to have occasionally denoted its occurrence, but these are rare exceptions, and the indications af- forded by one are often extremely different from those presented by another. In those animals, in which generation is only accom- plished during a period of generative excitement, the period of conception can be determined with accuracy; for, in by far the majority of such cases, a single copulation will fecundate; the ex- istence of the state of heat indicating that the generative organs are ripe for conception. In the human female, where the sexual intercourse can take place at all periods of the year, conception is by no means as likely to follow a single intercourse; for,although she may be always susceptible of fecundation, her genital organs are perhaps at no one time so powerfully excited as in the animal durin'g the season of love. It is not for the physiologist to inquire into the morbid causes of sterility in either male or female; nor is it desirable to relate all the visionary notions that have prevailed regarding the circumstances that favour conception. It would cer- tainly seem more likely to supervene when the venereal orgasm oecurs simultaneously in both parties; and when the sperm is thrown well forwards towards the mouth of the uterus. We have already shown, that preternatural openings of the urethra, which interfere with this projection of the sperm in the proper direction, certainly render fecundation less probable. It has been generally affirmed by writers, that conception is apt to take place more readily immediately after menstruation ; either, it has been imagined, because the uterus continues slightly open, so as to admit the sperm more easily into its cavity, or because the whole apparatus is in a state of some excitement. This opinion is problematical; and, accordingly, a female is in the habit of reckoning from a fortnight after her last menstrual period; for as she might have fallen with child immediately after menstruation, or not until immediately preceding the following menstruation; a difference of three weeks might occur; and she, therefore, takes the middle point between those periods; that is, ten days or a fort- night after her last menstruation, or, what is the same thing, ten days or a fortnight before the first obstructed menstruation. Sir 318 GENERATION. Everard Home, however, differs on this topic from the generality of physiologists,—affirming that, in the human species, the fulness of the vessels of the womb, prior to menstruation, corresponds with the state of heat in the female quadruped, and shows that, at that period, the ova are most commonly fit for impregnation. "The females in India," he observes, "where, from the warmth of the climate, all the internal economy respecting the propagation of the species goes on more kindly than in changeable climates, reckon ten months as the period of utero-gestation. In the Apo- crypha, the wisdom of Solomon, Chap. VII., v. 2,—'And in my mother's womb was fashioned to be flesh in the time of ten months.' This circumstance seems to prove, that immediately before menstruation, when all the appendages of the womb are loaded with blood, the ova and the ovaria are more frequently ready for impregnation, in the climates most congenial for propa- gation; and therefore the mode of reckoning is from the previous menstruation, which is ten months before the birth." It has been attempted to ascertain what age and season are most prolific. From a register, kept by Dr. Bland of London, it would appear, that more women, between the ages of twenty-six and thirty years, bear children than at any other period. Of two thousand one hundred and two women delivered, eighty-five were from fifteen to twenty years of age; five hundred and seventy-eight from twenty-one to twenty-five; six hundred and ninety-nine, from twenty-six to thirty; four hundred and seven from thirty-one to thirty-five; two hundred and ninety-one from thirty-six to forty; thirty-six from forty-one to forty-five; and six from forty-six to forty-nine. At Marseilles, according to Raymond, women conceive most readily in autumn and chiefly in October; next in summer; and lastly in winter and spring; the month of March having fewest con- ceptions. Morand again says, that July, May, June, and August are the most frequent monthsfor conception; and November, March, April, and October successively the least frequent. Mr. Burns asserts, that the register for ten years of an extensive parish in Glasgow, renders it probable that August and September are most favourable for conception; and lastly, Dr. Gouverneur Emerson, who has employed himself most profitably on the Medical Statistics of Philadelphia, has furnished the following table of the number of births, during each month, for the ten years ending in 1830. FECUNDATION. 319 ^ 09 « Si «j 5»« « 3 k'5 -So S I is 'sareuiaj •sap3jv •S3p3UI3J 'S3pijy[ •S3p3UI3J •sarej^ CMCMOvOrH-^-^i-HCTiCM V) b- CTl 00 CM O Vi n cji io ci h. oo h W (M Q> (M CT (M CO oo o (o n k vi h _tH cm cm cm CM cm CO VI b- <0 VO rf VO i-i NiOiOOl HKCO CM CM CM CM CO CM CO 00 ■<* ; CM b- CO CM l iH rH ( b- 00 CM CM i <0 b- i CO TH CO CO I •S3HJU13J N (N o o in co h h i< n k »o » n CM CM CM CM (M CM CO »o CM : CTl 00 i CM CM ' ■sapH j ■SSnUUSJ b- ai en o ■■# *o o "* CO b- CT> CTl 00 iH JM CM CM CM CM CM CO CO (M -* V) O K oo CM CM CM CM CO CO CM i-h CO < o »o CO CM i •sayeK j (M CM CM -tf CMJM <0 i-l ■* CO CO CM -* CM CM CO CO cm ^S3|T3UU3j[ I 00 •sapiv uj •sapuiaj __CM cti o o b- CMJM b- CM b- 00 O «3 Tf O CM_CM Is. CT> CM CM CTl CO CM CO CM >C b-b- CM CM CM V- Kb. 1OO100 CM CM CM CO rH i CO 00 C0JMJ 00 CTl 00 Tf . CMJMj >o CTl Ol 00 i CM CM K"> rH lO CO -* CO CM CM CM CM CM to CO CM CM •sspw O CO CO CM CM CM rH CTl 00 >o rH CM CM CTi CO -* CM CM ■sspjuisj I •S3pi\[ COCMK r-< CM CM -tf »o : CMJMj bo © CM O CM CO ■S9IBU13J CM rH rH O . O rH o CO CO T 1 CMCO^OCM^CTiOOOCTiCM 1 ^IcMCMCMCMCMCMCMCOCMco 1 iriSOiOiCOViKNOO •S3IBW 1 inOOiKiOMOMnK 1 " 1 CM CM CM CM CM CO CO CO CO ro •SHV3A rHCMCOT#tOnine calen- dar months or forty weeks; but we have no less hesitation in affirming, that it may be protracted, in particular cases, much be- yond this. We find in animals, where the date of impregnation can be rigidly fixed, that whilst the usual term can be determined without difficulty, numerous cases are met with in which the period is protracted, and there is no reason to doubt, that the same thing happens occasionally to the human female. In a case detailed by Dr. Dewees, an opportunity occurred for dating with precision the time of fecundation. The case is, like- wise, interesting in another respect, as demonstrating that fecunda- tion does not necessarily arrest the succeeding catamenial discharge. The husband of a lady, who was obliged to absent himself many months, in consequence of the embarrassment of his affairs, return- ed one night clandestinely; his visit being known only to his wife, her mother, and Dr. Dewees himself. The lady was, at the time, within a week of her menstrual period; and, as the catamenia ap- peared as usual, she was induced to hope, that she had escaped impregnation. Her catamenia did not, however, make their appear- ance at the next period; the ordinary signs of pregnancy super- vened; and in nine months and thirteen days, or in two hundred and ninety-three days from the visit of the husband, she was deli- vered. In his evidence before the House of Peers, in the cause alluded to, Dr. Granville stated his opinion, that the usual term of utero- gestation is as we have estimated it; but he, at the same time, detailed the case of his own lady, in whom it had been largely pro- tracted. Mrs. Granville passed her menstrual period on the 7th of April, and on the 15th of August following she quickened;—that is, four months and six or seven days afterwards. In the early part of the first week in January, her confinement was expected and a medical friend desired to hold himself in readiness to attend. La- bour pains came on at this time, but soon passed away; and Mrs. G. went on till the 7th of February, when labour took place, and the delivery was speedy. The child was larger and stronger than usual, and was considered by Dr. Granville,—as well as by Dr. A. T. Thomson, the Professor of Materia Medica in the University of London,—as a ten months child. 332 generation. If, in this case, we calculate that conception occurred only the day before the interruption of menstruation, three hundred and six days must have elapsed between impregnation and birth; and if we take the middle period between the last menstruation and the inter- ruption, the interval must have been three hundred and sixteen, or three hundred and eighteen days. The limit, to which the protraction of pregnancy may possibly ex- tend, cannot be aligned. It is not probable, however, that it ever va- ries largely from the ordinary period. The University of Heidelberg allowed the legitimacy of a child, born at the expiration of thirteen months from the date of the last connubial intercourse; and a case was decided by the Supreme Court of Friesland, by which a child was admitted to the succession, although it was not born till three hun- dred and thirty-three days from the husband's death; or only a few days short of twelve lunar months. These are instances of the ne plus ultra of judicial philanthropy, and, perhaps we might say, credulity. Still although extremely improbable we cannot say that they are impossible. This much, however, is clear, that real excess over two hundred and eighty days is by no means frequent; and we think, in accordance with the civil code now in force in France, that the legitimacy of an infant born three hundred days after the dissolution of marriage may be contested; although we are by no means disposed to affirm, that if the character of the woman be irreproachable, the decision should be on the side of illegitimacy. At the end of seven months of utero-gestation and even a month earlier the foetus is capable of an independent existence; provided, from any cause, delivery should be hastened. This is not, however, the full period, and. although labour may occur at the end of seven months, the usual course is for the foetus to be carried until the end of nine calendar months. If the foetus is extruded prior to the pe- riod at which it is able to maintain an independent existence, the process is termed abortion or miscarriage; if between this time and the full period, it is called premature labour. With regard to the causes, that give rise to the extrusion, we are in utter darkness. It is in truth as inexplicable as any of the other instinctive operations of the living machine. Yet although this is generally admitted, the discussion of the subject occupies a consi- derable space in the works of some obstetrical writers. Our know- ledge appears to be limited to the fact, that when the foetus has undergone a certain degree of development, and the uterus a cor- responding distention, its contractility is called into action, and the uterine contents are beautifully and systematically expelled. Nor can we always fix upon the degree of distention, that shall give occasion to the exertion of this contractile power. Sometimes, it will supervene after a few months of utero-gestation so as to pro- duce abortion; at other times it will happen when the foetus is just parturition. 333 viable; and at others, again, and in the generality of cases, it is not elicited until the full period. In cases of twins, the uterus will admit of still greater distention before its contractility is aroused. A day or two preceding labour, a discharge is occasionally ob- served from the vagina of a mucous fluid, more or less streaked with blood. This is termed the show, because it indicates the commence- ment of some dilatation of the neck, or mouth of the womb,—the forerunner of labour or travail. The external organs, at the same time, become tumid and flabby. The orifice of the uterus, if an examination be made, is perceived to be enlarging; and its edges are thinner. Along with this, slight grinding pains are experienced in the loins and abdomen. After an uncertain period, pains of a very different character come on, which commence in the loins, and appear to bear down towards the os uteri. These are not constant, but recur, at first after long intervals, and subsequently after shorter;—the body of the uterus manifestly contracting with great-force, so as to press the ovum down against the mouth of the womb, and to dilate it. In this way, the membranes of the ovum protrude through the os uteri with their contained fluid, the pouch being occasionally termed the bag of waters. Sooner or later the membranes give way, the ivaters are discharged, and the uterus contracts so as to embrace the body of the child, which was previously impracticable, except through the medium of the liquor amnii. At the commencement of labour, the child's head has not entered the pelvis, the occiput, as in the marginal figure, being Fig. 144. generally towards the left acetabulum ; but, when the uterine contractions be- come more violent, and are accompanied by powerful efforts on the part of the abdominal muscles, the head enters the pelvis, the mouth of the womb be- comes largely dilated, and the female is in a state of agitation and excitement, owing to the violence of the efforts, and the irresistible desire she has of assisting them as far as lies in her power. When the head has entered the pelvis, in the position described,in which the long diameter corres- ponds to the longdiameter of the pel vis,it describes,laterally,an arc of 334 GENERATION. a circle, the face passing into the hollow of the sacrum, and the occiput behind the arch of the pubes, as in Fig. 145. By the conti- nuance of the pains, the head presents at the vulva. The pains now become most ur- gent and forcing. Theoscoc- cygis is pushed backwards, and the perineum is distend- ed—at times so considera- bly, as to threaten, and even to effect laceration; the anus is also forced open and pro- truded; the nymphasand ca- runculae of the vagina are ef- faced; the labia separated, and the head clears the vulva, from the occiput to the chin, experiencing a vertical ro- tation as depicted in Fig. 146. When the head is ex- truded,the shoulders and rest of the body readily follow, on The child, however, still re- mains attached to the mother by the navel-string, which has to be tied, and divided at a few fingers' breadth from the umbilicus. After the birth of the child,the female has generally a short interval of repose; but, in a few mi- nutes, slight bearing down pains are ex- perienced, owing to the contraction of the uterus for the separation of the placenta, and of the membranes of the ovum, called the se- cundines or after- birth. The process of parturition is accomplished in a longer or shorter account of their smaller dimensions. PARTURITION. 335 time, according to the particular conditions of the female and foetus, in different individuals, and in the same individual in different la- bours. The parts, however, when once dilated, yield much easier afterwards to similar efforts, so that the first labour is generally the most protracted. After the separation of the secundines, the female is commonly left in a state of debility and fatigue; but this gradually disappears. The uterus also contracts; its vessels become tortuous, small, and their orifices are plugged up. For a short time blood continues to be discharged from them; but as they become obliterated by the return of the uterus to its usual size, the discharge loses its sangui- neous character, and is replaced by one of a paler colour, called the lochia, which gradually disappears, and altogether ceases in the course of two or three weeks after delivery. For a day or two after delivery coagula of blood form in the in- terior of the uterus, especially in the second and subsequent labours, which excite the organ to contraction for their expulsion. These contractions are accompanied with pain, and are called after-pains: as their object is the removal of that which interferes with the re- turn of the uterus to its proper dimensions, it is obvious that they ought not to be officiously interfered with. Whilst the uterus is contracting its dimensions, the other parts gradually resume the condition they were in prior to delivery; so that in the course of three or four weeks, it is impracticable to pronounce positively, whether delivery has recently taken place or not. Labour, as thus accomplished, is more deserving of the term in the human female than in animals; and this is partly Fig. 147. owing to the large size of the foetal head, and partly to the circumstance, that in the animal the axis of the pelvis is the same as that of the body, whilst in the hu- man female, the axis of the brim, as represented by the dotted straight lines in Fig. 146, forms a considerable angle with that of the outlet. The position of the child, exhibited in Fig. 144,—with the face behind and the oc- cipital before,—constitutes the usual presentation in natural labour. Of twelve thousand six hundred and thirty-three children, born at the Hospice de la Ma- terniti of Paris, twelve thousand one hundred and twenty, accord- 336 GENERATION. ing to M. Jules Cloquet, were of this presentation; sixty-three had the face turned forward; one hundred and ninety-eight were breech presentations; (see Fig. 147;) in one hundred and forty-seven cases the feet presented; and in three the knees. All these, however, are cases, in which labour can be effected without assistance; the knee and feet presentations being identical, as regards the process of delivery, with that of the breech. But whenever any other part of the foetus presents, the position is unfavourable, and requires that the hand should be introduced into the uterus, with the view of bringing down the feet,and converting the case into a foot presentation. The details of this subject, however, belong more appropriately to ob- stetrics. When the child has been separated from the mother, and con- tinues to live by the exercise of its own vital powers, it has still to be dependent upon her for the nutriment adapted to its tender con- dition. Whilst in utero this nutriment consisted of fluids placed in contact with it, but, after birth, a secretion serves this purpose, which has to be received into the stomach and undergo the diges- tive process. This secretion is the milk. It is prepared by the mammae or breasts, the number, size, and situation of which are characteristic of the human species. Each breast contains a mam- mary gland, surrounded by the fat of the breast, and resting on the pectoralis major muscle. It is formed of several lobes, united by a somewhat dense, cellular tissue, and consisting of smaller lobules, which seem, again, composed of round granulations, of a rosy-white colour, and of about the size of a poppy seed. The glandular gra- nula give origin to the excretory ducts, called tubuli lactiferi or galactophori, which are tortuous,extensible, and transparent. These enlarge and unite with each other, but so that those of each lobe re- main distinct from, and have no communication with, the ducts of any other lobe. All these finally terminate in sinuses, near the base of the nipple, which are fifteen or eighteen in number, and open on the nipple, without having communication with each other. The size and shape of the breast are chiefly caused by the cel- lular tissue in which the mammary gland is situated: this is co- vered by a thin layer of skin, which is extremely soft and delicate, and devoid of folds. In the middle of the breast is the tubercle, called the nipple,—a prominence consisting of an erectile spongy tissue,differing in colour from the rest of the breast,—and around it is the areola, which is of a rosy hue in youth, but becomes darker in the progress of life, and the capillary system of which is so deli- cate as to blush, like the countenance, under similar emotions. The changes, produced on the areola by gestation, have been already described. The skin, at the base of the nipple, and on its surface, is rough, owing to the presence of a number of sebaceous follicles, which secrete a fluid for the lubrication of the part, and for defend- ing it from the action of the saliva of the infant during lactation. Numerous arteries, veins, nerves and lymphatics,—the anatomical LACTATION. 337 constituents of organic textures in general,—also enter into the composition of the mammas and nipples. The secretion of milk is liable to longer intermissions than any other function of the kind. In the unmarried and chaste female, although the blood, whence milk is formed, may be constantly passing to the nipple, no secretion takes place from it. It is only during gestation and for some time afterwards, that the necessary excitation exists to produce it. Yet although largely allied to the generative function,—the mammae undergoing their chief develop- ment in puberty and becoming shrivelled in old age,—the secretion may arise independently of impregnation ; for it has been witnessed in the unquestionable virgin, in the superannuated female, and even in the male sex. The fact as regards the unimpregnated female is mentioned by Hippocrates. Baudelocque states, that a young girl at Alengon, eight years old, suckled her brother for the space of a month. Dr. Gordon Smith refers to a manuscript in the col- lection of Sir Hans Sloane, which gives an account of a woman, at the age of sixty-eight, who had not borne a child for more than twenty years, and who nursed her grandchildren, one after another; and Dr. Francis, of New York, describes the case of a lady, who, fourteen years previously, was delivered of a healthy child after a natural labour. " Since that period," he remarks, " her breasts have regularly secreted milk in great abundance, so that, to use her own language, she could at all times easily perform the office of a nurse." But these, and cases of a similar nature, of which there are many on record, do not possess the same singularity as those of the function being executed by the male. Yet we have the most unquestionable authority in favour of the occurrence of such in- stances. The Bishop of Cork relates a case in the Philosophical Transactions for 1741, of a man who suckled his child after the death of his wife. Humboldt adduces one of a man, thirty-two years of age, who nursed his child for five months on the secretion from his breasts; and Captain Franklin, in his "Journey to the shores of the Polar Sea," gives a similar instance. It appears, therefore, that the secretion of milk may be caused, independently of a uterus, by soliciting the action of the mammary glands, but that this is a mere exception to the general rule, ac- cording to which the secretion is as intermittent as gestation itself. We have noticed, as one of the signs of pregnancy, that the breasts become enlarged and turgid, denoting the aptitude for the formation of the fluid; and it not unfrequently happens that, towards the mid- dle and latter periods of pregnancy, milk will distil from the nip- ples. This fluid, however, as well as that which flows from the breasts during the first two or three days after delivery, differs somewhat from milk, containing more serum and butter, and less caseum, and it is conceived to be more laxative, so as to aid the ex- pulsion of the meconium. This first milk is called colostrum, pro- togala, &c, and, in the cow, constitutes the biestings or beastings. Vol. II. 43 338 GENERATION. Generally, about the third day after confinement, the mammas be- come tumid, hard, and even painful, and the secretion from this time is established, the pain and distention soon disappearing. It is hardly necessary to discuss the views of Richerand, who considers the milk to be derived from the lymph; of others who derive it from the chyle; or of Girard of Lyons, who gratuitously asserts, that there is in the abdomen an apparatus of vessels,—in- termediate between the uterus and mammae,—which continue in- active, except during gestation, and for some time after delivery, but, in those conditions, are excited to activity. All these notions are entirely hypothetical, and there is no reason for believing, that this secretion differs from others, as regards the kind of blood from which it is separated. The separation takes place in the tissue of the gland, and the product is received by thc lactiferous ducts, along which it is propelled by the fresh secretion continuously arriving, and by the contractile action of the ducts themselves, the milk re- maining in the ducts and sinuses, until the mammas are, at times, considerably distended and painful. The excretion of the milk takes place only at intervals. When the lactiferous ducts are sufficiently filled, a degree of distention and uneasiness is felt, which calls for the removal of the contained fluid. At times, the flow occurs spontaneously; but, commonly, only when solicited either by sucking or drawing the breast, the secretion under such circumstances being very rapid, and the con- traction of the galactophorous ducts such, as to project the milk through the orifices in a thready stream. Milk is a highly azoted fluid, composed of water, caseum, sugar of milk, certain salts,—as the muriate, phosphate, and acetate of potassa, with a vestige of lactate of iron and earthy phosphate,— and a little lactic acid. According to Berzelius, it consists of cream, and milk properly so called,—the cream consisting of butter, 4.5; cheese, 3.5; whey, 92.0;—arid the whey of milk and salt, 4.4;—the milk containing, water, 928.75; cheese, with a trace of sugar, 28.01; sugar of milk, 35.00; muriate of potassa, 1.70; phosphate of potassa, 0.25; lactic acid, acetate of potassa, and lac- tate of iron, 6.00; and phosphate of lime, 0.30. Human milk contains more sugar of milk and less cheesy matter than that of the cow; hence it is sweeter, more liquid, less coagula- ble, and incapable of being made into cheese. Its quantity and cha- racter differ according to the quantity and character of the food,— a circumstance, which was one of the great causes of the belief, that the lymphatics convey to the mammas the materials for the secre- tion. The milk is, however, situated in this respect like the urine, which varies in quantity and quality, according to the amount and kind of solid or liquid food taken. The milk is more abundant, thicker, and less acid, if the female lives on animal food, but pos- sesses the opposite qualities when vegetable diet is used. It is apt, also, to be impregnated with heterogeneous matters, taken up from the digestive canal. The milk and the butter of cows indicate un- FQ5TAL ANATOMY. 339 equivocally the character of their pasturage, especially if they have fed on the turnip, wild onion, &c. Medicine, given to the mother, may in this way act upon the infant. The quantity of milk secreted is not always in proportion to the bulk of the mammas; a female whose bosom is of middle size often secreting more than another in whom it is much more developed;— the greater size being usually owing to the larger quantity of adi- pous tissue surrounding the mammary gland, and this tissue is in nowise concerned in the function. The secretion of milk usually continues until the period, when the organs of mastication of the infant have acquired the necessary development for the digestion of solid food: it generally ceases during the second year. For a great part, or the whole of this time, the menstrual flux is suspended; and if both the secretions,—mam- mary and menstrual—go on together, the former is usually impo- verished and in small quantity. Whilst lactation continues, the female is less likely to conceive; and hence the importance,—were there not even more weighty reasons,—of the mother's suckling her own child, in order to prevent the too rapid succession of children. When menstruation recurs during suckling, it is an evidence that the womb is again fit for impregnation. OF FOETAL EXISTENCE. The subject of foetal existence forms so completely a part of the function we are considering, that its investigation naturally succeeds to that of the part performed by the parents in its production; and especially as the development of the foetus is synchronous with all the uterine changes that have been pointed out. By most writers on physiology it has been the custom to include this subject under the same head as gestation, but the anatomy and physiology of the foetus have recently been so much studied as to sanction their sepa- ration. Anatomy of the Foetus. The uncertainty, which hangs over the immediate formation of the new individual, has been already mentioned; and it is not ne- cessary for us to do more than refer to the description of the differ- ent views regarding the predominance of the paternal or maternal influence over the character of the'product of generation. The mi- croscopical observations of Mr. Bauer, under the superintendance of Sir Everard Home, would seem to show, that the human ovum and that of the quadruped consist of a semitransparent, elastic, ge- latinous substance, enveloped in two membranous coverings; that this substance is formed in the ovarium independently of the male influence, but requires the application of such influence to undergo its developments. The period, at which the embryo is first perceptible in the 340 GENERATION.—OF THE FOETUS. ovule, differs in different animals. Haller asserts, that in sheep, whose term of gestation is five months, he could observe nothing more than a homogeneous mucus for the first sixteen days; but, at this time, membranes seemed to envelope the ovule and to give it shape; and on the twenty-fifth day, an opaque point indicated the foetus. Haighton, in experimenting on rabbits, could detect no change before the sixth day, and the foetus was not perceptible till the tenth. In the case, related by Sir Everard Home to which we have so frequently referred, the embryo was perceptible, under the microscope of Mr. Bauer, and although its weight did not probably exceed a grain, the future situation of the brain and spinal marrow was apparent. From this period, and especially after the fifteenth day, the ovule can be separated into two distinct sets of parts,—the dependencies of the foetus, and the foetus itself. These, in the course of pregnancy, become more and more readily se- parable. Each will require some consideration. Prior to this, however, it may be well to refer to the changes that the egg undergoes during incubation; where we have an oppor- tunity of observing the transmutations at all periods of foetal forma- tion, independently of all connexion with either parent. The subject has engaged the attention of physiologists of all ages; but it is chiefly to those of more modern times—as Hunter, Cuvier, Dutrochet, Parker, Rolando, Sir Everard Home, MM. Prevost and Du- mas, &c. that we are indebted for more precise information on the subject; although, unfortunately, they are by no means of accord- ance on many points. The investigations of Sir Everard Home, aided by those of the excellent microscopic observer, Mr.* Bauer, are peculiarly interesting from the engravings that accompany them, some of which we shall borrow in elucidation of the follow- ing brief description. The egg of a bird, of a hen for example, consists of two descrip- tions of parts;—those which are but little concerned in the deve- lopment of the new being, and which remain after the chick is hatched,—as the shell and the membrane lining it,—and such as undergo changes along with those of the chick and co-operate in its formation,—as the white, the yolk, and the cicatricula or molecule. The shell is porous, to allow of the absorption of air through it; and of the evaporation of a part of the albumen or white. In the ova- rium it is albuminous, but in the cloaca becomes calcareous. The membrane, membrana albuminis, that lines the shell, is of a white colour, and consists of two layers, which separate from each other at the greater end of the egg, and leave a space filled with air, ow- ing to the evaporation of the white and the absorption of air. This space is larger the older the egg. Th<^ white does not exist, whilst the egg is attached to the ovary. It is deposited between the yolk and the shell as the egg passes through the oviduct. Of the white there are two distinct kinds;—the outermost, thin and fluid, which evapo- rates in part, and is less abundant in the old than in the fresh laid egg, FOETAL ANATOMY. 341 Fig. 147 «. and another, situated within the last, which is much denser, and only touches the shell at the smaller extremity of the egg by a prolongation of its substance, which has been called the ligament of the white. The yolk seems to be, at first sight, a semifluid mass without organization; but by examining it, it is found to consist of a yolk-bag, two epidermic membranes, which envelope it as well as the cicatricula or molecule. Two prolongations of these mem- branes, knotty, and terminating in a flocculent extremity in the albumen, called chalazes, or poles are attached to the two ends of the egg and thus suspend it. It is also surrounded by a proper membrane; and lastly, under the epidermic coats of the yolk, and upon its proper coat lies the cicatricula, macula, tread of the cock, or gelatinous molecule from which the future embryo is to be formed. It is found before the yolk leaves the ovarium. The external membrane of the yolk, when it quits the yolk-bag, is very thin and deli- cate; its surface is studded over with red dots, which dis- appear in its passage along the oviduct. When this membrane is removed, there is a natural aperture in the thick, spongy covering under it, through which is seen the cicatricula or mo- lecule, surrounded by an areola, halo or circulus. On exami- nation, this areola proves to be nothing more than that part of the surface of the yolk, which is cir- cumscribed by the margin of the aper- ture. The molecule or cicatricula itself, Fig. 147^, has a granulat- aA annMM nno • onr\ The ova at different stages of increment. Ovarium of ajaying hen, eu appeal ante, dim natural size. according to Sir Everard Home is made up,in the centre, of globules iTooth part of an inch in diameter, surrounded by circles of a mixed substance; about two-thirds consisting of the same small globules, and one-third of larger oval globules, about -^V^h part of an inch 342 GENERATION.—OF THE FOETUS. Fig. 147 «. A new-laid egg, with its molecule, &c. in diameter; the last resembling in shape the oval red globules of the blood in the bird, excepting in colour. Besides the globules, there is some fine oil, which appears in drops, when the parts are immersed in water. Oval globules and oil are also met with in the yolk itself, but in small proportion and devoid of colour. When the egg leaves the ovarium, Fig.l47(1),theovarialyolk-baggives way at the median line,and the yolk drops into the commencement of the oviduct. The yolk-bags are exceedingly vascular, the outer membrane of the yolk being con- nected to them by vessels and fas- ciculi of fibres, but being readily separable from them. During the first hours of incubation no change is perceptible in the egg, but about the seventh, the molecule is evidently enlarged, and a mem- brane, containing a fluid substance, is observable. This membrane is the amnion. At this time a white line is perceptible in the mo- lecule which is the rudimental foetus; and even at this early period, according to Sir Everard Home, the brain and spinal marrow can be detected. The areola has extend- ed itself, and the surface, beyond the line which formed its bounda- ry, has acquired the consistence of a membrane, and has also a dis- tinct line by which it is circum- scribed. This Sir Everard calls the outer areola. In the space betweeen these two areolae are dis- tinct dots of an oily matter. In twelve hours, the rudiments of the brain are more distinct, as well as those of the spinal marrow. In thirty-six hours, the head is turned to the left side. The cere- brum and cerebellum appear to be distinct bodies. The iris is per- ceptible through the pupil. The intervertebral nerves are nearly formed; those, nearest the head, being the most distinct. A portion of the heart is seen. At Fig. 147 P). An egg, thirty-six hours after incubation. FOETAL ANATOMY. 343 this period, under the inner areola, apparently at the termination of the spinal marrow, a vesicle begins to protrude, which is seen earlier in some eggs than in others. The white of egg is found to be successively absorbed by the yolk, so that the latter is rendered more fluid and its mass augmented. The first appearance of red blood is discerned on the surface of the yolk-bag towards the end of the second day. A series of points is observed, which form grooves; and these closing constitute vessels, the trunks of which become connected with the chick. The vascular surface itself is called figura venosa or area vasculosa; and the vessel, by which its margin is defined, vena terminalis. The trunk of all the veins joins the vena portas, whilst the arteries, that ramify on the yolk- bag, arise from the mesenteric artery of the chick and have hence been called omphalo-mesenteric. In two days and a half, the spinal marrow has its posterior part inclosed: the auricles and ventricles of the heart are perceptible, and the auricles are filled with red blood. An arterial trunk from the left ventricle gives off two large vessels,—one to the right side of the embryo, the other to the left;—sending branches over the whole of the areolar membrane, which is bounded on each side by a large trunk carrying red blood; but the branches of the two trunks do not unite, there being a small space on one side, which renders the circle incomplete. This Sir Everard Home calls the areolar circulation. In three days, the outer areola has extended itself over one-third of the circumference of the yolk, carrying the marginal arteries along with it to the outer edge but dimi- nished in size. The brain is much enlarged; the cerebellum being still the larger of the two. The spinal marrow and its nerves are most distinctly formed; and the eye appears to want only the pig- mentum nigrum. The right ven- tricle of the heart contains red blood: the arteries can be traced to the head: the rudiments of the wings and legs are formed, and the vesicle is farther enlarged, but its vessels do not carry red blood. It has forced its way through the ex- ternal covering of the yolk, and opened a communication through this Slit, by Which a part of the Egg, opened three day. after incubation. albumen is admitted to mix itself with the yolk, and gives it a more oval form. At this period, the embryo is generally found to have changed its position and to be wholly turned on the left side. In four days, the vesicle is more enlarged, and more vascular, its Fig. 147 W. 344 GENERATION.—OF THE FOETUS. vessels containing red blood. The optic nerve and pigmentum ni- grum of the eye are visible. The outer areola extends half over the yolk, with which a larger portion of the white is now mixed. In five days the vesicle has acquired a great size, and become exceedingly vascular; the yolk too has become thinner, in conse- quence of its admixture with more of the albumen. In^ix days, the vascular mem- brane of the areola has extended farther' over the yolk. The vesi- cle, at this time, has suddenly ex- panded itself in the form of a dou- ble night-cap over the yolk, and its coverings are beginning to in- close the embryo, the outermost layer being termed the chorion, the innermost the middle mem- brane. The amnion contains a fluid, in which the embryo is sus- pended by the vessels of the vesi- cular membrane. The brain has become enlarged so as to equal in size the body of the embryo. Its The two eyes equal the whole brain in size. The parietes of the tho- rax and abdomen have begun to form; and the wings and legs are nearly completed as well as the bill. At this period muscular action has been noticed. In seven days, the vesicle,—hav- ing extended over the embryo,— has begun to inclose the areolar covering of the yolk, and a pulsa- tion is distinctly seen in the trunk that supplies the vesicular bag with blood. The pulsations were, in one case, seventy-nine in a minute, whilst the embryo was kept in a temperature of 105°; but when the temperature was dimi- nished, they ceased,and when again raised to the same point, the pulsa- tion was reproduced. The muscles of the limbs now move with vigour. In eight days, the anastomosing branches of the vesicular circula- tion have strong pulsation in them. In nine days the vesicle has nearly inclosed the yolk. Egg, five days after incubation. vessels are distinctly seen. Egg, ten days after incubation. FOETAL ANATOMY. 345 In ten days no portion of the yolk is observable on the outside of the vesicle. The embryo being taken out of the amnion,—now become full of water,—the thorax is found to be completely formed, and the roots of the feathers very distinct. The contents of the egg, during the. formation of the embryo, become much dimi- nished in quantity, and the void space is gradually occu- pied by a gas, which was examined by Mr. Hatchett, and found to be atmospheric air, deposited at the great end of the egg between the layers of the membranelining the shell. Even prior to in- cubation, there is always a small portion of air in this place, which is supposed to be employed in aerating the blood, from the time Of its Embryo ofthe egg, Fig. 147(6), showing the openingin the ,. , . . j ■% abdomen, from which portions of the vesicular and areolar hrst acquiring a red COIOUr, membranes and turns of the intestines are protruding. till superseded in that office m^edtwodiameters- by the external air acting through the eggshell upon the blood in Fig. 147(8). the vessels of the vesicular membrane, with whicb it is lined. Between the period of fourteen and eighteen days, the yolk becomes com- pletely inclosed by the areolar mem- brane; and at the expiration of the latter period the greater part of the yolk is drawn into the body, as in the marginal figure. At twenty days, the chick is completely formed, the yolk is entirely drawn in, and only portions of the membrane belonging to the ve- sicle are seen externally. The yolk- bag has a narrow tube, half an inch long, connecting it to the intestine, eight inches above the openings of the caeca into the gut. The whole of these changes, which in the viviparous animal are effected within the womb of the mother, take place in the incubated chick , .r o ., i Embryo eighteen days old.—Half the natural by virtue of its own powers; and 8 size. Vol. II. 44 346 GENERATION.—OF THE FOETUS. without any assistance, except that of the atmospheric air and of a certain degree of warmth. In the course of incubation the yolk becomes constantly thinner and paler by the admixture of the white; and at the same time innumerable fringe-like vessels, with flocculent extremities, of a singular structure, form on the in- ner surface of the yolk-bag, and hang into the yolk. The office of these is presumed to be, to absorb the yolk and to convey it into the veins of the yolk-bag, where it is assimilated to the blood and applied to the nutrition of the new being. Blumenbach states, that in numerous and varied microscopical examinations of the yolk- bag, in the latter weeks of incubation, he thinks he has observed the actual passage of the yolk from the yellow flocculent vessels of the inner surface of the bag into the blood-vessels which go to the chick. He has, at all events, seen manifest yellow streaks in the red blood contained in those veins. When the chick has escaped from the shell, the yolk, we have seen, is not exhausted, but is re- ceived into the abdomen, and as it communicates with the intestinal tube, it is for some time a source of supply to the young animal, until its strength is equal to the digestion of its appropriate food. The highly vascular chorion is manifestly an organ of aeration, like the placenta of the mammalia. I. BEPENBENCIES OF THE F(E TUS.—These are the parts of the ovum, that form its parietes, attach it to the uterus, connect it with the foetus, and are inservient to the nutrition and development of the new being. They consist,—First, of two membranes, which constitute the parietes of the ovule and which are concentric; the outermost called the chorion, the innermost, filled with a fluid, in which the foetus is placed, and called the amnion or amnios. Secondly, of a spongy, vascular body, situate without the chorion, covering about one-quarter of the ovule, and connecting it with the uterus, —the placenta. Thirdly, of a cord of vessels,—extending from the placenta to the foetus, the body of which is penetrated at the umbi- licus, by the vessels,—called the umbilical cord or navel string. Besides these dependencies, anatomists have described a vesi- cle,—filled with a fluid supposed to be of a nutritious character, and which has been assimilated to the yolk of the egg of oviparous animals,—called the umbilical vesicle; and another vesicle, which is only presumed to exist in the human ovum, because it is found in that of other mammalia, called the allantois. It is a sort of elon- gated bladder, between the chorion and amnion and communicates with the urinary bladder by the urachus. These last organs con- sequently belong more particularly to comparative anatomy ; and were this not the case, the great dissidence, that prevails amongst authors, regarding their structure and uses, would incline us to pass them over without much notice. The other dependencies will re- quire a more detailed description. FOETAL anatomy. 347 1. The chorion or endochorion is the outermost of the mem- branes of the ovule. About the twelfth day after conception, ac- cording to Velpeau, it is thick, opaque, resisting, and flocculent at both surfaces. These fiocculi, in the part of the ovum that corres- ponds to the tunica decidua reflexa, aid its adhesion to that mem- brane; but, in the part where the ovum corresponds to the uterus, they become developed to constitute the placenta. At its inner surface the chorion corresponds to the amnion. These two mem- branes are, however, separated during the earliest period of foetal existence, by a serous fluid; but at the expiration of three months, the liquid disappears and they are afterwards in contact. By many anatomists, the chorion is conceived to consist origi- nally of two laminae; Velpeau, however, denies this, and asserts, that he has never been able to separate them, even by the aid of previous maceration. As the placenta is formed on the uterine side of the chorion, the membrane is reflected over the foetal surface of that organ, and is continued over the umbilical cord, as far as the umbilicus of the foetus, where it is confounded with the skin, of which it conse- quently appears to be a dependence. As pregnancy advances, the chorion becomes thinner, and less tenacious and dense, so that at the full period, it is merely a thin, transparent, colourless membrane, which is much more delicate than the amnion. Haller and Blumenbach affirm it to be devoid of vessels; but, according to Wrisberg, it receives some from the umbilical trunks of the foetus, and, according to others, from the decidua. Dutro- chet conceives it to be an extension of the foetal bladder. 2. The amnion lines the chorion concentrically. It is filled with a serous fluid, and contains the foetus. In the first days of foetal ex- istence, it is thin, transparent, easily lacerable, and somewhat re- sembling the retina. At first it adheres to the chorion only by a point, which corresponds to the abdomen of the foetus ; the other portions of the membranes being separated by the fluid already mentioned, called the false liquor amnii. Afterwards the mem- branes coalesce and adhere by very delicate cellular filaments; but the adhesion is feeble, except at the placenta and umbilical cord. In the course of gestation, this membrane becomes thicker and tougher; and, at the full period, is more tenacious than the chorion, elastic, semitransparent and of a whitish colour. Like the chorion, it covers the foetal surface of the placenta, en- velopes the umbilical cord, passes to the umbilicus of the foetus, and commingles there with the skin. It has been a question whether the amnion is supplied with blood- vessels. Haller maintained the affirmative, and asserts, that he saw a branch of the umbilical artery creeping upon it. The fact of the existence of a fluid within it and which is presumed to be se- creted by it, is also greatly in favour of the affirmative. But, admit- 34S GENERATION.—OF THE FOETUS. ting that it is supplied with blood-vessels, a difference has existed, with regard to the source whence they proceed; and anatomical in- vestigation has not succeeded in dispelling it. Monro affirms, that on injecting warm water into the umbilical arteries of the foetus, the water oozed from the surface of the amnion. Wrisberg, however, asserts, that he,noticed the injection to stop between the chorion and amnion; and again, Chaussier obtained the same results as Monro, by injecting the vessels of the mother. The amnion contains a serous fluid, the quantity of which is in an inverse ratio to the size of the new being; so that its weight may be several drachms, when that of the foetus is only a few grains. At first, the liquor amnii,—for so it is called,—is transparent; but at the full period it has a milky appearance, owing to fiocculi of an albuminous substance held in suspension by it. It has a saline taste, a spermatic smell, and is viscid and glutinous to the touch. Vau- quelin and Buniva found it to contain, water, 98.8; albumen, mu- riate of soda, soda, phosphate of lime, and lime, 1.2. That of the cow, according to these gentlemen, contains amniotic acid; but Prout, Dulong, and Labillardiere and Lassaigne have not been able to detect it. Prout found some sugar of milk in the liquor amnii of the human female; Berzelius detected fluoric acid in it; Scheele free oxygen; and Lassaigne, in one experi- ment, a gas resembling atmospheric air; in others a gas composed of carbonic acid and azote. The chymical history of this substance is, consequently, sufficiently uncertain. Nor is its formation placed upon surer grounds:—some physiologists ascribing it to the mo- ther, others to the foetus;—opinions fluctuating, according to the presumed source of the vessels that supply the amnion with ar- terial blood. It has even been supposed to be the transpiration of the foetus, or its urine. The reply to these views is, that we find it in greater relative proportion when the foetus is small. Meckel thinks that it proceeds chiefly from the mother, but that about the termination of pregnancy, it is furnished in part by the foetus. The functions, however, to which, as we shall see, it is probably inservient, would almost constrain us to consider it a se- cretion from the maternal vessels. The quantity varies in different individuals and in the same in- dividual, at different pregnancies, from four ounces to as many pints. Occasionally, it exists to such an amount as even to throw obscurity over the very fact of pregnancy. An instance of this kind, strongly elucidating the necessity of the most careful attention on the part of the practitioner in such cases, occurred in the practice of a respectable London practitioner,—a friend of the author. The abdomen of a lady had been for some time enlarging by what was supposed to be abdominal dropsy: fluctuation was evi- dent, and the case appeared to be unequivocal. A distinguished accoucheur with a surgeon of the highest eminence were called FOETAL anatomy. 349 in consultation, and after examination, the latter declared, that "it was an Augean stable, which nothing but the trocar could clear out." As the lady, however, was even then complaining of intermittent pain, it was deemed advisable to make an examination per vaginam. The os uteri was found dilated and dilating, and, in a few hours after this formidable decision, she was delivered of a healthy child, the gush of liquor amnii being most enormous. After its discharge the lady was reduced to the natural size, and the dropsy, of course, disappeared! 3. Placenta. This is a soft, spongy, vascular body, formed at the surface of the chorion, adherent to the uterus, and connected with the foetus by the umbilical cord. The placenta is not in existence during the first days of the embryo state. At this period, the ovule is cover- ed with the shaggy secretion or granulations by which the chorion is united to the decidua reflexa, where this membrane covers it, and by which it adheres to the uterus and forms the placenta, where the decidua is wanting,—as it is supposed to be in one of the views with regard to the decidua. The formation of the placenta is dif- ferently accounted for according to those views. In the opinion of some, the fiocculi, which are at first spread uniformly over the whole external surface of the chorion, gradually congregate from all parts of the surface into one, uniting with vessels, proceeding from the uterus, and traversing the decidua, to form the pla- centa;—the decidua disappearing from the uterine surface of the pla- centa about the middle of pregnancy, so that the latter comes into immediate contact with the uterus. In the opinion of others, the placenta is formed by the separation of the layers of the chorion, and by the development of the different vessels, that creep between them. Again, Velpeau maintains, that the placenta forms only at the part of the ovule, which is not covered by the decidua, and which is immediately in contact with the uterus; and that it results from the development of the granulations that cover this part of the chorion; these granulations or villi, according to Velpeau, being gangliform organs containing the rudiments of the placental vessels. This is an interesting topic of general anatomy, but one on which we are precluded from dwelling. In whatever manner originally produced, it is distinguishable in the second month, after which it goes on successively increasing. Prior to the full term, however, it is said to be less heavy, more dense, and less vascular, owing to several of the vessels, that formed it, having become obliterated and converted into hard, fibrous filaments; a change which has been re- garded as a sign of maturity in the foetus, and a prelude to its birth. At the full period, its extent has been estimated at about one- fourth of that of the ovum; its diameter from six to eight inches; its circumference, twenty-four inches; its thickness from an inch to an inch and a quarter, at the centre, but less than this at the circum- ference; and its weight, with the umbilical cord and membranes, from twelve to twenty ounces. All this is subject, however, to much 350 GENERATION.—OF THE FOBTUS. Uterine surface of the plaeenta. variation. It is of a circular shape, and the cord is usually inserted into its centre. It may be attached to any part of the uterus, but is usually found towards the fundus. Of its two surfaces, that which corresponds to the uterus, is divided into ir- regularly rounded lobes or cotyledons, and it is covered by a soft and delicate cellulo-vascular membrane, which, ac- cording to Chaussier,— who believes that the de- cidua invests the whole ovum,—is the decidua. Wrisberg, Lobstein, and Desormeaux, how- ever, who consider that the decidua disappears from behind the placenta about the fourth or Fig. 149. fifth month, regard it as a new membrane; whilst Velpeau maintains that the decidua never exists there. The foetal or umbilical surface is smooth, polished, covered by the chorion and amnion and exhibits the dis- tribution of the umbilical ves- sels, and the mode in which the cord is attached to the organ. The following are the ana- tomical constituents of the placenta, as described by anatomists. First. Blood- FcEtal surface of the placenta. -■-»»»«#« vessels, from two sources,— the mother and the foetus. The former proceed from the uterus, and consist of arteries and veins, of small size but considerable num- ber. The vessels, which proceed from the foetus, are those that constitute the umbilical cord;—viz. the umbilical vein, and the um- bilical arteries. These vessels, after having penetrated the foetal surface of the placenta, divide in the substance of the organ, so that each lobe has an arterial and a venous branch, which ramify in it, but do not anastomose with the vessels of other lobes. Second- ly. Expansions of the chorion, which are described by some as dividing into cellular sheaths and accompanying the vessels to their FOETAL ANATOMY. 351 final ramifications;—an arrangement which is, however, contested by others. Thirdly. White filaments, which are numerous in pro- portion to the advancement of pregnancy, and which seem to be only obliterated vessels. Fourthly. A kind of intermediate cellu- lar tissue, serving to unite the vessels together, and which has been regarded, by some anatomists, as an extension of the decidua ac- companying those vessels. Lastly. A quantity of blood poured into this intermediate cellular tissue, which may be removed by washing. In addition to these constituents, a glandular structure has been presumed to exist in it; as well as lymphatic vessels; and Chaussier and Kibes say nerves, proceeding from the great sympathetic of the foetus. The uterine and the foetal portions of the placenta are quite dis- tinct from each other, during the two first months of foetal life; but afterwards they constitute one mass. Still the uterine vessels re- main quite distinct from the foetal; the uterine arteries and veins communicating freely with each other, as well as the foetal arteries and veins; but no direct communication existing between the ma- ternal and foetal vessels. 4. Umbilical cord.—From the foetal surface of the placenta a cord of vessels passes, which enters the umbilicus of the foetus, and has hence received the name umbilical cord, as well as that of navel-string. It forms the medium of communication between the foetus and the placenta. During the first month of foetal existence, the cord is not percep- tible; the embryo appearing to be in contact, by the anterior part of its body, with the membranes of the ovum. In an embryo, a month old, Beclard observed vessels creeping for a certain space between the membranes of the ovum, from the abdomen of the foetus to a part of the chorion, where the rudi- ments of the future placenta were visible. During the fifth week, the cord can first be detected, at which period it is straight, short, and very large, owing to its con- Fig. 150. taining a portion of the intestinal canal. It presents also, three or four dilatations, sepa- rated by as many contracted por- tionsor necks; but these gradually disappear, the cord lengthens and be- comessmaller,and occasionally it is twisted, knotted and tuberculated in a strangely in- 352 GENERATION.--OF THE FOETUS. explicable manner, (Fig. 150.) At the full period, the length of thecord varies; but, on the average, it is perhaps about twenty inches. It is composed of three vessels,—the umbilical vein, two arteries of the same name, of a peculiar jelly-like substance, and is surrounded, as we have seen, by the amnion and chorion. The vessels will be more particularly described hereafter. They are united by a cel- lular tissue, containing the jelly ofthe cord, a thick albuminous se- cretion, which bears some resemblance to jelly, and the quantity of which, is very variable. In the foetus, the cellular tissue is continu- ous with the sub-peritoneal cellular tissue; and in the placenta, it is considered to accompany the ramifications of the vessels. It has been already remarked, that Chaussier and Ribes have traced branches of the great sympathetic of the foetus as far as the placenta. According to most obstetrical physiologists, when pregnancy is multiple, the ova in the uterus are generally distinct, but contiguous to each other. By others, it has been affirmed that two or more children may be contained in the same ovum, but this appears to require confirmation. The placenta of each child, in such multiple cases, may be distinct; or the different placentae may be united into one, having intimate vascular communications with each other. At other times, in twin cases, but one placenta exists. This gives origin to two cords, and at others, to one only, which afterwards bifur- cates and proceeds to both foetuses. Maygrier, however, affirms unconditionally, that there is always a placenta for each foetus; but that it is not uncommon, in double pregnancies, to find the two placentae united at their margins; the circulation, however, of each foetus being distinct, although the vessels may anastomose. II. OF THE FCETUS.—-The ovule does not reach the uterus un- til towards the termination of a week after conception. On the seventh or eight day it has the appearance referred to in the case so often cited from Sir Eve- rard Home; the future situations of the brain and spinal marrow being recogni- with the aid of a powerful micro- On the thirteenth or fourteenth day, according to Maygrier, the ovum is perceptible in the uterus, and of about the size of a pea, containing a turbid fluid, in the midst of which an opaque point is suspended,—the punctum saliens. ovum and embryo, fifteen days The weight of this has been valued at about ul"■ Divided integuments.-c, c. Divided . ■'..,.. „ «nbs and intercostal muscles.—e, e. Lobes of ObSCUre, in ltS phySlOlOgy, Of any Of thymus gUnd.-g,g, h,h. Lungs.-*. Right ,, c iU U J auricle of „the heart.—A. Right ventricle.— the Organs Ol the DOdy. ri,o. Right and left lobes of the liver.-jft. Sto- The thyroid gland, which has been JSfh5&£r T^^SSS^v^^ described in another place, and whose ^^^1.-^^^^: ?he functions are equally obscure, is also collapsed umbilical cord. largely developed in the foetus; as well as the supra-renal capsules. 360 GENERATION.—OF THE fcetus. The lungs, not having received air in respiration, are collapsed and dense, containing no more blood than is necessary for their nu- trition. They are of a dark colour, like liver, and do not fill the cavities of the chest. Their specific gravity is greater than that of water,and consequently they sink in that fluid. On cutting into them, no air is emitted, and no hemorrhage follows. The absolute weight, however, of the lungs is less; no more blood, as we have seen, being sent to them than what is necessary for their nutriment; whilst, after respiration is established, the whole of the blood passes through them; the vessels are consequently filled with blood, enlarged, and the organs themselves increased in absolute weight. Ploucquet asserts, from experiments, that the weight of the lungs of a full-grown foe- tus, which never respired, is to that of the whole body, as 1 to 70; whilst jn those, in which respiration has been established, it is as 1 to 35; the absolute weight being thus doubled. These numbers cannot, however, be considered to afford a satisfactory average; the exceptions being most numerous, but all show that, as might be expected, the absolute weight is less prior to the establishment of respiration. The subject is one of great interest, connected with infanticide, and has been treated in a competent manner by Dr. T. Beck in his Elements of Medical Jurisprudence,—decidedly, in our opinion, the best medico-legal work in existence. It is, however, in the circulatory system of the foetus, that we meet with the most striking peculiarities. The heart is proportionably larger and more conical than in the adult. The valve of Eustachius— at the left side of the mouth of the inferior vena cava, where this vessel joins the sinus venosus,—is larger than at an after period, and is sup- posed to direct the principal part of the blood of that cava directly through the opening which exists between the right and left auricle. This opening, which is called the foramen ovale or foramen of Botal, is in the septum between the auricles, and is nearly equal in size to the mouth of the inferior cava. It is situated obliquely, and has a mem- brane, forming a distinct valve, and somewhat of a crescentic shape, which al- lows part of the blood of the right auricle to pass through the opening into the left auricle, but pre- vents its return. The pulmonary artery, instead of bifurcating as in the adult, divides into three branches;—the right and A, A. Lungs.-B. Right auricle.-C. Leftauricle.-D. Right left going fo the lungS of ri^us.016*"12, Pulm°nary artery-*. Aorta.-*. Ductus arte- the corresponding side, FCETAL PECULIARITIES. 361 whilst the middle branch,—to which the name ductus arteriosus has been given,—opens directly into the aorta; so that a great part of the blood of the pulmonary artery passes directly into that ves- sel. From the internal iliac arteries, two considerable vessels arise, called the umbilical arteries. These mount by the sides of the bladder, as in Fig. 156, on the outside of the peritoneum and per- forate the umbilicus in their progress to the umbilical cord and pla- cepta. The umbilical vein, which is also a constituent of the cord, and conveys the blood from the placenta to the foetus, arises from the substance of the placenta by a multitude of radicles, which unite together to form it. Its size is considerable. It enters the umbi- licus, (Fig. 156;) passes towards the inferior surface of the liver, and joins the left branch of the vena porta hepatica. Here a vessel arises called the ductus venosus, which opens into the vena cava inferior, or joins the left vena hepatica, where that vein enters the cava. A part only of the blood of the umbilical vein goes directly to the vena cava; the remainder is distributed to the right and left lobes of the liver, especially to the latter. The digestive apparatus exhibits few peculiarities. The bowels, at the full period, always contain a quantity of greenish, or deep black, viscid faeces, to which the term meconium has been ap- plied, owing to their resemblance to the inspissated juice of the poppy, (/M.jjxwy, 'a poppy.') It appears to be a compound of the secre- tions from the intestinal canal and bile, and frequently contains down or fine hairs mixed with it. The liver is very large; so much so as to occupy both hypochon- driac regions; and the right and left lobes are more nearly of a size than in the adult. The urinary bladder is of an elongated shape, and extends almost to the umbilicus. The muscular coat is somewhat thicker and more irritable than in the adult, and it continues to possess more power during youth. The common trick of the schoolboy—of send- ing the jet over his head—is generally impracticable in more ad- vanced life. From the fundus of the bladder, a ligament of a conical shape, called the urachus, (Fig. 156,) ascends between the umbilical arteries to the umbilicus; becoming confounded in this place with the abdominal aponeuroses, according to Bichat, and forming a kind of suspen- sory ligament to the bladder. It is sometimes found hollow in the human foetus, but such a formation Bichat considers to be pre- ternatural. In the foetal quadruped, it is a large canal, which transmits urine to a bag, called allantois, placed between the am- nion and chorion and presumed to be, in some way, inservient to the nutrition of the foetus; but the notions on this subject are ex- tremely vague and imprecise. Lastly, the genital organs require some notice. The succes- Vol. II. 46 362 GENERATION.—OF THE FQ3TUS. sive development of this part of the system has given rise to some singular views regarding the cause of the sex of the foetus. During the first few weeks, the organs are not perceptible; but about the termination of the fifth week, a small, cleft eminence ap- pears, which is the rudiment of the scrotum or the vulva, accord- ing to the sex. In the sixth week, an aperture is perceptible, common to the anus and genital organs, in front of which is a pro- jecting tubercle. In the seventh and eighth weeks, this tubercle seems to be tipped by a glans, and grooved beneath by a channel which extends to the anus. In the eleventh and twelfth weeks, the perineum is formed and separates the anus from the genital or- gans. In the fourteenth week, the sex is distinct; but there still remains, for some time, a groove beneath the clitoris or penis, which becomes closed in the former, and is made into a canal in the latter. The striking similarity between the male and female organs has led Tiedemann to conclude, that the female sex is the male, ar- rested at an inferior point of organization. In his view, every em- bryo is originally female; the cleft, described above, being the vulva, the tubercle, the clitoris; to constitute the male sex, the cleft is united so as to form a raphe, the labia majora are joined to form the scrotum, the nymphse to form the urethra, and the clitoris is trans- formed into a penis. In support of this opinion Tiedemann as- serts, that the lowest species of animals are almost all females; and that all the young acephali and aborted foetuses, which have been examined, are of that sex. Others again, have affirmed, that the sexes are originally neuter, and that the future sex is determined by accidental circumstances, during the first week of foetal life; whilst Geoffroy St. Hilaire maintains, that the difference of sex is owing to the distribution of the two branches of the spermatic artery. If they continue in ap- proximation, proceeding together,—the one to the testicle, the other to the epididymis, the individual is male; if they separate,—the one going to the ovary, the other to the cornua of the uterus,—the indi- vidual is female. The degree of predominance of the cerebrospi- nal system, he thinks, determines the approximation or separation of the two arterial branches. This predominance being greater in the male, the spermatic arteries are more feeble and consequently in greater proximity; and vice versa. Leaving these phantasies of the generalizing anatomist, on a sub- ject on which we must, probably, ever remain in the dark, let us inquire into the phenomena of the descent of the testes in the foetus. In the early months of foetal life, the testicle is an abdominal vis- cus, being seated below the kidney. About the middle of the third month of utero-gestation, it is about two lines long, and is situated FOETAL PECULIARITIES. 363 behind the peritoneum, which is reflected over its ventral surface At this time, a sheath of perito- neum may be observed, passing from the abdominal ring to the lower part of the testicle, and containing a ligament, called gubernaculum testis, which is considered to be formed of elastic cellular tissue, proceeding from the upper part of the scrotum, and from the part of the general aponeurosis of the thigh near the ring, and of some muscular fibres coming from the internal ob- lique and transversalis muscles. The head of the foetus in utero be- ing the lowest part, the testis has ne- cessarily to ascend into the scrotum, and consequently some force must be exerted upon it. This is supposed to be effected by the contraction of the gubernaculum testis. About the Seventh month the testes are in pro- A. Testicle.—B. Peritoneal covering or tunica , n .. t^. , -'— albuginea.—C. Peritoneum of the loins.—D. Pe- greSS towards the SCrotum. .fclg. 1OO ritoneum descending before the testicle.—F. Pe- exhibits one about to leave the ab-ritoneum^abdomen- domen and enter the scrotum, into which it generally passes about the eighth month. In this de- scent, the organ successively abandons one portion of the pe- ritoneum to pass behind an- other immediately below, until the lowest part of the pouch, formed by the peritoneum, around the testicle, as in Fig. 159, becomes the tunica albu- ginea or first coat; whilst the portion of peritoneum, that de- scended before the testicle, be- comes, when the testicle has fully descended, the second coat or tunica vaginalis. As soon as the testicle has reached the lower part of the scrotum, the neck of the pouch approaches a closure, and this is commonly effected at birth. Sometimes, however, it re- mains open for some time, the intestines pass down, and congenital hernia is thus induced. A. Testicle in the scrotum.—B. Prolongation of the peritoneum.—C. Peritoneum lining the abdomen.—D. Peritoneum forming the tunica vaginalis.—E. Cavity of the peritoneum.—F. Kidney. 364 GENERATION.--OF THE FC3TUS. Physiology of the Foetus. In investigating this interesting point of human physiology, we shall inquire into the functions, in the order of the classification we have adopted of the functions of the adult. Over many of the topics that will have to engage attention, the deepest obscurity rests; whilst the hypotheses, indulged regarding them, have been of the most fanciful and mystical character. I. Animal functions.—The external senses in general are mani- festly not in exercise during foetal life: of this there can be no doubt, as regards the sense of sight; and the same thing probably applies to the taste, smell, and hearing. With regard to tact, however, we have the best reason for believing that it exists, par- ticularly towards the latter periods of utero-gestation. The cold hand, applied over the abdomen of the mother, will instantly elicit the motions of the child. The brain and nervous system of the foetus must, therefore, have undergone the development, necessary for the reception of the impression made through the medium of the mo- ther, to convey such impression to the percipient organ, and to ac- complish perception. The existence of most of the internal sensations or wants would of course be supererogatory in the foetal state, where the functions, to which they excite after birth, are themselves wanting. It is proba- ble, that there is no digestion except of the mucous secretions of the tube; no excretion of*fseces or urine, and certainly there is no pulmonary respiration. It is not improbable, however, that in- ternal impressions, originating in the very tissue of the organs, may be communicated to, and appreciated by, the brain. We have strong reason for believing, that pain may be experienced by the foetus; for if it be destroyed by any sudden influence, in the latter periods of pregnancy, death will generally be preceded by irregular move- ments, which are manifest to the mother, and frequently lead her to anticipate the result. Adelon asks, whether it may not be af- fected, under such circumstances with convulsions, similar to those that animals experience when they die suddenly, especially from hemorrhage? It is impossible to reply to this question, but that the child suffers appears evident. The most elevated of the functions of relation—the mental and moral faculties—would seem to be needless to the foetus, and conse- quently little, if at all, exercised. Bichat and Adelon, considering that its existence is purely vegetative, are of opinion that they are not exerted at all. Cabanis, however, suggests, that imperfect es- says may, at this early period, be made by virtue of the same in- stinct that impels animals to exercise their organs prior to the pe- riod at which they are really able to derive service from them; as in the case, of the bird, which will shake its wings before they are covered wfth feathers, and when yet incapable of bearing them. NUTRITION OF THE FQ3TUS. 365 It is difficult to deny the foetus all intellectual and moral mani- festation. This must doubtless be obscurely rudimental, but still we may conceive that some may exist, if we admit, that the brain is in a state for the perception of impressions, and that tact is prac- ticable, whilst instinct is in full activity. We find, moreover, that the power of motion, voluntary as well as involuntary, exists certainly after the fifth month, and probably much earlier, could it be appreciated. During the latter months of utero-gestation, the motion of the foetus appears to be almost inces- sant, and can be distinctly felt, by placing the hand upon the abdo- men. At times, indeed, it is manifest to the sight. The cause of these movements is by no means clear. It is probable, however, that they are instituted for the purpose of inducing a change in po- sitions which may have become irksome, and for assuming others; for we have already remarked, that the foetus readily appreciates any sudden succussion, given to it through the mother; hence that it possesses tact; and, as we can readily understand, may experience fatigue from the maintenance of an inconvenient posture. This im- pression is conveyed to the brain, which sends out volition to the ap- propriate muscles,and the position is changed. Allthisproves,thatthe cerebral functions are exerted, but for a few definite objects only. The function of expression is of course almost, if not entirely, null in the foetus. There are cases upon record, however, where children are said to have cried in utero, so as to be heard distinctly, not only by the mother, but by those around her. Indeed, the ob- jection, that an infant may respire before it is born, and yet not come into the world alive,—in which case there will be buoyancy and dilatation of the lungs,—has been seriously brought forward against the docimasia pulmonum or lung-proof of infanticide. We would not be considered as believing these cases to be mere fabrica- tions, or that the phenomenon is impossible,—except, indeed, whilst the membranes are in a state of integrity. When they have given way, and the child's mouth presents towards the os uteri, breathing may be practicable, and may have occurred; but very positive and unexceptionable testimony is required to establish such an astound- ing event. II. Functions of Nutrition.—These functions are not as numer- ous in the foetus as they are in the adult. Their object is, however, the same;—the formation of the various parts of the organized ma- chine, and their constant decomposition and renovation. During the first few days of foetal existence, whilst the ovum is within the ovarium or Fallopian tube, and for a short period after its passage into the womb, the new being probably derives its nutriment from the albuminous matters with which it is in contact in the ovum, in the same manner as the egg of the oviparous ani- mal obtains the nutriment necessary for its full development during incubation, from the matters surrounding it. But when it has at- tained the interior of the uterus, it is supposed that the ovum ab- 366 GENERATION.—OF THE FOETUS. sorbs nutriment from the mother. Chaussier conceives, that the ovule, on leaving the Fallopian tube, plunges into the midst of the sero-albuminous substance, which is copiously secreted in the uterus for the formation of the decidua, and that it nourishes itself by absorbing a quantity of this by its external surface, like the vegetable, and the lowest tribes of animals. The decidua, how- ever, appears to be intended for a specific purpose, and is formed even prior to the passage of the ovule into the uterus. This, with the fact of the ovule containing nutritive matter within it for the nutrition of the embryo, is sufficient to render the view of Chaus- sier improbable. The liquor amnii, in which the child is situated during the whole period of utero-gestation, has been regarded by many physiologists as concerned in foetal nutrition; but great dissidence has pre- vailed with regard to the mode in which it is introduced. The arguments, usually adduced in favour of this function of the liquor amnii, are,—the nutritive nature of the fluid, young animals having been fed upon it for several weeks,—the fact of its being more abun- dant and richer in animal matter in proportion as the foetus is young, —its continual contact with the foetus, whose surfaces, internal as well as external, have been supposed to possess a greater absorbent power in proportion to the nonage of the foetus,—and the fact of foetuses, devoid of umbilical cord, having undergone their develop- ment without the aid of a placenta. The circumstance of the first developments being made in the ovarium from the absorption of the nutritive matter surrounding the embryo, is so far in favour of the foetus obtaining its nutriment from the substances in contact with it, rather than by means of the ma- ternal blood; and the view is favoured by the phenomena that oc- cur in eggs hatched out of the body, where of course there can be no farther communication with the mother. The most forcible arguments, however, are those deduced from the fact, which seems unquestionable, that neither the placenta nor umbilical cord is indispensably necessary to foetal development. Adelon disposes of this in the most summary manner; affirming that " there is no authentic instance of a foetus devoid of umbilical cord and placenta, attaining full uterine growth." The case is not, however, got rid of so easily, and it environs this intricate subject with additional difficulties. The kangaroo, opossum, and wombat, breed their young without either placenta or umbilical cord. The embryos are inclosed in one or more membranes, which are not attached to the coats of the uterus, and are supplied with nourishment, and apparently with air, from a gelatinous matter, by which they are surrounded. Good has cited a case from Hoffmann of a foetus born in full health and vigour, with the funis sphacelated and divided into two parts; and another, from Van der Wiel, of a living child, exhibited without any umbilicus, as a public curiosity. One of the most singular cases, however, that has ever occurred, NUTRITION OF THE FG3TUS. 367 was observed by Dr. Good himself in 1791. The labour was natu- ral; the child, scarcely less than the ordinary size, was born alive; cried feebly once or twice after birth, and died in about ten minutes. The organization, both internal and external, was imperfect in many parts. There was no sexual character whatever, neither penis nor pudendum; nor any interior organ of generation. There was no anus or rectum, no funis, no umbilicus. The minutest investigation could not discover the least trace of any. With the use of a little force, a small, shrivelled placenta, or rather the rudiment of a pla- centa, followed soon after the birth of the child, without a funis or umbilical vessels of any kind, or any other appendage by which it appeared to have been attached to the child. In a quarter of an hour afterwards, a second living child was protruded into the va- gina and delivered with ease, being a perfect boy, attached to its placenta by a proper funis. The body of the first child was dis- sected in the presence of Dr. Drake of Hadleigh, and of Mr. Anderson of Sunbury, to both of whom Dr. Good appeals for the correctness of his statement. In the stomach a liquid was found resembling the liquor amnii. How could nutrition have been effected, then, in this case? Cer- tainly not by blood sent from the mother to the child, for no appa- ratus for its conveyance was discoverable; and are we not driven to the necessity of supposing that the food must have been obtained from the fluid within the ovum? This case,—when taken with the arguments already adduced; along with the facts, that the embryo is found at an earlier period in the uterus than the placenta, which as we have seen cannot be detected till some weeks after concep- tion; and that extra-uterine foetuses have frequently no placenta, but obtain their nutriment from the surrounding parts,—seems to constrain us to admit, that the liquor amnii may have more agency in the nutrition of the new being than is generally granted. Pro- fessor Monro, amongst other reasons,—all of which are of a nega- tive character,—for his disbelief in this function of the liquor amnii, asserts, that if the office of the placenta be not that of afford- ing food to the embryo, it becomes those, who maintain the con- trary doctrine to determine what other office can be allotted to it, and that till this is done, it is more consistent with reason to doubt the few and unsatisfactory cases, at that time brought for- ward, than to perplex ourselves with facts directly contradictory of each other. The case, given by Dr. Good since Professor Monro's remarks were published, is so unanswerable and so unquestionable, that it affords a positive fact, of full or nearly full foetal develop- ment, independently of placenta and umbilical cord; and the fact must remain, although our ignorance of the functions of the pla- centa, be " dark as Erebus." Amongst those physiologists, who admit the liquor amnii to be a fluid destined for foetal nutrition, a difference prevails, regarding the mode in which it is received into the system. Buffon, Osian- 368 GENERATION.—OF THE FffiTUS. der and others consider, that it is absorbed through the skin. In the foetal state, the cuticle is extremely thin; and, until within a month or two of the full period, can be scarcely said to exist. There is consequently not that impediment to cutaneous absorption, which we have seen, exists in the adult. The strong argument, however, which they offer in favour of such absorption is the fact, that the foetus has been found developed, although devoid of both mouth and umbilical cord; and Professor Monro, in opposing the function as- cribed to the liquor amnii, refers to cases of monstrous formations, in which no mouth existed, nor any kind of passage leading to the stomach. Others, as Boerhaave and Haller are of opinion that the fluid enters the mouth and is sent on into the stomach and intestines; and in support of this view, they affirm, that the liquor amnii has been found in these viscera;—that it has been shown to exist in the sto- mach and pharynx. Heister on opening a gravid cow, which had perished from cold, found the liquor amnii frozen, and a continuous mass of ice extending to the stomach of the foetus. The physiologists, who believe that the liquor amnii is received into the stomach, differ as to what happens to it in that organ. Some suppose, that it is simply absorbed, without undergoing digestion; others, that it must be first subjected to that process. According to the former opinion, it is simply necessary, that the fluid should come into contact with the mucous membrane of the alimentary passages; and they affirm, that if digestion occur at all, it can only be during the latter months. Others, however, conceive, that the waters are swallowed or sucked in, and that they undergo true digestion. In evidence of this, they adduce the fact of meconium existing at an early period in the intestinal canal, which they consider as evidence that the diges- tive function is in action; and in farther proof of this they affirm, that on opening the abdomen of a new-born infant, the chyliferous vessels were found filled with chyle; which could not, they say, have been formed from any other substance than the liquor amnii; and lastly, that fine silky down has been found in the meconium, similar to that which exists on the skin of the foetus, and which is conceived to have entered the mouth along with the liquor amnii. These reasons are forcible, but they do not explain the de- velopment, in the cases above alluded to, in which there was no mouth; and of course, they cannot apply to acephalous foetuses. Moreover, it has been properly remarked, that the presence of me- conium in the intestinal canal merely proves that digestion has taken place, and the same may be said of the chyle in the chylife- rous vessels: neither one nor the other is a positive evidence of the digestion of the liquor amnii: both might have proceeded from the digestion of the stomachal secretions. It has also been affirmed, that the meconium exists in the intestines of the acephalous foetus, and in those in which the mouth is imperforate. Lastly, with re- NUTRITION OF THE FffiTUS. 369 gard to the down discovered in the meconium, it has been sug- gested as possible that it may be formed by the mucous membrane of the intestine, which so strongly resembles the skin in structure and functions. Others have supposed that the liquor amnii is received by the respiratory passages, from the circumstance, that, in certain cases, the fluid has been found in the trachea and bronchi; some presum- ing, that it readily and spontaneously enters at the nostrils and passes to the trachea and bronchi; others that it is forced in by the pressure of the uterus; and others again, that it is introduced by the respiratory movements of the foetus. Views have differed in this case, also, regarding the action exert- ed upon it after introduction;—some, presuming that it is absorbed immediately; others, that it is inservient to a kind of respiration; and that, during foetal existence, we are aquatic animals,—consuming the oxygen or atmospheric air which Scheele and others have stated to exist in the fluid. It is scarcely necessary to seriously oppose these gratuitous specu- lations. The whole arrangement of the vascular system of the foe- tus, so different from that which is subsequently established, and the great diversity in the lungs, prior and subsequent to respiration, would be sufficient to refute the idea, had it even been shown, that the liquor amnii always contains one or other of these gases, which is by no means the fact. The case of the acephalous foetus is also an obstacle to this view as strong as to that of the digestion of the li* quor amnii. As if to confirm the remark of Cicero—-"nihil tarn absurdum, quod non dictum sit ab aliquo philosophorum,"—it has been ad- vanced by two individuals of no mean pretensions in science, that the liquor amnii may be absorbed by the genital organs or by the mammas. Lobstein supports the former view, Oken the latter. Lobstein asserts, that the fluid is laid hold of by the mammas, is elaborated by them, and conveyed from thence into the thymus gland, the thoracic duct, and the vascular system of the foetus! Of these various opinions, the one that assigns the introduction of the fluid to the agency of the cutaneous absorbents appears to carry with it the greatest probability. It must be admitted, however, that the whole subject is environed in obscurity, and requires fresh, repeated, and accurate experiments and observations to en- lighten us. But it may now be asked, with Monro, what are the nutritive functions performed by the placenta? We have seen that vessels pass between the mother and the maternal side of the placenta, and that others pass between the foetus and the foetal side, but that the two sides are so distinct, that we are justified in regarding them as two placentas,—the one maternal, the other foetal,—simply united to each other. Vol. II. 47 370 generation.—of the fcetus. At one time it was supposed, that a direct communication exists between the maternal and foetal vessels, but this notion has been lono- exploded. We have the most decisive evidence, that the con- nexion is of the most indirect nature. Wrisberg made several ex- periments, which showed that the fluid of the foetal circulation is not drained when the mother dies from hemorrhage. It has been shown, too, that if the uterine arteries be injected, the matter of the injection passes into the uterine veins after having been effused into the lobes of the placenta, and the same thing happens when the ute- rine veins are injected. If, on the other hand, the injection be thrown into the umbilical arteries or vein, the matter passes from one of these sets of vessels into the other, is effused into the foetal side of the placenta, but does not pass into the uterine vessels. When, however, an odorous substance, like camphor, is injected into the maternal veins of an animal the foetal blood ultimately assumes a camphorated odour. Magendie injected this substance into the veins of a gravid bitch, and extracted a foetus from the uterus, at the ex- piration of three or four minutes: the blood did not exhibit the slightest odour of camphor; whilst that of a second foetus, ex- tracted at the end of a quarter of an hour, had a decidedly campho- rated smell. This was the case, also, with the other foetuses. Such communication may, however, have been owing to the same kind of transudation and imbibition, of which we have spoken under the head of absorption, and may consequently be regarded as entirely adventitious; and the fact of the length of time, required for the detection of the odorous substance, favours this idea; for if a com- munication, of even an indirect nature, existed between the mother and the foetus, the transmission ought certainly to have been effect- ed more speedily. The transmission of substances from the foetal to the maternal placenta is yet more difficult. Magendie was never able to affect the mother by poisons injected into the umbilical arteries and di- rected towards the placenta; and he remarks, in confirmation of the results of the experiments of Wrisberg, that if the mother dies of hemorrhage, the vessels of the foetus remain filled with blood. Another fact, that proves the indirect nature of the connexion which exists between the parent and child, is the total want of corres- pondence between the circulation of the fcetus and that of the mother. By applying the stethoscope to the abdomen of a pregnant female, the beating of the heart is observed to be twice as frequent as that of the mother. Again, examples have occurred in which the foetus has been extruded with the placenta and membranes entire. In a case of this kind, which occurred to Wrisberg, the circulation con- tinued for nine minutes; in one, described by Osiander, for fif- teen minutes; in some, by Professor Chapman, for from ten to twenty minutes; and in one by Professor Channing, of Boston, and Dr. Selby, of Tennessee, where a bath of tepid water was used to resuscitate the fcetus, for an hour. In other cases of a simi- nutrition of the fcetus. 371 lar kind, where the child could scarcely breathe and was in danger of perishing, the life of the placenta has been maintained by keep- ing it in water of a temperature nearly equal to that of the body, and the child has been saved. All these facts prove demonstra- tively, that the foetus carries on a circulation independently of that of the mother, and that whatever passes between the foetal and ma- ternal vessels is probably exhaled from the one and absorbed by the other, as the case may be. The fluid sent to the foetus is sup- posed by some,—indeed by most physiologists,—to be the mater- nal blood. Schreger, however, maintains that the communication of any nutritious fluid from the mother to the foetus and vice versa takes place by means of lymphatics, and not by blood-vessels; and that the maternal vessels exhale into the spongy tissue of the pla- centa the serous part of the blood, which is taken up by the lym- phatics of the foetal portion, and conveyed into the thoracic duct. The facts, previously brought forward, show, that the fcetus may be developed without any umbilical cord or umbilicus; and those we have just detailed, exhibit, that the foetal circulation is at all events largely independent of that of the mother; whilst the posi- tion, that the placenta is the medium by which nutritive matter of any kind passes from the mother to the foetus and vice versa rests upon singularly feeble and inadequate evidence. The functions, which it appears to execute, will engage attention presently. Lastly, Lobstein and Meckel suppose, that the gelatinous sub- stance of the cord is one of the materials of foetal nutrition. This opinion they found on the circumstance of the albuminous nature of the substance, and the great size which it gives to the cord at the early periods of foetal life, as well as on the great development of the absorbent system of the foetus, proceeding from the umbili- cus to the anterior mediastinum. All these speculations regarding the various sources of nutritive matter are sufficient evidence of the uncertainty that prevails op this interesting topic; yet Magendie affirms, "that it appears cer- tain, that the placenta imbibes from the mother the materials neces- sary for the development, of the organs!" Some of the most recent writers on the subject are of opinion, that the sources whence the nutritive matter is derived varies at different periods of gestation. Lobstein, for example, thinks,that the venous radicles of the rudimental placenta obtain nutritious fluids from the mother, prior to the formation of the arteries; but that afterwards all circulation between the uterus and placenta ceases; and the umbilical vesicle, (a small body of the size of a large pea seated,as we have seen, in the umbilical cord between the chorion and amnion, and supposed to communicate with the intestine, and to contain a nutritive fluid,—but of the anatomy of which we know but little,) the liquor amnii, and the jelly of the cord are the nutri- tive materials. Meckel considers, that the placenta is in no case 372 GENERATION.—OF THE FOETUS. the source of nutritive matter. He regards it as an organ for the aeration of the blood; whilst nutrition is effected by the fluid of the umbilical vesicle, at the commencement; by the liquor amnii till mid-term; and by the jelly of the cord for the remainder of gesta- tion. Lastly, according to Beclard, nutrition is accomplished, during the first weeks, by the fluid of the umbilical vesicle; after- wards by the liquor amnii, and the jelly of the cord; and, as soon as the placenta is formed, by that organ. It is manifest, however, that we cannot regard as nutritive mat- ters those substances that are secreted by the foetus itself. It is impossible, that any development could occur without the recep- tion of materials from without. We have seen, that when the ovum passes from the ovarium to the uterus, it contains within it a mole- cule and fluids, which are probably destined for the nutrition of the new being, and which afford the necessary pabulum for the in- crease, that occurs between impregnation and the period at which an adhesion is formed between the ovum and the inner surface of the uterus. The mother, having furnished the nutritive material in the ovum, she must continue to provide it in the uterus; and so soon as a vascular communication is formed between the exterior of the ovum and the interior of the uterus, nutritive elements are doubtless received by the embryo;—for otherwise it would perish from inanition. What then can be the nature of these elements? Do they consist of blood, which is laid hold of by the foetus at this early period, when no circulatory system is apparent; or are the blood-vessels distributed to the membranes of the ovum, to enable them to continue the secretion of that nutritive matter, which they took with them from the ovarium, and which must necessarily have had a maternal origin? The latter certainly is the more probable supposition, and it is a strong argument in favour of the amnion being supplied with blood from the uterus, rather than from the foetus; for, if we admit it to be in any manner inservient to nutrition, its production must be extraneous to the body which it has to nourish. These observations apply equally to the jelly of the um- bilical cord, which is probably secreted by the membranous enve- lopes, and may consequently be regarded as a nutritive material derived from the parent. On the whole, therefore, it appears at least doubtful, whether the foetus receives from the mother any nutritive fluid through the pla- centa; whilst there is strong reason for believing, that, from the very earliest period of foetal formation to the last, it is nourished on secretions formed at the expense of the mother, and that these are, essentially, the liquor amnii and.the jelly of the cord. If we admit this, however, it is obvious, that the nutritive fluid, when received into the system will have to be formed into blood by the action of the foetus, in a manner, bearing some analogy to what occurs in the adult, or in the simplest of living beings, in which *■ NUTRITION OF THE F03TUS. 373 the nutritive fluid is absorbed at the surface of the body. Of the mode in which such conversion is effected we are in the same dark- ness, that envelopes all the mysterious processes which are esteem- ed organic and vital; but that the foetus is capable of effecting it we have irrefragable proof in the oviparous animal, where there can be no communication, after the egg is laid, between the embryo and the parent. Yet we find it forming its own blood from the yolk surrounding it, and undergoing its full and regular development from causes seated in itself alone. Of those physiologists who consider that the mother sends her blood to the placenta, to be taken up by the foetal vessels, all do not conceive, that it is in a state adapted for the nutrition of the new being: some are of opinion that the placenta or the liver, or both, modify it, but in a manner which they do not attempt to explain. In favour of such an action being exerted by the placenta, they state that it is clearly the organ which absorbs the fluid, and that every organ of ab- sorption is necessarily one of elaboration;—a principle which we have elsewhere proved to be unfounded; and, moreover, that the blood, conveyed to the foetus by the umbilical vein, differs essentially in colour from that conveyed to it by the umbilical arteries,—a fact, which we shall see, can be accounted for more satisfactorily. In support of the view, that a second change is effected in the liver, they affirm, that a great part of the foetal blood ramifies in the sub- stance of that organ before it reaches the heart; a part only going by the ductus venosus; and that the great size of the liver, during foetal life, when its function of secreting bile can be but sparingly exerted, is in favour of this notion. The opinion, that some change is effected upon the blood in the liver, is certainly much more philosophical and probable than the belief of Haller, that the object of its passage through that organ is to deaden the force with which the mother projects the fluid into the foetal vessels. We have seen, that it is extremely doubtful, whether she transmits any; and that if she does, the communica- tion is extremely indirect. M. Geoffroy Saint-Hilaire appears also to think, that the blood of the mother, which he conceives to be sent through the placenta to the foetus, is unfitted for foetal life, before it has under- gone certain modifications. The blood, according to him, which leaves the placenta, proceeds in part to the liver and the remainder to the heart. In the liver it forms the material of the biliary secre- tion, or at least of a fluid, which, when discharged into the intes- tines, irritates them, and provokes a copious secretion from the mucous or lining membrane. This mucus, according to M. Saint- Hilaire, is always met with in the stomach and intestines of the fcetus; whilst the presence of meconium, and of other excrementi- tious matters in the intestines, shows, that digestion must have taken place. This digestion he considers to be effected upon the mucus, 374 GENERATION.—OF THE FCETUS. secreted in the mannerjust mentioned; and, in support of its being in- servient to sanguification, he affirms, that its quantity is too great for the simple purpose of lubricating the parts; that mucus is the first stage of all organic compounds; that it predominates in all young beings; is the foundation of every organ; more capable of assimilation than any other substance, &c. But independently of the whole of this view being entirely hypothetical, it cannot be esteemed probable, that the foetus is nourished by one of its own secretions. All se- cretions must be formed from blood. Blood must, therefore, pre- exist in the foetal vessels, and the process, indicated by Saint- Hilaire, be unnecessary. Allusion has already been made to the opinions of Schreger, on the nutrition of the foetus. These were developed in a letter written by him, in 1799, to Soemmering. He considers, that all communication of nutritious matter between the mother and foetus occurs through the lymphatics, which he has described as existing in considerable numbers in the placenta and umbilical cord. The red blood, flowing in the maternal vessels, is too highly charged with carbon, and with other heterogeneous substances, he thinks, to serve for the nutrition of the foetus. Its serous part, which is purer and more oxygenized, is therefore alone exhaled. The uterine arteries pour this serum into the spongy texture of the pla- centa, whence it is taken up by the lymphatics of the foetal por- tion. These convey it along the umbilical cord to the thoracic duct, whence it passes into the left subclavian, vena cava supe- rior, right auricle and ventricle, ductus arteriosus, aorta; and, by the umbilical arteries, is returned to the placenta. In this course, it is mixed with the blood, and becomes itself converted into that fluid. When it attains the placenta, the blood is not poured into the cells of that organ, to be transported to the mother, but it passes into the umbilical vein, the radicles of which are continuous with the final ramifications of the umbilical arteries. Lateral pores, however, exist in the latter, which suffer fluids to escape, that can- not be elaborated by the foetus, or which require to be again sub- mitted to the maternal organs, before they are fitted for its sup- port. These fluids, according to Schreger, are not absorbed by the veins of the uterus, but by the lymphatics of that viscus, which are so apparent in the pregnant state and have been injected by Cruikshank,Meckel, &c. In his view, therefore, the conversion of the serous fluid into blood, is chiefly effected in the lymphatic sys- tem, and it has been a favourite hypothesis with many physiologists, that those organs, regarding whose functions we are so profoundly ignorant, and whose development is so much greater during intra- uterine than extra-uterine existence,—as the thymus, and thyroid glands, and the supra-renal capsules,—are, in someway, connected with the lymphosis or haematosis of the foetus. We have already referred to the conjectures, that these organs RESPIRATION OF THE F03TUS. 375 are diverticula for the blood of those parts, the functions of which are not exerted until an after period of existence. Broussais makes the thyroid a diverticulum to the larynx; the thymus a di- verticulum to the lungs, and the supra-renal capsules to the kid- neys. Notwithstanding these ingenious speculations, however, our darkness, with regard to the true functions of these singular organs, is not the less impenetrable. To conclude. The most plausible opinion, that we can form on this intricate subject is, that the mother secretes the substances, which are placed in contact with the foetus, in a condition best adapted for its nutrition; that in this state they are received into the system, by absorption, as the chyle or the lymph is received in the adult,—undergoing modifications in their passage through the fostal placenta, as well as in every part of the system, where the elements of the blood must escape for the formation of the various tissues. With regard to the precise nutritive functions, executed in the foetal state, and first as concerns digestion, it is obvious, that this cannot take place to any extent, otherwise excrementitious matter would have to be thrown out, which, by entering the liquor amnii, would be fatal to many important functions, and probably to thevery existence of the foetus. Yet that some digestion is effected is manifest from the presence of meconium in the intestines, which is proba- bly the excrementitious matter, arising from the digestion of the mucous secretions of the alimentary canal. Respiration, as accomplished by lungs, does not exist; and we have already seen, that the idea of the foetus possessing the kind of respiration of the aquatic animal is inadmissible. An analogous function to the respiration of the adult however oc- curs, as respects the changes effected upon the blood. It is pro- bable, that the blood is sent to the placenta to be aerated there, as it is in the lungs in extra-uterine existence. Such was the opinion of Sir Edward Hulse, of Girtanner, Stein, and we may say, such is the opinion of many of the most enlightened phy- siologists of the present day. The chief arguments, adduced in support of this opinion, are,—the absolute necessity for air to every living being, animal or vegetable; the no less necessity, for a free' circulation of blood along the umbilical cord to the placenta, to the life of the foetus; the analogy of birds, in which the umbilical ves- sels are inservient to respiration by receiving the external air through the pores of the shell, so that if the shell be covered with varnish, respiration is prevented and the chick dies. The sensible evidences of these changes being effected by the placenta are not like those, which we possess regarding the aera- tion of the blood in its passage through the lungs of the adult, where the venous, differs so essentially from the arterial blood. It is indeed asserted, in works of anatomy, that " the effete blood of the 376 GENERATION.—OF THE FCETUS. umbilical arteries becomes regenerated in the placenta, assumes a brighter hue, and is returned to the foetus by the umbilical vein," but this is not in accordance with experiment and observation. Bichat made numerous dissections of young pigs whilst still in utero, and he uniformly found the blood of the arteries and veins presenting the«ame appearance and resembling the venous blood of the mother. Not the slightest difference was observed between the blood of the aorta and that of the vena cava; nor between that of the carotid artery and of the jugular vein. He made the same observations in three experiments of a similar kind on the foetuses of the dog. He also frequently examined human foetuses that had died in utero, and always found the same uniformity between the arterial and venous blood: hence he concludes, that there is no difference between the arterial and the venous blood of the foetus, at least in appearance. Similar experiments by Auten- rieth furnished the same results. It is important to bear this fact in mind, inasmuch as it may be received as one of the evi- dences that a foetus has not respired. The apparent identity, however, between the blood passing to the placenta by the umbilical arteries and that returning by the cord is not real. The slightest reflection will show, that they must be essentially different. It is from the blood, carried by the umbilical vein and distributed over the body, that all the organs of the foetus have to derive the materials of their nutrition and de- velopment; and being deprived of these materials the fluid must necessarily be different in the umbilical arteries from what it is in the umbilical vein. The researches of more modern che- mistry have not been directed to the foetal blood, but Four- croy analyzed it and found it differ materially from the blood of the child that had respired. He asserts, that its colouring matter is darker, and seems to be more abundant; that it is desti- tute of fibrine and of phosphoric salts, and is incapable of becoming florid by exposure to the influence of atmospheric air. Under the head of circulation it was remarked, that the coloration of the blood is perhaps of no farther importance than as indicating, that the vital change of aeration has taken place in the lungs. In this case, we have the vital change effected without any such colora- tion. Yet how, it may be asked, is the modification in the blood produced where no placenta and no umbilical cord exists? And can we suppose that in such cases the aeration is effected by the liquor amnii containing an unusual quantity of oxygen, as has been presumed by some physiologists? These are embarrassing ques- tions—more easily propounded than answered. It is in the foetal circulation that we observe the most striking peculiarities of intra-uterine existence. Of its condition at the very earliest periods we know little that is not conjectural. We will, therefore, consider it as it is effected during the last months of utero-gestation. From the sketch already given of the circulatory FOETAL CIRCULATION. 377 organs of the foetus, it will be recollected, 1st, that the two auri- cles of the heart communicate by an aperture in the septum, called the foramen ovale, which has a valve opening towards the left ventricle; 2dly, that near the orifice of the vena cava inferior is the valve of Eustachius, so situated as to direct the blood of the cava into the foramen ovale; 3dly, that the pulmonary artery has a vessel passing from it into the aorta,—the ductus arteriosus; 4thly, that two arteries, called umbilical, proceed from the inter- nal iliacs to the umbilicus and placenta; and, lastly, that the um- bilical vein from the placenta pours part of its blood into the vena porta; and a part passes by the ductus venosus,—a foetal vessel,— into the inferior cava. The course of the circulation, then, is as follows:—The blood of the umbilical vein,—the radicles of which communicate with those of the umbilical arteries in the placenta,—proceeds along this vein to the umbilicus, and thence to the liver. A part of this traverses the ductus venosus, enters the vena cava inferior, and becomes mixed with the blood from the lower parts of the foetus; the re- mainder passes into the vena porta, is distributed through the liver, and, by means of the hepatic veins, is likewise poured into the vena cava- In this manner it attains the right auricle. Owing to the arrangement of the valve of Eustachius, the blood passes immediately through the foramen ovale into the left auricle,— without being mixed with the fluid proceeding from the upper parts of the body into the right auricle through the vena cava su- perior. The left auricle is consequently as much developed as the right, which it would scarcely be, did it receive only the blood from the lungs. Were it nOt as large, it is obvious, that it would be insufficient to carry on the circulation, when the whole of the blood passes through the lungs, and is poured into it. after respira- tion is established. The above are the opinions of Wolf and Sabatier regarding the use of the Eustachian valve. According to this view, if the valve did not exist, the aerated blood, conveyed to the heart by the ductus venosus, instead of being directed into the left auricle through the foramen ovale, would pass into the right auricle, and thence,—in part, at least,—into the right ventricle; from which it would be transmitted, through the pulmonary artery and ductus arteriosus, into the descending aorta; so that no part of the body, above the opening of the duct into the aorta, could receive the aerated blood, whilst much of that, which passed along the aorta, would be returned to the placenta by the umbilical arteries. But as the blood is directed into the left auricle by the Eustachian valve, it passes from thence into the left ventricle, and is forced by it into the aorta, which distributes it to every part of the sys- tem, and thus conveys the regenerated fluid to every organ. Dr. Wistar has also suggested, that, without this arrangement of the Eustachian valve, the coronary arteries, distributed to the heart, Vol. II. 48 378 GENERATION.—OF THE FCETUS. would be unfit for supporting the life of that organ, inasmuch as they would be deprived of a regular supply of revivified blood. From the left auricle, the blood passes into the left ventricle, and from the left ventricle into the ascending aorta and to the upper parts of the body, from which it is brought back, by the vena cava superior, into the right auricle; thence it is transmitted into the right ventricle, and, by the contraction of the ventricle, into the pulmonary artery. By this vessel it is sent,—the greater part through the ductus arteriosus into the descending aorta, and a small part to the lungs. From the lungs it is returned into the left auricle by the pulmonary veins. Through the descending aorta the blood, conveyed in part by the ductus arteriosus, and in part by the contraction of the left ventricle, is distributed, partly to the lower extremities, from which it is returned by correspond- ing veins into the vena cava inferior, and partly by the umbilical arteries to the placenta. This view of the circulation supposes what is disputed,— that the blood of the vena cava superior and of the vena cava inferior does not undergo admixture in the right auricle; whence it would follow, that some parts of the body receive a purer blood than others,—the upper parts, as the head and neck, receiving that which flows immediately from the placenta, whilst the lower parts do not obtain it until it has circulated through the upper. Under any view it is manifest, that it is not the whole of the blood, which is distributed to the organ of aeration, as in the adult, but a part only as in the batracia. Bichat and Magendie contest, and we think successfully, the explanation of Wolf and Sabatier, regarding the use of the valve of Eustachius and the non-admixture of the blood of the two cavae in the right auricle. In their opinion, the two bloods do commin- gle; but, owing to the existence of the foramen ovale and the ar- rangement of the valve of Eustachius, the left auricle is filled simultaneously with the right; and, consequently, the same kind of blood must be distributed to both the upper and lower portions of the body. The uses of the foramen ovale and ductus arteriosus are explained as follows. As the left auricle receives but little blood from the lungs, it could furnish but a small quantity to the left ventricle, did it not receive blood through the foramen ovale; and again, as the lung is exerting no function, during the state of fcetal life, the blood is sent along the pulmonary artery and ductus arteriosus into the aorta, so that the contraction of both ventricles is employed in propelling the blood along the aorta to the lower parts of the body and to the placenta. Without this union of forces it is conceived, that the blood could not be urged forward as far as the placenta. After all, then, the great difference between the fcetal and adult circulation is,—that, in the former, a part of the blood only pro- ceeds to the organ of sanguification; that the aerated blood is MONSTROSITIES. 379 poured into the right auricle instead of the left; that, instead of proceeding through the lungs, a part of the blood gets at once to the left side of the heart, and the remainder goes directly from the pulmonary artery into the aorta; that a part of the aortic blood proceeds to the lower extremities, and the remainder goes to the placenta, from which it is returned into the inferior cava. With regard to the nutrition, (properly so called,) of the foetus, it is doubtless effected in the same manner as in the adult; and our ignorance of the precise nature of the mysterious process is equally great. During the whole of foetal existence it is energeti- cally exerted, and especially during the earlier periods. Soemmer- ing has asserted, that the growth of the foetus fluctuates; that in the first month it is greatest; in the second, less; in the third, greater; less, again, in the fourth ; and then greater until the sixth, when it diminishes until birth. There are one or two singular circumstances, connected with the nutrition of the foetus, which cannot be passed over without a slight notice. Owing to inappreciable causes, the different parts of the foetus, or some particular part, may be preternaturally developed or be defective, giving rise to what have been termed monstrosi- ties. Three kinds of monsters may be considered to exist. The first comprises such as are born with an excess of parts, as with two heads on one trunk, two trunks to one head; with four arms and four legs; twins with a band uniting them, as in the case of the Siamese twins, &c. The second includes those in which parts are defective, as acephali, anencephali, &c.; and the third, those in which there is deviation of parts, as where the heart is on the right side, the liver on the left, &c; where, in other words, there is transposition of the viscera. The hypotheses, that have been advanced to account for these formations, as well as for those in which the parts are irregularly developed, may be reduced to three; the others, that have been indulged, having no probability in their favour. First. They have been attributed to the influence of the imagination of the mo- ther over the foetus in utero. Secondly. To accidental changes, experienced by the fcetus at some period of uterine existence; and Thirdly. To some original defect in the germs. The first of these causes has been a subject of keen controversy amongst physiologists, at all periods. We have seen, that the mo- ther transmits to the foetus the materials for its nutrition; and that, to a certain extent, the nutrition is influenced by the character of the materials transmitted; so that if these be not of good quality or in due quantity, the foetus will be imperfectly nourished, and may even perish. Any violent mental emotion may thus destroy the child, by modifying the quantity or quality of the nutritive matter sent to it. Small-pox, measles, and other contagious diseases can also be unquestionably communicated to the fcetus in utero; so 380 GENERATION.—OF THE FffiTUS. that the life of the foetus is indirectly but largely dependent upon the condition of the mother. But the maternal influence has been conceived to extend much beyond this; and it has been affirmed, that the excited imagination of the mother may occasion an alteration in the form of particular parts of the foetus, so as to give rise to naevi and to all kinds of mothers' marks, as they have been termed. These may consist of spots resembling raspberries, grapes, &c; or there may be deficient formation of particular parts,—and some of the cases, that have been adduced in favour of their having been induced by impressions, made upon the mother during pregnancy, are sufficiently striking. There are numerous difficulties, how- ever, in the way of accepting the cause assigned. If a child be born with nsevi of any kind, the recollection of the mother is racked to discover, whether some event did not befal her during gestation to which the appearance can be referred, and it is not often difficult to discover some plausible means of explanation. Cases have occurred in which the mother, when a few months advanced in pregnancy, has been shocked by the sight of a person who had lost his hand, and the child has been born devoid of a hand. A young female, a few months gone with child, visited a brother in one of the hospitals of London who was wounded in the side. His condition affected her extremely. Her child was born with a deep pit precisely in the same part that was wounded in the brother. These are samples of the thousands of cases, that have been re- corded, or that have occurred to different individuals. Similar instances have even been related of the inferior animals. In the extracts from the minute book of the Linnean Society of London, an account is given, by Mr. George Milne, F. L. S., of the ef- fect of the imagination of a female cat on her young. One after- noon, whilst Mr. Milne and his family were at tea, a young fe- male cat, which had arrived at the middle of gestation, was lying on the hearth. A servant, by accident, trod very heavily on her tail; she screamed violently, and, from the noise emitted, it was evident, that a considerable degree of terror was mingled with the feeling from the injury. From so common a circumstance no ex- traordinary result was expected; but, at the full time, she dropped five kittens, one of which was perfect, but the other four had the tail remarkably distorted; and all distorted in the same manner. Are we to consider these and similar cases of mal-formation or monstrosities to be dependent upon the influence of the ma- ternal imagination upon the foetus in utero; or are we to re- gard them as coincidences, the cause being inappreciable, but such as we find to give occasion to vicious organization, where no coincidence with excited imagination can be discovered? Under the head of generation we have combated the notion, that the mother's fancy can have any effect during a fecundating copu- lation. Let us see, then, what we have to admit in a case where MONSTROSITIES. 381 a female is, we will suppose, four months advanced in pregnancy, when she is shocked at the appearance of one who has lost his arm, and the child is born with the like defect. It has been seen, that the communication between the mother and the foetus is of the most indirect character, and that no endeavours have succeeded in throwing substances from one side of the placenta to the other; that the circulation of the foetus is totally distinct from that of the mother; and that she can only influence the foetus through the nu- tritive material she furnishes—whatever be its character—and con- sequently that such influence must be exerted upon the whole of the foetus and not upon any particular part. Yet, in the suppositi- tious case we have taken, the arm must have been already formed, and the influence of the mother's fancy must have been exclusively exerted upon its absorbents, so as to cause them to take up again that which had been already deposited! The case we have assumed is not environed with more difficulty than any of the kind. It is a fair specimen of the whole. Yet how impracticable for us to believe, that the effect can be in any way connected with the assigned cause; and how much more easy to presume, that the coincidence, in such cases, is accidental. Cases of hare-lip are perpetually occurring, yet we never have the ma- ternal imagination invoked; because; it is by no means easy to dis- cover any similitude between the affection and extraneous objects. Moreover, in animals of all kinds—even in the most inferior, as well as in plants—monstrous formations are incessantly happening where maternal imagination is out of the question. As a cause of monstrosities, therefore, the influence of the ma- ternal imagination has been generally regarded as an inadmissible hypothesis. By many it has been esteemed ridiculous; yet it mani- festly receives favour withSirEvERARDHoME,and isperhaps hardly worthy of the strong epithets of condemnation that have been ap- plied to it, although sufficiently incredible. The third hypothesis, with regard to defective germs, we have already canvassed under generation, and attempted to prove it insufficient. The second, consequently, alone remains, and is almost univer- sally adopted. Independently of all disturbing influences from the mother, the foetus is known to be frequently attacked with spontaneous diseases, such as dropsy, ulceration, gangrene, cuta- neous eruptions, &c. Some of these affections occasionally destroy it before birth. At other times, it is born with them; and hence they are termed connate or congenital. Where a part has been wanting, the nerve or blood-vessel or both, proceeding to it have likewise been found wanting; so that the defect of the organ has been thus explained; without our being able, however, to understand the cause of the deficiency of such nerve or blood-vessel. In some of the cases of monstrosities a confusion of two germs seems to have occurred. Two vesicles have been fecundated, 382 GENERATION.—OF THE F03TUS. and subsequently commingled, so that children have been pro- duced with two heads and one trunk, or with two trunks and one head, &c. &c. The animal temperature of the foetus cannot be rigidly deter- mined. The common belief is, that it is some degrees lower than that of the mother; and it is affirmed, that the temperature of the dead foetus is higher than that of the living. The foetus must, there- fore, possess the means of refrigeration. Edwards found, in his experiments, that the temperature of young animals is inferior to that of the adult; which is in accordance with the general belief regarding that of the foetus in utero. In some cases, as in those of the kitten, puppy and rabbit, if they be removed from the mother and exposed to a temperature of between 50° and 70°; their tem- perature will sink,—as happens to the cold-blooded animal,—to nearly the same degree. The faculty of producing heat he found to be at its minimum at birth; but it progressively increased, until in about fifteen days the animal acquired the power in the same degree with the adult. This was not the case, however, with all the mammalia. It seemed to be confined to those animals that are born blind; in which a state of imperfection probably existed in other functions. It was the same with birds as with the mammalia; birds, hatched in a defective state, as regards their organs generally, have the power of producing heat defective; whilst others, born in a more perfect condition, have the organs of calorification more capable of exercising their due functions. The opinions with regard to the temperature of the human infant vary. Haller asserts, that it has less power of producing heat than the adult, and such is the opinion of Despretz, Edwards, and the generality of physiologists. The latter gentleman estimates it at 94.25° of Fahrenheit. On the other hand Dr. John Davy affirms, that the temperature of young animals generally, and that of a newly-born child, which he particularly examined, was higher than in the adult. It is impossible to account for this discordance; but the general results of experiments will be found to agree with those of Edwards. The foetus certainly possesses the power of forming or separating its own caloric; otherwise its temperature should correspond with that of the mother, which, we have seen, is not the fact. That the secretions are actively exercised in the foetus is proved by the circumstance, that all the surfaces are lubricated nearly as they are subsequently. The follicular secretion is abundant, and at times envelopes the body with a layer of sebaceous matter of considerable thickness. Vauquelin and Buniva have asserted, that this is a deposit from the albumen of the liquor amnii; but in reply to this it may be urged that we do not find it except on the body of the foetus. It is not on the placenta or umbilical cord, and is most abundant on those parts of the foetus, where the follicles are most numerous. The fat also exists in quantity after the fifth FUNCTIONS OF REPRODUCTION. 383 month. The greatest question has been with regard to the exist- ence, in the foetal state, of some of the secretions which are of an ex- crementitious character. For example, by some, the urinary secretion is supposed to be in activity from the earliest period of uterine existence, and its product to be discharged into the liquor amnii. Such is the opinion of Meckel, but it does not rest on any basis of observation. The only circumstances, that in any manner favour it, are the fact of the existence of the kidneys at a very early period; and that at the full time, the bladder contains urine, which is evacuated soon after birth. On analysis, this is found to be less charged with urea and phosphoric salts than in after life. Of the meconium we have already spoken. It is manifestly an excretory substance, produced, probably, by the digestion of the fluids of the alimentary canal. Vauquelin analyzed the meconium evacuated after birth, and found it composed of water, about two- thirds; of a substance of a vegetable nature,but sui generis, about one- third; mucus, a few hundredth parts, and a little bile. It appears, consequently, to be less azoted than the excrement of the adult. Lastly, the cutaneous perspiration is supposed to be a foetal excretion, and to be poured into the liquor amnii; but although this is probable, we have no positive evidence on the subject. III. Functions of Reproduction.—These require no consider- ation. They are inactive during the foetal state, except that the testicles and the mammas appear respectively to secrete a fluid, which is neither sperm nor milk, and is found in the vesiculas se- minales in the one case, and in the lactiferous ducts in the other. 38-1 AGES. OF THE AGES. Under this head we have to include the modifications that oc- cur in the functions during the life of man, from birth until disso- lution. The different ages may be separated as follows:—Infancy, comprising the period from birth till the second dentition;—child- hood, that between the second dentition and puberty;—adolescence, that between puberty and manhood;—virility, that between youth and old age;—and old age. Sect. I. Infancy. The age of infancy extends from birth to the second dentition, or until about the seventh or eighth year. By Hall6, and after him by Renauldin, Rullier, Adelon, and others, this has been again subdivided into three periods, which are somewhat distinct from each other, and may therefore be adopted with advantage. The one comprises the period between birth and the first denti- tion,—generally about seven months; a second embraces the whole period of the first dentition, or up to about two years; and the third includes the whole interval, that separates the first from the second dentition. 1. First period of Infancy. As soon as the child is ushered into the world,.it assumes an independent existence, and a series of changes occurs in its functions of the most sudden and surprising character. Respiration becomes established, after the manner in which it is to be effected during the remainder of existence; and the whole of the peculiarities of fcetal circulation cease,—the organs of these peculiarities being modified in the manner to be described presently. As soon as the child is extruded it begins to breathe, and at the same time to cry. What are the agencies, then, by which this first inspiration is effected, and this disagreeable impression is made upon the new being at the moment when it makes its ap- pearance amongst us ? This has been an interesting topic of in- quiry amongst physiologists. A few of the hypotheses, that have been indulged, will be sufficient to exhibit the direction which the investigation has taken. Whytt,—whose views were long popular, and still have sup- porters,—conceived, that before birth the blood of the foetus is properly prepared by the mother; and that when, after birth, it no longer receives the necessary suppty, an uneasy sensation is experienced in the chest, which may be looked upon as the appe- tite for breathing, in the same manner as hunger and thirst are ap- first period of infancy. 385 petites for meat and drink. To satisfy this appetite, the brain excites the expansion of the chest, to prevent the fatal effects that would ensue, if the lungs were not immediately aroused to action. This appetite is supposed to commence at birth, owing to the circulation being quickened by the struggles of the foetus at that period, and to an additional quantity of blood passing through the lungs, which excites them to action, and seems to be the im- mediate cause of the appetite. Haller ascribed the first inspiration to the habit which the foetus has acquired, whilst in the uterus, of taking into the mouth a portion of the liquor amnii; and he supposed, that it still con- tinues to open its mouth, after leaving the mother, in search of its accustomed food. The air, consequently, rushes into the lungs, expands them; the blood is distributed through them, and a regu- lar supply of fresh air is needed to prevent the blood from stag- nating in its passage from the right to the left side of the heart. Dr. Wilson Philip regards the muscles of inspiration as en- tirely under the control of the will; and he thinks, that they are thrown into action by the uneasy sensation experienced by the new being, when separated from the mother, and having no longer the necessary changes produced upon the blood by her organs. Adelon thinks it probable, that the series of developments, oc- curring during gestation, predispose to the establishment of respi- ration. According to him, the lungs gradually increase in size during the latter months; the branches of the pulmonary vessels become enlarged, and the ductus arteriosus less; so that the lungs are prepared for the new function they have to execute. In addi- tion to these alterations, he conceives, that the process of ac- couchement predisposes to the change; that, by the contractions of the uterus, the circulation of the blood must be necessarily mo- dified in the placenta, and consequently in the foetus,—for he is a believer in the doctrine, that the foetus receives blood from the mother by the placenta. Owing to this disturbance in the circula- tion, more blood is sent into the lungs; and, when the child is born, it is subjected to new and probably painful impressions. " For instance," he remarks, "the external air, by its coldness and weight, must cause a disagreeable impression on the skin of the infant, as well as on the origin of all the mucous membranes; and, perhaps, the organs of the senses being, at the same time, suddenly subjected to the contact of their proper irritants, receive painful impressions from them. These different impressions being transmitted to the brain, they are reflected into the different de- pendencies of the nervous system, and, consequently, into the nerves of the inspiratory muscles: these muscles, thus excited, enter into contraction, in the same manner as the heart is stimu- lated to renew its contractions, during syncope, by inspiring a stimulating vapour." None of these views satisfactorily explain the true physiology Vol. II. 49 386 AGES. ' of the first inspiration; nor is it probable, that any can be devised, which has not its difficulties. That which has been embraced by Dr. Bostock and Sir Charles Bell appears to us to be liable to fewer objections than any we have seen; and to explain the pro- cess, so far as is perhaps practicable, on mechanical principles. The first respiratory act, according to them, seems to be purely mechanical, and to result from the change of position which the child undergoes at birth. From the mode in which it rests in utero, every thing is d'one that position could effect, to diminish the dimensions of the chest; and any change in this position must have the effect of liberating the lungs from a portion of the pres- sure which they sustain. The head cannot be raised from the breast, nor the knees removed from the abdomen, without straight- ening the spine, and the spine cannot be reduced to a straight line without elevating the ribs, and permitting the abdominal viscera to fall; but the ribs cannot rise, nor the diaphragm descend, With- out enlarging the chest; and as the chest enlarges, the lungs, which are the most elastic organs of the body, will expand their air-cells, hitherto collapsed by external pressure, and the external air will rush in. The same cause is considered to account for the new circulatory movement. The blood, which, in the fcetus, had passed through the foramen ovale and the ductus arteriosus without visiting the lungs, is solicited from its course by the expansion of the chest, which draws the blood through the pulmonary artery as forcibly as it does air through the windpipe. The blood, thus exposed to the air in the lungs, becomes arterialized, and from this moment the distinction between the arterial and venous blood is established. The circulation, through the vessels peculiar to the fcetal condition, now ceases, even without any ligature being placed upon the um- bilical cord. The sudden and important changes supervening in this manner, guide us to the decision of an interesting medico-legal inquiry,— viz. whether, in a case of alleged infanticide, the child has respired or not;—in other words, whether it has been born alive or dead? After respiration has been established, the lungs, from being dark-coloured and dense, become of a florid red hue; are light and spongy, and float on water; on cutting into them the escape of the air in the air-cells occasions a crepitus, and a bloody fluid ex- udes ; there is closure, or an approach to closure, of the foramen ovale; the ductus arteriosus is empty, as well as the ductus veno- sus; and the absolute weight of the lungs may be doubled. Respiration having been once thoroughly established, the indi- vidual enters upon the period of infancy, which has now to en- gage our attention. The animal functions during this period undergo considerable development. The sense of tact is but little evinced, but it exists, as the child appears sensible to external cold. At first the touch FIRST PERIOD OF INFANCY. 387 is not exerted under the influence of volition, but towards the ter- mination of the period it begins to be active. The taste is almost always null at first. Adelon thinks, that it is probably exerted on the first day as regards the fluids, which the infant sucks and drinks. We have daily evidence, however, that at an early period of exist- ence, the most nauseous substances, provided they are not irrita- ting, will be swallowed indiscriminately, and without the slight- est repugnance; but before the termination of the period we are now considering, the taste becomes inconveniently acute, so that the exhibition of nauseous substances, as of medicine, is a mat- ter of more difficulty. The smell is probably more backward than any of the other senses; the development of its organ being more tardy, the nose being small, and the nasal sinuses not in existence. In the first few weeks, sight and hearing are imperfectly exerted, but subsequently they are in full activity. The internal sensa- tions, being instinctive, exist; all those atjeast that are connected with the animal and nutritive functions. Hunger and thirst ap- pear during the first day of existence; the desire of passing the urine and fasces is doubtless present, notwithstanding they appear to be discharged involuntarily ; and the morbid sensation of pain is often experienced, especially in the intestinal canal, owing to flatus, acidity, &c. During the first part of the period the child exhibits no mental and moral manifestations; but, in the course of a few weeks, it begins to notice surrounding objects, especially such as are brilliant, and to distinguish between the faces to which it has been accustomed and those of strangers; awarding the smile of recognition or of satisfaction to the former, the look of gravity and doubt to the latter. Locomotion is, at this time, utterly impracti- cable, as well as the erect attitude. The muscular system of the child is not yet sufficiently developed, the spinous processes of the vertebras are not formed, and it has not learned to keep the centre of gravity—or rather the vertical line—within the base of sustentation. The function of expression is at the early part of the period confined to the vagitus or squalling, which in- dicates the existence of uneasiness of some kind; but, before the termination of the period, it unites smiles and even laughter to the opposite expressions, and will attempt to utter sounds, which cannot yet be considered as any attempt at conventional lan- guage. Sleep is largely indulged. Soon after birth it is almost constant, except when the child is taking nutriment. Gradually the waking intervals are lengthened; but still much sleep is needed, owing to the frail condition of the nervous system, which is soon exhausted by exertion however feeble, and requires intermission. After birth, the child has to subsist upon a different aliment from that with which it was supplied whilst in the maternal womb. Its digestion, therefore, undergoes modification. The nutriment is now the milk of the parent, or some analogous liquid, which is sucked in, in the manner described under the head of Bigestion. 3S8 AGES. For this kind of prehension the mouth of the infant is well adapt- ed. The tongue is very large, compared with the size of the body, and the want of teeth enables the lips to be extended forwards and to embrace the nipple more accurately and conveniently. The ac- tion of sucking is doubtless as instinctive as the appetite for nutri- ment, and equally incapable of explanation. The appetite appears to be almost incessant, partly owing to the rapidity of the growth demanding continual supplies of nutriment, and partly perhaps owing to a feeling of pleasure experienced in the act, which is ge- nerally the prelude to a recurrence of sleep broken in upon, appa- rently, for the mere purpose of supplying the wants of the system, or the artificial desire produced by frequent indulgence. Often we have the strongest reason for believing, that the great frequency of the calls of the appetite is occasioned by the habit, with many mothers, of putting the child constantly to the breast; whilst in those children that have been trained, from the earliest period of existence, to receive the nutriment at fixed hours only, the desire will not recur until the lapse of the accustomed interval. Digestion is, at this age, speedily accomplished; the evacuations being frequent,—two or three or more in the course of the day, —of a yellow colour, something like custard, or curdy, and having by no means the offensive smell, which they subsequently possess. During the first days after birth they are dark and adhe- sive, and consist of the meconium, already described. Young mothers are apt to be alarmed at this appearance, which is entirely physiological, and always exists. The respiration of the infant is more frequent than in the adult, nearly in the proportion of two to one, and it is chiefly accomplished by the muscles that raise the ribs, on account of the great size of some of the abdominal viscera, which do not permit the diaphragm to be readily depressed. The stethoscope exhibits the respiration to be also much more sonorous; so characteristic, indeed, is it in this respect, that it has been called "puerile," by way of distinction. It appears to indicate a greater degree of dilatation of the bronchial ramifications, and, consequently, a greater admission of air than occurs in after life. The circulation is more rapid; the pulsations at birth being nearly twice as numerous as in the adult. Nutrition is very active in the. development of the different organs. Calori- fication becomes gradually more energetic from the time of birth. The recrementitial secretions, as well as the excrementitial, are as regularly formed as in the adult; but the products vary some- what. The urine, for instance, is less charged with urea, and con- tains benzoic acid; the perspiration is acidulous, &c. &c. Adelon asserts, that these excretions are frequently insufficient for the necessary depuration, and that nature, therefore, establishes others that are irregular and morbid, in the shape of cutaneous efflorescences, &c. These can scarcely be regarded as depurations, unless we consider all cutaneous eruptions, that are connected with SECOND PERIOD OF INFANCY. 389 gastric or digestive irritation, to be thus induced, which is more than problematical; especially as most of them are neither pustu- lar nor vesicular, and therefore, not accompanied by any sensible exudation. 2. Second period of infancy, or first dentition.—This period embraces the whole time of dentition, and is considered to include the age between seven months and two years. In it, the external senses are in great activity, and continually furnishing to the in- tellect the means for its development, connected with the universe. The internal sensations are likewise active. From these united causes, as well as from the improved cerebral organization, the in- tellect is more strengthened during this period than perhaps dur- ing any other. The senses are continually conveying information, and perception is, therefore, most active, as well as memory; whilst imagination and judgment are feeble and circumscribed. The faculty of imitation is strong, so that by hearing the spoken language, and appreciating its utility, the child endeavours to pro- duce similar sounds with its own larynx, and gradually succeeds,— the greater part of its first language consisting of imitations of sounds emitted by objects, which sounds are applied to designate the object itself, in the manner we have seen elsewhere. The affective faculties are likewise unfolded during this period, but generally those of the selfish cast are predominant, and require the most careful attention for their rectification. Even at this early time of life, the effect of a well-adapted education is striking, and spares the child from numerous inconveniences, to which unlicens- ed indulgence in its natural passions would inevitably expose it. The general feeling is, that the infant is not yet possessed of the necessary intelligence to pursue the course that is indicated; but it is surprising how soon it may be made to understand the wishes of its instructor, and with what facility it may be moulded, at this tender age, in almost any manner that may be desired. During this period, the child is capable of standing erect and of walking. Previous to this, these actions were impracticable, for the reasons already stated, as well as owing to the weight of the thoracic and abdominal viscera; to the spine having but one curvature, the con- vexity of which is backwards; to the smallness of the pelvis, and its inclination forwards, so that it scarcely supports the weight of the abdominal viscera; and to the smallness of the lower limbs and the feebleness of their muscles, which are insufficient to prevent the trunk from falling forward. These imperfections are, however, gradually obviated, and the child commences to support itself on all-fours; a position assumed much more easily than the biped attitude, owing to the centre of gravity being situated low, and the base of sustentation being large. In this attitude he moves about for some time, or his locomotion is effected by pushing a chair before him, or by being steadied by his nurse. Gradually he passes from place to place on his feet, by laying hold of surrounding objects, and, in proportion as the 390 AGES. bones and muscles become developed, and the obstacles to progres- sion are removed, he succeeds in walking alone; but it is some time before he is capable of running or leaping. Perhaps the average period, at which the infant begins to walk, is about twelve months; but we see great difference in this respect. When once the infant is fairly on his legs, the whole of his wak- ing hours is spent in incessant activity and amusement. His func- tions of expression are commensurate with his intellectual deve- lopment, which we have seen to be great in this period. Sleep, which is now more interrupted, is still imperiously and frequently demanded, the nervous system being devoid of that strength, which it subsequently possesses, and therefore requiring repose. One of the most important changes going on at this age concerns the function of digestion. This is the process of dentition, which usually commences about the seventh month, and continues till the end of the second year at least. Prior to the appearance of the teeth, mastication is of course impracticable; and the food, best adapted for the delicate powers of the infant, is that afforded by the maternal breast, or a substitute which resembles it as closely as possible. The appearance, however, of teeth would seem to indicate that the infant is about to be adapted for more solid aliment. As early as the second month of utero-gestation, if the jaws be carefully examined, the germs of the teeth are perceptible in their substance, under the form of membranous follicles of an oval shape, attached by their deep-seated extremity to avascular ana nervous pedicle, and by their superficial extremity to the gum. The cavity of these folli- cles, according IoBeclard, is at first filled with a colourless, lim- pid fluid; but a kind of vascular and nervous papilla or pulp soon forms in it, which commences at the deep-seated portion of the follicle, proceeds towards the other extremity, and ultimately fills it,—the fluid diminishing in proportion to the increase of the pulp. About the termination of the third month, ossification begins, and a little sooner in the lower than in the upper jaw. This consists, at first, in a deposition of ivory matter on the surface of the pulp and at its top; which goes on increasing in width until it covers the whole of the dental pulp with a shell of bone. It augments also in thickness at the expense of the dental pulp, which becomes gradually less and less. When the bony shell has extended as far as the neck of the tooth, the external membrane or sac of the tooth, —for the follicle consists of two membranes—attaches itself close- ly, but not by adhesion to the part. The inner membrane becomes much more vascular, and the enamel is secreted by it. A thickish fluid is observed to be poured out from the inner surface which is soon consolidated into a dark, chalky substance, and afterwards becomes white and hard. At birth, the coronae of the incisors are formed; those of the canine are not completed; whilst the molares have only their tu- bercles. The root or fang is formed last of all. As ossification proceeds, the corona of the tooth presses upon the gum, a portion SECOND PERIOD OF INFANCY. 391 of the follicle being interposed, which is gradually absorbed, as well as the gum, and the tooth issues. The age, at which the teeth make their appearance, varies. Oc- casionally, children have been born with them, whilst in other cases they have not pierced the gum until after the period we are considering. Generally, however, the middle incisors of the lower jaws appear about the seventh month, and, subsequently, those of the upper jaw; next the inferior and superior lateral incisors in succession; then the first lower molares, and the first upper; next the inferior and superior canine teeth, successively; and, lastly, the second molares of each jaws. The approximate times of their appearance are thus estimated by Mr. Thomas Bell. From five to eight months, the four central incisors. From seven to ten, the four lateral incisors. From twelve to sixteen, the four anterior molares. From fourteen to twenty, the four canine. From eighteen to thirty-six, the four posterior molares. Fig. 160. 1. Front view of the temporary teeth. 392 AGES. Dentition is necessarily a physiological process, but it is apt to be a cause of numerous diseases. The whole period of its con- tinuance is one of great nervous susceptibility,—so that the sur- geon never operates during it unless when compelled,—and wc can understand, that the pressure, exerted by the tooth on the gum, and the consequent inflammation and irritation, may lay the foundation of numerous diseases. More are doubtless ascribed to the process than it is entitled to, but still they are sufficiently nu- merous; and all require, in their management, the free division of the distended gum, so as to set the presenting part of the tooth at liberty. Whilst the teeth are appearing, the muscular structure of the body generally is acquiring strength, and the salivary organs are described by anatomists as becoming much more developed. The food of the child is now diversified, and it begins to participate in the ordinary diet of the table. The excrementitious matters are consequently altered in their character, particularly the alvine, which become firmer, and acquire the ordinary faecal smell; the urea is still, however, in the generality of cases, in less proportion than in the adult. The other functions require no particular men- tion. The mortality, during this period, is great. The bills of mor- tality of London show, that the deaths under two years of age are nearly thirty per cent, of the whole number. In Philadelphia, during a period of twenty years ending with 1826, the propor- tion was rather less than a third. The cholera of infants is the great scourge of our cities during the summer months, whilst in country situations it is comparatively rare; and it is always found to prevail most in crowded alleys, and in the filthiest and impurest habitations. There is something in the confined and deteriorated atmosphere of a town, which seems to act in a manner directly unfavourable to human life, and of the young especially This is not confined to man. It is applicable also to the animal. Experiments were instituted by Jenner, and since him by Dr. Baron, which show that a privation of free air and of their na- tural nourishment has a tendency to produce disorganization and death. Dr. Baron placed a family of young rabbits in a confined situation, and fed them with coarse green food, such as cabbage and grass. They were perfectly healthy when put up. In about a month one of them died,—the primary step of disorganization being evinced by a number of transparent vesicles in the external surface of the liver. In another, which died nine days after, the disease had advanced to the formation of tubercles in the liver. The liver of a third, which died four days later, had nearly lost its true structure, so completely was it pervaded by tubercles. Two days afterwards a fourth died : a number of hydatids was at- tached to the lower surface of the liver. At this time, Dr. Baron removed three young rabbits from the place where their com- CHILDHOOD. 393 panions had died to another situation, dry and clean, and to their proper accustomed food. The lives of these were obviously saved by the change. He obtained similar results from experiments of the same nature performed on other animals. 3. Third period of infancy.—This requires no distinct consi- deration ; the growth of the child and the activity of the functions going on as in the preceding period, but gradually acquiring more and more energy. Within this period a third molaris appears, which is not, however, a temporary tooth, but belongs to the per- manent set. During the whole of infancy, the dermoid texture—both skin and mucous membranes—is extremely liable to be morbidly af- fected; hence the frequency of eruptive diseases, and of diarrhoea, aphthae, croup, bronchitis, &c, many of which are of very fatal tendency. Owing, also, to the susceptibility of the nervous sys- tem, convulsions, hydrocephalus, and other head affections are by no means infrequent. Sect. II.—Childhood. Childhood may be considered to extend from the seventh to the fifteenth year, or to the period of puberty; and it is parti- cularly marked by the shedding of the first set of teeth, and the appearance of the second. It is manifest, that in the growth of the jaws with the rest of the body, the teeth, which, for a time, may have been sufficient in magnitude and number, must soon cease to be so; hence the necessity of a fresh set which may re- main permanently. The process for the formation of the permanent teeth is similar to that of the milk or temporary teeth; yet it pre- sents some remarkable points of difference; and it affords us an- other surprising instance of the wonderful adaptation of means to definite objects, of which we have so many in the human body. This process has been well described by Mr. Thomas Bell,— in his recent work on the "Anatomy, Physiology, and Diseases of the Teeth,"—an individual whose opportunities for observation have been unusually numerous, and to whose zeal and' ability in his profession, as well as in the prosecution of natural science, it affords us pleasure to testify. The rudiments of the permanent teeth are not original and inde- pendent like those of the temporary. They are derived from the latter, and continue, for a considerable time, attached to, and inti- mately connected with, them. At an early period in the formation of the temporary teeth, the investing sac gives off a small process or bud, containing a portion of the essential rudiments, namely, the pulp, covered by its proper membrane. This constitutes the rudiment of the permanent tooth. Vol. II. 50 394 AGES. It commences in a small thickening on one side of the parent sac, which gradually becomes more and Fig. 161. more circumscribed, and at length b assumes a distinct form, though still connected with it by a pedicle. For a time the new rudiment is contain- ed within the same alveolus as its generator, which is excavated by the absorbents for its reception. It o.-Peimanent rudiment given off from the is not, according tO Mr. BeLL, in 'T^rmane^mliment given off from the consequence of the pressure of the temporary in a moiaris. new rudiment upon the bone, that this absorption is occasioned, but by a true process of anticipation; for he states that he has seen in the human subject, and still more evidently in the foal, the commencement of the excavation before the new sac was formed, and consequently before any pres- sure could have taken place on the parietes of the socket. The absorption does not indeed begin in the smooth surface of the socket, but in the cancelli of bone immediately behind it. By de- grees, a small recess is thus formed in the parietes of the alveolus, in which the new rudiment is lodged, and this excavation con- tinues to increase with the increasing size of the rudiment, whilst, at the same time, the maxillary bone becomes enlarged, and the temporary tooth, advancing in its formation, rises in Fig. 162. the socket. The new cell is thus gradually separated from the other, both by being itself more and more deeply excavated in the substance of the bone, and also by the formation of a bony partition between them, as seen in the marginal figure, 162, which exhibits the connexion between the temporary tooth and the perma- nent rudiment, as it exists after the former has passed through the gum. As the temporary tooth grows and rises in the jaw, the connecting cord or pedicle elon- gates, and although the sac, from which it is derived, is gradually absorbed, it still remains attached to the neck of the temporary tooth. The situa- tion of each permanent rudi- ment, when its corresponding temporary tooth has made its appearance through the gum,is deeper in the jaw and a little behind the latter, as repre- sented in the marginal illustra- tions of the upper and lower jaw after the whole of the temporary teeth have passed through the gum. Figs. 163 and 164. From these it will be understood, how the upper part of the sac of CHILDHOOD. 395 thepermanentrudiment,—being,by meansofthecord connected with the gum,—gradually as- sumes the same relation to Fig. 164- the gum, as was origi- nally sustained by the temporary rudiment. The ossification of the permanent teeth com- mences from the third to the sixth month after birth, for the incisors and first molaris; about the ninth month for the canine teeth; about three years for the second molaris; at three years and a half for the fcturth ; and at ten years for the fifth; but all this is liable to much variation. The permanent teeth, during their formation, are crowded to- gether in the jaw; but as soon as they have advanced to a certain point, and can no longer be contained within their own alveoli, absorption of the anterior parietes of those cavities takes place, and the teeth are allowed to come in some measure forwards. In consequence of such absorption it frequently happens, that not only the socket of the corresponding temporary tooth, but that of the tooth on each side is opened to the permanent one. Absorp- tion now occurs in the root of the temporary tooth,—generally at the part nearest its successor, and this gradually proceeds as the latter advances, until the root is completely removed, when the crown falls off, leaving room for the permanent tooth to supply its place. It does not seem that this absorption of the root is pro- duced by pressure on the part of the permanent tooth, as it often happens, according to Mr. Bell, that the root of the temporary tooth is wholly absorbed, and the crown falls out spontaneously, long before the succeeding tooth has approached the vacant space. As a general rule, however, the actions must be regarded consen- taneous; and Mr. Bell thinks, that this absorption resembles that, already referred to, for the formation of a new cell to receive the permanent pulp, and that if may be termed, like it, a "process of anticipation." In both instances, the existence, though not the pressure, or even the contact, of the new body is necessary to ex- cite the action of the absorbent vessels; and we accordingly find, that in those cases, by no means unfrequent, in which the tempo- rary teeth retain their situation in the mouth, with considerable firmness, until adult age, the corresponding permanent ones have not been formed." The following are the periods at which the permanent teeth ge- nerally make their appearance. They are extremely irregular, however, in this respect, and the estimate must consequently be regarded as a general approximation only. 396 AGES. Anterior or first great molares, 6£ years. Middle incisors,.....7 Lateral incisors, 8 « Anterior bicuspids, or first lesser molares, - 9 Posterior bicuspids, or second lesser molares, 10 Canine teeth,......11 or 12 Second great molares, - - - - - 12 or 13 Third great molares or dentes sapientias, - 17 to 20 When these have all appeared, the set is complete, consisting of thirty-two teeth, sixteen in each jaw,—the number of temporary teeth having been only twenty. The accompanying figure repre- sents the upper and lower permanent teeth in their alveoli or sock- ets, the external alveolar plate having been removed to show the mode in which they a»e articulated. Fig. 166 represents the same teeth when removed from the socket. Fig. 165. Upper and lower teeth of the left side of the jaws. Whilst the jaws are becoming furnished with teeth and increas- ing in size, they undergo a change of form, and the branches be- come more vertical, so as to favour the exertion of force during mastication. When the teeth issue from the gums they are most favourably situated for the act of mastication; the incisors are sharp, the canine pointed, and the molares studded with conical asperities; but, in the progress of age, they become worn on the surfaces that come in constant contact. ADOLESCENCE. 397 Fig. 166. b c d e f g a, a. Central incisors.—b, b. Lateral incisors.— c.c. Canine teeth.—d,d. First bicuspidati.—e, e, Se- cond bicuspidati.-/,/. First molares.—g, g. Second molares.—A, h. Third molares or dentes sapientias. During the occurrence of these changes, which embrace the whole of the period we are considering, and extend, at times, into the two next, the animal functions, especially that of sensibility, become surprisingly developed, and the intellectual and moral re- sults of a well adapted system of education are strikingly apparent. The nutritive functions are likewise performed with energy, the body not yet having attained its full growth; and, towards the end of the period, the organs of reproduction commence that de- velopment, which we have to describe under the next period. Sect. III. Adolescence. The commencement of this age is marked by one of the most extraordinary developments that the frame experiences, and its termination by the attainment of full growth in the longitudinal direction. The period of the former of these changes is termed puberty; that of the latter the adult age. The age of adolescence has been considered to extend from fifteen years to twenty-five in men ; and from fifteen to twenty-one in women ; but this is only an approximation like the other divi- sions of the ages, all of which are subject to great fluctuations in individual cases. During the periods we have considered, no striking difference exists between the appearance of the male and female, except as regards the generative organs; but about the age of puberty essen- tial changes occur that modify the characteristics of the two sexes in a manner which they maintain through the remainder of existence; and these changes affect the whole of the economy to a greater or less degree. In the male, the skin loses more or less of its delicacy and white- ness ; the hair becomes darker, the cellular tissue condensed, and 398 AGES. the muscles more bulky, so that they are strongly marked beneath the surface; the beard appears, as well as hair upon the pubes, chest, and in the axillae. The different parts of the body become developed in such manner that the centre of the frame now falls about the pubes. The encephalon has increased in size, especially at the posterior and inferior part,—the cerebellum, and has be- come firmer. The ossification of the bones, in the direction of their length, terminates towards the end of the period. The mus- cles become more red and fibrinous, losing the gelatinous charac- ter they previously possessed, and, in the animal, exhibiting those striking changes which we see from veal to beef, from lamb to mutton, &c. The larynx undergoes great augmentation, and the glottis particularly is elongated and widened. The jaws complete their growth, and the dentes sapientias appear, so as to make up the full complement of sixteen in each jaw. The changes in the nutritive organs are not great, consisting chiefly in their develop- ment to correspond with the increased size of the frame. The greatest modification is produced in the organs of reproduction, which are now in a state to exercise their important functions. The testicles, at the period of puberty, suddenly enlarge so as to attain twice the diameter they previously possessed; and the se- cretion of sperm is accomplished. The penis is also greatly in- creased in size; and, according to Adelon, "becomes susceptible of erection." This susceptibility, however, exists long before this age. It may be noticed even in the first period of infancy. The scrotum assumes a deeper colour. Such are the chief changes that supervene in the male. In the female, they are not quite so striking;—the general habit remaining much the same as during childhood. The skin pre- serves its primitive whiteness; and instead of the cellular tissue becoming more condensed, and the muscles more marked, as in the male, fat is deposited in greater quantity between the muscles, so that the form becomes more rotund. New hair appears only on the organs of reproduction and in the axillae, whilst that of the head begins to grow more rapidly. The development of the genital organs is as signal as in the male. The ovaries attain double their previous dimensions; the uterus enlarges; and a secretion takes place from it which has been elsewhere described—the menstrual flux; the mons veneris and labia pudendi are covered with hair; the labia enlarge, and the pelvis has its dimensions so modified as to render labour practicable. At an early age, the long diameter of the brim is from before to behind; but it now assumes the opposite direction, or from side to-side; and the bosom, which, prior to this age, oould scarcely be distinguished from that of the male, becomes greatly augmented; fat is deposited so as to give the mammas their rotundity; the mammary gland is enlarged; and the nipple of greater size;—changes fitting the female for the new duties which she may be called on to exercise. ADOLESCENCE. 399 The functions undergo equally remarkable modifications, under the new and instinctive impulse which animates every part of animal life. The external senses attain fresh and peculiar activity; the intellectual faculties become greatly developed, and this is the period, during which the mental character is more modified and improved by education than any other. It embraces the whole time of scholastic application to the higher studies; and prior to the end of the period, the male youth enters upon the avocation which i3 to be his future support, and both sexes may become established in life in the new relations of husband and wife, and of parent and child. It is during this age, that the indescribable feel- ing of interest and affection is experienced between individuals of the two sexes; and that the boldness of the male contrasts so strik- ingly with the captivating modesty of the tender female:— " That chastity of look, which seems to hang-, A veil of purest light o'er all her beauties." The muscles having acquired their strength and spring, the severer exercises are now indulged, and mechanical pursuits of all kinds,— military or civil,—are undertaken with full effect. The expres- sions participate in the altered condition of the mental and moral manifestations, and indicate vivacity, energy, and enthusiasm. The voice of the male acquires a new character, and becomes graver, for reasons assigned elsewhere; whilst that of the female experi- ences but slight modification. The nutritive functions of digestion, absorption and respiration experience but little change; but nutrition, strictly so called, is evidently modified, from the difference which we notice in the development and structure of the various organs. The muscles contain more fibrine; the blood is thicker and richer in glo- bules; and the excretions manifest a higher degree of animaliza- tion. Urea has usurped the place of benzoic acid in the urine; and the cutaneous transpiration has lost its acidulous smell, and become rank and peculiar. Lastly, the sexual functions are now capable of full and active exercise, and appear to be intimately connected with the spirits, energy, and development of many parts of the economy. If the genital organs do not undergo the due change at puberty, or if the testes of the male or the ovaries of the female be removed prior to this age, considerable modification occurs. This is more manifest in the male, inasmuch as the ordinary changes, that supervene at puberty, are in him more marked than in the female. The removal of the testicles, prior to puberty, arrests those changes. The beard does not appear, nor the hair in the axillae or on the pubes, as in the entire male; and if those animals, in which the males are distinguished by deciduous horns, as the stag,—or by crests and spurs, as the cock, be castrated before their appearance, they never present themselves. If, however, they be castrated 400 AGES. after puberty, they retain these evidences of masculine character. The eunuch, likewise, who becomes such after the appearance of the beard, preserves it, although to a less extent than usual. The development of the larynx is arrested by castration, so that the voice retains, with more or less change, the treble of the pe- riod prior to puberty; and hence this revolting operation has been had recourse to for the sake of gratifying the lovers of music. In the progress of age, we find that, during the progressive evo- lution of the organs, one set will be liable to morbid affections at one period, and another set at another. In the early ages, the mu- cous membranes and the head are peculiarly liable to disease; and at the period we are now considering, affections of the respiratory organs become more prevalent. It is, indeed, the great age for pulmonary consumption,—that fatal malady, which, it was sup- posed by Sydenham, destroys two-ninths of mankind. In the female, whose proper feminine functions do not appear at the due time or are irregularly exercised, the commencement,—and indeed the whole of this period,—is apt to be passed in more or less sickness and suffering. Sect. IV. Virility or Manhood. Halle has divided this age into three periods,—crescent, con- firmed and decrescent virility. The first of these extends from the age of twenty-five to that of thirty-five in the male, and from twenty-one to thirty in the female; the second from thirty-five to forty-five in the male, and from thirty to forty in the female. Nei- ther of these will require remark, the whole of the functions throughout this work,—when not otherwise specified,—being de- scribed as they are accomplished in manhood. Owing to the par- ticular evolution of organs, however, the tendency is not now so great to morbid affections of the respiratory function. It is more especially the age for cephalic and abdominal hemorrhage; accordingly, apoplexy and hemorrhoidal affections are more fre- quent than at any previous period. In decrescent virility,—in which Halle comprises the period of life between forty and fifty in the female, and between forty- five and sixty in the male,—signs of decline are manifest. The skin becomes shrivelled and wrinkled; the hair is gray, or white and scanty; the teeth are worn at the top, chipped, loose, and many, perhaps, lost. The external senses, especially the sight, are more obtuse, partly owing to a change in the physical portions of the organ, so that powerful spectacles become necessary, and partly owing to blunted nervous sensibility. Owing to the same cause the intellectual faculties are exerted with less energy and effect, and the moral manifestations are more feeble and less excitable. Locomotion is less active, owing to diminution in the nervous power, as well as probably to physical changes in the muscles, so that the individual begins to stoop,—the tendency of the body to OLD AGE. 401 bear forwards being too great for the extensor muscles of the back to counteract. The expressions participate in the condition of the intellectual and moral acts, and are consequently less exerted than in former periods. The nutritive functions do not exhibit any very remarkable change, and will even remain active until a good old age. The functions of reproduction show the greatest declension, especially in the female. The male may preserve his procrea- tive capabilities much longer than this period, but in the fe- male the power is, usually, entirely lost, the loss being indi- cated by the cessation of menstruation. After this, the ovaries shrivel, the uterus diminishes in size, the breasts wither, the skin becomes brown and thick, long hairs appear on the upper lip and chin, and all those feminine points are lost which were previously i so attractive. The period of the cessation of the menses is liable to many different disorders, which are the source of much annoy- ance, and are frequently attended with fatal consequences. Prior to their total disappearance, they become extremely irregular in their recurrence, sometimes returning every fortnight, debilitating by their frequency, and by the quantity of the fluid lost, and lay- ing the foundation, in many cases, for uterine or other diseases of a serious character. Cancerous affections of the mammae or labia, which had been previously dormant or not in existence, now arise or become developed, and at times with extreme rapidity. In con- sequence of the great liability to such affections, this has been call- ed the critical age, critical period, or critical time of life. Sect. V. Of Old Age. This is the age when every thing retrogrades. It is the prelude to the total cessation of the functions, where the individual ex- pires,—which is but rarely the case,—from pure old age. This period, again, has been divided into three stages:—inci- pient or green old age, reaching to seventy years; confirmed old age or caducity, to eighty-five years; and decrepitude, from eighty-five years upwards. In incipient or green old age, the declension, which had oc- curred in the period of decrescent virility, is now more marked. The intellectual and moral manifestations exhibit more manifest signs of feebleness; the muscular powers totter, and require the aid of a support,—as well to convey a part of the weight of the body to the ground as to enlarge the base of sustentation. The muscles of the larynx participate in this general vacillation; the "Bigmanly voice Turning again toward childish treble, pipes And whistles in his sound," and is broken and tremulous. Vol. II. 51 402 AGES. The appetite is great, and the powers of digestion considerable, but mastication is large- ly deteriorated. In the first place, the teeth fall out, in consequence of the constant deposition of fresh layers in the dental cavities which ultimately close them, and obliterate the ves- sels that pass to the in- ternal papillae for their nutrition. As soon as the teeth have fallen out, the alveolar pro- cesses, which support- ed them, waste away by absorption, and the depth of the jaw is thus greatly lessened. On these accounts, the jaws only approach each other at the fore- part ; the chin projects, and the angle of the jaw is thrown more forward. As the teeth and the sockets disappear, the alveolar mar- gins become thin and sharp,, and the gum hardens over them; the chinand nose necessarily approach; (Fig. 168.) the lips fall in,and the speech is inarticu- Fig. 168. late. We can thus understand the pecu- liarities of the mas- tication of the aged. They are compelled to bite with the an- terior portions of the jaws; for this reason, as well as owing to the greater obliquity of the insertion of the levator muscles of the lower jaw, but little force can be ex- erted; and, owing to the too great size of the lips, the saliva cannot be retained. Respiration is not as readily accomplish- ed, partly owing to the complete ossification of the cartilages of the ribs, but chiefly to diminished muscular powers. The valves of the heart, and many of the blood-vessels, especially of the extre- mities, become more or less ossified, and the pulse is slow and inter- OLD AGE. 403 mittent. Nutrition is effected to such a degree only as to keep the machine in feeble action; and animal heat is formed to an inade- quate extent, so that the individual requires the aid of greater ex- traneous warmth. In many cases the powers of reproduction in the male are now completely lost. In confirmed old age, the debility of the various functions goes on augmenting. The mental and corporeal powers almost totter to their fall, and often a complete state of dementia or dotage exists. Frequently, however, we are gratified to find full Intellectual and moral enjoyment prevailing even after this period, with the pos- session of considerable corporeal energy. The author has had the honour to enjoy the friendship of two illustrious individuals of this country, who have filled the highest office in the gift of a free people, one of whom is now no more, but the other he trusts destined to live for many years to come: both enjoyed, after the lapse of eighty-two summers, the same commanding intel- lectual powers and the same benevolence that ever distinguished them. In this stage, locomotion becomes more difficult; the appetite is considerable, and the quantity eaten at times prodigious, the diges- tive powers being incapable of separating the due amount of chyle from the quantity of aliment which was sufficient in the previous ages. Difficulty, however, sometimes arises in defecation, the muscular powers being insufficient to expel the excrement. From this cause accumulations occasionally take place in the rectum, which may require the use of mechanical means, as injections, the introduction of an instrument to break them down, &c. Genera- tion is, usually, entirely impracticable, erection being impossible; and during the whole of this and the next stage, the urinary or- gans are liable to disorder,—irritability about the neck of the bladder, and incontinence of urine, being frequent sources of an- noyance. Finally, to this stage succeeds that of decrepitude, so well de- scribed by Shakspeare:— " Last scene of all, That ends this strange, eventful history, Is second childishness, and mere oblivion; Sans teeth, sans eyes, sans taste, sans every thing." The loss of power, mental and corporeal, becomes progressively greater; and in addition to the abolition of most of the external senses,—especially those of sight and audition—the intellectual faculties are, perhaps, entirely gone; all muscular motion is lost, and paralysis requires constant confinement to the bed, or to the easy chair; the excretions are passed involuntarily; sensibility be- comes gradually extinct, and life finally flits away as impercep- tibly as the twilight merges in the shades of night. 404 AGES. Such is a brief description of the chief changes that befal the body in the different ages. To depict them more at length would be inconsistent with the object and limits of this ele- mentary work. It is clear, that, although the divisions we have adopted from Hall6, are entirely arbitrary, must run into each other, and be liable to numerous exceptions;—certain well- marked changes occur about the commencement or termination of many of them, and singular diversity takes place in the successive evolutions of organs: whilst some are predominant at one time, they fall behind others at a previous or subsequent period; and such changes may lay the foundation for morbid affections, at one age in certain organs, which do not prevail at another. The ancients, who believed that great mutations occur at particular in- tervals,—every three, seven, or nine years, for example, as the particular number might be at the moment in favour,—compared these periods to knots uniting the different stages of life, and giving the economy a new direction. These knots they called the cli- materic or climacteric years, and they conceived the body to be especially liable to disease at the periods of their occurrence. The majority assigned them to the number seven and its multiples; and the fourteenth and twenty-first years especially, were conceived to be replete with danger. Others applied the term climacteric to years resulting from the multiplication of seven with an odd num- ber, and especially with nine: the sixty-third year being by almost all regarded as the grand climacteric. The error, with the an- cients, lay, in considering that the numbers exerted any agency. Every one admits the influence of particular evolutions on health; and at the present day, the word climacteric is generally restricted to certain periods of life, at which great changes supervene, inde- pendently of any numerical estimate of years;—such as the period of puberty in both sexes; that of the cessation of the menses, or the critical time of life in the female, &c. Lastly, it need hardly be remarked, that the different ages we have described, instead of extending through the protracted period of eighty-five years and upwards, may be varied by original con- stitution, climate, habits of life, &c. so that the stages may be shorter than usual, and all the signs of decrepitude occur many years earlier. SLEEP. 405 OF SLEEP. The difference between the two classes of animal and nutritive functions is strikingly exhibited in the phenomena we have now to consider. Whilst the former are more or less suspended, the latter continue their action with but little modification. The functions of sensibility, voluntary motion, and expression, cannot be indulged for any length of time, without fatigue being induced, and a necessity existing for the reparation of the nervous energy which has been expended during their action. After a time,—the length of which is somewhat influenced by habit,—the muscles have no longer power to contract, or the external senses to receive impressions; the brain ceases to appreciate; mental and moral manifestations are no longer elicited; and the whole of the functions of relation become torpid, and remain in this state until the nervous system has been renovated, and adapted for the repeti- tion of those functions, which, during the previous waking condi- tion, had been exhausted. This state constitutes sleep; which, con- sequently, may be defined—the periodical and temporary suspen- sion of all or of most of those functions that connect us with the universe. The suspension occurs in these functions and in these only; and hence the consideration of sleep in many physiological treatises has immediately followed that of the functions of rela- tion. The nutritive functions continue regularly in action from the earliest period of foetal formation; before mental manifestations exist in the embryo, and during sleep. For them there is no ces- sation, and scarcely any declension of activity, until the decadency of the frame affects them along with the whole of the machinery. Sleep, in the language of poetry, has been compared to death; and Dr. Good has stated that the resemblance between them is not less correct upon the principles of physiology, than it is beautiful among the images of poetry. " Sleep is the death or torpitude of the voluntary organs, while the involuntary continue their accus- tomed actions. Death is the sleep or torpitude of the whole." Physiologically the difference appears to us considerable. Dur- ing the whole of sleep a process of renovation is probably going on in the organs of animal life, which adapts them for subsequent activity, and contrasts signally with the state of annihilation that constitutes death; hence the important difference between healthy sleep, and the state of coma, induced by any morbid cause; from which the patient is aroused languid and exhausted, instead of active and recruited. The fcetus in utero is also described by some as being in a perpetual sleep, until aroused by the new actions estab- lished at birth. It is probable, however, that there are, even in 406 SLEEP. this case, something like alternations of activity and suspension in the nervous functions. We have seen elsewhere that they are manifestly more or less exerted during intra-uterine existence; nervous energy must therefore be expended; and renovation,—to a much less extent, it is true, than in the new-born child,—be ne- cessary. Linn.e:us, under the term somnus plant arum, expresses a pe- culiar state in the constitution of many plants during the night, evinced by a change of position,—generally a drooping or folding together of their leaves or leaflets; such a change being occasioned by the withdrawal of the stimulus of light, and, probably, it has been conceived, constituting a state of rest to their vital functions; but it is obvious that there can be no similitude,between this con- dition and that of the sleep of animals, which is confined to the func- tions of relation,—functions that do not even exist in the vegetable. The approach of sleep is indicated by signs that are unequivo- cal, and referable to the encephalon. The great nervous centre of animal life, feeling the necessity for renovation, an internal sensa- tion arises in it, as well as in the whole of the nervous system over which it presides, termed sleepiness, or the sensation, or want, or desire of sleep, which, provided the waking state has been protracted, ultimately becomes irresistible, and will draw on sleep in spite/of every effort to the contrary. It is affirmed, that boys, exhausted by exertion, dropped asleep amid the tumultuous noise of the battle of the Nile; and the fatigued soldier has been oftea known to sleep amid discharges of artillery. Noises will at first prevent sleep, but the desire is ultimately so invincible, that they cease to produce any effect. In the noisy inns of large towns, where the perpetual arrivals and departures of travellers keep up an incessant din and confusion, sleep may be for a time withheld, but it ultimately supervenes, although the tumult may be even ten- fold; and if the noise should, from any cause, suddenly cease, the individual will probably awake. It is reported of the proprietor of some vast iron-works, who slept close to them, notwithstanding the noise of sledge-hammers, forges and blast-furnaces, that he would immediately awake if any interruption occurred during the night. This effect of habit is seen in the infant, which has been accustomed to the cradle. The moment the motion and noise of the cradle, or the sound of the nurse's voice,—if she has been in the custom of singing the child to sleep,—ceases, it awakes. When the desire for sleep sets in vigorously, the animal functions become more obtuse, until they progressively fail to be exerted. The cessation does not occur in all simultaneously. The power of volition is gradually lost over the muscles; the eyes cannot be kept open; the upper eyelid falls, and if we attempt to raise it again, it appears to be weighed down; the arms fall where gravity would take them; the extensor muscles of the back, deprived of volition, SLEEP. 407 cease to contract, and the head falls suddenly forward, occasioning nodding, which rouses the brain to momentary action, to be again, however, lost. If the individual be in the erect attitude, his limbs bend under him; and if in the sitting posture, the head gradually falls upon the chest; the extensors of the trunk no longer contract with sufficient force to obviate its tendency to fall forwards; and the attitude, unsupported, can no longer be maintained. The same gradual suspension occurs in the muscular movements concerned in speech and in the production of the voice, which becomes feeble, confused, broken and ultimately lost. All the strictly voluntary muscles have, in short, their action suspended, if we except the orbicularis palpebrarum muscle, which, according to Broussais, now contracts to close the eye and shut off the stimulus of light. If we determine to resist the desire for sleep, we yawn' and stretch, for the reasons elsewhere assigned, and endeavour to arouse the functions to renewed activity. If the state of wakefulness has not been long protracted, we are successful; but all our endeavours fail, if the nervous system be so far exhausted as to render repa- ration indispensable. From the commencement of sleepiness, the action of the senses is enfeebled, and gradually suspended. The sight yields first, the closure of the eyelids preventing the organ from being impressed by its special irritant. The smell yields after the taste; the hear- ing after the smell; and, lastly, the touch sleeps; although the spe- cial irritants may continue to reach the organs of these senses. All the internal sensations, hunger, thirst, &c, as well as the morbid sensation of pain, are no longer appreciated. The intellectual and moral manifestations exhibit, from the commencement of the feeling of heaviness, the languor which pervades the frame. The will gradually ceases to control the functions that are under its domain, until ultimately the power of volition is lost. In the less perfect kind of sleep, or in slumber, the ideas flit in a disorderly manner, constituting a kind of delirium; but when sleep is complete the whole encephalic organ appears to be at rest, and perceptions are no longer accomplished. • The special irritants, applied to the external senses, excite no sensation. Many physiologists affirm that the internal functions of nutrition acquire more energy during sleep; but Broussais properly disputes the affirmation, and maintains that the want of action in the senses, muscles, and intellect, must necessarily occa- sion diminished energy in the nutritive functions. During sleep, circulation and respiration appear to be retarded; perspiration is less active, and digestion more tardy than in the waking condition. The difference in the last respect is so great, that, as Broussais re- marks, the appetite recurs many hours before the usual time where long watching is indulged, and an additional meal becomes necessary; proving the truth of the old French proverb,—" qui dort dine." Secretion, nutrition, and calorification are also less 408 SLEEP. energetically performed than usual. Absorption, alone, according to some is more active ; but there seems not to be sufficient reason even for this assertion. This notion of the greater activity of the nutritive organs is as old as Hippocrates, and has been ac- quiesced in by almost all subsequent writers without examination, especially as it seemed to show a kind of alternation and equipoise between the respective periods of activity of animal and organic life. During sleep, then, all the animal functions are suspended, and the body generally remains in a state of semiflexion, the one which, as we have elsewhere seen, requires little natural effort. To this, however, there are numerous exceptions depending upon habit. The easiest position for the body is perhaps on the back. It is the one assumed in extreme debility, when the prostration is so great that the individual sinks down in the bed like a dead weight; but the extensor muscles of the thigh and leg, under such circum- stances, become fatigued, and relief is obtained by drawing the feet upwards so as to elevate the knees. This is a common attitude in the most debilitating maladies, and is often maintained until within a short time prior to dissolution. Sleep can persist with the exer- cise of certain muscles. Couriers, on long journeys, will nap on horseback, and coachmen on their boxes. The author has seen a servant boy erect and asleep in the intervals between the demands for his services at the table. During the first sleep, the suspension of the animal functions is most complete; but, towards morning, some of them become less asleep, or more excitable than others. The intellectual and moral faculties are frequently inordinately active, giving occasion to dreams, which, with some individuals, occupy a great portion of the period allotted to rest. The sense of tact, too, is easily roused. If we lie in a position which is disagreeable, it is soon changed; the limbs are drawn away if irritated in any manner; the clothes are pulled up, if the air is disagreeably cold, &c. The sense of sight and the voluntary motions are least readily aroused, so that those functions which fall asleep the last are most easily awakened, and they gradually resume their activity in the order in which they lost it. After six or eight hours of sleep,—more or less according to circumstances,—the individual awakes, not generally at once, how- ever; a state of slumber, like that which preceded sleep, now suc- ceeding it. The organs, which are the last to resume their acti- vity, require to be excited to the performance of their functions. The eyes are rubbed; stretching is indulged, which recals the nervous influx to the muscles; whilst sighing and yawning arouse the muscles of respiration, and compensate, in some mea- sure, for the minor degree of aeration of the blood accomplished during sleep. The urine is discharged, and the phlegm, that may have collected in the air passages expectorated: these ex- SLEEP. 409 cretions have accumulated during sleep, because, owing to dimi- nished sensibility, the call for their evacuation has not been as urgent. In cases of catarrh, accompanied by copious mucous secre- tion, and in phthisis pulmonalis, the fluid will collect in surprising quantity in the air-passages during sleep, and it is expectorated as soon as the brain is sufficiently aroused to respond to the sensation. When the individual is fully awake, the energy, with which the animal functions are exercised, exhibits that the nervous system must have entirely recruited during its state of comparative inac- tion. The period of sleep, necessary for this purpose, varies in different individuals, and at different ages. Some require eight or ten hours; others not more than three or four; and others are said to have been contented, throughout the whole course of along life, with not more than one or two. Men of active minds, whose attention is engaged in a series of interesting employments, sleep much less than the lazy and the listless. The great Frederick of Prussia, and the yet more great Napoleon, are said to have spent a surprisingly short time in rest; but with respect to the latter, the fact is controverted by one, who had the best opportunities for observation. It is probable, however, that in these cases, the sleep is more intense, and that such of the animal functions, as re- quire rest indispensably, are completely suspended during the whole period consigned to it. These are the functions of volun- tary motion more particularly; the intellectual and moral facul- ties requiring a much shorter period of repose, as is manifest by their incessant activity during dreaming,—a condition which, with some, continues through almost the whole night. The same indi- vidual, too, will spend a shorter time in sleep, when strongly in- terested in any pursuit, than in the monotonous occurrences of or- dinary life, and when any subject occupies us intently, it will frequently keep us awake in spite of ourselves; but, although the period of sleep may be protracted much beyond the accustomed hour by unusual excitation, the effect of the stimulus becomes in- sufficient, and sleep comes on under circumstances which appear most unfavourable to it. The lunatic affords us a wonderful ex- ample of powerful resistance to sleep and fatigue, or rather of the short period which is necessary for the renovation of the nervous system, kept almost incessantly upon the stretch, as it is in many of these distressing cases. In infancy and youth, whilst the animal functions are extremely active, the necessity for sleep is greatest; in mature age, where time is more valued and the cares are more numerous, it is less indulged; whilst the aged may be affected in two opposite ways; they are either in a state of almost constant somnolency, or their sleep is short and light. Sleep has been regarded, by the physiologist, as complete, and in- complete. The former is characterized by suspension of all the animal functions; a state, the existence of which has been doubted Vol. H. 52 410 SLEEP. by many. Certain it is, that it can occur but rarely, as all the or- gans must have stood in equal need of rest and renovation; and none have preserved, from the preceding state of waking, a pecu- liar susceptibility for action. The nearest approach to it occurs in the first hours of repose; but after this it becomes incomplete; some of the functions are not equally sound asleep, and conse- quently respond to excitants with different degrees of facility; whilst the various organs do not require the same time for repara- tion, and therefore awake at different intervals; hence dreams arise, which occur chiefly towards morning, or after the sleep has become incomplete; that is,when some of the animal functions are more or less actively, but irregularly, exercised. Anciently, dreams were regarded as supernatural phenomena, under the control of the children of Somnus or Sleep,—Mor- pheus, Phobetor or Icelos, and Phantasos. These three chil- dren, according to Ovid, were capable of transforming themselves into any form; the employment of Morpheus being, to counterfeit the forms of men; Phobetor imitated the likeness of brutes and objects of terror; and Phantasos that of inanimate creatures. " MonpHEtrs of all his num'rous train express'd The shape^of man and imitated best: The walk, the words, the gesture could supply, The habil mimic and the mien belie; Plays well, but all his action is confin'd, Extending not beyond our human kind. Another, birds, and beasts, and dragons, apes, And dreadful images and monster shapes: This demon Icelos, in heaven's high hall The gods have named, but men Phobetoh call. A third is Phantasos, whose actions roll On meaner thoughts, and things devoid of soul: Earth, fruits and flowers, he represents in dreams, And solid rocks unmov'd, and running streams." Garth's Ovid, {Mttam. lib. xi. fab. x.) For a long time, dreams were supposed to reveal future events by types and figures; as when Hecuba dreamed she had conceived a firebrand, and Caesar that he should lie with his mother; which was interpreted, that he should enjoy the empire of the earth,— the common mother of all living creatures. Oneiromancy was, hence, an encouraged art, and ministered largely to the credulity and superstition of the people. Strange to say, there are yet those, who look upon dreams to be typical and instructive, and conse- quently supernatural! Mr. Baxter and Bishop Newton openly maintained this doctrine. They divide dreams into two kinds,— good and evil,—and conceive that two kinds of agents, good and evil spirits, are concerned in their production; they consequently ac- count for the one or the other sort of dreams, according as the one or the other kind of agents obtains a predominancy! It is not necessary to combat these views,—which must, of course, be as applicable to animals as to man,—especially as they are univer- DREAMS. 411 sally discarded. Dreaming is now properly considered to be an irre- gular action of the brain, in which the great controlling power of the will has suspended its agency, and allowed the memory and imagina- tion unlimited sway,so that the most singularand heterogeneous ideas are formed,—still kept, however, somewhat in train by the force of association. At times, indeed, this influence is so great, that every part of the dream appears to go on in the most natural and con- sistent manner. We witness the scenes that have occurred during our waking hours; and we seem to see, hear, walk, talk, and perform all the ordinary offices of life. The mind reasons, judges, wills, and experiences all the various emotions. Generally, the whole process is confined to the brain, but, at times, the muscles are thrown into action, and the expression of the feelings and emotions occurs, as in the waking state. The dreamer moves, speaks, groans, cries, sings, &c. and if the dream concerns the ge- nerative function, the external organs respond, and emission takes place in the male to such an extent, occasionally, as to constitute a true disease, or to be the cause of such,—the paroniria salax of Good, the gonorrhoea dormientium, or night pollution of others. During the prevalence of a passion, too, the nutritive organs, in which its effects are experienced whilst awake, may be equally concerned during sleep. The respiration is short and interrupted, and sighs, groans, or laughter, according to the character of the emotion, are elicited; the heart beats with more or less violence, and this state of excitement will often continue after the individual has been completely aroused. The nightmare, ephialtes, or incubus, affords us an example of suf- fering as intense as could well be experienced during our waking moments. A sensation of distressing weight is felt at the epigas- trium, and of impossibility of motion, speech or even respiration: the dreamer fancies that some horrible form, or some ferocious being is approaching him, and that all chance of escape is precluded; or that he is about to fall, or is falling, from a lofty precipice; and the anguish which he suffers is indicated by loud groans, or by such painful feelings, apparently in the organs to which the emotions are referred, that he wakes. The ideas at these times are even more vivid than during the waking condition; the perceptions that predominate not being detracted from by extra- neous impressions. On many of these occasions, when we awake, the dream is fresh upon the memory; and, by resigning ourselves again to slumber, we can recal it, should it be of an agreeable character, or dispel it altogether by rousing ourselves thoroughly. On account of the greater vividness of the ideas during sleep, and their freedom from all distraction, intellectual operations are sometimes effected in a surprising manner; difficulties being occa- sionally solved, which have obtained the mastery during waking. To a minor degree, every one must have experienced more or less 412 SLEEP. of this. Composition, poetical or other, is often effected with the greatest facility; and a clue is occasionally afforded which leads to the solution of previous difficulties. Cardan had a notion that he composed one of his works during sleep. Condillac, who at- tended greatly to this matter, remarked particularly that whilst engaged, with his " Cours d'Etude" he frequently broke off a subject, before retiring to rest, which he developed and finished the next morning according to his dreams. Condorcet saw in his dreams the final steps of a difficult calculation, which had puzzled him during the day; and Dr. Gregory, of Edinburgh, composed thoughts, and clothed them in words which were so just in point of reasoning, and so good in point of language, that he used them in his lectures, and in his written lucubrations. Vol- taire, Lafontaine, Franklin, Coleridge, and others, have made similar remarks; and events of the kind must have occurred, in some shape, to almost every one. Dr. Good relates a singular instance which happened to a friend of his, who, amongst other branches of science, had deeply cultivated that of music, of which he was passionately fond. He was a man of irritable temperament, ardent mind, and most active and brilliant imagination; and " was hence," says Dr. Good, " prepared by nature for energetic and vivid ideas in his dreams." On one occasion, during his sleep, he composed a very beautiful little ode, of about six stanzas, and set the same to very agreeable music, the impression of which was so firmly fixed in his memory, that, on rising in the morning, he copied from his recollection both the music and the poetry. In these cases the will must direct, more or less, the intellectual process. It is scarcely conceivable that the train of reasoning could go on so connectedly and effectively by association alone. That the will can, in some degree, be kept awake, or in a condi- tion susceptible of being readily aroused, is shown by the facility with which we awake at a determined hour, and exercise a degree of watchfulness during sleep; as well as by the facts, previously mentioned, regarding the courier who sleeps on his horse, or the coachman on his box. There is a kind of dreaming, in which the sleep is more com- plete than during ordinary dreams; where the body has, conse- quently, less capability of receiving impressions, but where the will has a certain degree of power over the muscles of voluntary motion. This is somnambulism, or sleep walking. During the continuance of this state, the individual can apparently see, hear, walk, write, paint, speak, taste, smell, &c. and perform his usual avocations, yet remain so soundly asleep that it is impossible to awake him without making use of violence. Cases are on record, and of an authentic nature, of individuals who have risen from bed asleep, with their eyes closed, and have not only walked about the room or house, going up or down stairs, finding their way readily and avoiding obstacles, but have passed with safety through very dreams. 413 dangerous places, as windows, or on the roofs of houses. They have executed, too, yet more difficult feats; such as dressing themselves, going out of doors, lighting a fire, bathing, saddling and bridling a horse, riding, composing verses, &c. and executing all the actions of life correctly, and even acutely; yet they have been asleep during the whole of these acts. The eyes have been shut, or if open, have been incapable of perceiving the brightest light held before them; and the iris has not exhibited its irritability by contracting, so that it is doubtful whether the ordi- nary functions of the eyes are generally executed during somnam- bulism; and the fact, of the serious accidents that occasionally befal the sleep walker, is in favour of this conclusion. It must be re- marked, however, that in the opinion of some physiologists the sight is awake and employed, and there are cases which strongly favour the idea. The peculiarity of somnambulism is, that the train of thoughts is always directed towards one point, and this so profoundly, that notwithstanding the activity of the imagination, and the firm hold it takes on the mind, no recollection is retained of the occurrences during sleep, after the individual awakes, either spontaneously, or by being forcibly aroused. The causes of imperfect or incomplete sleep, and hence of dreams, are various. The fact, already referred to, of the different organs of the animal functions having their distinct periods of waking and rest, would induce us to suppose, that it ought not to be always equally profound and durable: yet there are individuals whose sleep is nearly complete throughout; but they are not many. The previous occupation of the sleeper exerts great influence. If it has been of a fatiguing nature, all the faculties rest equally long and soundly; but if the fatigue extends beyond the due point, a degree of excitability of the brain is left which renders it extremely lia- ble to be aroused. In this way we understand, why dreams should bear upon subjects that have long occupied the mind in its waking state; the tension of the mind by those subjects having left consi- derable excitability, as respects them, and a disposition to resume them under the slightest irritation. The presence or absence of irritants—external or internal—ex- erts likewise a great effect on the soundness of sleep, and the for- mation of dreams. The stillness of night and the absence of light are hence favourable to repose: the position, too, must be one de- void of constraint; and the couch soft and equable, and especially such as the individual has been accustomed to use. Sleep is im- practicable in a badly-made bed; and every one must have experi- enced the anti-soporific influence of a strange bed, the arrangement of which, as to quantity, pillows, &c. differs from that to which he has been habituated. It is not, however, by external irritants that the sleep is usually disturbed. The state of the system itself will react upon the brain, and give occasion to broken sleep, and to 414 SLEEP. dreams of the most turbulent character. Irritations, existing in the * viscera, are frequently the cause of dreams,—in children more es- pecially; and a hearty supper, especially if of materials difficult of digestion, will bring on the whole train of symptoms that cha- racterize nightmare. In like manner, any thing that impedes the action of the functions of respiration, circulation, &c. may occasion the wildest phantasies. All these internal impressions are more vividly perceived for the reasons already stated. The nervous system is no longer ex- cited by the ordinary impressions from the external senses; and if these internal impressions are insufficient to prevent sleep alto- gether, they may excite dreams. During this incomplete kind of sleep, the external sensations are not wholly at rest; particularly that of touch or tact, which, as it is the last to sleep, is the first to awake. Impressions made on it will excite the most exaggerated representations in the brain, in the shape of dreams. The bite of a flea appeared to Descartes the puncture of a sword: an uneasy position of the neck will excite the idea of stran- gulation: a loaded stomach will cause the sleeper to feel as if a heavy weight,—a house, or a castle, or some powerful monster,— were on his stomach. Moreau de la Sarthe gives the case of a young female, who, from the application of her cold hand against her breast, when asleep, dreamed that a robber had entered her apartment and had seized hold of her. Galen dreamed that he had a stone leg, and, on waking, found that his own was struck with paralysis. Mr. Dugald Stewart gives a similar case, to show how an impression made upon the body, during sleep, may call up a train of associated ideas, and thus produce a dream. A gentleman, (Dr. Gregory,) who, during his travels, had ascended a volcano, having occasion, in consequence of indisposition, to ap- ply a bottle of hot water to his feet when he went to bed, dreamed that he was making a journey to the top of Mount iEtna, and that he found the heat of the ground almost insupportable. Sir Walter Scott mentions an analogous instance, which was told him by the nobleman concerned. He had fallen asleep, with some uneasy feel- ings arising from indigestion, which brought on the usual train of visionary terrors. At length, they were all summed up in the ap- prehension that the phantom of a dead man held the sleeper by the wrist, and endeavoured to drag him out of bed. He awoke in horror, and still felt the cold, dead, grasp of a corpse's hand on his wrist. It was a minute before he discovered that his own left hand was in a state of numbness, and with it he had accidentally encircled his right arm. I/j again, the organ of hearing be wakeful, the dreamer may hear an individual speak to him and may reply; so that occasionally se- cret thoughts and feelings have been elicited. The author has him- self replied several times connectedly in this manner; and he has been able to lead on others, especially children,—whose sleep is DREAMS. 415 often interrupted by the existence of irregular internal impressions, —to answer a few times in the same manner. In the explanation of the cause of dreaming, we have the most plausible application of the theory of Gall regarding the plurality of organs in the brain. Every explanation, indeed, takes for grant- ed, that certain faculties are suspended whilst others are active. Gall's view is, that, during sleep, particular organs of animal life enter into activity; and hence, that the perceptions and ideas which depend on these organs awake; but in such case their activity takes place without any influence of the will;—that when one organ only is in activity, the dream is simple;—the dreamer caresses the object of his affection; he hears melodious music, or fights his ene- mies, according as this or that organ is exercising its functions:— that the greater the number of organs in activity at the same time, the more confused or complicated will be the dream, and the greater the number of extravagancies: that, when the organs are exhausted by watching and labour, we generally do not dream during the first hours of sleep, unless the brain is extremely irri- table; but, in proportion as the organs get rid of their fatigue, they are more disposed to enter into activity, and hence, near the time for waking, we dream more and with greater vivacity. "Dream- ing, consequently," he concludes, " is only a state of partial wak- ing of animal life; or, in other words, an involuntary activity of certain organs, whilst others are resting." In many respects, the state of the mind, during dreaming, re- sembles that in the delirium of fever, as well as in insanity. The imagination and memory may be acting with unusual vivacity, whilst the perceptions or the judgment may be most erroneous;— at times the perception being accurate and the judgment-suspend- ed, so that the individual will be most incoherent; whilst, at others, the perceptions may be inaccurate and the judgment right, so that the individual will reason correctly from false premises. As in dreams, too, the delirious may have their ravings modified by im- pressions made on the external senses. Sir Walter Scott cites the case of a lunatic confined in the infirmary of Edinburgh, whose malady had assumed a gay turn. The house, in his idea, was his own, and he contrived to account for all that seemed inconsistent with his imaginary right of property;—there were many patients in it, but that was owing to the benevolence of his nature, which made him love to relieve distress. He went little, or rather never abroad,—but then his habits were of a domestic and rather seden- tary character. He did not see much company, but he daily re- ceived visits from the first characters in the celebrated medical school of the city, and he could not, therefore, be much in want of society. With so many supposed comforts around him, with so many visions of wealth and splendour, one thing alone disturb- ed his peace. "He was curious," he said, "in his table, choice in his selection of cooks, had every day a dinner of three regular 416 SLEEP. courses and a dessert, and yet somehow or other, every thing he ate tasted of porridge." The cause of this was, that the lunatic actually ate nothing but this at any of his meals; and the impres- sion made upon his palate was so strong as to modify his delusion. Nearly allied to dreams in its physiology, or more properly, perhaps, pathology, is the subject of hallucinations, illusions, or waking dreams, in which the mind may be completely sound, and yet the cerebral or percipient part of the brain, concerned in the senses, be so deranged as to call up a series of perceptions of objects which have no existence except in the imagination. Such hallucinations are constant concomitants of insanity, delirium, and dreaming; but they may occur also when the individual is wide awake, and in the full possession of his reasoning powers; he may see the phantasm, but at the same time totally disbelieve in the existence of any extraneous body. The most common illusions of this kind affect the senses of sight and hearing. It has fallen to the lot of the author to meet with some singular and serious cases of this affection ; where, for example, the indivi- dual, wide awake, has heard the doors of his house violently slammed, his windows thrown up and down, the bells set a ring- ing, himself subjected to personal violence; yet there has been no slamming of doors, no throwing up and down of windows, no ringing of bells, no personal violence; the whole has been an illu- sion, a waking dream, and of this no one has been more entirely aware than the sufferer himself. One of the most impressive cases of this kind is that of Nicolai, the eminent bookseller of Berlin, which has been detail- ed by Dr. Ferriar, and by Dr. Haslam, in his " Medical Juris- prudence, as it relates to Insanity"—a tract, reprinted in this country, along with others, by Dr. Cooper. Nicolai laid his case before the Philosophical Society of Berlin. He traced his indisposition, for it was manifestly such, to a series of disagreeable incidents that had befallen him. The depression, thus induced, was aided by the consequences of neglecting a course of periodical bleeding to which he had accustomed himself. This state of health brought on a disposition to spectral illusions, and, for a time, he was regularly haunted by crowds of persons entering his apart- ment, and addressing him or occupied solely in their own pursuits, until as his health was restored, they gradually disappeared, and ultimately left him, entirely. Yet Nicolai, who was a man of unusually strong intellect, was throughout satisfied, that they were mere hallucinations. The cases of this kind, now on record, are many and curious. Every one engaged in extensive practice, or in frequent commu- nion with the world, must have seen or heard of them. There are none, however,which strike us as more extraordinary,and which are at the same time more elucidative of the subject, than the two follow- ing, related by Sir Walter Scott. The first of these was frequently WAKING DREAMS. 417 related in society, and in the class-room, by an old preceptor of the author, the late truly learned and accomplished Dr. James Gregory of Edinburgh. A patient of Dr. Gregory, a person of some rank, having re- quested the doctor's advice, made the following singular statement of his complaint. "I am in the habit of dining at five, and, ex- actly as the hour of six arrives, I am subjected to the following painful visitation. The door of the room, even when I have been weak enough to bolt it, which I have sometimes done, flies wide open; an old hag, like one of those who haunted the heath of Forres, enters with a frowning and incensed countenance, comes straight up to me with every demonstration of spite and indigna- tion, which could characterize her who haunted the merchant Abudah, in the oriental tale; she rushes upon me, says something, but so hastily that 1 cannot discover the purport, and then strikes me a severe blow with her staff. I fall from my chair in a swoon, which is of longer or shorter endurance. To the recurrence of this apparition I am daily subjected; and such is my new and sin- gular complaint." The doctor asked, whether his patient had in- vited any one to sit with him when he expected such a visitation. He was answered in the negative. The nature of the complaint was so singular; it was so likely to be imputed to fancy, or even to mental derangement, that he shrunk from communicating the circumstance to any one. "Then," said the doctor, "with your permission, I will dine with you to-day, tete-a-tete, and we will see if your malignant old woman will venture to join our com- pany." The patient accepted the proposal with hope and gratitude, having expected ridicule rather than sympathy. They met at din- ner, and Dr. Gregory, who suspected some nervous disorder, exerted his brilliant powers of conversation to keep the attention of his host engaged, and prevent him from thinking of the ap- proach of the fated hour to which he was accustomed to look for- ward with so much terror. He succeeded in his purpose better than he had expected. The hour of six came almost unnoticed, and, it was hoped, might pass by without any evil consequence. But scarcely had it struck, when the gentleman exclaimed, m an alarmed voice,—"the hag comes again," and dropped back in his chair in a swoon, in the manner he had described. The doctor had him bled, and satisfied himself that the periodical illusions arose from a tendency to apoplexy. The second case is even more extraordinary. It was related by the medical gentleman under whose care it fell, and of whom "I can only say," says Sir Walter, " that if I found myself at liberty to name him, the rank, which he holds in his profession, as well as his attainments in science and philosophy, form an undisputed claim to the most implicit credit." This gentleman was called in to attend the illness of a person, who stood high in a particular department of the law, which often Vol. II. 53 41S SLEEP. 'placed the property of others subject to his discretion and control, and whose conduct was therefore open to public observation. He had, for years, borne the character of a man of unusual steadiness, good sense, and integrity. He was, at the time of the physician's visit, confined chiefly to his chamber, sometimes to his bed; yet occasionally attending to business, and exerting his mind, appa- rently with all its usual strength and energy, in the management of the weighty matters entrusted to him; nor did there, to a su- perficial observer, appear any thing in his conduct, while so en- gaged, that could argue vacillation of intellect or depression of mind. His outward symptoms indicated no acute or alarming dis- ease; but slowness of pulse, absence of appetite, difficulty of di- gestion, and constant depression of spirits seemed to draw their origin from some hidden cause, which the patient was determined to conceal. The deep gloom, the embarrassment which he could not conceal from his friendly physician, the brevity and obvious constraint with which he replied to the interrogatories of that gen- tleman, induced him to take other methods for attaining correct information. He applied to the sufferer's family, to learn, if pos- sible, the source of that secret grief which was evidently corrod- ing him ; yet not the slightest clue could be discovered. He had finally recourse to serious argument with the invalid himself, urging to him the folly of devoting himself to a lingering and me- lancholy death, rather than tell the subject of affliction, which was thus wasting him:— "There's matter in these sighs: these profound heaves You must translate: 'tis fit we understand them." He specially pressed upon him the injury he was doing his own character, by suffering it to be inferred, that the secret cause of his dejection and its consequences was something too scandalous or flagitious to be made known; bequeathing, in this manner, to his family, a suspected and dishonoured name, and leaving a me- mory, with which might be associated the idea of guilt, which the criminal had died without confessing. The patient, moved more by this species of appeal than by any that had been previously urged, expressed his desire to speak out frankly to the doctor. Every one else was removed, and the door of the sick-room made secure, when he began his confession as follows:—"You cannot, my dear friend, be more conscious than I, that I am in the course of dying under the oppression of the fatal disease which consumes my vital powers; but neither can you understand the nature of my complaint, and manner in which it acts upon me, nor if you did, I fear, could your zeal and skill avail to rid me of it." " It is possible," said the physician, "that my skill may not equal my wish of serving you: yet medical science has many resources, of which those, unacquainted with its powers, never can form an es- waking dreams. 419 timate. But, until you plainly tell me your symptoms of com- plaint, it is impossible for either of us to say, what may or may not be in my power, or within that of medicine." "I may answer you," replied the patient, " that my case is not a singular one, since we read of it in the famous novel of Le Sage. You remem- ber, doubtless, the disease of which the Duke D'Olivarez is there stated to have died?" "Of the idea," replied the doctor, "that he was haunted by an apparition, to the actual existence of which he gave no credit, but died, nevertheless, because he was overcome and heart-broken by its imaginary presence." "I, my dearest doctor," said the sick man, "am in that very case; and so pain- ful and abhorrent is the presence of the persecuting vision, that my reason is totally inadequate to combat the effects of my morbid imagination, and 1 am sensible I am dying a wasted victim to an imaginary disease." The medical gentleman listened attentively to his patient's statement, and avoiding, for the time, any opposi- tion to the sick man's preconceived fancy, contented himself with a more minute inquiry into the nature of the apparition with which he conceived himself haunted, and into the history of the mode by which so singular a disease had obtained the mastery of his imagi- nation, secured, as it seemed to be, against so irregular an attack by strong intellectual powers. The patient replied, that its ad- vances had been gradual, and at first not of a Terrible or even dis- agreeable character. To illustrate this he gave the following ac- count of its progress. " My visions commenced two or three years since, when I found myself, from time to time, embarrassed by the presence of a large cat,* which came and disappeared I could not exactly tell how, till the truth was finally forced upon me, and I was com- pelled to regard it as no domestic household cat, but as a bubble of the elements which had no existence save in my deranged visual organs or depraved imagination. Still I had not that positive objection to the animal, entertained by a late gallant Highland chieftain, who has been seen to change to all the colours of his own plaid, if a cat happened by accident to be in the room with him, even though he did not see it. On the contrary, I am rather a friend to cats, and endured with so much equanimity the pre- sence of my imaginary attendant that it had become almost in- different to me; when, within the course of a few months, it gave place to, or was succeeded by, a spectre of a more important sort, or which at least had a more imposing appearance. This was no other than the apparition of a gentleman-usher, dressed as if to wait upon a lord-lieutenant of Ireland, a lord high commissioner of the Kirk, or any other who bears on his brow the rank and stamp of delegated sovereignty. This personage, arrayed in a * It is singular that this animal has played a part in most of the cases of hallu- cination that have attracted the author's attention. 420 sleep. court dress, with bag and sword, tamboured waistcoat, and cha- peau-bras, glided beside me like the ghost of Beau Nash; and whether in my house or in another, ascended the stairs before me, as if to announce me in the drawing-room; and sometimes ap- peared to mingle with the company, though it was sufficiently evi- dent, that they were not aware of his presence, and that I alone was sensible of the visionary honours which this imaginary being seemed desirous to render me. This freak of the fancy did not produce much impression upon me, though it led me to entertain doubts on the nature of my disorder, and alarm for the effect it might produce upon my intellects. But that modification of my disease had likewise its appointed duration. After a few months, the phantom of the gentleman-usher was seen no more, but was succeeded by one, horrible to the sight, and distressing to the imagination, being no other than the image of death itself—the apparition of a skeleton. Alone or in company, the presence of this phantom never quits me. I, in vain, tell myself a hundred times over that it is no reality, but merely an image summoned up by the morbid acuteness of my own excited imagination, and de- ranged organs of sight. But what avail such reflections, while the emblem at once and presage of mortality is before my eyes, and while I feel myself, though in fancy only, the companion of a phantom, representing a ghastly inhabitant of the grave, even while I yet breathe on the earth? Science, philosophy, even reli- gion, has no cure for such a disorder; and I feel too surely, that I shall die the victim to so melancholy a disease, although I have no belief whatever in the reality of the phantom which it places before me." The physician was distressed to find that this visionary ap- parition was so strongly fixed in the imagination of his patient. He ingeniously urged the sick man, who was then in bed, with questions concerning the circumstances of the phantom's appear- ance, trusting that he might lead him, as a sensible man, into such contradictions and inconsistencies as might bring his common sense, which seemed to be unimpaired, so strongly into the field as to combat successfully the fantastic disorder which produced such fatal effects. "This skeleton, then," said the doctor, " seems to you to be always present to your eyes?" " It is my fate, unhap- pily," replied the invalid, "always to see it." "Then I under- stand," continued the physician, " it is now present to your ima- gination?" " To my imagination it certainly is so," answered the sick man. " And in what part of the chamber do you now con- ceive the apparition to appear?" the physician inquired. " Imme- diately at the foot of my bed, when the curtains are left a little open," answered the invalid; " the skeleton, to my thinking, is placed between them, and fills the vacant space." " You say you are sensible of the delusion," said his friend ; "have you firmness to convince yourself of the truth of this? Can you take courage WAKING DREAMS. 421 enough to rise and place yourself in the spot so seeming to be oc- cupied, and convince yourself of the illusion?" The poor man sighed and shook his head negatively. " Well," said the doctor, " we will try the experiment otherwise." Accordingly he rose from his chair by the bed-side, and placing himself between the two half-drawn curtains, at the foot of the bed, indicated as the place occupied by the apparition, he asked if the spectre was still visi- ble? " Not entirely so," replied the patient, " because your per- son is between him and me ; but I observe his skull peering above your shoulder." The doctor resorted to other means of investi- gation and cure, but without success. The patient sank into deeper and deeper dejection, and died in the same distress of mind in which he had spent the latter months of his life. The circum- stances of his singular disorder were concealed, so that he did not, by his death and last illness, lose any of the well-merited reputation for prudence and sagacity, which had attended him during the whole course of his life. These are striking cases of the illusions that may occur during even our waking moments; and they may, doubtless, account for some of the stories of apparitions, of which so many are upon re- cord. In the hypochondriac, we meet with all kinds of hallucination, and it is one of the most striking of the symptoms of every variety of insanity; but in the cases we have adduced, notwithstanding the constancy and permanency of the illusion, the individual himself has been entirely satisfied that the whole affair had no real exist- ence. Had he believed in the existence of these phantoms, and acted from a conviction of their reality, he might with propriety have been deemed insane. An instance of this kind is told in the Me- moirs of the Count Maurepas of one of the princes of the house of Bourbon, who supposed himself to be a plant, and after having fixed himself in the garden, called upon his servant to come and wa- ter him. His belief argued unsoundness of mind, yet even here the hallucination, we are told, appeared to be confined to this subject. In youth, when the imagination is extremely vivid, we can call up images in the mind at pleasure, varying them as we may think proper. Similar illusions appear to have been experienced by the poet Cowper:— " Me, oft, has fancy, ludicrous and wild, Sooth'd with a waking dream of houses, towers, Trees, churches, and strange visages, express'd In the red cinders, while with poring eye I gazed, myself creating what I saw." In the nervous, the delicate and the imaginative, uneasy sensa- tions can be experienced, when and where the individual wishes. After sedentary habits, long continued, the author has been able to experience pain in any part of the system, where he has chosen; aad to make it shift at pleasure from one organ to another. In the cases of hullucination which we have given at length, as 422 SLEEP. well as in every other kind, the cerebral part of the organ of sense is directly or indirectly excited into action;—often by disease of the brain, or of some distant organ which reacts upon it. Hence it occurs as a precursor of apoplexy, epilepsy, or other cerebral affection, or it may accompany or be aggravated by disorder of the digestive function. It has been seen, that although the passions or emotions are cerebral phenomena, they are felt in the nutri- tive organs; and we can understand, how a disordered state of those organs may react upon the brain, and call up all kinds of illu- sions;—generally during sleep, but at times even during our wak- ing moments. In this way, we account for the frightful dreams that follow an overloaded stomach, or that accompany impeded respiration or circulation. One of the most distressing symptoms of hydrothorax or water in the chest, which interferes more or less with both these vital functions, is the disturbed sleep, and the frightful sense of impending danger, which nightly distress the un- fortunate sufferer. It appears, then, that in all cases of hallucination, occurring in those of sound or diseased mind, asleep or awake, the cerebral or percipient part of the organ of the sense concerned is irresistibly affected, so as to call up the memory of objects, or to form others which have no existence except in the imagination; but all this is accomplished without any impression being made upon the exter- nal senses from without, even when such senses appear to be most actively exercised. In dreams this must manifestly be the case. We see a friend long since dead; we parade the streets of a town, which we have never visited; see, hear, feel and touch the different objects. All this must be cerebral; and not less certainly, is it the case in the hallucinations of insanity, or in those that occur in the waking condition. The object we see is not in existence, yet it is a regularly defined creation; a cat in one instance, a gentleman- usher in another, and a skeleton in a third. It cannot depend upon any depraved condition of the organ of sense, as in such case the representation of the mind would be amorphous, irregular, or con- fused; not a complete metamorphosis as is invariably the case. Yet we are surprised to see Sir Walter Scott stale, that he thinks " there can be little doubt of the proposition, that the external or- gans may, from various causes, become so much deranged as to make false representations to the mind; and that, in such cases, men, in the literal sense, really see the empty and false forms, and hear the ideal sounds, which in a more primitive state of society, are naturally enough referred to the action of demons or disem- bodied spirits. In such unhappy cases, the patient is intellectually in the condition of a general, whose spies have been bribed by the enemy, and who must engage himself in the difficult and delicate task of examining and correcting, by his own powers of argument, the probability of the reports, which are too inconsistent to be trusted to." waking dreams. 423 The explanation is poetic, but manifestly untenable. A theory which has been offered to account for the various spectral illusions, occurring in any of the modes we have mentioned, is, that, in all the organs of sense, the mind possesses the power of retransmit- ting, through the nervous filaments to the expansion of the nerves that are acted upon by external objects, impressions which these nerves have previously transmitted to the brain, and that the vi- vidness of the retransmissions is proportional to the frequency with which the impressions have been previously transmitted; that these reproduced impressions are in general feeble in the healthy state of the body, though perfectly adapted to the purposes for which they are required; but in other states of the body, they ap- pear with such brilliancy as to create even a belief in the external existence of those objects from which the impressions were origi- nally derived. " When the mind," says a recent writer on this subject, " ac- quires a knowledge of visible objects it is by means of luminous impressions, conveyed to the sensorium from each impressed point of the retina, through the corresponding filaments of the optic nerve, and when the memory is subsequently called upon, by an act of the will, to present to us an object, that has been previously seen, it does it by retransmission along the same nervous filaments, to the same points of the retina. In the first case, when the pre- sence of the luminous object keeps up a sustained impression upon the nervous membrane, the filaments which transmit it to the brain are powerfully excited; but in the process of retransmission by an effort of memory, the action of the nervous filaments is com- paratively feeble, and the resultant impression on the retina faint or transient. When the memory, however, is powerful, and when the nervous filaments are in a state of high excitability, the im- pression becomes more vivid; and, as in the case of spectral illu- sions, it has the same strength and distinctness, as if it were pro- duced by the direct action of luminous rays. In the one case, the result of the impression and its retransmission to the retina is a voluntary act of the mind, but in the other it is involuntary, the controlling power being modified or removed, or the nerves being thrown into a state of easy excitation by some unhealthy action of the bodily organs." According to this view, it is indispensable that the perception in every case of illusion shall be referred to the nerves of the organ, by which such perception is ordinarily effected; to the re- tina, if vision be concerned; to the auditory nerve, if audition-and so on. But this retransmission along the nerves appears to be wholly unnecessary. When an impression is made upon a sen- sitive surface, as we have elsewhere shown, sensation is not ac- complished, until the impression has been conveyed to the brain by an appropriate organ, and the brain itself has acted; and if we interfere in any manner with the cerebral part of the function, per- 424 SLEEP. ception is not effected. From the moment, however, that the ac- tion of the brain has taken place, the idea formed can be recalled by the exercise of memory: and we have no doubt, that this could take place although the eyes were extirpated. The memory might call up previous perceptions, when the functions of the retina are entirely destroyed. Were it otherwise, it would be impossible for those, who have lost their sight from paralysis of the retina, of which many cases are constantly occurring, to call up any of the scenes and images, of which the brain took cognizance prior to the supervention of their blindness. In dreams, too, we exert every one of the senses; some with the greatest activity. We see, hear, taste, smell, feel; and, in addition to this, walk, run, fly, and exe- cute the ordinary acts of life not only without apparent difficulty, but with a facility, that surprises us. Yet can we suppose, that, in all these cases, the feeling is actually produced by retransmission along the nerves to the organ to which it is referred? It has been asserted, that when examination is carefully made it will be found that the images, recalled by the memory, follow the motions of the head and of the eye; but that this is not the case during sleep is manifest. The individual may remain precisely in the same position, and yet he will seem to move about in all direc- tions in his dreams; will appear to see objects behind as well as be- fore; and in situations towards which it is impossible that the mo- tions of his head and eye should be directed. Even in most of the illusions of our waking hours, the remark ought to be reversed. The encephalic action is the first of the links in the chain of phe- nomena; and the motions of the head and the eye follow the images recalled by the memory. When the unfortunate subject of one of the cases of hallucination saw the gentleman-usher preceding him into company and circulating amongst the assembled guests; as well as when he observed the skeleton at the foot of his bed; the per- ception had, owing to disease, so completely taken possession of a part of the encephalic organ of vision, that the idea was constantly in the mind; and volition being actively exercised, the head and the eye were directed towards the phantasm. Yet the perception was not so powerful, as to preclude the reception of impressions from without, as was shown by the skeleton seeming to be shut off by the body of the physician, so that the skull only was seen peering above his shoulder. Another fact, which shows that the whole phenomenon may be entirely encephalic, is the occurrence familiar to the operative surgeon, of a patient, whose lower limb has been amputated, complaining of an uneasy sensation,as of itching, in a particular toe, and in a particular part of a toe. This is at times a symptom of an extremely distressing character. It is obviously impossible, that, in this case, there can be any external impression made on the part to which the feeling is referred; or that any retransmission can occur from the brain; the limb having been removed from the SLEEP. 425 body. Broussais asserts, that if a person tells you he suffers in a limb which he no longer has, it is because he experiences irrita- tion in the extremities of the divided nerve, but this, in no respect, removes the difficulty. The sensation is referred to a part, which has no existence except in the imagination. But to return to sleep. We have said, that the object of sleep is to repair the loss which the nervous system has sustained during the previous condition of waking. This may consequently be re- garded as the great exciting cause of sleep; but we have seen also that certain states of the mind may postpone the usual period of its recurrence. If, indeed, we allow the attention to flag, and suspend the due exercise of volition, sleep can be indulged at almost any hour of the day. In the same manner, any monotonous impression, or action of the brain in thought; the rocking of a cradle to the restless child; or the song of the nurse; the murmurs of a bubbling brook, &c. may soothe us to rest. A like effect is produced by substances, as narcotics, which, by a specific action on the nervous system, prevent the ordinary sources of irritation from being ap- preciated, as well as by certain morbid affections of the brain,—com- pression, concussion, inflammation, &c. In these cases, however, the sleep is morbid, and is an evidence of serious mischief,—often of fatal disease; whilst true sleep is as natural as the waking state, and is always— "Man's rich restorative; his balmy bath, That supples, lubricates and keeps in play, The various movements of that nice machine, Which asks such frequent periods of repair!" Yet Haller, Hartley, and numerous others have supposed that natural sleep is likewise dependent upon an accumulation of blood or other fluids in the vessels of the head, pressing upon the brain and thus impeding its functions. In support of this opinion, it is asserted, that all the phenomena which attend the sleeping state seem to prove a determination of blood to the head. The face is flushed; the head is hotter; the skin more moist; and it is generally during the night, or when first awake, that bleeding from the nose and apoplexy take place: the frequency of erection during sleep is affirmed to be owing to the pressure exerted on the cere- bellum, which, in the theory of Gall, is the encephalic organ of generation; and lastly, it.is argued, that narcotics and vinous and spirituous liquors produce sleep by causing a similar congestion of blood within the cranium. The case, by no means unique, of the beggar whose brain was exposed, and in whom a state of drow- siness was induced when the brain was pressed upon, which could be increased by increasing the pressure, until at length he became co- matose, has also been cited by Hartley and others. But all these are cases of morbid suspension of the animal functions, and are no Vol. II. 54 426 SLEEP. more to be assimilated to true sleep, than the drowsiness, which Flourens found to prevail in his experiments on animals when the cerebral lobes were removed. The believers in the hypothesis, that congestion of the vessels of the brain is the cause of sleep, consider, that the heaviness and stupor, observable in those who indulge too much in laziness and sleep, are owing to the long-continued pressure injuring the cere- bral organs. Other physiologists have assumed the opposite ground, and affirmed that during sleep the blood is distributed to the brain in less quantity, and is concentrated in the abdomen, to augment the action of the nutritive functions; whilst Cabanis holds, that during sleep, there is a reflux of the nervous powers towards their source, and a concentration in the brain of the most active principles of sensibility. On all these topics our ignorance is extreme. We know nothing of the state of the encephalon in sleep. Its essence is as impene- trable as that of every other vital function. Dr. Bostock asserts, that it is not more beyond our grasp than the other functions of the nervous system. This we admit: he has indeed afforded us in his own work indubitable evidences of our utter want of acquaintance with the essence of all those functions. The state of sleep is as natural, as instinctive, as that of waking: both are involved in mystery, and their investigation, as Mr. Du- gald Stewart has suggested, is beyond the reach of the human faculties. Reverie has been considered to resemble sleep, and, in its higher grades, to be not far removed from the condition of somnambulism. It is characterized by the attention or volition being directed so intently towards particular topics, during wakefulness, that the im- pressions of surrounding objects are not appreciated. Various grades of this condition of the mind may be traced from the slightest degree of absence or brown study, to a state of total abstraction, in which the attention is entirely wound up, and riveted to a particular sub- ject. Most persons must have experienced more or less of this, when any subject of severe study, or any great gratification, anxiety, or distress has strongly occupied the mind. If engaged in reading, they may follow every line with the eye; turn over leaf after leaf, and at length awake from the reverie, which had oc- cupied the imagination, and find that not the slightest impression has been made on the mind, by the pages which the eye had pe- rused, and the hand had run over. If walking in a crowded street, they have probably proceeded some way under the influence of revery, moving the limbs as usual, performing various acts of vo- lition, winding safely among the passengers, avoiding the posts and other obstacles, yet so exclusively occupied by the conceptions of the mind, as to be totally unconscious of all these acts of their volition, and of the objects which they have passed, which must necessarily have impressed their senses so as to regulate SLEEP. 427 those actions, but, owing to the attention having been bent upon other topics, the perceptions have been evanescent. In elucidation of the power of a high degree of revery to render an individual torpid to all around him, the case of Archimedes, at the time of his arrest, has been quoted by writers. When the Roman army had at length taken Syracuse by stratagem, which the tactics of Archimedes had prevented them from taking by force, he was shut up in his closet, and so intent on a geometrical demonstration that he was equally insensible to the shouts of the victors, and the outcries of the vanquished. He was calmly tracing the lines of a diagram, when a soldier abruptly entered his room, and clapt a sword to his throat. " Hold friend," said Archimedes, " one moment, and my demonstration will be finished." The soldier^ surprised at his unconcern at a time of such extreme peril resolved to carry him before Marcellus; but as the philosopher put under his arm a small box full of spheres, dials, and other instruments, the soldier, conceiving the box to be filled with gold, could not re- sist the temptation, and killed him on the spot. It is to the capability of indulging to the necessary extent in this kind of mental abstraction, that we are indebted for the solu- tion of every abstruse problem, relating to science or art, and for some of the most beautiful conceptions of the poet. From indul- gence, however, in such abstractions, a habit is often acquired, which may be carried so far as to render the individual unfit for society, and to give him a character for rudeness and ill-breed- ing,*of which he may be by no means deserving. Some most amiable and estimable men have, from long habits of abstraction, contracted the disease, (aphelxia,) as Good has constituted it, and have found the cure tedious and almost impracticable: at times, indeed, it appears to have terminated in mental alienation. The difference between this state and that of sleep is, that the attention and volition are here powerfully directed to one object, so as to be torpid to the impressions of extraneous bodies; whilst sleep is characterized by a suspension or diminished exercise of these faculties. 4 428 correlation of functions. CORRELATION OF FUNCTIONS. The wonderful and complicated actions of the frame are variously correlated, to accomplish that astonishing harmony which prevails in the state of health, as well as to produce the varied morbid phenomena,—often at a distance from the part originally diseased, —which characterize different pathological conditions. It is not, therefore, simply as a physiological question that the study of the correlation of functions interests the medical inquirer. It is im- portant to him in the study of every department which concerns the doctrine of the healthy or diseased manifestations, and the modes adapted for their removal. These correlations may be of various kinds;—physical, in which the effect exerted is entirely of a mechanical character■; functional, in which the action of one organ is inseparably united to that of another, to accomplish a particular object; and sympathetic, in which there is no physical action or direct catenation of functions; but where an organ, at a distance from one affected, is excited to irregular or regular action in consequence of the condition of the latter. In the description of the different functions, numerous opportu- nities occurred for showing the influence, which organs, in the immediate vicinity of each other, may mutually exert so as to modify their functions. The action of the muscles,—particularly those that contract the larger cavities, as the abdomen and thorax,—on the parts with which they come in contact, must be entirely mechanical. In this way, the diaphragm and the abdomi- nal muscles act in vomiting and defecation. During the operation of blood-letting, the flow of blood can be augmented by moving the muscles of the hand; and it is probable that the constant mo- tion of the muscles of respiration impresses a succussion on different organs, which may aid them in accomplishing their functions, al- though the effect of this is doubtless exaggerated. Every change of position, either of the whole body or of a part, has, likewise, some effect in modifying the actions performed by it or by neigh- bouring organs, although such effect may not be easily appreciable. A similar case of mere mechanical influence, which seems to be important to the proper action of certain organs, is exhibited in the pulsation of the different arteries. It has been seen, that a suc- cussion is in this way given to the brain, which appears to be ne- cessary to it; for, if this source of stimulation is in any manner withdrawn, fainting is induced. Perhaps, however, the strongest case that can be offered of modification of function by mechanical CORRELATION OF FUNCTIONS. 429 causes, is that of the gravid uterus, which, by its pressure, gives rise to numerous symptoms in other organs, that are often the source of much annoyance during gestation. The functional correlations or synergies are of much more moment to the physiologist and pathologist Many of these have also been described in the preceding history; a brief notice of them will be all that is now requisite. For the maintenance of the healthy function we know that certain conditions are necessary, and that if these be modified, in the whole or in any part of the body, dis- ease and death may be the result, even although the derangement may, in the first instance, concern only an apparently unimportant part of the frame ; the affection by correlation spreading gradually to more and more essential organs and functions, until the disorder is ultimately too great to allow of a continuance of the vital move- ments. In this respect, man differs from an ordinary piece of hu- man mechanism,in which the various parts are so adapted to each other as to produce a certain result. If one of these parts be destroyed, the whole machine may have its motion arrested. But the effect is owing to the destruction of one part only, the others remaining sound, whilst death, or the stoppage of the living ma- chine, does not necessarily follow the destruction of any except a few essential organs, and is generally owing to the derangement of many. We shall find, indeed, that except in cases of sudden death, it is extremely difficult to say which of the three truly vital organs has first ceased to act; and that in all such cases death begins in one or other of the organs essential to vitality, and soon extends to the rest. The essentially vital organs are the respiratory, circulatory, and the organs of innervation; but the great use of respira- tion is to change the blood from venous to arterial; in other words, to induce a conversion in it by its passage through the lungs, without whioh it would be inadequate for the mainte- nance of life in any organ; and the object of the circulation is, to distribute it to the various parts of the frame as the grand vivi- fying and reparatory material. If, also, the organs of innervation be destroyed, the nervous influence is no longer conveyed to the different parts of the frame; and as the presence of this influence is everywhere indispensable, the functions may cease from this cause; so that we may regard, as essential elements to the existence of the frame and of every part of the frame, the proper supply of arterial blood and of the nervous influence. In the production and distribution, however, of these agencies, a number of func- tions is concerned, giving rise to the correlation, which is the object of our present inquiry. If, in any manner, the blood does not meet with the due aeration, as in the ordinary cases of suffo- cation, death supervenes, in the order elsewhere described; and if a slight degree of aeration is accomplished, but still not enough for the necessities of the system, instead of suffocation, the individual dies more gradually: the functions fail in the same order; black 430 CORRELATION OF FUNCTIONS. blood circulates through all the textures; hence lividity, especially of those parts where the cuticle is extremely thin, as in the lips, and wherever the mucous membranes commingle with the skin; the blood gradually becomes inadequate to keep up the action of the brain and nervous system generally, as well as to stimulate the heart, and the individual gradually expires. If, again, the blood, although properly converted in the lungs, is not duly distributed to the organs, owing to the failure of the circulatory powers,— either from direct or indirect causes,—the organs exhibit their correlation in the same manner, and syncope or fainting, or positive death, may be produced. Often, however, the stoppage of the ac- tion of the heart is but for a short time. Owing to some painful impression, sudden emotion, or other cause, the organ ceases to contract, either suddenly,—when the person falls down as if deprived of life,—or gradually, when the connexion of the different functions, and the order in which they fail, is manifest. Of this kind, of what the surgeon calls morbid sympathy or con- stitutional irritation, we have a good example in the effect of a trifling operation upon a delicate, and often upon a strong, in- dividual. Bleeding will sometimes induce fainting, both directly, by the abstraction of fluid from the vessels, so that the brain may cease to act; and indirectly, when the quantity removed can- not be presumed to have exerted any influence. Some, indeed, will faint from the slightest puncture and loss of blood, or even from the sight of that fluid. In these last cases, if the syncope come on gradually, a feeling of great anxiety and oppression, occa- sionally of vacuity, exists in the epigastric region; the perceptions become confused, the sight obscured, tinnitus aurium and dizziness supervene, the respiration is embarrassed, the face pale, the extremi- ties cold, and the different parts of the body are covered with a cold, clammy sweat, until ultimately loss of sensation and motion super- venes, and the individual is temporarily dead; from which state, however, he soon recovers in the generality of cases, provided he is kept in the recumbent posture, so that the blood may readily pass to the brain. On other occasions, the heart will not cease its pulsations, but will continue to send blood, in undue quantity, to the brain, so that all the above symptoms may ensue, except the temporary privation of vitality. In consequence of the severe pain induced by a displacement of two of the bones of the wrist, by a fall from a carriage, the author remained a considerable time de- prived of sight, and at the same time suffering from great anxiety, yet the action of the heart never ceased, so as to induce complete syncope. The third vital function,—that of innervation,—when suspended or diminished, draws on a train of pathological phenomena, in the order described under the head of death; suspending'respiration and circulation suddenly, if the cause applied be sufficient; more gradual- ly, and with the symptoms characterizing apoplexy or compres- CORRELATION OF FUNCTIONS. 431 sion of the brain, if the cause act in a minor degree. All the three vital functions are consequently correlative, and so inti- mately associated, that if a malign influence act upon one, the ef- fect is speedily extended to the other. Owing to the necessity for the blood possessing certain attri- butes, the most important of which are obtained by its circulation through the lungs, we can readily understand, that if the functions of nutrition are not properly exerted, the composition of that fluid may be imperfect, and disorder take place in various parts of the frame from this cause. Thus, if digestion or the formation of chyle be not properly executed, the blood is not duly renovated, and may be so far impoverished, that the play of the functions are interfered with. We have elsewhere shown, that if omni- vorous man be restricted to one kind of diet he will fall off, and become scorbutic, and that the affection will be removed by allow- ing him diet of another kind;—vegetables, if animal food have in- duced it, and vice versa. Enlarged mesenteric glands, conse- quent, or not, on inflammation of the mucous membrane of the in- testine, and the latter affection itself, are cases which may inter- fere with chylosis, and consequently with the constitution of the blood. In like manner, if nutrition and the various secretions are not duly performed in the tissue of the organs, and especially if the two great depurations,—the urinary and cutaneous,—be obstructed, the blood may suffer, and although the due changes from venous to arterial may be effected in the lungs, its character may not be such as to adapt it for the healthy execution of the various func- tions. The humorists assigned too much importance to the condi- tion of the humours in the production of disease; the solidists, on the other hand, have denied it almost all agency. The medium between these exclusionists is probably the nearest to na- ture. The solitary fact of black blood being unfit to maintain the vitality of any organ sufficiently exhibits its lethiferous influence. How the arterial blood exerts its agency, independently of its action as a fluid of nutrition, is beyond our knowledge. It appears to exert a necessary action of stimulation, but in what manner, or on what element, we know not: probably, however, its chief influence may be on the nervous tissue, as the privation of arterial blood occasions the immediate cessation of the action of the brain. The second of the essential elements to the continued existence of the frame and of every part of it is the nervous influence. In the higher classes of animals, this is dispensed from three great centres,—the encephalon, the spinal marrow, and the great sym- pathetic. The presidency, however, may be fairly assigned, in man and in the higher animals, to the first of these. If it fails, death soon becomes general. This, however, is liable to great va- riation in different animals, and likewise in different functions. In man, if the nervous supply be cut off from any part, the part dies. 432 CORRELATION OF FUNCTIONS. Physical integrity, continuity, and a due supply of arterial blood, are necessary to the proper exercise of the nervous power. In a former part of this work, the wonderful resistance to death, which characterizes the amphibia, and the comparative independence of each portion of the body, in some of the lower orders of animals, were pointed out. The polypus can be divided into numerous pieces, yet each may constitute of itself a distinct animal. The snail,after decapitation,reproduces the head; and a similar repara- tory power is possessed by other animals. We have elsewhere seen, that volition is seated lower in the inferior than in the supe- rior orders of animals; and that in man it is chiefly,—some say wholly,—restricted to the encephalon. It appears, likewise, that the dependence of the rest of the ner- vous system on the great nervous centres is less in young than in old animals. Edwards regarded the new-born child as resembling, in many respects, the cold-blooded animal, and Redi, Rolando, and Flourens, and Legallois found that the tenacity of life, after decapitation, was much greater the nearer to birth. The functions also differ with regard to their dependence upon the encephalon. Disease may attack the animal functions and suspend them for a considerable length of time,—as in apoplexy, —before the organic functions are interfered with. This is a topic, however, which will be discussed under the head of DEATH. We may conclude, then, that "life," to use the language of a gifted preceptor of the author,—M. Beclard,—"consists essen- tially in the reciprocal action of the circulation of the blood and innervation; death always following the cessation of such recipro- cal action." But this conclusion is applicable only to animals; al- though both circulation and innervation are admitted in the vege- table by some physiologists. Legallois, from his experiments deduced the unwarrantable inference, that " life is owing to an impression made by arterial blood on the brain and spinal marrow, or to the principle which results from this impression;"—a defini- tion which would exclude the numerous animals of the lower classes, as well as vegetables, which are deficient in both brain and spinal marrow. The conclusion of Beclard is the limit to our knowledge on this subject. Yet some have endeavoured to discover which of the two functions,—circulation or innervation,—holds the other in domination. They, who consider the nervous substance to be first formed in the foetus, ascribe the supremacy to it; whilst the be- lievers in the earlier formation of the sanguiferous system look upon it as the prime agent. We know no more than that both " Maintain With the mysterious mind and breathing mould A co-existence and community." In every important function of the body we find this correlation SYMPATHY. 433 or catenation of organs existing; all working to one end, and all requisite for its perfect accomplishment. How many organs, for example, are required to co-operate in the elevated function of sensibility! The encephalon, the seat of thought, receives by the external senses the various impressions which act upon them from without, and, by the internal sensations, such as arise in the economy and are generally the indexes of the physical necessities or wants. The intellectual and affective faculties enable us to ap- preciate the various objects that occasion our sensations, and indi- cate our social and moral wants: under their direction volition is sent out, which acts upon the various muscles, and produces such movements as may be required for carrying into effect the sugges- tions of the mind. Between all these acts there is the closest cate- nation. In like manner, we observe the correlation between the animal, and the nutritive, and reproductive functions. The internal sen- sation of hunger suggests to the mind the necessity for a supply of aliment; the external senses are called into action to discover the proper aliment; when discovered, it is laid hold of by mus- cular movements under the direction of volition, is subjected to various voluntary processes in the mouth, and then passed on, by a mixed voluntary and involuntary action, into the stomach. In like manner, the desire for sexual intercourse may be excited in the mind through the organs of vision or touch; the organs of gene- ration are aroused to action, and the union of the sexes is accom- plished by the exertion of muscles thrown into contraction by volition. The same catenation is exhibited after a fecundating copulation: menstruation, which was previously performed with regularity, is now arrested; the breasts become developed; milk is formed in them, and whilst the female suckles her child, unless the period is unusually protracted, the nonexistence of the men- strual function continues. Almost all the phenomena of disease are connected with this correlation of functions. Derangement takes place in one organ or structure of the body, and speedily all those that are correlated with it participate in the disorder. Hence, in part, arises the com- bination of disordered nervous, circulatory and secretory function, which characterizes general fever; and the various associated mor- bid actions that constitute disease in general. There is another kind of connexion which distinguishes the ani- mal body from a piece of ordinary mechanism yet more than those we have considered. In this, owing to an impression made upon one organ, distant organs become affected, without our being able to refer the transmission to mechanical agency, or to the associa- tion of functions which we have just described. This kind of association is called sympathy. A particle of snuff or other irri- tating substance, impinging on the Schneiderian membrane, pro- duces itshing there, followed by a powerful action of the whole Vol. II. 55 434 CORRELATION OF FUNCTIONS. respiratory apparatus,* established for its removal. The sneez- ing, thus induced, is not caused by the transmission of the irrita- tion through the intermediate organs to the respiratory muscles; nor can we explain it by the mechanical or functional connexions of organs. It is produced by this third mode of correlation:—in other words, it is a case of sympathy. Again, a small wound in the foot will produce locked jaw, with- out our being able to discover, or to imagine, any greater connex- ion between the foot and the jaw than there is between the foot and other organs of the body. We say that it is caused by sym- pathy existing between these organs, and, so long as we use the term to signify the unknown cause of these connexions, it is well. It must be understood, however, that we attach no definite idea to the term; that it is only employed to express our ignorance of the agent or its mode of action; precisely as we apply the epithet vital to a process which we are incapable of explaining by any physi- cal facts or arguments. Of sympathetic connexions, we have numerous examples in the body; at times, inservient to accomplishing a particular function; but generally consisting of modifications of function produced by the action of a distant organ. Of the sympathetic connexion be- tween the parts of the same organ, for the execution of a func- tion proper to the organ, we have an example in that between the iris and the retina; the former will contract or dilate accord- ing to the degree of stimulation exerted by the light on the lat- ter; and the effect is greater when the light is thrown on the re- tina than w'hen thrown on the iris itself. A similar kind of sympathy exists between the state of the mammae and that of the uterus, during pregnancy; although this has been frequently referred to ordinary functional correlation or synergy; but the connexion is sufficiently obscure to entitle it to be placed under this division. Sympathies of continuity are such as occur between various parts of membranes that are continuous. For example, the slightest taste or smell of a nauseous substance will bring on an effort to vomit,—the whole of the first passages being unfavourably disposed for its reception. In disease we have many examples of this kind of sympathy. During dentition the child is subject to various gas- tric and intestinal affections. If a source of irritation exist in any part of the intestinal or other mucous membrane, no uneasy sensa- tion may be experienced at the seat of irritation, yet it may be felt at the commencement of the membrane or where it commingles with the skin:—thus, itching at the nose may indicate irritation of the digestive mucous membrane;—itching or pain of the glans penis, stone in the bladder, &c. These facts prove that in disease a sympathetic bond unites the parts concerned, and such is probably the case in health also. We have the same thing proved in the effect produced on the action of glands by irritating the orifices of their excretory ducts. The presence of food in the SYMPATHY. 435 mouth excites the secretion of the salivary glands, and that of chyme in the duodenum augments the secretion of the liver. In the same manner a purgative, as calomel, which acts upon the up- per part of the intestinal canal, becomes a cholagogue; and duode- nitis occasions a copious biliary secretion. These cases have, how- ever, been considered by many, to belong more appropriately to functional correlation, as it is presumable that the propagation of the irritation from the orifice of the excretory duct takes place directly, and along branches of the same nerves as those that sup- ply the glandular organs. It is by this sympathy of continuity that we explain the action of certain medicines. In bronchial irritation, for example, the cough will frequently be mitigated by smearing the top of the larynx by a demulcent,—the soothing influence of which extends to the part irritated. A variety of sympathy, differing somewhat from this, is the sympathy of contiguity or contiguous sympathy, in which an organ is affected by an irritation seated in another immediately contiguous to it. The association in action, between the lining membrane of the heart and the muscular tissue of the organ, has been adduced as an instance of this kind, and chiefly from the experiments of Bi- chat and Nysten, which showed that any direct irritation of the muscular tissue of the heart has not as much influence as that of the membrane which line3 it. A similar association is presumed to exist between the mucous and muscular coats of the alimentary canal, and the same kind of evidence is adduced, to prove that thc connexion is sympathetic. Other instances of sympathy are,—the convulsive contraction of the diaphragm and abdominal muscles in vomiting consequent on the condition of the stomach, as well as the convulsive action of the respiratory muscles in sneezing, coughing, &c. The general uniformity in the motion of the two eyes has been adduced as an additional instance; but Adelon has judi- ciously remarked, that the evidence in favour of this view is in- sufficient. For clearness of vision it is necessary that the luminous rays should impinge upon corresponding points of the two retinas, and should fall as nearly as possible in the direction of the optic axes. For this purpose, the muscles direct the eyes in the proper manner; and subsequently, from habit, the balls move in harmony. We constantly hear, also, a fact adduced from pathology as an in- stance of sympathy. A molar tooth is lost on one side of the jaw; and it is found, perhaps, that the next tooth that decays is the cor- responding molar tooth of the opposite side:—or a tooth has become carious, and we find the one next to it soon afterwards in the course of decay. These have been regarded as evidences of sympathy, remote and contiguous. This is not probable. The corresponding teeth of the two sides are similarly situated as regards the supply of nerves, vessels, and every anatomical element; and experience 436 CORRELATION OF FUNCTIONS. shows us that the molar teeth—and especially the second great molares—decay sooner than the others. If one, therefore, becomes carious, we can understand why its fellow of the opposite side should be more likely to suffer. The opinion, that contiguous teeth are likely to be affected by the presence of a carious tooth, either by sympathy, or by direct contact, is almost universally be- lieved, and promulgated by the dentist. Both views are probably alike erroneous. If the inner side of the second molaris be de- cayed, we can understand why the corresponding side of the third should become carious, without having recourse either to the mysterious agency of sympathy, or the very doubtful hypo- thesis of communication by contact,—especially as the caries ge- nerally begins internally. The contiguous sides of the teeth are situated almost identically, as regards their anatomical elements; and, consequently, if a morbid cause affects the one, the other is the next likely to suffer, and is very apt to do so. Extracting the diseased tooth prevents this, because it removes a source of irrita- tion, which could not but act in a manner directly injurious on the discharge of the functions of the tooth next to it. The fact of the sympathy that exists between organs of ana- logous structure and functions is familiar to every pathologist. That of the skin and mucous membranes is the most intimate. In every exanthematous disease, the danger is more or less dependent upon the degree of affection of the mucous membranes; and the di- rect rays of the sun, beaming upon the body in warm climates, in- duce diarrhoea and dysentery. Acute rheumatism is a disease of the fibrous structures of the joints; but one of its most serious extensions, or metastases, which- soever they may be called, is to the fibrous structure of the pericar- dium. Barthez, a most respectable writer, gives a case of this kind from Theden which is inexplicable, and probably of doubt- ful authenticity. A patient, affected with paralysis of the right arm, applied a blister to it, which produced no effect, but acted on the corresponding part of the other arm. The left becoming after- wards paralyzed, a blister was put upon it, which also acted upon the other arm, not on the one to which it was applied! Owing to this consent of parts, Broussais has established the pathological law,—that when an irritation exists for a long time in an organ, the textures that are analogous to the one which is dis- eased are apt to contract the same affections. As examples of the more distant kinds of sympathies, we may cite the effect, produced upon the stomach by distant organs, and vice versa. Amongst the earliest signs of pregnancy are nausea and vomiting; loathing of food; fastidious appetite, &c. These symptoms are manifestly induced by a sympathetic connexion be- tween the uterus and stomach; inasmuch as they are not adventi- tious, but occur more or less in all cases of pregnancy. Their ab- sence, at least, is a rare exception to the rule. Hunger or dyspepsia, SYMPATHY. —IMAGINATION. 437 again, impresses a degree of languor,—mental and corporeal,— which is proverbial; whilst the reception of food and its vigorous digestion give a character of energy, and buoyancy, greatly con- trasting with opposite circumstances. In disease, too, we find sym- pathies existing between the most distant portions of the frame, and although these are not apparent to us in health, we are. per- haps justified in considering, that an occult sympathy exists be- tween them in health, which only becomes largely developed, and obvious to us, when the parts are affected with disease. It is pro- bable, too, that in the successive evolution of organs at different periods of life, new sympathies may arise which did not previous- ly exist or were not observable. The changes that supervene in the whole economy at puberty strikingly illustrate this;—changes which do not occur in those who, owing to malformation, are not possessed of the essential parts of the reproductive system, or who have had them abstracted prior to this period. The effect of the intellectual and moral faculties on the exercise of the functions of other parts is strongly evidenced, especially in disease. The influence of the mind over the body is, indeed, a subject which demands the attention of every pathologist. In health, we notice the powerful effect induced by the affective faculties upon every function. All these are caused by sympa- thetic association with the brain; the action of the organs being in a state of excitation or depression, according to the precise charac- ter of the emotion. The'intellectual manifestations probably exert their influence in a manner less evident, but not the less certain. The effects of one of them, at least, on the bodily functions are re- markable. We allude to the imagination; to which we can as- cribe most of the cures that are said to have been effected by modes of management,—often of the most disgusting character,— which have been from time to time in vogue, have fretted their hour on the stage and then sunk into that insignificance from which they ought never to have emerged. We have had occasion to allude to the excited imagination of the maniac, the hypochondriac, and the nervous, and have remarked, that hallucinations may exist in those of sound mind;—phantoms created by the imagination; pains felt in various bodily organs, &c; and we can hence understand, that, under particular circum- stances, we may have actual disease produced in this manner; and, at other times, the feeling,—which may be as distressing to the patient,—of a disease, which has no existence except in the ima- gination. It is to the effect produced by the imagination that we must ascribe the introduction into medicine of magic, sorcery, in- cantations, Perkinism, Mesmerism, Hohenlohism, and other off- springs of superstition or knavery. The enthusiasm, that has at- tended the application of these three last modes of acting upon the imagination in our own times, is most extraordinary. Perkinism, it is well known, is the product of our own soil. Its proposer, 438 CORRELATION OF FUNCTIONS. Dr. Elisha Perkins of Connecticut, is represented to have been a man of strict honour and integrity; but manifestly of an ardent imagination, and unbounded credulity. Impressed with the idea, that metallic substances might exert some agency on the muscles, and nerves of animals, and be inservient to useful purposes as ex- ternal agents, in the treatment of disease, he professed to institute various experiments, until he ultimately fancied he had discovered a composition, which would serve his purpose, and of which he formed his metallic tractors. These consisted of two instruments, one having the appearance of steel, the other of brass. They were about three inches long, and pointed at one extremity; and the mode of their application was to draw the points over the affected parts in a downward direction for about twenty minutes each time. The effects seemed to be miraculous. The whole class of diseases on which the imagination is known to exert its efficacy; rheumatism; local pains of various kinds, and in various parts; pa- roxysms of intermittents, &c. &c. yielded as if by magic. The ope- ration was termed Perkinism, by the Faculty of Copenhagen, in honour of the discoverer; and institutions were formed in great Britain and elsewhere, which were, for a time, regarded as sources for the dispensation of health to multitudes of wretched sufferers. Yet, in a very brief space of time, the enthusiasm and the institu- tions died away; and no one, at the present day, believes, that the effect was any thing more than an additional case showing the suc- cess, that must ever follow, for a time, the efforts of quackery; and exhibiting the total failure of the same agents, when deprived of the mystery that had previously enthralled them. Whilst the de- lusion, regarding Perkinism or tradoration, was at its height, Dr. Haygarth determined to ascertain how far the effects could be as- cribed to the power of the imagination. He, accordingly, formed pieces of wood into the shape of tractors, and with much assumed pomp and ceremony applied them to a number of sick persons, who had been previously prepared to expect something extraordi- nary. He not only employed them in nervous diseases, but in all kinds of cases; and the effects were found to be most astonishing. Obstinate pains of the limbs were suddenly cured. Joints that had been long immovable, were restored to motion, and " in short," says Dr. Bostock, "except the renewal of lost parts, or the change of mechanical structure, nothing seemed beyond their power to accomplish." The history of these operations leads us to be still more impress- ed with the extensive influence, that may be exerted by the mind over the body: they teach the practitioner the importance of having its co-operation, whenever it can be procured; and the dis- advantages which he may expect to ensue, where the imagination is either arrayed against himself personally, or the plan of treatment which he is adopting. The physician, who has the confidence of his patient, will be successful—if he adopt precisely the same plan SYMPATHY. 439 of treatment that would be pursued by one who has it not—in cases where the latter would totally fail. Again, pathology is invoked as affording us perhaps the best evidences of the existence of extensive sympathetic relations be- tween various parts of the frame, which are supposed to be con- stantly going on unseen during health, but become developed, and more obvious, in disease. The case, we have previously given, of the general effects produced upon the system by local irritation of a part, shows the extent of such association. An insignificant portion of the body may become inflamed,and,if the inflammation continues, the stomach is disordered,—as indicated by loss of appetite, nausea and vomiting; the respiration is hurried, as well as the circulation;— the senses are blunted; the intellectual and moral faculties obscured; and languor and lassitude indicate the nervous irritation and con- straint. The moral consideration of sympathy does not concern us. It is a subject,—and one of interest to the moral philosopher,—to ac- count not only for these secret causes which attract individuals to- wards each other, but which repel them, and occasion antipathies. To a certain extent, however, it trends into the province of the physiologist. The tender, susceptible individual, from observing another suffering under pain, feels as if labouring under the same inconvenience, and by a very rapid, yet complex, intellectual process, constituted of numerous associations, may be so powerful- ly impressed as to sink under their influence;—thus, the sight of blood will so powerfully impress the mind, in this sympathetic manner, that the individual may faint, and the vital functions be for a time suspended. The sight and suffering of a woman in labour will cause abortion in another; and hence the propriety of excluding those, who are pregnant, from the chamber of the par- turient female. Hysteric and convulsive paroxysms are induced in a similar way; of which the convulsionnaires of all times must be regarded as affording singular and instructive examples. Lastly; the mysterious consent, which we observe between various parts of the body, has given rise to some of the most strange and absurd superstitions that can be imagined. It was believed, for instance, almost universally in the 15th cen- tury, that an intimate sympathy exists, not only between parts of a body forming portions of one whole, but also between any sub- stance that had previously formed part of a body and the body itself: that if, for example, a piece of flesh was sliced from the arm of one person and made to unite to that of another, the graft- ed portion would accurately sympathize with the body of which it had previously formed part, and undergo decay and death along with it; and it was even proposed to turn this sympathy to account. It was recommended, for instance, that the alphabet should be traced on the ingrafted portion; and it was affirmed, that when any of the letters, so traced, were touched, the party from whom the 440 CORRELATION OF FUNCTIONS. piece of flesh had been taken would feel similar impressions; so that, in this manner, a correspondence might be maintained. Some went even farther than this, asserting, that such a miracu- lous sympathy exists between the human body and all that has previously formed part of it, that if we were to run a hot iron into the excrement of any person, he would feel a sensation of burning in the part, whence it had proceeded. It was also a notion that grafts of flesh, united to another body, die when the person dies from whom they have been taken. In a recent work on animal magnetism, the case of a man at Brussels is given, who had an artificial nose, formed after the old Taliaco- tian method, which served every useful purpose, until the per- son, from whom the graft had been taken, died, when it suddenly became cold and livid and finally fell off. Tagliacozzi himself lived in an era of superstition, when this belief in the synchronous death of the parent and graft was universally credited; and the folly has not escaped the notice of Butler:— " So learned Taxiacotius from The brawny part of porter's bum, Cut supplemental noses which Would last as long as parent breech; But when the date of nock was out, Oft dropped the sympathetic snout." Little less singular was the superstition,—that the wounds of a murdered person will bleed afresh, if the body be touched, ever so lightly in any part by the murderer. This idea gave rise to the trial by bier-right, which has been worked up by Sir Walter Scott with so much dramatic skill, in one of his more recent no- vels—St. Valentine's day, or the Fair Maid of Perth. The an- nals of judicial inquiry furnish us with many instances of this gross superstition, which still exists amongst the lower orders in some parts of Great Britain, and probably also amongst the credulous and uninformed of this country. In the year 1688, a gentleman, of the name of Stansfield, was tried at Edinburgh for the murder of his own father, and found guilty. Having strangled him, he caused the body to be thrown into water, to have it supposed that the death had been by suicide. The appearances about the corpse, however, were such, that both the faculty of physic and that of surgery gave it as their opinion that the deceased had been strangled and not drowned. The indictment in the case, amongst other things, remarks:—"That upon the----day of November last, the said Sir James Stans- field, coming from Edinburgh to his house at New Milns, and going into his chamber to rest, about ten o'clock at night, and be- ing alone in the room, under the credit, trust, and assurance of the said Philip his son, and his own servants within his family; the said Philip did consult with one George Tomson and divers sympathy. 441 other persons how to murder him; and that, accordingly, they did murder and strangle him in his bed-chamber; and, in the dead of night, carried him from the said room, and threw him into a pond near the house. That the next morning, when the body was found, the said Philip caused it to be buried in haste, and refused to stay till his friends and physicians viewed it. That the body, being taken up again by authority, and inspected by surgeons, it appeared to have been strangled and not drowned; and that his nearest relations being required to lift the corpse into the coffin after it had been inspected; upon the said Philip Stansfield touching of it (' according to God's usual method of discovering murder,' says the framer of the indictment) it bled afresh upon the said Philip, and that thereupon he let the body fall, and fled from it in the greatest consternation; crying,—Lord, have mercy upon me! And that the said Philip being found by an assize to be actor, art and part of the aforesaid crimes, one or other of them, he ought to be punished, &c. &c." On this portion of the indict- ment, the King's advocate remarked:—" That as to the body bleed- ing, although several persons touched it, none of their hands were besmeared with blood but the prisoner's; and that the body hav- ing lain two days in the grave, in a cold season, the blood must naturally be congealed. That the lifting about the body, and even the incision that was made, causing no such effusion before, but only of some water or gore, and should upon the prisoner's first touching it begin to bleed afresh ! he must ascribe it to the won- derful providence of God, who, in this manner, discovers murder, especially since no natural reason could be assigned for it; and that the horrible impressions it made on the prisoner, notwithstanding his resolution to the contrary, might be urged as another argument of his guilt." A case of a similar character is given in the Annual Register for 1767, as having occurred in our own country. It is contained in the attestation of John Demarest, coroner of Bergen County, New Jersey. The superstition, too, is noticed by many of the older poets. Thus, Shakespeare, in his Richard III:— " O! gentlemen, see, see! dead Henry's wounds Open their congeal'd mouths, and bleed afresh! Blush, blush, thou lump of foul deformity; For 'tis thy presence that exhales this blood." And Webster, in his tragedy of Appius and Virginia, publish- ed about the middle of the 17th century:— "See Her wounds still bleeding at the horrid presence Of yon stern murderer, till she find revenge." It would be endless to enumerate the various superstitions that prevailed, a few centuries ago, on topics more or less remotely Vol. II. 56 442 CORRELATION OF FUNCTIONS. connected with this subject. We pass on, therefore, to the interest- ing, but abstruse, inquiry into the agents by which sympathy is accomplished. The opinions of physiologists have, from time to time, rested chiefly;—on the membranes, the cellular tissue, the blood-vessels, and the nerves; whilst there have been some, who, in the difficulty of the subject, have supposed sympathy to be devoid of all organic connexion; and others, again, have presumed, that all the parts, we have mentioned, are concerned. The rapidity, however, with which sympathies are evidenced, has led to the abandonment of all those opinions; and the generality of physiologists of the pre- sent day look to the nervous system as the great source and me- dium of communication of the different irradiations, by which dis- tant organs are supposed to react, in this manner, upon each other. The rapidity, indeed, with which the various actions of the ner- vous system are executed,—the apparent synchronism between the reception of an impression on an organ of sense, and its per- ception by the brain, as well as between the determination of the will and its effect upon the muscle,—naturally attracted the atten- tion of physiologists to this system as the instrument of sym- pathy. The modes, in which it is supposed to be accomplished, are:— either by the parts, that sympathize, receiving ramifications from the same nervous trunks, or from such as are united by nervous anastomosis; or by the nervous irradiation emanating from one or- gan, proceeding to the brain, and being thence reflected to every dependency of the system, but so that certain organs are more mo- dified by such reflection than others; hence the distinction into what have been termed direct sympathies and cerebral sympa- thies. Of the direct sympathies we have already given some examples, —as that between the mucous and muscular coats of the intes- tines; and if our acquaintance with the precise distribution and connexion of the various parts of the nervous system were more intimate, we might perhaps explain many of the cases that are yet quite obscure to us. The researches of Sir Charles Bell, re- garding the nerves concerned in respiration, have thrown great light on those associations of organs which we notice in the active exercise of the respiratory function. It has been elsewhere shown, that although the whole of the nerves, composing his respiratory system, may not be apparently in action during ordinary respira- tion, yet that when the function has been greatly excited, the as- sociation becomes obvious; parts, that are remote in situation, are combined in function, and all the nerves that animate them are found to arise from the same column of the spine. The opinion of Boerhaave, Meckel, and some others is, that all sympathies are accomplished in this direct manner. On the other hand, Haller, Whytt, Georget, Broussais, Adelon, and others, make the SYMPATHY. 443 majority of sympathies to be produced through the medium of the brain. Bostock indeed affirms, that the facts, adduced by Whytt, are of such a nature as "to prove, that the co-operation of the brain is essential in those actions which we refer to the ope- ration of sympathy." In many cases this is doubtless the fact;—as in sneezing and coughing; but there are others in which such co- operation seems improbable. Something like sympathy exists in the vegetable; in which if we admit, with some naturalists, a ru- dimental nervous system, we have no reason for presuming that there is any thing like a centre for the reception or transmission of impressions. We find that the properties of the vital principle are exemplified by the formation of a body of a certain magnitude, form, structure, composition and duration, and that this applies to all organized bo- dies, vegetable as well as animal. Where such appearance of de- sign consequently exists, we ought to expect that in the vegetable, also, a harmony or consent must reign amongst the various func- tions, tending to the accomplishment of that uniformity, which enables us always to recognise the particular varieties of the vege- table kingdom, and which has kept them as distinct, probably, in their characters, as when first created by Almighty power. The irritation of a single leaflet of the Mimosa pudica or sensitive plant causes the whole leaf, as well as the footstalk, to contract. Dr. John Sims irritated a leaflet of this plant, taking the greatest pains to avoid moving any other part of the leaf; yet the whole contracted and the footstalk dropped. In order, however, to be sure, that mechanical motion, communicated by the irritation, had no share in the contraction, he directed a sunbeam, concentrated by a lens, on one of the leaflets, when the^leaf, again, contracted and the footstalk dropped. Of this kind of vegetable irritability we have many examples, some of which are alluded to under another head. If, in the winter, the branch of a vine be introduced into a hothouse, it will produce a luxuriant crop of leaves, blossoms and fruit, the materials of which can only be derived from the ex- citement of the roots produced by sympathy with the parts ex- posed to the warm air: this will take place even during a frost, in which situation the roots would have been in a torpid state, but for the sympathetic influence developed in the parts above ground by warmth. From these, and other facts of an analogous character, Sir Gilbert Blane concludes, that the functions of living nature, in all its departments, are kept up by a mutual concert and corres- pondent accordance of every part with every other part, and that it would be in vain to waste time in endeavouring to account for them by groping among dark analogies and conjectures; and that it is better to assume them as facts, on which are founded the ulti- mate and inscrutable principles of the animal economy. We have, certainly, much to learn regarding the agents of sympathies, and the modes in which they are operated; but still we know enough 444 correlation of functions. to infer, that in many cases, in animals, the nerves appear to be the conductors; that the brain is, in others, the centre to which the organ in action transmits its irradiations, and by which they are re- flected to the sympathizing organ; and that,in others again, the effect is caused in the absence of nervous centre, and perhaps even of nerves, in a manner which, in the present state of our knowledge, is inexplicable, and is, therefore, supposed to be essentially or- ganic and vital,—epithets, however, as we have more than once expressed, that merely convey a confession of our total ignorance of the processes to which they are appropriated. individual differences. 445 OF INDIVIDUAL DIFFERENCES AMONGST MAN- KIND. The differences, which we observe amongst the individuals of the great human family, are as numerous as the individuals them- selves; but this dissimilarity is not confined to man or to the ani- mal kingdom; the vegetable exhibits the same; for whilst we can readily refer any plant to the species and variety to which it may have been assigned by the botanist, accurate inspection shows us, that, in the precise arrangement of the stalk, branches, leaves, or flowers, no two are exactly alike. We shall not, however, dwell on these trifling points of difference, but restrict ourselves to the broad lines of distinction, that can be easily observed, and an at- tention to which is of some moment to the physician. Such are the temperaments, constitutions, idiosyncrasies, acquired differences, and the varieties of the human species or the different races of mankind. Of these, the last belongs especially to the natural his- torian, and consequently will be but briefly noticed. Sect. I. Of the Temperaments. The temperaments are defined to be,—those individual differences, which consist in such disproportion of parts, as regards volume and activity, as to sensibly modify the whole organism, but without in- terfering with the health. The temperament is, consequently, a physiological condition, in which the action of the different func- tions is so tempered as to communicate certain characteristics, which may be referable to one of a few divisions. These divisions are by no means the same in all physiological treatises. The ancients ge- nerally admitted four,—denominated from the respective fluids or humours, the superabundance of which in the economy was sup- posed to produce them;—the sanguineous, caused by a surplus of blood; the bilious or choleric, produced by a surplus of yellow bile; the phlegmatic, caused by a surplus of phlegm, lymph, or fine wa- tery fluid, derived from the brain; and the atrabiliary or melan- cholic, produced by a surplus of black bile,—the supposed secretion of the atrabiliary capsules and spleen. This division was continued for ages without modification, and still prevails, with one or more additional genera. The epithets have been retained in popular language without our being aware of their parent- age. For example, we speak of a sanguine, choleric, phlegmatic, or melancholic individual or turn of mind, with precisely the acceptation given to them by the Hippocratic school,—the possessors of these tern- 446 individual differences. peraments being presumed to be, respectively, full of high hope and buoyancy; naturally irascible, dull and sluggish; or gloomy and low- spirited. Metzger admits only two,—theirritable,(reizbare,) and the dull or phlegmatic, (trage.) Wrisberg eight,—the sanguine, sanguineo-choleric, choleric, hypochondriac, melancholic, bceo- tian, meek, (sanftmuthige,) and the dull or phlegmatic. Ru- dolphi also eight,—the strong or normal, the rude, athletic or bceotian, the lively, the restless, the meek, the phlegmatic or dull, the timorous, and the melancholic;—whilst Broussais enumerates the gastric, bilious, sanguine, lymphatico-sanguineous, anemic, nervous, bilioso-sanguine, nervoso-sanguinc, and melancholic. It is obvious, that if we were to apply an epithet to the possible modifications, [caused by every apparatus of organs, the number might be extended much beyond any of these. Perhaps the divi- sion most generally adopted is that embraced by Richerand, who has embodied considerable animation, with much that is fanciful, in his description. In this division, the ancient terms have been re- tained, whilst the erroneous physiological basis, on which they rested, has been discarded. A short account of these temperaments is necessary, rather for the purpose of exhibiting what has been and is still thought by many physiologists, than for attesting the reality of many of the notions that are mixed up with the subject. With this view, the temperaments may be divided into the san- guine, the bilious or choleric, the melancholic, the phlegmatic, and the nervous. 1. The sanguine temperament* This is supposed to be depen- dent upon a predominance of the circulatory system; and hence is considered to be characterized by strong, frequent, and regular pulse; ruddy complexion; animated countenance; good shape, al- though distinctly marked; firm flesh; light hair; fair skin; blue eyes; great nervous susceptibility, attended with rapid successibi- UtL as the French term it; that is,—facility of being impressed by external objects and of passing rapidly from one idea to another; quick conception; ready memory; lively imagination; addicted to the pleasures of the table; and amorous. The diseases of the tem- perament are generally violent; and are chiefly seated in the cir- culatory system,—as fever, inflammations and hemorrhages. The physical traits of this temperament, according to Richerand, are to be found in the statues of Antinous and the Apollo Bel- videre: the moral physiognomy is depicted in the lives of Mark Antony and Alcibiades. In Bacchus, both the forms and the character are found; and no one, in modern times, in M. Riche- rand's opinion, can be found to exhibit a more perfect model of it than the celebrated Duke De Richelieu;—amiable, fortunate and valorous, but light and inconstant to the termination of his brilliant career. If individuals of this temperament apply themselves to labours of any kind that cause the muscles to be greatly exerted, these temperament. 447 organs become largely developed, and a subdivison of the sanguine temperament is formed, which has been called the muscular or athletic. This is characterized by all the outward signs of strength; the head is small; the neck strong; the shoulders broad; the chest large; the hips solid; the muscles prominent, and the interstices well marked. The joints, and parts not covered with muscles, seem small; and the tendons are easily distinguished through the skin, by their prominence. The susceptibility to external impressions is not great; the individual is not easily roused; but when he is, he is almost indomitable. A combination of the physical powers, im- plied by this temperament, with strong intellect, is rarely met with. The Farnesian Hercules is conceived to offer one of the best specimens of the physical attributes of the athletic temperament. 2. The bilious or choleric temperament. This is presumed to be produced by a predominance of the liver and biliary organs in gene- ral. The pulse is strong, hard, and frequent; the subcutaneous veins are prominent; the skin is of a brown colour,inclining to yellow; hair dark; body moderately fleshy; muscles firm and well-marked; the passions violent, and easily excited; the temper abrupt and im- petuous; great firmness and inflexibility of character; boldness in the conception of projects, and untiring perseverance in their ful- filment. It is amongst the possessors of this temperament that the greatest virtues and the greatest crimes are met with. Richerand enumerates Alexander, Julius Cesar, Brutus, Mahomet, CharlesXII, Peter the Great,CROMWELL, SextusV, and the Car- dinal Richelieu. To these Good has added, Attila, Charle- magne, Tamerlane, Richard III, Nadir Shah, and Napoleon. The moral faculties are early developed; so that vast enterprises may be conceived and executed at an age when the mind is ordi- narily far from being matured. The diseases are generally com- bined with more or less derangement of the hepatic system. The whole of the characters, however, indicate that an excited state of the sanguiferous system accompanies that of the biliary organs; so that the epithet—cholerico-sanguine—might, with more pro- priety, be applied to it. Where this vascular predominance does not exist, whilst derangement is present in some of the abdomi- nal organs, or in the nervous system, we have the next genus pro- duced. 3. Melancholic or atrabilious temperament. Here the vital functions are feebly or irregularly performed; the skin assumes a deeper hue; the countenance is sallow and sad; the bowels are tor- pid, and all the excretions tardy; the pulse is hard and habitually contracted; the imagination is gloomy, and the temper suspicious. The characters of Tiberius and of Louis XI, are considered to be instances of the predominance of this temperament; and, in addition to these, Richerand has enumerated Tasso, Pascal, Gilbert, Zimmermann, and Jean Jacques Rousseau. 44S individual differences. 4. The phlegmatic, lymphatic or pituitous temperament. In this case, the proportion of the fluids is conceived to be too great for that of the solids; the secretory system appearing to be active, whilst the absorbent system does not act so energetically as to pre- vent the cellular texture from being filled with the humours. The characteristics of this temperament are:—soft flesh; pale skin; fair hair; weak, slow and soft pulse; figure rounded, but inexpressive; the vital actions more or less languid; the memory by no means tenacious, and the attention vacillating; with aversion to both men- tal and corporeal exertion. Pomponius Atticus—the friend of Cicero—is offered as an ex- ample of this temperament, in ancient times; Montaigne in more recent history. The latter, however, possessed much of the ner- vous susceptibility that characterizes the more lively temperaments. Dr. Good suggests the Emperor Theodosius as an example in ear- lier times; and Charles IV, of Spain,—who resigned himself almost wholly into the hands of Godoy;—Augustus, King of Saxony, who ■ equally resigned himself into the hands of Napoleon,—and Fer- dinand of Sicily, who surrendered for a time the government of his people to the British,—as instances in our own day. It would not be difficult to find, amongst the crowned heads of Europe, others that are equally entitled to be placed amongst these wor- thies. 5. The nervous temperament. Here the nervous system is greatly predominant; the susceptibility to excitement from external impres- sions being unusually developed. Like the melancholic tempera- ment, this is, however, seldom natural or primitive. It is morbid or secondary, being induced by sedentary life, sexual indulgence, or morbid excitement of the imagination, from any cause. It is characterized by small, soft, and, as it were, wasted muscles; and generally, although not always, by a slender form; great vividness of sensation; and promptitude and fickleness of resolution and judgment. This temperament is frequently combined with some of the others. The diseases, that are chiefly incident to it, are of the hysterical and convulsive kind; or those to which the epithet nervous is usually appropriated. Voltaire, and Frederick the Great are given by Richerand as examples of this tempera- ment. Such are the temperaments, described by most writers. The slightest attention to their reputed characteristics will show the im- perfection of their definition and demarcation; so imperfect, indeed, that it is extremely rare for us to meet with an individual, whom we could unhesitatingly refer to any one of them. They are also sus- ceptible of important modifications by climate, education, &c, and may be so combined as to constitute innumerable shades. The man of the strongest sanguine characteristics may, by misfortune, assume all those that are looked upon as the indexes of the melancholic or atrabilious; and the activity and impetuosity of the bilious tempera- constitution. —idiosyncrasy. 449 ment, may, by slothful indulgence, be converted into the lym- phatic or phlegmatic. It is doubtful, and more than doubtful, also, whether any of the mental characteristics, assigned to the tempe- raments, are dependent upon them. The brain, we have elsewhere seen, is the organ of the mental and moral manifestations; and although we may look upon the temperaments as capable of modi- fying its activity, they cannot probably affect the degree of perfec- tion of the intellect;—^its strength being altogether dependent upon cerebral conformation. It is even doubtful whether the tempera- ments can interfere with the activity of the cerebral functions. In disease of the hepatic, gastric or other viscera we certainly see a degree of mental depression and diminished power of the whole nervous system; but this i$ the effect of a morbid condition, and continues only so long as such morbid condition endures. Nor is it probable, that any predominance of the nutritive functions could induce a permanent influence on the cerebral manifestations. What- ever might be the effect for a while, the nervous system would ultimately resume the ordinary action which befitted its primitive organization. Similar arguments to those have induced M. Georget,—a young physician of great promise and experience in mental affections, now no more,—to consider the whole doctrine of the temperaments as a superstition connected with the humoral pa- thology, and to believe, that the brain alone, amongst the organs, has the power, by reason of its predominance or inferiority, to mo- dify the whole economy. That a difference of organization exists in different individuals is obvious; it is upon this that differences in constitution are de- pendent; but that there is an arrangement of the nutritive organs or apparatuses, which impresses upon individuals all those mental and other modifications known under the name of temperaments, is, we think, sufficiently doubtful. The constitution of an individual is the mode of organization proper to him. A man, for example, is said to have a robust, or a delicate, or a good, or a bad constitution, when he is apparently strong or feeble, usually in good health, or liable to frequent at- tacks of disease. The varieties in constitution are, therefore, as nu- merous as the individuals themselves. A strong constitution is con- sidered to be dependent upon the due development of the principal organs of the body, on a happy proportion between those organs, and on a fit state of energy of the nervous system; whilst the feeble or weak constitution results from a want of these postulates. Our knowledge, however, of these topics, is extremely limited, and con- cerns the pathologist more than the physiologist. Sect. II.—Of Idiosyncrasy. The word idiosyncrasy is used, by many physiologists, synony- Vol. II. 57 450 INDIVIDUAL DIFFERENCES. mously with constitution; but it is generally appropriated to the peculiar disposition, which causes an individual to be affected by extraneous bodies, in a way in which mankind in general are not acted upon by the same agents. In all cases, perhaps, these pecu- liarities are dependent upon inappreciable structure, either of the organ concerned, or in the nervous branches distributed to it; at times, derived from progenitors ; at others acquired,—often by as- sociation,—in the course of existence. Hence arise many of the antipathies to particular animate and inanimate objects, which we occasionally meet with, and of which Broussais relates a singular instance in a Prussian captain, whom he saw at Paris in 1815. He could not bear the sight of a cat, a thimble, or an old woman, with- out becoming convulsed, and making frightful grimaces. The as- sociations must have been singularly complicated to occasion an an- tipathy to objects differing so signally from each other. Wagner, of Vienna, has collected a multitude of cases of idiosyncrasy; and the observation of every individual, whether of the medical profes- sion or not, must have made him acquainted with those peculiari- ties, that render a particular article of diet, which is innoxious, and even agreeable and wholesome to the generality of individuals, productive, in some, of the most unpleasant effects. Haller knew a person who was always violently purged by the syrup of roses. A friend of the author is purged by opium, which has an opposite effect on the generality of individuals. Dr. Paris says he knew two cases, in which the odour of ipecacuanha always produced most distressing dyspnoea. The author knew a young apothecary, who could never powder this drug without the super- vention of the most violent catarrh. A friend of Tissot could not take sugar without its exciting violent vomiting. Urticaria or net- tle-rash is very frequently occasioned, in particular constitutions, by taking shell-fish. The same effect is induced on two young fe- male friends of the author by eating strawberries; and similar cases are given by Roose. M. Chevalier relates the case of a lady, who could not take powdered rhubarb without an erysipelatous ef- florescence showing itself, almost immediately, on the skin; yet she could take it in the form of infusion with perfect impunity. The above idiosyncrasies apply only to the digestive function. We find equal anomalies in that of the circulation. In some, the pulse is remarkably quick, upwards of one hundred in the mi- nute; in others, it is under thirty. That of Napoleon is said to have beaten only forty-four times in a minute. It may also be unequal, and intermittent, and yet the individual be in a state of health. The senses offer us some of the most striking cases of this kind of peculiarity. Many strong individuals cannot bear the smell of the apple, cherry, strawberry, or that of musk, peppermint, &c. Pope Pius VII. had such an antipathy to musk, that on one occa- sion of presentation, an individual of the company having been natural and acquired differences. 451 scented with it, his holiness was obliged to dismiss the party al- most immediately. The idiosyncrasies of taste are also numerous: some of these cases of singular and depraved sense we have described under the sense of taste. De jean gives the case of an individual of distin- guished rank who was fond of eating excrement. Certain animals, again, as the turkey, have an antipathy to the co- lour of red ; and Von Buechner and Tissot cite the case of a boy who was subject to epileptic fits whenever he saw any thing of a red colour. Occasionally, we meet with similar idiosyncrasies of audition. Sauvages relates the case of a young man, labouring under intense head-ache and fever, which could not be assuaged by any other means than the sound of the drum. Rousseau asserts, that a young Gascon was affected with incontinence of urine whenever he heard the sound of the bagpipe; and the noise of water issuing from a pipe threw Bayle into convulsions. The author has a singular pe- culiarity of this kind, derived from some accidental association in early life. If a piece of thin biscuit be broken in his presence,— nay, the idea alone is sufficient,—the muscles that raise the left angle of the mouth, are contracted, and this irresistibly. The sense of tact is not free from idiosyncrasies. Wagner cites the case of a person, who felt a sensation of cold along the back, whenever he touched the down of a peach with the point of his finger; or when the down came in contact with any part of his skin. He was remarkably fond of the fruit, yet was unable to indulge his appetite unless a second person previously removed the skin. Pro- chaska relates the case of a person, who was affected with nausea whenever he touched this fruit. It is, of course, all important that the practitioner should be ac- quainted with these idiosyncrasies, and so far the notion of " know- ing the constitution,"—which is apt to be used to the prejudice of the young practitioner or of any except the accustomed medical at- tendant,—has some reason in it. It is the duty, however, of the patient to put the practitioner in possession of Ihe fact of. such pe- culiarities, so that he may be enabled to guard against them, and not take that for morbid which is the effect of simple idiosyncrasy. Sect. III. Of Natural and Acquired Differences. The temperaments, constitutions, and idiosyncrasies may, as we have seen, either be dependent upon original conformation, or they may be produced by external influences; hence they have been divided into the natural and acquired. Under the former head are included all those individual differences, derived from pro- genitors, which impress upon the individual, more or less of re- semblance to one or both parents. It has been properly observed by a recent writer, that the individuality of any human being that ever existed, was absolutely dependent on the union of one particu- 152 individual differences. lar man with one particular woman; and if either the husband or the wife had been different, a different being would have been ushered into existence. For the production of Shakespeare, or Milton, or Newton, it was necessary that the father should marry the identical woman he did marry. If he had selected any other wife, there would have been no Shakespeare, no Milton, no Newton. Sons might have been born of other women, but they would not have been the same, either in mental or physi- cal qualities. All this, however, enters into the question of the effects of the influence of both parents on the foetus in utero, which we have considered elsewhere. It was there shown, that the influence exerted by the father is limited to the material which he furnishes at a fecundating copulation, and that, it is probable, no material modification is wrought by the mother after the union of the two substances,—maternal and paternal,—which compose the new being. Amongst the natural differences, those that relate to sex are the most striking. In a previous part of this volume we have described the peculiarities of the sexual function in both male and female, but the other important differences have not been detailed. All the descriptions, when not otherwise specified, were presumed to apply to the adult male. At present, it will be only necessary to advert to the peculiarities of the female. The stature of the female is somewhat less than that of the male, the difference being estimated at about a twelfth. The chief parts of the body have not the same mutual proportions. The head is smaller and rounder; the face shorter; the trunk longer, especially the lumbar portion, and the chest more convex. The lower extre- mities, especially the thighs, are shorter, so that the half of the body does not fall about the pubes as in man, but higher. The neck is longer; the abdomen is broader, larger, and more prominent; the pelvis has a greater capacity to adapt it for gestation and parturi- tion. The long diameter of the brim is from side to side, whilst, in the male, it is from before to behind; the arch of the pubis is larger, and the tuberosities of the ischia more widely separated, so that the outlet of the pelvis is larger than in the male; the hips are broader, and, consequently, the spaces between the heads of the thigh-bone are greater; the knees are more turned in, and larger than in the male; the legs are shorter, and the feet smaller. The shoulders are round, but the width across them, compared with that of the hips, is not so great as in man; the arms are shorter, but fatter, and more rounded; the same is the case with the fore- arm ; the hand is smaller, and softer, and the fingers are more de- licate. The whole frame of the female is more slender; the bones are smaller, their tissue is less compact, and the prominences and cor- responding depressions are less marked; the subcutaneous cellular tissue is more abundant, and filled with a whiter and firmer fat; a similar adipous tissue fills up the intervals between the muscles, so CHARACTERISTICS of the female. 453 that the whole surface is rounder, and more equable, than that of the male; the skin is more delicate, whiter, better supplied with capillary vessels, and less covered with hair; the hair of the head, on the other hand, is longer, finer, and more flexible; the nails are softer and of a redder hue; the muscles of the countenance are less distinctly marked, so that the expression of the eye, and the emo- tions which occasion elevation or depression of the angles of the mouth,—laughing and weeping, for example,—are more strongly marked. On the whole, the general texture of the organs is looser and softer. The above observations, however, apply to what may be termed the standard female,—one whose natural formation has not been interfered with by employments which are usually assigned to the other sex. It can be>readily understood, that if the female has been accustomed to the laborious exercise of her muscles, they may be- come more and more prominent, the interstices between them more and more marked, the projections and depressions of the bones on which they move more distinct; the whole of the delicacy of structure may be lost; and the skeleton of the female, thus circum- stanced, may be scarcely distinguishable from that of the inactive male, except in the proportions of the pelvis, in which the sexual differences are chiefly and characteristically situated. Many of the functions of the female are no less distinctive than the structure. The senses, as a general principle, are more acute, whether from original delicacy of organization, or from habit, is not certain;—probably both agencies are concerned. The intellectual and moral faculties are also widely different, and this, doubtless, from original conformation; although education may satisfactorily account for many of the differences observable between the sexes. Gall is one of the few anatomists who have attended to the compa- rative state of the cerebral system in the sexes; and the results of his investigations lead him to affirm, that there is a striking differ- ence in the development of different parts of the encephalon in the two sexes, which he thinks may account for the difference observa- ble in their mental and moral manifestations. In the male, the an- terior and superior part of the encephalon is more developed; in the female, the posterior and inferior; the former of these he con- ceives to he the seat of the intellectual faculties; the latter of those feelings of love and affection, which seem to preponderate in the character of the female. We have elsewhere said, however, that the views of Gall, on this subject, are not yet received as confirm- ed truths, and that we must wait until farther experience and mul- titudinous observations shall have exhibited their accuracy, or want of foundation. Independently, however, of all considerations de- duced from organization, observation shows, that the female exhi- bits intellectual and moral differences which are by no means equivo- cal. The softer feelings predominate in her, whilst the intellec- tual faculties have the preponderance in man. The evidences and 454 INDIVIDUAL DIFFERENCES. character of the various shades of feeling and susceptibility, and the influence of education and circumstances on these develop- ments, are interesting topics for the consideration of the moral phi- losopher, but admit of little elucidation from the labours of the physiologist. The only inference, to which he can arrive, is, that .the causes of the diversity are laid in organization, and become un- folded and distinctive by education., The precise organization he is unable to depict, and the influence of circumstances on the mind it is scarcely his province to consider. The function of muscular motion is, owing to organization, more feebly executed. We have already remarked, that the bones are comparatively small, and the muscles more delicately formed. The energy of the nervous system is also less; so that all the elements for strong muscular contraction are by no means in the most favour- able condition; and, accordingly, the power the female is capable of developing by muscular contraction is much less than in the male. Her locomotion is somewhat peculiar,—the wide separation of the hip-joints, owing to the greater width of the pelvis, giving her a characteristic gait. The vocal organs exhibit differences which account for the difference in the voice. The chest and the lungs are of smaller dimensions; the trachea is of less diameter; the larynx smaller; the glottis shorter and narrower; and the cavities, communicating with the nose, are of smaller size. This arrange- ment causes the female voice to be weaker, softer, and more acute. The muscles of the glottis, and the ligaments of the glottis them- selves, are apparently more supple, so as to admit of the production of a greater number of tones, and to favour singing. The phenomena of expression, as we have often remarked, keep pace with the con- dition of the intellectual and moral faculties, and with the suscepti- bility of the nervous system. As this last is generally great in the female, the language of the passions, especially of the softer kind, are more marked in her. The functions of nutrition present, also, some peculiarities. With regard to digestion, less food is generally required; the stomach is less ample; the liver smaller, and frequently,—at least more fre- quently than in the male,—the dentes sapientiae do not appear. The desire for food at the stated periods is not so powerful; and it is generally for light and agreeable articles of diet rather than for the very nutritious; but the appetite returns more frequently, and is more fastidious, owing to the greater sensibility of the digestive apparatus. This, however, is greatly an affair of habit, and we have more instances of prolonged abstinence in the female than in the male. The circulation is generally more rapid, the pulse being less full, but quicker. Of the seeretions, that of the fat alone requires mention, which is usually more abundant and the product firmer. The cutaneous transpiration is less active, and the humour has a more acidulous odour. The urine is said, by some writers, to be less abundant, and less charged with salts; whence, it is asserted, acquired Differences. 455 there is less disposition to calculous affections. So far, however, as we have had an opportunity for judging, it is secreted in greater quantity, and this may partly account for its seeming to have a smaller quantity of salts in any given amount; but the truth is, the freedom of the female from calculous affections is greatly owing to the shortness and size of the urethra, which admits the calculus to be discharged with comparative facility; and it is a common obser- vation, that where the males of a family, hereditarily predisposed to gout, become, owing to their greater exposure to the exciting causes, affected with that disease, the females may be subject to calcu- lous disorders,—the two affections appearing to be, in sorr>e respects, congenerous. For the reasons already mentioned, however, stone rarely forms in the bladder of the female, and the operation of lithotomy is scarcely ever necessary. The desire to evacuate the contents of the bladder occurs more frequently in the female, probably, in part, owing to habit; and, in part, to the greater mo- bility of the nervous system. In addition to these differences, as regards the secretions, the female has one peculiar to herself,—menstruation,—which has already engaged attention. In the progress of life, too, the glandular system undergoes evolutions which render it especially liable to disease. About the period of the cessation of the menses,—sooner or later,—the mammae frequently take upon themselves a diseased action, and become scirrhous and cancerous so as to require the or- gans to be extirpated. In the treatment of disease, these sexual peculiarities have to be borne in mind. Owing to the greater mobility of the nervous sys- tem in the female, she usually requires a much smaller dose of any active medicine than the male; and, during the period when the sexual functions are particularly modified, as during menstruation, gestation, and the child-bed state, she becomes liable to various affections, some of which have been referred to elsewhere; others belong more appropriately to works on pathology or obstetrics. The acquired differences, which we observe amongst individuals, are extremely numerous. The effect of climate on the physical and mental characteristics is strikingly exhibited. The temperate zone appears to be best adapted for the full development of man, and it is there that the greatest ornaments of mankind have flourished, and that science and art have bloomed in exuberance; whilst in the hot, enervating regions of the torrid zone, the physical and moral energy are prostrated; and the European or Anglo-American, who has en- tered them full of life and spirits, has left them after a few years residence, listless and shorn of his proudest characteristics. Nor is the hyperborean region more favourable to mental and corporeal development; the sensibility being obviously blunted by the rigours of the climate. The effect of locality is, perhaps, most signally exem- plified in the Cretin, and the Goitreux of the Valais, and of the 456 individual differences. countries at the base of lofty mountains in every part of the globe; as well as in the inhabitants of our low countries, who are con- stantly exposed to malarious exhalations, and bear the sallow im- print on the countenance. It has seemed to the author, that, in the Legislative Halls of Virginia, it has not been difficult to designate, by this means alone, the inhabitants of the upper and of the lower country. Not less effective in modifying the character of individuals is the influence of the way of life, education, profession, government, &c. The difference between the cultivated and the uncultivated; between the humble mechanic, who works at the anvil or the lathe, and him whose avocation, like that of the lawyer and the physi- cian, consists in a perpetual exercise of the organ of intellect; and between the debased subject of a tyrannical government, and the independent citizen of a free state,— '^Lord of the lion heart and eagle eye," is signal and impressive. To these acquired differences in individuals from extraneous or intrinsic causes we must refer habit, which has been defined,—an ac- quired disposition in the living body, become permanent, and as imperious as any of the primitive dispositions. It is a peculiar state or disposition of the mind, induced by the frequent repetition of the same act. Custom and habit are frequently used synonymously: but they are distinct. Custom is the frequent repetition of the same act; habit is the effect of such repetition. By custom we dine at the same hour every day; the artificial appetite induced is the effect of habit. The functions of the frame are variously modified by this dispo- sition, being at times greatly developed in energy and rapidity, at others largely diminished. If a function be over and over again exerted to the utmost extent of which it is capable, both as regards energy and activity, it becomes more and more easy of execution; the organ is daily better adapted for its production, and is so ha- bituated to it, that it becomes a real want,—a second nature. It is in this way, that we accustom the organs of speech, locomotion, &c. to the exercise of their functions, until, ultimately, the most various combinations of the muscular movements of the tongue and limbs can be executed with surprising facility. If, on the contrary, the organs of any function possess unusual aptitude for accomplishing it, and we accustom ourselves to a minor degree of the same, we ultimately lose a part of the aptitude, and the organs become less inclined, and less adapted to produce it. By custom, we may thus habituate ourselves to receive an unusually small quantity of nutriment into the stomach, so that at length it may become impracticable to digest more. A similar effect occurs as regards the quantity of the special irri- ACQUIRED differences.—HABIT. 457 tant, which we allow to impinge on any of the organs of sense. If we accustom them to be feebly impressed, yet sufficiently so for the performance of their functions, they become incapable of supporting a greater quantity of the special irritant without indicating suffering. The miner can see into the farthest depths of his excavations, when, to the eye of one who has descended from the bright light of day, all seems enveloped in obscurity. In this case, the sensibility of the organ of sight is developed, to such an extent, that if the individual be brought into even a feeble light, the impression is extremely painful. The nyctalope is precisely so situated. His nervous system of sight is so irritable, that, although he can see well in the night, he is incapable of accurate discrimination by day. On the other hand, exposure to intense light renders the sensibility of the visual ner- vous system so obtuse that objects are not so readily perceived in ob- scurity. The hemeralope, who sees in the day and not in the night, and who is consequently the anthiteton of the nyctalope, has the nervous system of vision unusually dull, and incapable of excite- ment by feeble impressions. It may be laid down, as a general principle, that if we gradually augment the stimulus applied to any organ of sense, it becomes less susceptible of appreciating minor degrees of the same irritant; so that, in this way, an augmented dose of the irritant is progressively required to produce the same effect. This is daily exemplified by the use of tobacco,—either in the form of chewing, smoking, or snuffing,—which becomes a confirmed habit, and can only be aban- doned, without doing great violence to the feelings, by attention to the principle deduced from practice,—that by gradually following the opposite course to the one adopted in acquiring the habit,—that is, by accustoming the nerve of sense to a progressive diminution in the dose of the stimulus, an opposite habit may be formed, and the evil be in this manner removed. When by habit we acquire extreme facility in executing any function, it may be executed apparently without the direct inter- ference of volition. This is peculiarly applicable to the voluntary motions. We have elsewhere shown, however, that, in this case,habit only communicates the facility, and that there is no natural sequence of motions, and, consequently, no reason, as in executing a rapid mu- sical movement, why one movementofthefingersshouldfollowrather than another, unless volition were the guiding power. Volition, as Dr. Parr has remarked, is not an exertion of mind, but apparently a simple impulse directed almost necessarily to an end; and it is affected by custom, nearly like the organs of the body. Thus, a sensation, which excited a perceptible exertion of volition will, in time, produce it, and the correspondent action, without our being sensible of its interference; and so rapid is this progress, that we seem to will two ends or objects at the same time, though they are evidently, when examined, distinct operations. But though by custom we are no longer sensible of bodily impressions,or of the exer- Vol. II. 58 45S INDIVIDUAL DIFFERENCES. cise of volition, yet the corporeal organs in their several functions, acquire, like those of the mind, peculiar accuracy of discrimination. 1 fie musician is not, for instance, sensible of his willing any one motion; yet with the most exquisite nicety he touches a particular part of the string, and executes a variety of the nicest and most complicated movements with the most delicate precision. It isa common remark, that" habit blunts the feeling but improves the judgment." To a certain extent this is true; but the feeling is not blunted unless the stimulant, which acts upon the organ of sense, be too powerful and too frequently repeated. When moderately exercised, the effect of education, in perfecting all the senses, is strongly exhibited, as we have elsewhere seen. Sensations, often repeated, cease to be noticed, not because they are not felt, but because they are not heeded; but if the attention be directed to the sensation, custom adds to the power of discrimination. Hence the sailor is able to detect the first appearance of a sail in the distant horizon, when it cannot be perceived by the landsman; and the same kind of discrimination is attained by the due exercise of the other senses. This greater power of discrimination is doubtless owing to improvement in the cerebral or percipient part of the visual apparatus; but we have no evidence, that the organ of vision has its action necessarily blunted. It has been presumed, by some physiologists and metaphysicians, that the will, by custom and exercise, may acquire a power over certain functions of the body that were not originally subject to it; nay, some speculatists have gone farther, and affirmed, that all the involuntary functions were originally voluntary, and that they have become involuntary by habit. Stahl and the other animists, who regarded the soul as the formative and organizing agent in animals, asserted, that it excites the constant movements of the heart, and of the respiratory, digestive and other nutritive organs, by habits so protracted and inveterate, and so naturalized within us, that these functions can be effected without the aid of the will, and without the slightest attention being paid to them. Respiration, according to them, is originally voluntary; but, by habit, the will becomes spontaneity; so that there is no farther occasion to invoke volition. Respiration goes on night and day, when we are asleep as well as awake; and they regard as a proof, that the action was origi- nally dependent upon free will, that we are still able to accelerate or retard it at pleasure. They cite, moreover, the case of Colonel Townshend, related in another part of this work, to show, that the action of the heart is capable of being influenced by the will; and the fact that it is accelerated or retarded under the different passions. Condillac, Lamarck* and Dutrochet fantastically assert, that • The views of this distinguished naturalist regarding the effect of habit on organization, which he considers to tend to greater and greater complication, are most singular and fantastic. It is not, he considers, the organs of an animal that have riven rise to its habits; on the contrary, its habits, mode of life, and those of its ancestors have, in the course of time, determined the shape of its body, the ACQUIRED DIFFERENCES.--HAHIT. 159 the different instincts, observed to prevail so powerfully in animals, are mere products of an acquired power transmitted through suc- cessive generations. The objections to all these views are,—that the functions in question are as well performed during the first day of exist- ence as at an after period, and are apparently as free from the exer- cise of all volition. The heart, indeed, beats through foetal existence for months before the new being is ushered into the world; and when, if volition be exerted at all, it can only be obscurely. The case of Colonel Townshend is strange, passing strange, but it is almost unique, and the power of suspending the heart's action was pos- sessed by him a short time only prior to dissolution. All the functions in question must, indeed, be esteemed natural, and in- stinctive, inseparably allied to organization; and hence differing from the results of habit which is always acquired. The opinion of Bichat, on the other hand, was, that habit influ- ences only the animal functions and has no bearing on the organic or nutritive. But this is liable to objections. We have seen, under digestion, that if a bird, essentially carnivorous in its nature, be re- stricted to vegetable food, the whole digestive economy is modified, and it becomes habituated to the new diet. We know, also, that where drains are established in any part of the body, they become, in time, so much a part of the physiological condition of the frame, that they can only be checked with safety by degrees. In the administration of medicines, habit has always to be attend- ed to. The continued use of a medicine generally diminishes its power—hence the second dose of a cathartic ought to be larger than the first, if administered within a few days. Certain cathartics are found, however, to be exceptions to this. The Cheltenham waters are one. The constitution, so far from becoming reconciled to lead by habit, is rendered more and more sensible to its irritation. Emetics, too, frequently act more powerfully by repetition. Dr. Cullen asserts, that he knew a person so accustomed to excite vo- number and condition of its organs, and the faculties, which it enjoys. Thus the otter, the beaver, the waterfowl, the turtle, and the frog were not made web- footed that they might swim; but their wants having attracted them to the water in search of prey, they stretched out their toes to strike the water, and move rapidly along its surface. By the repeated stretching of their toes, the skin, which united them at the base, acquired a habit of extension, until, in the course of time, they became completely web-footed. In like manner, the antelope was not endowed with alight, agile form, in order that it might escape by flight from the carnivorous animal; but by being exposed to the danger of being devoured by lions, tigers, and other beasts of prey, it was compelled to exert itself by running with great celerity; a habit, which, in the course of many generations, gave rise to the peculiar slenderness of its legs, and the agility and elegance of its form. The cameleopard, again, was not gifted with a long flexible neck, because it was destined to live in the interior of Africa, where the soil was arid, and devoid of herbage; but, being reduced, by the nature of the country, to support itself on the foliage of lofty trees, it contracted a habit of stretching itself up to reach the high boughs, until its forelegs became longer than the hinder, and its neck so elongated that it could raise its head to the height of twenty feet above the ground! 460 INDIVIDUAL DIFFERENCES. miting, on himself, that the one-twentieth part of a grain of tartar- ized antimony was sufficient to produce a convulsive action of the parts concerned in vomiting. As a general principle, however, remedies lose their effect by habit, and this is particularly the case with tonics; but if another tonic be substituted for a day or two, and then the former be resumed, it will produce all its previous effects. Association, employed abstractedly, is a principle of the animal economy nearly allied to habit. When two or more impressions of any kind have been made upon the nervous system, and repeated for a certain number of times, they become associated; and if one of them only be produced it will call up the idea of the others. It is a principle, which is largely invoked by the metaphysician, and by which he explains many interesting phenomena of the human mind, especially those connected with our ideas of beauty, or the contrary; our likes and dislikes, and our sense of moral propriety.* Darwin employed it to explain many complicated functions of the economy; and he laid it down as a law, that all animal motions, which have occurred at the same time or in immediate succession, become so associated that when one of them is reproduced, the other has a tendency to accompany or succeed it The principle has, doubtless, great agency in the production of many of the phy- sical, as well as mental, phenomena; but its influence has been over- rated; and many of the consecutive and simultaneous actions, to which we have referred under the head of correlation of functions, take place, apparently, as well the first time they are exerted, as subsequently. Sucking and deglutition are good cases of the kind. Soon after birth, the muscles of the lips, cheeks, and tongue are con- tracted to embrace the nipple, and to diminish the pressure in the interior of the mouth; and as soon as the milk has flowed to the necessary extent into the mouth, certain voluntary muscles are con- tracted. These propel the milk into the pharynx, where its farther progress is accomplished by muscles, associated or connected func- tionally, but not in the sense we are now employing the epithet; for here one action could not suggest another, according to the defini- tion we have given of association, which requires that the acts should have been executed previously. Many of the cases, in fact, ascribed by Darwin and Hartley to the agency of this principle, are instinctive actions, in which a correlation, as in the * The effect of this principle is forcibly and feelingly expressed by one of the most illustrious of British bards:— " And slight withal may be the things which bring Back to the heart the weight, which it would fling Aside for ever: it may be a sound, A tone of music, summer's eve, or spring, A flower, the wind, the ocean, which shall wound, Striking th' electric chain wherewith we're darkly bound; And how and why we know not, nor can trace Home to its cloud this lightning of the mind." Childe Harold, Canto iv. ACQUIRED DIFFERENCES.—IMITATION. 461 case of deglutition, exists, but without our being able to explain the nature of such correlation, any more than we can explain other complicated actions and connexions of the nervous system, of which this is doubtless one. Some of the most obstinate diseases are kept up by habit, or by accustomed associated motions; and, frequently, the disease will seem to continue from this cause alone. Whenever intermittent fever, epilepsy, asthma, chorea, &c. have been long established, the difficulty of removing the influence of habit, or the tendency to re- currence, is extreme. Lastly, the principle of imitation falls appropriately under this section. It may be defined as—that consent of parts, depending on similar organization, which, under the influence of the brain, enables them to execute acts similar to those executed by the same parts in another individual. Imitation, consequently, requires the action of the brain; and differs from those actions that are natural or in- stinctive to organs. For example, speech requires the action of imitation; whilst the ordinary voice or cry is effected by the new- born, and by the idiot, who are incapable of all observation, and consequently of imitation. The mode in which speech is acquired, offers us one of the best examples of this imitative principle, if we may so term it. At a very early period, the child hears the sounds addressed to it, and soon attaches ideas to them. It dis- covers, moreover, that it is capable of producing similar sounds with its own larynx, and that these sounds are understood, and are in- servient to the gratification of its wants; and, in this way, speech, as we have elsewhere seen, is acquired. The difficulty is to un- derstand in what manner this singular consent is produced. Sir Gilbert Blane has properly remarked, that the imitation of ges- tures is, at first sight, less unaccountable than that of sounds; as they are performed by members which are objects of sight, and would seem therefore to be more readily transferable to the corresponding parts of another person: but he probably errs, when, farther on, he remarks, that when children begin to articulate, they first attempt those letters, in the pronunciation of which the motions of the organs are the objects of sight; such as the p and b, among consonants, and the broad a, among the vowels, " giving occasion to a well-known etymology, from the infantile syllables, expressive of father and mother in all languages." We do not think that this explanation is happy; and have elsewhere attempted to show, that the combina- tion of letters, and the words referred to, are first enunciated, because they are the easiest of'all combinations; and that the expressions of mama, papa, &c. are employed long before the child has acquired the power of imitation, and long prior to his attaching the meaning to the words which he is subsequently made to adopt. It is certainly singular how the child can learn to imitate sounds, where the action of the organs concerned is completely concealed from view. The only possible way of explaining it is to presume, that it makes repeated attempts with its vocal ap- 462 INDIVIDUAL DIFFERENCES. paratus to produce the same sound which it hears; and that it re- collects the sensation produced by the contraction of the muscles when it succeeds, so as to enable it to repeat the contraction of the muscles, and the sensation, at pleasure. This is, however, a case, in which volition is actively exerted. We have others, where the action occurs in spite of the individual, as in yawning. We see the action in a second person, and, notwithstanding all our attempts to the contrary, the respiratory organs are excited through the brain, and we accomplish the same act. Nay, even thinking of the action will be sufficient to arouse it. Of a like nature to this, is the sym- pathetic contraction of the uterus, which comes on, where a preg- nant female is in the lying-in chamber during the accouchement of an- other, and to which we have referred under the head of Sympathy. Many morbid phenomena are excited in a similar manner;—of these, squinting and stammering are familiar examples. Sect. IV. Of the Varieties of Mankind. To determine the number of varieties, into which the great hu- man family may be divided, is a subject which has been considered to belong so completely to the naturalist, that we shall pass it over with a brief inquiry. If we cast our eye over the globe, although we may find that mankind agree in their general form and organization, there are many points in which they differ materially from each other. With those forms, proportions and colours, which we consider so beautiful in the fine figures of Greece,—to use the language of Mr. Law- rence,—contrast the woolly hair, the flat nose, the thick lips, the retreating forehead, advancing jaws, and black skin of the negro; or the broad, square face, narrow oblique eyes, beardless chin, coarse, straight hair, and olive colour of the Calmuck. Compare the ruddy and sanguine European with the jet black African, the red man of America, the yellow Mongolian, or the brown South-Sea Islander; the gigantic Patagonian, or the dwarfish Laplander; the highly civilized nations of Europe, so conspicuous in arts, science, literature, in all that can strengthen and adorn society, or exalt and dignify human nature, to a troop of naked, shivering, and starved New Hollanders, a horde of filthy Hottentots, or the whole of the more or less barbarous tribes, that cover nearly the entire continent of Africa; and although we must refer them all to the same species, they differ so remarkably from each other as to admit of being classed in a certain number of great varieties; but, with regard to the preeise number, naturalists have differed materially. Whatever changes have been impressed upon mankind, can, of course, apply only to the descendants of Noah. The broad distinc- tions, we now meet with, could not have existed in his immediate family, saved with him at the time of the deluge. They must ne- cessarily have all been of the same race. None of our investigations on this subject can, consequently, be traced back into antediluvian VARIETIES OF MANKIND. 463 periods. Hence the point, on which the ark rested, must be looked upon as the cradle of all mankind. The question of the original residence of man has frequently en- gaged the attention of the philologist. It is one which could be answered positively by the historian only, but unfortunately the evidence we possess of an historical character is scanty in the ex- treme, and the few remarks, in the sacred volume, not sufficient to lead us to any definite conclusion. As far back as the date of the most remote of our historical records, which extend to about two thousand years prior to the Christian era, we find the whole of Asia and a part of Africa,—probably a large part,—peopled by different nations, of various manners, religion, and language; carrying on ex- tensive wars with each other, with here and there civilized states, possessing important.inventions of all kinds, which must have re- quired a length of time for discovery, improvement, and diffusion. After the subsidence of the deluge, the waters would first recede from the tops of the highest mountains, which would thus be the earliest habitable; and in such a situation the family of Noah in- creased, and thence spread abroad on the gradual recession of the waters. The earliest habitable spot was probably the elevated re- gion of middle Asia,—the loftiest in the world,—not the summits, which would be unsuitable, in every respect, for human existence, but some of the lofty plains, such as that, of which the well-known desert Kobi or Schamo forms the highest point, and from whence Asia sinks gradually towards the four quarters, and the great moun- tain chains proceed that intersect Asia in every direction. This has been suggested by Herder and Adelung as the cradle of the human race. In the declivities of this elevated region, and of its mountain chains, all the great rivers arise that flow on every side through this division of the globe. After the deluge, it would therefore soon become dry, and project, like an extensive island, above the flood. The cold and barren elevation of Kobi would not itself have been well adapted for the continued residence of our se- cond parents, but immediately on its southern side lies the remark- able country of Tibet, separated by lofty ridges from the rest of the world, and containing within itself every variety of climate. Although on the snow-capt summits the severest cold perpetually prevails, summer eternally reigns in the valleys and well-watered plains. The rice, too, the vine, pulse, and a variety of other pro- ductions of the vegetable kingdom, which man employs for his nu- trition, are indigenous there; and those animals are found in a wild state, which man has domesticated and taken along with him over the earth;—the ox, horse, ass, sheep, goat, camel, swine, dog,, cat, and even the valuable reindeer,—his only friend and companion in the icy deserts of polar countries. Zimmermann, indeed, as- serts, that every one of the domesticated animals is originally from Asia. Close to Tibet, and immediately on the declivity of this great central elevation, is the charming region of Kaschemire, the lofty site of which tempers the southern heat into a perpetual spring. 464 INDIVIDUAL DIFFERENCES. The probabilities in favour of the cradle of mankind having been situated to the south of the elevated region of middle Asia are con- sidered to be strengthened by the circumstance of the nations in the vicinity possessing a rude, meagre and imperfect language, such as might be imagined to have existed in the infancy of the human in- tellect and of the world. Not less than two hundred millions of people are found there, whose language appears to be nearly as simple as it must have been soon after its formation. Kaschemire, by reason of the incessant changes which it has experienced in ancient and modern times, has, indeed, kept pace with the rest of the world in the improvement of its language, but not so, apparently, with Tibet— itsneighbour—andwithChina,and the kingdoms of Ava,Pegu,Siam, Tunkin, and Cotschinschina. All these extensive countries and these alone in the known world, according to Adelung, betray the im- perfection of a newly-formed or primitive language. As the earliest attempt of the child is a stammering of monosyllabic notes, so, says that eminent philologist, must have been that of the original child of nature; and the Tibetans, the Chinese, and their two neighbours to the south continue to stammer monosyllabically, as they must have been taught thousands of years ago in the infancy of their race. " No separation of ideas into certain classes, whence arose the parts of speech in cultivated languages. The same sound which denotes joyful, signifies joy and to gladden,awA this in every person, num- ber and tense. No art, connexion, or subordinate ideas are united to the rude, monosyllabic root, thereby communicating richness, clearness and euphony to their meagre tongue. The rude, mono- syllabic, radical ideas are placed perhaps broken and detached from each other, the hearer being left to supply the intermediate ideas. As the monosyllable admits of no inflection, the speaker either makes no distinction between cases and numbers, or he seeks for aid, in cases of great necessity, in circumlocution. The plural he forms, like the child, either by repetition,—tree, tree,—or by the addition of the words much or more, as tree much, tree more. I much or I more is the same to him as we." From these and other circumstances Adelung infers, that these monosyllabic languages are primitive and the honorable ancestors of all others;* that the immediate descendants of Noah originally occupied the favoured region, which has been described, and, as population increased, spread into the neighbouring districts, selecting, by preference, the near and charming regions of the south, east, and west. Hence we find in the countries immediately bordering on Tibet, the earliest formed states, and the oldest civi- lization. History refers us to the east, for the primordial germs of most of our ideas, arts and sciences, whence they subsequently * This argument of Adelung is, however, more plausible perhaps than sound. It has been correctly remarked by the distinguished Duponceau, that, in all lan- guages, there is a strong tendency to preserve their original structure, and that from the most remote period to which the memory of man can reach, a monosyl- labic language has never been known to become polysyllabic, or vice versa. VARIETIES OF MANKIND. 465 spread to the countries farther to the west,—to Media, Persia, and western Asia. It is probable that from this part of Asia, the sons of Noah,—Shem, Ham and Japheth,—branched off in various di- rections so as to constitute the three distinct stocks, which are found to have divided the old world from time immemorial. These three are 1, the White, Caucasian, Arabico-European, or Euro- pean; 2, the Olive, Mongolian, Chinese, Kalmuck, or Asiatic; and 3, the Negro, Ethiopian, African, Hottentot, &c. each of which has its own principal habitat;—the white being found chiefly in Europe and Asia Minor, Arabia, Persia, and India, as far as the Ganges, and in North Africa; the Mongol occupying the rest of Asia, and having its focus on the plateaux of Great Tartary and Tibet; and the negro race covering almost the whole of Af- rica, and some of the isles of New Guinea, the country of the Pa- pous, &c. The white or Caucasian variety are supposed to be the descendants of Japheth, ("audax Japeti genus," Horace;) the Asiatic of Shem ; whilst Ham is regarded as the parent of the un- happy African. These three races,—the Caucasian, Negro, and Mongolian,—are alone admitted by Cuvier, whose classification will serve our purpose as well as any of the others to which reference will be made presently. 1. The Caucasian race is chiefly distinguished by the elegant form of the head, which approximates to a perfect oval. It is also remarkable for variations in the shade of the complexion and colour of the hair. From this variety the most civilized nations have sprung. The name Caucasian was given to it from the groupe of mountains, between the Cas- pian andtheBlack Sea,—tradi- tion seeming to refer the origin of this race to that part of Asia. Even at the present day the peculiar characteristics of the race are found in the highest perfection amongst the people, who dwell in the vicinity of Mount Caucasus,—the Georgi- ans and Circassians,—who are considered the handsomest na- tives of the earth. The marginal figure is given by Blumenbach as a speci- men of the Caucasian race, near the original residence whence the epithet is derived. It re- presents Jusuf Aguiah Efen- di, formerly ambassador from the Porte to London. The Caucasian race has been subdivided into several great na- Vol. II. 59 466 INDIVIDUAL DIFFERENCES. tions or families:—1. The Arabs, comprising the Arabs of the de- sert or the Bedouins, the Hebrews, the Druses and other inhabitants of Libanus, the Syrians, Chaldaeans, Egyptians, Phoenicians, Abys- sinians, Moors, &c. 2. The Hindoos on the European side of the Ganges;—as the inhabitants of Bengal, of the coasts of Coromandel and Malabar, the ancient Persians, &c. 3. The Scythians and European Tartars, comprising also the Circassians, Georgians, &c. 4. The Kelts, a dark-haired race, the precise origin of which is unknown, but presumed to be Indian. The descendants of this race are the Gauls, Welsh, Rhaetians, &c. &c.; and, lastly, the Goths, a fair- haired race, the ancestors of the Germans, Dutch, Swedes, Danes, &c. That the time of the first peopling of the European countries must have been very remote is exhibited by the fact, that at the dawn of history, the whole of Europe, from the Don to the mouth of the Tagus, was filled with nations of various physical characters and languages, and bearing striking marks of intermixture and mo- dification. At this period there were, in Europe, at least six great nations. 1st. The Iberians with the Cantabri, in Spain, in a part of Gaul, and on the coasts of the Mediterranean as far as Italy. 2dly. The Kelts in Gaul, in the British Isles, between the Danube and the Alps, and in a part of Italy. 3dly. The Germani or Goths, between the Rhine, the Danube and the Vistula. 4thly. The Thracians with the Illyrians, in the south-east of Europe, and in western Asia. 5thly. The Sclavi, in the north: and 6thly. The Fins in the north-east. It is not improbable but that these different races migrated from Asia in the order we have mentioned:—such is the theory of certain historians and phi- lologers, and there is some reason for adopting it. They, who mi- grated first, would probably extend their wanderings until they were arrested by some invincible obstacle, or until the arrival of fresh tribes would drive them onwards farther and farther towards the west. In this way they would ultimately reach the ocean, which would effectually arrest their farther progress, unless towards the south and the north. The descendants of the ancient Iberians do now actually occupy the west of Spain,—the residence probably of their forefathers. Nearly about the same time, perhaps, as the Iberians undertook their migration, the Kelts, a populous tribe, migrated from some part of Asia, and occupied a considerable portion of middle Europe. To these succeeded the Goths, to the north, and the Thracians to the south; whilst the Sclavi, the last of the Asiatic emigrants, wan- dered still farther north. It is not easy to determine the precise link occupied by the Fins in this vast chain of nations. They were first known to history as a peculiar people in the north of Europe, but whence they proceeded, or whether they occupied their posi- tion to the north of the Germani from choice, or were urged on- wards by their more powerful neighbours, we know not. So long as there was sufficient space for the nations to occupy, without disturbing the possessions of their neighbours, they proba- VARIETIES OF MANKIND. 467 bly kept themselves distinct; but as soon as the land was filled, a contest arose for the possession of more extensive or more eligible regions; wars were, consequently, undertaken, and the weaker gra- dually yielded their possessions, or their sovereignty, to the stronger. Hence, at the very dawn of history, numerous nations were met with, amalgamated both in blood and language;—for example, the Kelto-Iberians of Spain; the Belgae or Kymbri of Gaul and Britain; the Latins, and other nations of Italy, and probably many, whose manners, characters, and language had become so melted into each other as to leave little or no trace of the original constituents. The Letti, Wallachians, Hungarians, and Albanians of eastern Europe, are supposed to afford examples of such amalgamation, whilst the mighty Sclavonic nation has swallowed up numbers of less powerful tribes, and annihilated even their names for ever. This it is, which frequently embarrasses the philological historian ; and prevents him, without other evidence, from deducing with accuracy the parent stocks or the most important components in ethnical admixtures. 2. The Negro, African, Ethiopian or Black man of Gmelin, occupies a less extensive surface of the globe, embracing the coun- try of Africa, which extends from the southern side of Mount At- las to the Cape of Good Hope. This race is evidently of a less per- fect organization than the last, and has some characteristics which approximate it more to the monkey kind. The forehead is flatten- ed and retiring; the skull is smaller, and holds from four to nine ounces of water less than that of the European. On the other hand, the face, which contains the organs of sense, is more developed, and projects more like a snout. The lips are large; the cheek bones prominent; the temporal fossae hollower; the muscles of mastication stronger; and the facial angle is smaller;—the head of the negro, in this respect, holding a middle place between the Caucasian and the ourang-outang. The nose is expanded; the hair short and woolly, very black and frizzled. Skin black. This colour is not, however, characteristic of the race, as the Hottentots and Caffres are yellow. The marginal figure is the head of J. J. E. Capitein, se- Fig. 170. lected by Blumenbach as the representative of his race. He was an intelligent negro, and published several ser- mons and other works in La- tin and Dutch. His portrait was taken by Van Dyk. This case of great intelli- gence in the negro is not unique; and it exhibits what may be expected from him under favourable circum- r- stances. In almost all situa- tions in which he is found, it Nesr0 TOriety. 468 INDIVIDUAL DIFFERENCES. is in the state of slavery, and degradation, and no inference can be deduced regarding his original grundkraft—as the Germans call it—or intellectual capability under such circumstances. Haiti has af- forded numerous examples of the sound judgment, and even distin- guished ability, with which her sable inhabitants are capable of con- ducting, not only the municipal, but the foreign concerns of a con- siderable community. It must be admitted, however, that from or- ganization, this race would seem to be, cseteris paribus, less fitted for intellectual distinction than the Caucasian. 3. The Mongolian or Asiatic, Kalmuck or Chinese race, the brownman of Gmelin,is recognised by prominent and wide cheek bones; flat, square visage; small and oblique eyes; straight and black hair; scanty beard, and olive complexion. The marginal head is from Blumenbach. It is that of Feodor Ivanowitsch, a Kalmuck, given by Fig. 171. the empress of Russia to the heredi- tary princess of Baden. He was edu- cated at Carlsruhe, and was a most distinguished painter at Rome. The portrait was sketched by Feodor himself. The Mongols are spread over the central and eastern parts of Asia, with the exception of the peninsula of Ma- lacca. They likewise stretch along the whole of the Arctic regions, from Russia and Lapland to Greenland, and the northern parts of the Ameri- can continent, as far as Behring's Straits,—the Laplanders and Esqui- maux being evidently of the same race as the Koriaks, Kamtschadales, Japanese, &c. of the Asiatic conti- nent. Such are the three varieties whence, Mongolian variety. m the opinion of Cuvier, all the rest may be deduced. Rudolphi and others have added to these the race, which is peculiar to our own country, and has by some been esteemed indigenous. The American race or red man of Gmelin differs greatly in stature, colour, and physiognomy in various parts of the continent, but his medium height corresponds with thatof the European. His colour is from a cinnamon-brown to a deep copper. The hair is almost always black, straight and stiff. The features are large and strongly marked, except the eyes, which are commonly deep-seated, or sunk in large sockets. The forehead is generally low, somewhat compressed at the sides, and slightly retreating. Facial angle about 80°. Nose generally considerably raised from the face, some- times arched; cheek bones high, and widely separated; angle VARIETIES OF MANKIND. 469 of the jaw broad, and chin square. The accompanying head is that of Ongpatonga, (Big Elk,) chief of the Omawhaw Indians, and is taken from the American Natural History of the lamented GODMAN. Fig. 172. American variety. Other naturalists, as Blumenbach, Dumeril, Lawrence, &c. add to these four varieties a fifth,—the Malay or Australian;— the Tawny man of Gmelin, owing to the difficulty of referring it either to the Caucasian Indian, or to the Chinese Mongolian, situated in its vicinity. This Malay variety extends from Ma- lacca to the most remote islands of the great Indian and Pacific ocean, from Madagascar to the Maldives, inclusive; inhabits Su- matra, Java, Borneo, Celebes, and the adjacent islands; the Mo- lucca, Ladrones, Philippine, Marian, and Caroline groupes; New Holland, Van Dieman's Land, New Guinea, New Zealand, and the various islands scattered through the South Sea. It is termed Malay because supposed to have proceeded originally from the Peninsula of Malacca, and to have spread thence over the adjacent islands, a supposition which is not confirmed by history: on the contrary, according to Mr. Marsden, it is clearly demonstrated, that the Ma- lays went from Sumatra to Malacca in the twelfth century. No well-marked, common characters can be assigned to this variety; for, under the term Malay, races are included which seem to dif- fer materially from each other; so much so, indeed, as to induce many naturalists to refuse the admission of the Malay as a distinct 470 INDIVIDUAL DIFFERENCES. variety. Their colour may be said to be brown, in various shades, from a light tawny, to almost a black; the forehead is low and round; the nose full and broad; nostrils wide; mouth large; hair thick, crisp, and always black, as well as the iris. Fig. 119 exhibits an indivi- dual of this race: it is the head of a New Zealand chief. Cuvier, Rudolphi, Virey and others consider the Malay variety to be a mixture of the Mongol of Asia and the negro of Africa. In New Guinea, and the small islands around, the Papous are found, who resemble the negroes yet more strongly; and similar races are met with in the Archipelago of the Holy Ghost, and in the isles of Andaman and Formosa. They are presumed to belong really to the negro race, and to have descended perhaps from individuals of that variety, who had wandered, or been driven, from their original settlements. Some of them resemble the Guinea negro in every particular. Of late years, many other races have been added to those ad- mitted by Blumenbach; especially by Messrs. Virey, Desmou- lins, and Bory de Saint-Vincent. Virey admits two distinct spe- cies, which he determines by the size of the facial angle. To the one he refers all those in whom this angle is from 85° to 90°, in- cluding three races:—the white, the tawny and the copper-co- loured. As subdivisions of the first of these he distinguishes,—the Indo-Arab, the Keltic, and the Caucasian; of the second, the Chinese, the Mongolian Kalmuck, and the Ostiack Laplander; and of the third the American or Caraib. To the second species, in which the facial angle is only from 75° to 82°, he refers the dark- brown, the black, and the blackish races; the first of which com- prises the Malay or Indian variety; the second, the Caffre and the Negro; and the third, the Hottentot and the Papous. Desmoulins, from the state of the hair, the character of the fea- tures, the arrangement of the teeth, the colour of the skin, and the size of the facial angle,reckons eleven species, whom he denominates after the countries they inhabit;—viz. the Kelto-Scythian Arab,the Mongol, the Ethiopian, the Euro-African, the Austro-African, the Malay or Oceanic, the Papous, the Oceanic Negro, the Aus- tralasian, the Columbian, and the American. The seven first of these are but subdivisions of the Caucasian, Mongolian, and ne- gro divisions of Cuvier, and Desmoulins conceives, that an im- proved acquaintance with anthropology may justify subdivisions in the Columbian and American races, which he has separated. Bory de Saint-Vincent adopts the same principles as Desmoulins, and extends the species to fifteen, viz. the Japhetic, Arabic, Hindoo, Scythian, Sinic, Hyperborean, Neptunian, Australian, Colum- bian, American, Patagonian, Ethiopian, Caffre, Melanian, and Hottentot. We have briefly stated the various classifications of the naturalist, to exhibit the vacillation, which yet exists on the precise num- ber of races that should be admitted. Every division must neces- sarily be arbitrary, and the individuals composing each variety are varieties of mankind. 471 far from being alike. We find the greatest diversity, for example, amongst the nations of the Caucasian variety, and even amongst any of its subdivisions. The French can be distinguished from the German, the Spaniard from the English, &c. and if we were to push the system of subdividing, which appears at present to be fashion- able, we might constitute almost every nation of the globe into a distinct variety. It has been an oft agitated question, whether all the varieties amongst mankind must be regarded as belonging to the same spe- cies,—the differences, which we observe, having been accomplished by extraneous circumstances acting through a long succession of ages ; or whether they must not be regarded as distinct species, ab origine. By many, the discussion of this subject has been esteemed not only unnecessary but profane, inasmuch as the sacred historian has unequivocally declared that all mankind had a common origin. We have already remarked, however, that this is not a question, which concerns our first parents, but belongs exclusively to the family of Noah ; for, in his descendants, all these varieties must ne- cessarily have occurred. From the part of Asia, previously de- scribed, his immediate descendants probably spread abroad to the north and to the south, to the east and to the west; Europe being peopled by the migratory hordes which proceeded towards the north-west, and Africa by those from south-western Asia. These migrations probably all took place by land, except in the case of our own continent, where a slight sea-voyage, of not more than thirty-nine miles, across Behring's Straits, even in frail vessels, would be sufficient to transport the emigrants without much risk of misadventure; and even this short voyage would be rendered un- necessary during the winter season, the Strait being solidified into a continuous mass of ice. Europe probably received its inhabitants long before navigation occurred to any extent. Subsequently, when a coasting trade was first established,—to which the enterprise of nations would neces- sarily be limited in the first instance, until by improved vessels and a better system of management they were enabled to brave the ter- rors of the ocean and undertake their adventurous voyages of dis- covery,—many of the coasts, especially of the Mediterranean, re- ceived swarms of emigrants, a circumstance which accounts for the motley population observable, at an early period, in these regions. Carthage, we know, was settled by the Phoenicians, and Southern Italy and Spain, in this manner, received their, Greek colonies. Dr. Copland has even expressed his belief in the view, that this con- tinent was visited " by Phoenician navigators, the greater part of whom settled in it, particularly in Mexico; and that the imperfect navigation of that era prevented many of the adventurers, if not all of th^em, from returning." The notion is, however, altogether hypo- thetical. The greatest difficulty has been,—to comprehend how the 472 individual differences. Caucasian and Ethiopian varieties could have originated from the same source. The other varieties of mankind, if we exclude the negro, could be referred, without much hesitancy, to the same primitive stock,—the changes being caused by adventitious circum- stances operating for an immense period,—but it has seemed to many naturalists impossible to suppose, that the characters of the negro could, by any process, become converted into those of the European, or vice versa. The people of antediluvian times probably possessed but few physical differences, constituting one large family, modified, per- haps, to a certain extent, by circumstances, but not materially; the two antithetical races,—the white and the black,—first arising in postdiluvian periods. If we adopt this view, the question regarding the difference of species between the white and the black varieties requires no agitation. But how are we to explain the essential differences, as to form and colour, which we notice amongst the na- tions of the earth ? In the infancy of anthropology it was asserted, that the white races inhabit the cold and temperate regions of the earth, whilst the tawny and the darker races are situated under a more vertical sun. Within certain limits the sun is certainly possessed of the power of modifying the colour. The difference between one who has been for some time exposed to the rays of a tropical sun, and his brethren of the more temperate climates, is a matter of universal observation. The inhabitant of Spain is,in this way, distinguished from the French, German, English, &c; and hence we can understand, why the Southern Asiatic and African women of the Arab race, when con- fined within the walls of the seraglio, are as white as the fairest Europeans. There are many exceptions, however, to the notion which has prevailed, that, there is an exact ratio between the heat of the climate and the blackness of the skin. For example, at the extreme north of Europe, Asia, and America, we find the Lap- landers, Samoiedes, Esquimaux, &c. with the skin very brown, and the hair and iris black; whilst in the vicinity of the Laplanders are the Fins, people of large stature compared with the Laplanders, with fair skins and bluish-gray eyes. In the same manner, to the south of the Greenlander,—of short stature, brown skin, and dark hair,—is the tall and fair Icelander. The Kelt of Wales, and of the western coast of Ireland, of the north of Scotland, and of the west of Bretagne, is still distinguished by his dark hair and eyes, from the light-haired descendants of the Goth,—the German and the Scandinavian. A number of distinct tribes exist in the interior of Africa,—having a red or copper hue, with lank black hair, and in the midst of the black varieties of their species. A similar fact was observed by Humboldt in different parts of South America. Again, the negro race is not always found in the torrid zone. On our own continent none have ever been met with, except what have been imported; and these, after repeated descents, have still retain- varieties of mankind. 473 ed their original character; whilst, as we have seen, negroes are met with in Australia under a climate as cold as that of Washington. The fact of the slight mutation, effected by ages on the character of a race, is strikingly shown by the circumstance to which we have re- ferred elsewhere, that in some of the monuments of Egypt, visited by Belzoni and Champollion, representations of the negro, presumed to be upwards of three thousand years old, exhibit the features to , be almost identical with those of the negro of the present day. The Jew affords an example of the same immutability, as well as the Esquimaux, who strikingly retain the evidences of their Kalmuck origin. Complexion, and, to a certain extent, the figure are doubt- less modified by organization, but the essential characters of the organization remain little if at all changed. Volney has fancifully supposed, that the elongated visage of the negro is owing to the wry face habitually made under exposure to the rays of the sun. Independently, however, of the objection, that this would be wholly insufficient to account for the striking peculiarities of the negro head, it has already been remarked, that these pecu- liarities do not exist amongst other races, inhabiting equally hot climes; and that the negro himself is not confined to those climates, and ought, consequently, to lose the museau or snout, when the country is so cool as to render the wry face or moue unneces- sary. It may then, we think, be concluded, that the evidence, in favour of the colour of the negro, of the red man, or of the tawny, being pro- duced directly or indirectly by the solar rays, is insufficient to esta- blish the point. Still its effects are considerable: in all cases,how- ever, the children are born fair, and would continue so, if not ex- posed to the degree of solar heat which had produced the change in their progenitors. In addition to the influence of temperature and climate, that of food, and of different manners and customs has been frequently in- voked, but without any precise results being deduced. The effect of difference in manners and customs is shown in the result of do- mestication on animals,—as in the case of the wild and the disciplined horse; of the bison and the ox: which last is regarded as the bison in a state of tameness. The precise causes of such modification we know not. It is not confined to the animal, but is signally evidenced in the vegetable. The flower of the forest, when received into the parterre and carefully nurtured, will develope itself in such a man- ner as to be with difficulty recognisable. The change seems to be produced by variation in "climate and nutrition, but in what precise manner we know not. The powerful modifying influence of locality on the develop- ment of the moral and physical powers has been more than once referred to. Perhaps the most remarkable examples are met with at the base of lofty mountains, particularly of the Alps, and in some Vol. H 60 474 INDIVIDUAL DIFFERENCES. of the unhealthy districts of France especially. One of these is cretinism, a singular case of malformation, with which we are hap- pily unacquainted in the United States. This is a state of idiocy, which is remarkable in its subjects be- ing always more or less deformed, and in its appearing to originate from local influences. The cretin has every characteristic of the idiot; and, in addition, is often distinguished by a large goitre or swelling of the thyroid gland; by soft, flabby flesh; and by shrivelled, yellowish, or pale and cadaverous skins, covered at times with filthy cutaneous eruptions. The tongue is thick and pendent; the eyelids large and projecting; the eyes gummy, red and prominent; the nose flat; the mouth gaping and drivelling; the face puffy, and, at times, violet-colored, and the lower jaw elongated. In several the forehead is broad inferiorly, and flattened and retreating above, giving the cranium the shape of a cone rounded towards its smaller extremity. The stature of the cretin is generally small, scarcely ever exceeding four feet and a few inches; the limbs are frequently malformed, and almost always kept in a state of flexion. All the cretins are not affected with goitre. Some have large and short, whilst others have thin, and long, necks. Like the idiot, the cretin does not generally live long, scarcely ever surviving the thirtieth year. Authors have differed in opinion on the causes of this deplorable condition. It is observed almost exclusively in the deep and narrow valleys at the foot of lofty mountains, and in mountain gorges. Hence it is common in that part of the Alps called the Valais or Wallais; in the valley of Aost, La Maurienne, &c. It is met with, too, at the foot of the mountains of Auvergne, the Pyrenees, the Tyrol, &c. De Saussure, Esquirol, Fodere, Rambuteau, and all who have had an opportunity of observing these miserable wrecks of humanity, believe, that the great cause is the concentrated, moist, and warm air, which prevails throughout almost the whole of the year in the valleys and mountain gorges where it is found to exist. After all, perhaps, the strongest arguments,—in favour of extra- neous circumstances occasioning, in the lapse of ages, the different varieties, which we observe in the great human family,—are those derived from the changes that must have occurred amongst many of the inferior animals. The dog, in its wild state, has always pretty nearly the same characters; being covered with hair of the same colour; the ears and tail, and limbs, having the same shape; and it exhibits, apparently, the same powers and instincts; but on this matter our knowledge, derived from observation, is necessarily limited. Yet what a number of varieties are observed in the ani- mal when it becomes domesticated; and how different from each other, in shape, colour, character of skin and instincts, are the spaniel, hound, greyhound, pointer, mastiff, terrier, cur, pug, lap- dog, &c; differences certainly as great as between the varieties of VARIETIES OF MANKIND. 475 mankind. These differences, it is presumable, may have been pro- duced partly by the occurrence of accidental varieties, affecting per- haps a whole litter,—male and female; so that if these again were to be coupled, the variety, thus accidentally caused, may have become permanent. Such accidental varieties occasionally occur in the hu- man species, but they are soon lost, in consequence of the wise law that prevents individuals, within certain degrees of consanguinity, from marrying. It is by no means, uncommon, for example, for different children of the same family, from some accidental cause, to be born with six fingers. The author has met with two families in each of which more than one individual was thus circumstanced; and Sir Anthony Carlisle has detailed the remarkable case of a family from this continent, where the superfluity extended, in the case of a female, to two thumbs on each hand, and to six toes on each foot. She married and had several children, who, in their turn, became parents, and transmitted the peculiarity to their children to the fourth generation. Now, if the members of this family had con- tinued to marry in and in, a new race of individuals might have been perpetuated, possessing the unnecessary additions in question. Under existing laws and customs, however, it must always happen, that where such a peculiarity exists in one parent only, it must soon be- come extinct; yet, as we have seen, it may be pertinacious enough to persist for some generations. Fortunately, also, it happens, that no change which occurs accidentally in the parent after birth is liable to be extended to the progeny. Were it otherwise, it will be at once seen, the most strange and innumerable varieties of races would exist. Where a limb had become distorted or amputated, a stock of one-limbed animals would be formed; the docked horse would propagate a mutilated colt; the operation of circumcision performed on one parent ought to be sufficient for the whole of his descend- ants, &c. -&C. In addition to this mode of accounting for the great number of varieties in animals of the same species, the influence of a difference in manners and customs, which we have already considered, has been invoked; and it has been conceived, that the effect of civili- zation and refinement on the human race may be analogous to that of domestication on the inferior animals. This kind of influence is said to be particularly observable amongst the inhabitants of Hindusthan, where, in consequence of the division into castes, the same condition of life, and the same occupation are continued with- out change through many successive generations. The artisans, who are a superior class, are of a manifestly lighter complexion than the tillers of the soil; and in many of the islands of Polynesia the same difference exists between the classes as in Hindusthan. The believers, then, in the Mosaic account of the creation, and the deluge, must regard all the varieties of mankind to have descended from the same family,—that of Noah,—and the different changes, 476 INDIVIDUAL DIFFERENCES. which have been impressed upon their descendants, to be results of extraneous influences acting through a long succession of ages, add- ed to the production perhaps of accidental varieties, which may have occurred in the very infancy of postdiluvian existence, when the intermarriage of near relations was unavoidable, and when such varieties would necessarily be perpetuated. The race of Ham appears to have been separated, if not wholly, at least in part, from their brethren by the malediction of Noah; and whe- ther we consider that a physical alteration was comprised in the malediction, or that such alteration might occur accidentally, as in the cases of those with supernumerary toes and fingers, the very fact of intermarriage with the descendants of the other sons of Noah being prevented by the curse pronounced on Ham, (for many com- mentators read Ham for Canaan,) would necessarily lead to a per- petuation of the adventitious modification. But, it has been asked, if all mankind have descended from one family, which of the varieties, now extant, must be regarded as their representative. On this we have nothing but conjecture to guide us. It has been supposed, by some, to be more probable, that the changes, induced upon mankind, have been in consequence of a progress from a state of barbarism to one of refinement, than the reverse; and hence, it has been conceived, that the variety ought to be considered primary, which, through all the vicissitudes of hu- man affairs, has remained in the most degraded condition, and which in its structure, differs most materially from the variety that has uniformly enjoyed the greatest degree of civilization. Upon this principle, the Ethiopian would have to be regarded as the type of our first ancestors, and such is the opinion of Pritchard, and of Bos- tock. Blumenbach, however, maintains the converse view. Bishop Heber, again, suggests, whether the hue of the Hindoo, which is a brownish-yellow, may not have been that of our first parents, whence the transition, he thinks, to the white and black varieties might be more easy and comprehensible. Philology occasionally aids us in our historical deductions, but the evidence, afforded by it, has to be received with caution. The Hebrew names, like all original appellations, in perhaps all languages, are generally ex- pressive, and therefore worthy of consideration in questions of this nature. The Hebrew word Adam, (ens,) is not only the name of the first man, but it signified man in the abstract, corresponding to the Greek, xv6p&/7ro<;} and the Latin, Homo. We are told, in the sacred volume, that, " in the day that God created man, in the like- ness of God made he him ; male and female created he them ; and blessed them, and called their name Adam, in the day when they were created." The word Adam is derived from a Hebrew root, (oin,) signifying "to be red," and, accordingly, it is probable, that his original hue was not that of what we term the white variety of our species. VARIETIES OF MANKIND. 477 The remarks we have already made render it unnecessary to in- quire into the mode in which, according to the notion of Blumen- bach, of Dr. S. S. Smith, or of Dr. Rush, the black colour of the Ethiopian has been produced. Blumenbach imagined that the heat of the climate gives rise to an excessive secretion of bile; that in consequence of the connexion which exists between the ac- tion of the liver and the skin, an accumulation of carbonaceous mat- ter takes place in the cutaneous vessels, and that this process being continued for a succession of ages, the black colour of the skin be- comes habitual. Dr. Smith, of Princeton, had a similar opinion; he thought, that the complexion in any climate will be changed to- wards black, in proportion to the degree of heat in the atmosphere, and to the quantity of bile in the skin; and, lastly, Dr. Rush, in one of the strangest of the many strange views which have emanated from that distinguished, but too enthusiastic, individual, has attempted to prove, " that the colour and figure of that part of our fellow creatures, who are known by the epithet of negroes, are derived from a modification of that disease, which is known by the name of leprosy." The following are his deductions, from the " facts and princi- ples" adduced in a communication, read before the American Phi- losophical Society in 1792, and printed in the fourth volume of the Transactions of that respectable body:— " 1. That all the claims of superiority of the whites over the blacks, on account of their colour, are founded alike in ignorance and inhumanity. If the colour of the negroes be the effect of a dis- ease, instead of inviting us to tyrannize over them, it should entitle them to a double portion of our humanity, for disease all over the world has always been the signal for immediate and universal com- passion. "2. The facts and principles which have been delivered, should teach white people the necessity of keeping up that prejudice against such connexions with them, as would tend to infect posterity with any portion of their disorder. This may be done upon the ground I have mentioned without offering violence to humanity, or calling in question the sameness of descent, or natural equality of man- kind. " 3. Is the colour of the negroes a disease? Then let science and humanity combine their efforts, and endeavour to discover a remedy for it. Nature has lately unfurled a banner upon this subject. She has begun spontaneous cures of this disease in several black people in this country. In a certain Henry Moss, who lately travelled through this city, and was exhibited as a show for money, the cure was nearly complete. The change from black to a natural white flesh colour began about five years ago at the ends of his fingers, and has extended gradually over the greatest part of his body. The wool which formerly perforated the cuticle has been changed into 478 INDIVIDUAL differences. hair. No change in the diet, drinks, dress, employments, or situa- tion of this man had taken place previously to this change in his skin. But this fact does not militate against artificial attempts to dislodge the colour in negroes, any more than the spontaneous cures of many other diseases militate against the use of medicine in the practice of physic. To direct our experiments upon this subject I shall throw out the following facts,, " 1. In Henry Moss the colour was first discharged from the skin in those places, on which there was most pressure from cloth- ing, and most attrition from labour, as on the trunk of his body, and on his fingers. The destruction of the black colour was pro- bably occasioned by the absorption of the colouring matter of the rete mucosum, or perhaps of the rete mucosum itself, for pressure and friction it is well known aid the absorbing action of the lym- phatics in every part of the body. It is from the latter cause, that the palms of the hands of negro women who spend their lives at a washing tub, are generally as fair as the palms of the hands in labouring white people. "2. Depletion, whether by bleeding, purging, or abstinence, has been often observed to lessen the black colour in negroes. The effects of the above remedies in curing the common leprosy, satisfy me that they might be used with advantage in that state of leprosy which I conceive to exist in the skin of the negroes. " 3. A similar change in the colour of the negroes, though of a more temporary nature, has often been observed in them from the influence of fear. "4. Dr. Beddoes tells us that he has discharged the colour in the black wool of a negro by infusing it in the oxygenated muriatic acid, and lessened it by the same means in the hand of a negro man. The land-cloud of Africa, called by the Portuguese Ferrino, Mr. Hawkins tells us has a peculiar action upon the negroes in changing the black colour of their skins to a dusky gray. Its ac- tion is accompanied, he says, with an itching and prickling sensa- tion upon every part of the body which increases with the length of exposure to it so as to be almost intolerable. It is probably air of the carbonic kind, for it uniformly extinguishes fire. " 5. A citizen of Philadelphia, upon whose veracity I have per- fect reliance,* assured me that he had once seen the skin of one side of the cheek inclining to the chin, and of part of the hand in a negro boy, changed to a white colour by the juice of unripe peaches, (of which he ate a large quantity every year,) falling, and resting frequently upon those parts of his body. " To encourage attempts to cure this disease, of the skin in ne- groes, let us recollect that by succeeding in them, we shall produce a large portion of happiness in the world. We shall in the first * " Mr. Thomas Harrison." VARIETIES of mankind. 479 place destroy one of the arguments in favour of enslaving the ne- groes, for their colour has been supposed by the ignorant to mark them as objects of divine-judgments, and by the learned to qualify them for labour in hot, and unwholesome climates. " Secondly, We shall add greatly to their happiness, for however well they appear to be satisfied with their colour, there are many proofs of their preferring that of the white people. " Thirdly, We shall render the belief of the whole human race being descended from one pair, easy, and universal, and thereby not only add weight to the Christian revelation, but remove a ma- terial obstacle to the exercise of that universal benevolence which is inculcated by it." 480 LIFE. OF LIFE. The knowledge of the mode in which the various functions of the body are exercised constitutes the science of life. The manifestations of life have consequently been considered already. We have seen, that animal and vegetable substances, possess the ordinary properties of matter, but that these properties are singularly controlled, so that organized bodies, are prevented from undergoing those changes that inevitably occur so soon as they become deprived of vitality. The human body is prone to de- composition. It is composed of substances extremely liable to un- dergo putrefaction, and is kept at a temperature the most fa- vourable for such change; yet so long as life exists, the play of the ordinary affinities is prevented, and this constant resistance to the general forces of matter prevails throughout the whole of existence, even to an advanced old age, when it might be supposed the vital forces must be enfeebled almost to annihilation. The case of solution of the stomach after death, described in the first volume of this work, is an additional and forcible evidence of such re- sistance. So long as life continues in the stomach, the gastric secretions exert no action on the organ, but, when life becomes extinct, the same secretions act upon the stomach in the same man- ner that they do upon ordinary dead animal matter. What, then, is this mysterious power, possessed of such astonishing, such incom- prehensible properties? Our knowledge is limited to the fact above stated, that or- ganized matter, in addition to the general physical and chemical forces, possesses one other,—the vital force or principle, vitality or life. This principle exists, not only in the whole, but in every part, of a living body; and its existence is evidenced by the une- quivocal signs afforded by the various functions that have been considered, as well as by others to be presently described. Yet it is not equally evinced in all organs: some appearing to be pos- sessed of more vitality than others,—a result probably produced by peculiar texture, as it would seem irrational for us to admit a dif- ferent kind of vital principle, wherever its manifestations appear to be modified. Admitting the existence of this controlling principle, what, it may be asked, are the functions through which it immediately acts in keeping up the play of the living machine? It has been elsewhere seen, that, in animals, the reciprocal action of innervation and cir- culation are indispensable, and that if one of these functions be ar- rested, the other quickly ceases. This is only applicable, however, to animals; and it has been doubted whether it applies to all and to LIFE. 481 every part of them, whilst to the vegetable it is altogether inappli- cable, unless we regard it, with some physiologists, to possess a rudimental nervous system. The function of sensibility exhibits to us the mode in which the nervous system acts in connecting man with the objects around him, through the agency of volition; but a multitude of other acts take place within him, altogether unin- fluenced by volition, and yet indispensable for the maintenance of existence. These last acts are equally met with in the animal and vegetable; and hence a division has been made, by Bichat, into animal life, and organic life:—the former evidenced by those functions that are peculiar to animals—sensibility and voluntary motion—which require the presence of a great nervous centre, that may receive from, and transmit to, the different parts of the body, the nervous irradiation,—the necessary excitant of the different functions:—the latter evidenced by those functions that are com- mon to animals and vegetables, and are inservient to the nutrition of the frame, as digestion, absorption, respiration, circulation, &c, all of which go on without any direct exercise of volition; and oc- casionally, it has been believed, independently of all nervous influ- ence. Physiologists may, indeed, on this point, be divided into two classes:—they who consider that the whole of the organic func- tions are under the government of the nervous influence; and they who think that the nervous influence does not extend to all the or- ganic functions, but only to the principal of them. The supporters of the first opinion believe, that the agents, or conductors of the nervous influence, are less and less dependent upon the nervous centres, when such exist, the lower the animal is situated in the animal kingdom, and the lower the function; but they consider the nervous influence to be indispensable to every living being, and to every part of such being. In support of this opinion, they are of course compelled to believe, either that a ner- vous system exists in the vegetable, or that there is a system which appears to exert over every part of it an influence necessary for its life, and which is, consequently, analogous to the nervous system of animals. The organ of this influence is, by some bota- nists, considered to be the medulla or pith; whence medullary appendages set out, to be distributed to every part of the vegeta- ble, and which are particularly abundant, in such parts as are charged with very active functions,—as the flower. Brachet maintains this idea, and compares the knots of the pith to the gan- glions of the nervous system,—destruction of the pith, and especially of these knots, occasioning the death of the parts, that receive their filaments from them. Dutrochet, again, considers, that nervous corpuscles exist in the pith of vegetables, which constitute the ru- diments of a nervous system; only, in the vegetable, this system is diffused, instead of being collected in a mass. The believers in the earlier formation of the nervous system in the Vol. II. 61 482 LIFE. foetus will necessarily be in favour of this first opinion, and it would, of course, be strengthened if the results of the experiments of Du- mas on generation should be found correct, and if the spermatic animalcules, which, according to him, are the agents of fecundation, should be discovered to be the rudiments of the nervous system of the new individual, a circumstance, which, however, is as doubtful as the confirmation is difficult. The supporters of the second opinion, that the nervous influence does not extend to all the organic functions, assert, that it is chiefly ex- erted on those functions which are of the highest moment,—the most elevated in animality; that it is less and less in the inferior func- tions, and ultimately ceases in the lowest acts,—those that imme- diately accomplish nutrition and reproduction; and the arguments they adduce in favour of their views are, that these lowest acts exist in every living being—vegetable as well as animal; and that in the superior animal, and in man, there are many parts which do not ap- pear to contain nerves. They moreover consider the nervous sys- tem as one superadded to living beings, not only for life, nutrition and reproduction, but also, where necessary, for sensation, motion, &c, and hence the prolongations or extensions of this system ought to be sent to the organs of the internal or nutritive functions, for the purpose of connecting them with the organs of the external or sensorial functions; and that it is in these connexions only that in- nervation consists. In this view, consequently, the nervous influ- ence arises only from the necessity of connecting the organs; is but an indirect condition of life; exists in the upper animals only, and can in no way be invoked to account for vegetable life. The last is, in our view, the most accurate opinion. We cannot in the present state of knowledge, admit the existence of nerves in the vegetable: certainly no such thing as a nervous centre is disco- verable, and yet we find the most complicated acts of nutrition and reproduction exercised by it, and the principle of instinct, we shall find, as strikingly evidenced as in many animals. We are, there- fore, irresistibly led to the conclusion, that the manifestations of vitality are but little, if at all, connected with nervous influence, and that the nerves are added, in the upper animals and functions, for other purposes than that of directly communicating vital properties to the part. This deduction will be found confirmed by the facts to be hereafter mentioned, connected with the independence of the vital property of irritability of the nervous influence. We have elsewhere alluded to the similarity between the ner- vous and galvanic fluids, and to the notion which has even prevailed of the similarity if not identity between the vital principle and elec- tricity, as well as to the strange views of endosmose and exosmose, recently promulgated by Dutrochet, and which have been so hap- pily commented on by Dr. J. K. Mitchell. The mode, in which Dutrochet assimilates the phenomena of animal and vegetable life to the actions of endosmose and exosmose, is as follows. It is known life. 483 that the sap in vegetables ascends from the roots to the stalk; first, by the action of the spongioles or terminal buds of the roots, which are evidently organs for the absorption and impulsion of the sap; and secondly, by the action of the leaves, which, by exciting an action of transpiration and evaporation at the top of the plant,—the greater in proportion to the warmth and dryness of the air,—exert a kind of aspiration on the sap received by the spongioles. These spongioles Dutrochet considers to be cellular organs containing organic fluids in their interior; and, consequently, they cannot be plunged into water, without the fluid penetrating by endosmose, not only into their interior, but even as far as the top of the stalk. Hence, according to Dutrochet, endosmose constitutes the action of ab- sorption by the spongioles, and is the cause of the circulation of the sap. It presides, also, over the development and nutrition, the movements of composition and decomposition, of plants; for, as it consists of two opposite electric currents, it not only conveys fresh substances incessantly into the interior of the structures, and re- moves a part of those existing there, but also induces constant chy- mical modifications in the organic elements of parts;—every electrical action modifying the chymical nature of matter, as every chymical action induces a development of electricity. It is also the agent of the secretions. The exhalation of vegetables is, according to him, no more a simple physical evaporation than their absorption is the effect of capillarity. It also is a phenomenon of endosmose. He does not doubt, that capillarity, gravity, agitation by the winds, &c. exert an influence on the functions of vegetables, but he con- siders such influence to be accidental, and the true vital motor to be the electrical agent. He regards the medulla or pith of vegeta- bles to be to their organization, what the nervous system is to the organization of animals, and to be intended to dispense everywhere the vital activity, or electricity. As the conditions of endosmose,—namely, a vesicular structure and the presence of organic fluids denser than water in the vesicles, —exist in animals as well as in vegetables, Dutrochet invokes a similar influence in the case of the former as in that of the latter. In the same manner, as it occasions the progression of the sap in vegetables, it presides over the capillary circulation in animals, and especially over the progression of the blood in the veins, as well as over absorption, secretion, nutrition, &c. "All these actions, how- ever, take place by filtration through permeable, organic mem- branes,—all that has been said of the agency of the venous radicles in absorption, and of the arterial radicles in exhalation and nutri- tion, being, according to Dutrochet, physiological mythi. The sanguineous system constitutes a cavity devoid of^outlet, and it is by filtration through the parietes of the vessels, which constitute it, that it receives, and parts with, its elements. In short, endosmose is the essence of the life of animals, and as it is an electrical phe- nomenon, electricity, Dutrochet concludes, is the motor of the 484 LIFE. life of animals, as it is of that of vegetables. He, moreover, extends his theory to pathology, asserting, that as endosmose is the vital act par excellence and as it is a phenomenon of electricity, we may conceive that diseases may consist in some defect in endosmose or electricity, and that our therapeutical agents should be directed to the modification of such endosmose. Inflammation, for example, is, according to him, hyperendosmose. It is obvious, that the foundations of a theory, so extensive in its ramifications, ought to be tested by accurate, and repeated investi- gation, and that no deductions can be considered established, until this has been accomplished, and the base found to be impregnable. This has not been done. On the contrary, many of the positions have been seriously assailed by Poisson and Mitchell, and even Dutrochet's own faith seems to have been shaken in his electrical theory. The system of Bachoue de Vialer on innervation appears to rest on still less foundation. This, according to Adelon, is merely an application of the electro-chymical law of Becquerel, that, when two substances, made to communicate with each other by a conducting wire, simultaneously exert a chymical action with a third, a galvanic current is developed, which is always directed from the substance in which this action is strongest, towards that in which it is least. Now, says M. Bachoue, as the electric fluid is always evidenced during chymical action, and as in every organ, a simultaneous chymical action is constantly exerted by the trans- formation of arterial into venous blood; whilst by means of con- ductors,—the nerves,—the nervous centres communicate with every part of the organism,—in each nervous cord, a constant galvanic current must be established, proceeding from its central to its peri- pheral extremity, or vice versa, according as the ehymical action, whence this current emanates, predominates at the one or other extremity. This current, according to M. Bachoue, determines the play of each organ; and he explains, as follows, the mode in which it effects the different functions. First. The circulation be- ing continuous in animals, an agent, which is developed in a con- tinuous manner in their interior, must be looked for, as the cause of this function. This agent is the electric fluid, disengaged by the chymical action exerted simultaneously by the blood on the ner- vous centres, and on the organic tissues at the periphery; but as this action predominates in the centres, the galvanic current resulting from it is established from these centres towards the circulatory organs, and consequently the action of the latter is excited. To determine the current in this direction, nature occasions the af- flux of blood to the ganglions of the great sympathetic to predo- minate,—these ganglions being, in his view, the nervous centres, that preside over the circulation. A greater chymical action is thus induced in the ganglions, and of course a more marked centrifu- gal galvanic current. This arrangement has likewise the advantage LIFE. 485 of diminishing the conducting power of the nerves, in accordance with the principle in physics, that the power of any body as a con- ductor of electricity is less in proportion as such body exerts a more powerful electro-motive action, whence it results, that the circula- tion is freed as much as possible from the perturbations that might otherwise be caused in it by the currents incessantly traversing the other parts of the nervous system,—the cerebral and spinal nerves,— with which those of the great sympathetic communicate. So that the action of the circulatory organs is constantly provoked by the centrifugal galvanic current, resulting from the chymical action ex- erted by the blood simultaneously in the nervous centres, and in the organs at the periphery of the body; whilst the uninterrupted arrival of the blood in the organs constantly excites in them also the chymical action necessary for the development of the electricity, on which the continuity of the circulation is dependent. Secondly. M. Bachoue accounts, in the same way, for the mechanism of the sensorial functions. The contact between external agents and the sensitive, nervous extremities, renders the chymical action constant- ly produced by the contact of arterial blood there predominant; hence the production of a galvanic current passing from the circum- ference to the centre. This current excites the action of the brain to accomplish sensation ; and the brain, excited by the process, be- comes the seat of a more marked chymical action, which irradiates another, and a centrifugal, galvanic current to the muscles, that have to execute the movements. According to Bachoue's theory, therefore, all the phenomena of life are derived from a chymical action which gives rise to the de- velopment of electricity. He likewise extends his system to pa- thology. If the chymical action be comprised within due propor- tions, all the phenomena of life are performed in health; if, on the contrary, the proportions are inappropriate, disease results, which is always dependent on preternatural chymical actions giving rise to irregular galvanic currents. The remarks, made regarding the views of Dutrochet, are equally applicable to those of Bachoue. The very foundation, in- deed, has been assailed by the experiments of M. Pouillet, at the Hopital Saint Louis, of Paris, which contradict the existence of these centrifugal or centripetal galvanic currents, developed in the organs during the production of the vital phenomena. In the introductory remarks to the first volume of this work, the characters, which distinguish organized from inorganic bodies, were pointed out. All the characters of the former result from the in- fluence of the vital principle, which produces the body of a definite magnitude, shape, structure, composition and duration. There is, moreover, a power, possessed by bodies endowed with the living principle, of being acted upon by certain stimuli, and thrown into movement without the participation of the will. This has, indeed, by 486 LIFE. some physiologists, been considered to be the sole vital property,— with what truth we shall see hereafter. An inquiry into its mani- festations will aid us materially in determining whether or not the vital principle is effected directly through the medium of the nerves, and will tend to confirm an opinion, which we have already expressed on this subject. Prior to the time of Haller the nervous system was looked to as the great source of power in the body; and the contractile power of the muscles,—described at length under the head of muscular motion,—was considered to be wholly derived from the nerves, which were supposed to transmit the power to the muscular fibre as it was called for,—accurately regulating the quantity supplied. Haller contended for a vis insita, a power of irritability or contractility, essentially residing in the muscles themselves, inde- pendently of any condition of the nervous system, and called into action by stimuli, of which, in the case of the voluntary muscles, the nervous influence is one, contributing, however, like all other stimu- li, to exhaust it, instead of furnishing any fresh supply. We have else- where shown that a muscle is capable of being thrown into con- traction after a limb has been removed from the body, and for a considerable period after the cessation of respiration, circulation, and consequently of innervation, provided the appropriate stimuli be applied, so as to excite the vis insita which remains attached to the muscle for some time after dissolution; and if all the nerves, supplying the limbs of a frog, be divided, and cut out close to the place where they enter the muscles, the muscles will still retain their contractility in as great.a degree as when the nerves were entire. They who believe that the contractility of muscles is wholly derived from the nervous system, maintain, however, that, in such case, the stimulus may still act, through the medium of the portions of nerves that must always remain attached to the muscle, however carefully attempts may have been made to remove them; and some have supposed that these nervous fibres may even con- stitute an essential part of the muscular fibre. The most satisfac- tory reply, that has been made to this argument, is the following experiment of Dr. Wilson Philip. All the nerves, supplying one of the hind legs of a frog, were divided, so that it became com- pletely paralytic. The skin was removed from the muscles of the leg, and salt sprinkled upon them, which, being renewed from time to time, excited contractions in them for twelve minutes: at the end of this time they were found no longer capable of being ex- cited. The corresponding muscles of the other limb, in which the nerves were entire, and of which, consequently, the animal had a perfect command, were then laid bare, and the salt applied to them in the same way. In ten minutes they ceased to contract, and the animal had lost the command of them. The nerves of this limb were now divided, as those of the other had been, but the excita- bility of the muscles to which the salt had been applied was gone. LIFE. 487 Its application excited no contraction in them. After the experi- ment, the muscles of the thighs in both limbs were found to con- tract forcibly on the application of salt. It excited equally strong contraction on both sides. In this experiment, the excitability of the muscles, whose nerves were entire, was soonest exhausted; and hence Dr. Philip properly concludes, that the nervous influence, far from bestowing excitability on the muscles, exhausts it like other stimuli; and that the excitability or irritability is a property of the muscle itself. It seems, therefore, that this essential characteristic of living bodies is a distinct vital property, not confined, as Haller sup- posed, to the muscular structure, but existing over the whole body. In favour of its not being dependent upon the nerves, we have the fact of its presence in the vegetable as well as in the animal. Many plants exhibit the power in a remarkable manner. The barberry bush is one of these. In this flower, the six stamens, spreading moderately, are sheltered under the concave tips of the petals, till some extraneous body, as the feet or trunk of an insect in search of honey, touches the inner part of each filament near the bottom. The irritability of that part is such, that the filament im- mediately contracts there, and consequently strikes its anther, full of pollen, against the stigma. Any other part of the filament may be touched without this effect, provided no concussion be given to the whole. After a while, the filament retires gradually, and may be again stimulated; and when each petal, with its annexed fila- ment, is fallen to the ground, the latter, on being touched, shows as much irritability as ever. In another plant,—the Cistus helianthemum, dwarf cistus or lesser sunflower,—the filaments, when touched, execute a motion, the reverse of that of the barberry. They retire from the style and lie down, in a spreading form, upon the petals. Owing to the possession of this property, the Apocynum an- drosaemifolium or dogs-bane is extremely destructive to insect life. Attracted by the honey on the nectary of the expanded blossom, the instant the trunk of the fly is protruded to feed on it, the fila- ments close, and, catching the fly by the extremity of its proboscis, they detain the insect until its struggles end in death, occasioned apparently by exhaustion alone. The filaments then relax, and the body falls to the ground. These are only evidences, however, of particular psrts possessing unusual degrees of irritability. The property exists in every part of the plant, and, as in the animal, is the essential characteristic of the principle of life. Irritability or contractility forms a medium of communication between the various parts of the living machine, and is excited to action by extraneous influences. All its movements, how- ever, appear to be dependent upon the action of appropriate stimuli, and are, consequently, passively exercised. 488 LIFE. There is a power which has been conceived to be nearly allied to irritability, and is highly characteristic of organized bodies,— vegetable as well as animal,—whose movements or impulsions are active, and most varied. To this power, the term instinct has been appropriated by Virey, Fleming, Good, and others. It is an ex- tension of the ordinary acceptation of the term, but it enables us to understand the phenomena better than where we restrict it to those manifestations of man, or animals, that bear the semblance of reason. It is this power, which, according to those gentlemen, regulates the movements, that are requisite to obtain a supply of food, to remove or counteract opposing obstacles, and to fly from impending danger, or to repair injuries which may be occa- sioned. "In every organized system," says Dr. Good, "whether animal or vegetable, and in every part of such system, whether solid or fluid, we trace an evident proof of that controlling, and identifying power, which physiologists have denominated, and with much pro- priety, the principle of life. Of its cause and nature we know no more than we do of the cause and nature of gravitation, or mag- netism. It is neither essential mind nor essential matter; it is nei- ther passion nor sensation; but though unquestionably distinct from all these, is capable of combining with any of them; it is possessed of its own book of laws, to which, under the same circumstances, it adheres without the smallest deviation; and its sole and uniform aim, whether acting generally or locally, is that of health, preser- vation, or reproduction. The agency, by which it operates, is that which we denominate or should denominate instinct, and the ac- tions, by which its sole and uniform aim is accomplished, are what we mean or should mean by instinctive actions; or, to speak somewhat more precise^, instinct is the operation of the living principle, whenever manifestly directing its operations to the health, preservation, or reproduction of a living frame, or any part of such frame. The law of instinct, then, is the law of the living principle; instinctive actions are the actions of the living principle; and either is that power, which characteristically distinguishes organized from unorganized matter, and pervades and regulates the former, uniformly operating by definite means in definite circumstances, to the general welfare of the individual system or of its separate organs, advancing them to perfection, preserving them in it, or laying a foundation for their reproduction, as the nature of the case may require. It applies equally to plants and to animals, and to every part of the plant, as well as to every part of the animal, so long as such part continues alive. It is this, which maintains, from age to age, with so much nicety and precision, the distinctive characters of different kinds and species, which carries off the waste or worn out matter, supplies it with new, and in a thousand instances, suggests the mode of cure, or even effects the cure itself, in cases of injury or disease. It is 'the divinity that stirs within us' of Stahl, the vis medica- INSTINCT. 489 trix naturae of Hoffmann and Cullen and the physicians of our own day, &c. &c." Of the existence of this instinctive principle, we shall adduce a few examples from both the vegetable and the animal kingdom. When the seed of a plant is deposited in the ground, under circum- stances favourable for its development, it expands, and the root and stem are evolved. The root descends into the ground, manifestly not from the laws of gravitation, but owing to some inherent force, inasmuch as it penetrates the earth which is of much greater spe- dfic gravity than itself. The stem, too, bursts through the earth, and rises into the atmosphere, notwithstanding that the air is of much less specific gravity, until, having attained the height to which the action of the vital principle limits it, its upward develop- ment ceases. It rarely happens, however, that the root is capable of procuring nourishment sufficient for its future development in immediate contact with it. It, therefore, sends out numerous fila- mentous radicles in all directions to search after food, and to convey it to the proper organs. The number and direction of these filaments, and the distance to which they extend, are regulated by the neces- sities of the plant and the supply of the soil. A strawberry offset, planted in sand, will send out almost all of its runners in the direc- tion in which the proper soil lies nearest, and few, and sometimes none, in the direction in which it lies most remote. When a tree, which requires much moisture, has sprung up, or been planted in a dry soil, in the vicinity of water, it has been observed, that a much larger portion of its roots has been directed towards the water, and that, when a tree of a different species, and which requires a dry soil, has been placed in a similar situa- tion, it has appeared, in the direction given to its roots, to have avoided the water, and moist soil. When a tree, too, happens to grow from seed on a wall, it has been seen, on arriving at a cer- tain size, to stop for a while, and to send down a root to the ground. As soon as this root has been established in the soil, the tree has continued increasing to a large magnitude. The fact has been often noticed with respect to the ash,—a tree, which, in consequence of the profusion of its seed, is found more often scattered in wild and singular places, than any other not propagated by the agency of birds, or conveyed by the winds. We find, in all cases, that if the roots of a plant, spreading in search of nourishment, meet with interruption in their course, they do not arrest their progress, but either attempt to penetrate the op- posing body, or to avoid it by altering their direction. Dr. Flem- ing states, that he has repeatedly seen the creeping root of the Triticum repens or couch grass, piercing a potato, which had ob- structed its course. It is well known, too, that roots will pass under a stone wall or a ditch, and rise up on the opposite side. The nearest approximation to these manifestations of instinct, in Vol. II. 62 490 LIFE. the animal, occur in the formation of the new being, and in the first actions that take place after birth. From the moment of the admix- ture of the substances furnished by the parents at a fecundating co- pulation, there must be a principle existing in the embryo, which directs the construction and arrangement of its organs after a defi- nite manner, and always according to that peculiar to the species. In the egg this is seen, as we have elsewhere described, in the most distinct manner. The germ of the chick is surrounded, in the egg, by the nourishment requisite for its formation. Organ after organ becomes successively evolved, until the full period of incubation is accomplished, when it breaks the shell. At this time it has, within it, a portion of nutriment derived from the yolk drawn into the body. This' supplies its wants for a short period; but it soon be- comes necessary, that it should select and collect food for itself, and we observe it throwing its various organs into action for the prehension, mastication, deglutition, &c. of the food, as if it had been long accustomed to the execution of these functions. In the formation of the human foetus in utero the same instinctive action is observable in the successive evolution of organs, and in the limitation of the body to a determinate shape, size, structure, &c; and when these requisites have been attained, the child bursts the membranous envelope, and is extruded, to maintain thenceforth an existence independent of the mother. More helpless, however, than the young of the animal kingdom in general, the infant requires the fostering care of the parent, for the purpose of supplying it with the necessary nutriment, but as soon as food is conveyed to the lips, the whole of the complicated process of deglutition is effected for the first time, with the same facility as after long practice. As we des- cend in the animal kingdom we find these inward actions constitut- ing the instinct more and more largely exhibited. In the quadru- ped, it is not necessary that the nipple should be applied by the mother to the mouth of the new-born animal. It is sought for by the latter, invariably discovered, and as invariably seized hold of, by the appropriate organ of prehension—the mouth. The lips are applied; the air is exhausted; and the milk flows, according to exact principles of hydrostatics, but without the animal having the least knowledge of the physical process which it accomplishes. Natural- ists, indeed, assert, that before the calf has been more than half ex- truded from the mother, it has been seen to turn round, embrace, and suck the maternal teat. As we descend still farther in the scale of creation, we discover the manifestations of instinct yet more signally developed; until ul- timately, in the very lowest classes of animals, the whole of the functions are exercised much in the same manner as in the vegeta- ble; and appear to be wholly instinctive, without the slightest evi- dence of that intelligence, which we observe in the upper classes of the animal kingdom, and pre-eminently in man. This, however, INSTINCT. 491 applies only to the zoophyte; for, a short way higher up the scale, we meet with apparent intelligence, united with instinct in a man- ner that is truly surprising and mysterious. Again, the similarity of the actions of the instinctive principle, in the animal and vegetable, is exhibited by the reparatory power which both possess when injuries are inflicted upon them. If a branch be forcibly torn from a tree, the bark gradually accumulates around the wound, and cicatrization is at length accomplished. The great utility of many of our garden vegetables,—such as spin- ach, parsley, cress, &c.—depends upon the possession of a power to repair injuries, so that new shoots speedily take place where the leaves have been removed: similar to this is the reparatory process, instituted in the lobster that has lost its claw, and in the serpent de- prived of its tail. These parts are reproduced as the leaves are in the spinach or the parsley. But few animals, however, possess the property of restoring lost parts; whilst all are capable of repairing their own wounds when not excessive, and of exciting a sanative power, when labouring un- der disease. If a limb be torn from the body, provided the ani- mal does not die from hemorrhage, a reparatory effort is establish- ed, and if the severity of the injury does not induce too much irri- tation in the system, the wound will gradually fill up, and the skin form over it. To a lesser extent we see this power exerted in the healing of ordinary wounds, and in cementing broken bones; and although it may answer the purpose of the surgeon to have it supposed that he is possessed of healing salves, &c, he is well aware, that the great art, in these cases, is to keep the part entirely at rest, whilst his salves are applied simply for the purpose of keeping the wound moist; the edges in due apposition, where such is necessary, and extraneous bodies from having access to it,—his trust being al- together placed in the sanative influence of the instinctive power situated in the injured part, and in every part of the frame. It is to this power, that we must ascribe all the properties, assign- ed to the famous sympathetic powder of Sir Kenelm Digby,— which was supposed to have the wonderful property of healing wounds, when merely applied to the bloody cloths of the wounded person, or to the weapon that had inflicted the mischief. This pre- paration, at one time, enjoyed the most astonishing reputation. It was first employed at Florence in the commencement of the 17th century, by a Carmelite monk, who had just returned from India. The Grand Duke, hearing of the monk's marvellous cures, asked him for his secret, which he refused, fearing that the Duke would divulge it. Some time afterwards, Sir Kenelm Digby, having ren- dered an important service to the monk, the latter, out of grati- tude, communicated to him the composition of the powder; and Sir Kenelm took the secret with him to England. An opportunity soon occurred for testing its properties. A Mr. Howell, having been wounded in attempting to separate two of his friends engaged 492 LIFE. in a duel, was subjected to its employment. Four days after the infliction of the wound, Sir Kenelm dipped one of Mr. Howell's garters in a solution of the powder; and, immediately, it is as- serted, the wound, which was previously painful, became easy; but, as the garter grew dry, the pains returned, and were relieved by a fresh immersion in the solution. In five or six days the wound healed. James the first; his son, afterwards Charles the second; the Duke of Buckingham, and all the principal personages about the court were acquainted with the circumstances of the case; and James, whose enthusiasm was not counterbalanced by much judgment, and who was, withal, superstitious to the highest degree, obtained the secret from Sir Kenelm, and himself operated most astonishing cures. In no great length of time the composition trans- pired, and, as in all similar cases, the charm evaporated with the disclosure. Dryden alludes to the superstition in his Enchanted Island, where Miranda enters with Hippolito's sword wrapped up. " Hip. O my wounds pain me. (~She unwraps the sword. J Mir. I am come to ease you. Hip. Alas! I feel the cold air come to me; My wound shoots worse than ever. Mm. Does it still grieve you? (~She wipes and anoints the sword. J Hip. Now, methinks, there's something laid just upon it. Mm. Do you find no ease? Hip. Yes^ Yes; upon the sudden all this pain Is leaving me.—Sweet heaven, how am I eased!" The powder, employed by Sir Kenelm Digby, is asserted to have been the sulphate of copper prepared in a particular man- ner. Some affirm it to have been the ordinary green vitriol of commerce. The sympathetic ointments applied to the weapon were of va- rious characters, containing the most absurd, disgusting, and inert ingredients;—as we see in the following quotation from the Sylva Sylvarum, or Natural History of Lord Bacon, whose great mind was too frequently imbued with the superstitions and prejudices of his age. The mode of managing the wound itself sufficiently ac- counts for the good effects ascribed to the "cure by sympathy." "It is constantly received and avouched, that the anointing of the weapon that maketh the wound, will heal the wound itself. In this experiment, upon the relation of men of credit, though myself, as yet, am not fully inclined to believe to it, you shall note the points following: first, the ointment, with which this is done, is made of divers ingredients; whereof the strangest and hardest to come by, are the moss upon the skull of a dead man unburied; and the fats of a boar and a bear killed in the act of generation. These two last I could easily suspect to be prescribed as a starting hole; that if the experiment proved not, it might be pretended that the beasts were not killed in the due time; for as for the moss, it is certain there is INSTINCT. 493 great quantity of it in Ireland, upon slain bodies, laid in heaps un- buried. The other ingredients are, the blood-stone in powder, and some other things, which seem to have a virtue to staunch blood; as also the moss hath. And the description of the whole ointment is to be found in the chymical dispensatory of Crollitjs. Secondly, the same kind of ointment applied to the part itself, worketh not the effect; but only applied to the weapon. . Thirdly, which I like well, they do not observe the confecting of the ointment under any certain constellation; which commonly is the excuse of magical medicines when they fail, that they were not made under a fit figure of heaven. Fourthly, it may be applied to the weapon, though the party hurt be at a great distance. Fifthly, it seemeth the imagination of the party to be cured is not needful to concur; for it may be done without the knowledge of the party wounded; and thus much has been tried, that the ointment, for experiment's sake, hath been wiped off the weapon, without the knowledge of the party hurt, and presently the party hurt has been in great rage of pain, till the weapon was reanointed. Sixthly, it is affirmed, that if you cannot get the weapon, yet if you put an instrument of iron or wood, resembling the weapon, into the wound, whereby it bleed- eth,the anointing of that instrument will serve and work the effect. This I doubt should be a device to keep this strange form of cure in request and use; because many times you cannot come by the weapon itself. Seventhly, the wound must be at first washed clean with white wine, or the party's own water; and then bound up close in fine linen, and no more dressing renewed till it be whole. Eightly, the sword itself must be wrapped up close, as far as the ointment goeth, that it taketh no wind. Ninthly, the ointment, if you wipe it off from the sword and keep it, will serve again; and rather increase in virtue than diminish. Tenthly, it will cure in far shorter time, than ointments of wounds commonly do. Lastly, it will cure a beast as well as a man; which I like best of all the rest, because it subjecteth the matter to an easy trial." The line in the above quotation, marked in Italics, is the key to the solution of the whole mystery. It is, indeed, the practice adopted at the present day in the treatment of incised wounds; and to this, not to the influence of the sympathetic powder, or ointment, it need hardly be said, must the whole agency be ascribed. The wound was carefully defended from irritation by extraneous sub- stances, and given up to that instinctive principle, which, we have seen, repairs the injuries to which organized bodies are liable: and it has been suggested that the result furnished the first hint, which led surgeons to the improved practice of healing wounds by what is technically called the first intention. It is to this instinctive principle, so clearly evinced in surgical or external af- fections, but not less actively exerted in cases of internal mischief, that the term vis medicatrix naturas,has been assigned: and what- ever may be the objections to' the views entertained regarding its 494 LIFE. manifestations in disease, that such a power exists can no more be denied than that organized bodies are possessed of the vital prin- ciple. We have too many instances of recovery from injuries, not only without the aid of the practitioner, but even in spite of it, to doubt for a moment, that there is, within every living body, a prin- ciple, whose operations are manifestly directed to the health and preservation of the frame, and of every part of such frame. So far, then, it is manifest, that the instinctive actions of the animal and the vegetable are exerted according to the same laws, and probably through similar organs. This, at least, applies to the lowest of all animated beings, where the difference between them and the vegetable is small indeed. It applies equally to the human foetus, which can be considered but to vegetate during the greater part of utero-gestation; and even for some time after birth, its actions are purely instinctive, and differ but little from those of the vege- table, except that, owing to the organization of its nervous system, the acts are of a more complicated character. It is only when the brain has become duly developed, and the external senses fully so, that it exhibits so decidedly the difference between those acts which it had previously accomplished instinctively, and the elevated phe- nomena of sensibility, which man enjoys so pre-eminently, but which are likewise possessed, to a greater or less extent, by the whole animal creation. It is the difficulty, which occurs in pointing out the exact dif- ference between the manifestations of instinct and those of intelli- gence, that has induced some individuals to deny to animals the possession of the former. We have seen the mode in which the principle is evidenced in the zoophyte and in the vegetable; and it is but an extension of it, that we witness in the beings still higher in the scale. Yet how wonderful and inexplicable are its operations; and how forcible its impulsion in these minute animals that sur- prise us by the ingenuity and forethought with which all their ac- tions, for the preservation and reproduction of the species, are di- rected ! Let us take a few examples, from the many afforded by the insect tribe. The cells of the ordinary honey-comb are intended for the larvae of the different varieties of the occupants of the hive. These cells are usually placed horizontally, with their mouths open- ing towards the sides of the hive. The bottom of the cells, in- stead of forming one flat square, is composed of three lozenge- shaped pieces, so united as to make the cell end in a point; conse- quently, the whole forms a hexagonal tube, terminating in a pyra- midal cavity. If the two cells had been a single hexagonal tube, intersected in the middle by a flat, instead of a pyramidal, division, not only would the shape not have answered the purpose of the bees, but more wax would have been expended in its construction. Hence, it would seem, that both the body and the base of the tube are the best adapted for their object; that the greatest strength and INSTINCT. 495 the greatest capacity are obtained with the least expenditure of wax in a hexagonal tube with a pyramidal base. Reaumur, when inquiring into the habitudes of these industrious animals, requested Koenig, an able mathematician, to solve the fol- lowing question:—among all the hexagonal tubes, with pyramidal bases composed of three similar and equal rhombs, to determine that which having the same capacity, can be constructed with the least possible quantity of matter? Koenig, not aware of the precise object of Reaumur's inquiry* solved the problem, and found,—that if three rhombs or lozenges were so inclined to each other that the great angles measured 109° 26', and the little angles 70° 34', the smallest possible quantity of matter would be needed. Maraldi measured the an- gles actually formed at the bottom of a cell, and found that the great angles gave 109° 28', and the little 70° 32'. All this, how- ever, may be ascribed to blind instinct, proceeding uniformly in the same tract, without any evidence of the admixture of reason; but we have innumerable instances, in the same insects, to show, that their operations are varied according to circumstances, and that in- telligence is manifestly expended in the adaptation of their means to definite purposes. Of this we will assign but one example. Hu- ber, whose inquiries into this part of entomology have been singu- larly minute and accurate, having had great ravages committed on his hives by the sphinx atropos or death's-head moth, deter- mined to construct a grating which should admit a bee but not the moth. He did so, and the devastation ceased. He found, however, that in other hives, not protected by his agency, the bees had adopted a similar expedient for their defence; and these defences were variously constructed in different hives. " Here, was a single wall whose opening arcades were disposed at its higher parts; there, were several bulwarks behind each other, like the bastions of our citadels: gateways, masked by walls in front, opened on the face of the second rows, while they did not correspond with the apertures of the first. Sometimes a series of intersecting arcades permitted free egress to the bees, but refused admittance to their enemies. These fortifications were massy, and their substance firm and com- pact, being composed of propolis and wax." It would be endless, and beyond the design of this work, to enu- merate the various evidences of intelligence, exhibited by the insect tribe, in fulfilling the ends for which they have been destined by the Great Author of nature; but there are one or two, which have been recently given to the world in an interesting little volume, entitled, The Natural History of Insects, which are such signal instances of the union of instinct with intelligence, as to deserve special mention. A species of spider,—mygale cmentarm—inhabiting the south oT Europe, constructs a cylindrical cavity more than two feet long, in some sloping bank, calculated to let the water run off; the inside is lined with a web of fine silk. But, in addition to the sagacity of 496 LIFE. choosing a steep bank, and the luxury of furnishing its retreat with silk, this spider is capable of constructing a regular door; for this purpose, it joins and cements layers of clay or chalk with its gluti- nous secretions, and thus contrives to make a door exactly circular, and so nicely fitting into the aperture of the cell, as to prevent its being distinguished by the casual observer from the surrounding earth. But the most singular circumstance is yet to be told. The sagacious creature fabricates a hinge of silk, which it invariably fixes to the highest part of the aperture, so that it can very easily be pushed open from within by the insect, and shuts by its own weight. Thus barricadoed, the gallery furnishes a secure habitation for the male and female, with twenty or thirty of their young. No noise however loud, no thumping however violent, will bring the wary insect out of its cell; but if the least attempt be made to force the trap-door, the spider immediately runs to it, and fixing some of its legs to the silk that lines the door, and the rest to the walls of the cell, it pulls with all its might against the intruder. The fact has been proved by lifting the door with a pin, when the counter tugs of the spider, endeavouring to shut it, have been distinctly felt. The water spider—aranea aquatica—is no less singular in its habits, proceedings, and instincts. As soon as it has caught its prey on the shore, it dives to the bottom of the water and there devours it. It is, consequently, an amphibious animal, although seeming to be better adapted for living in contact with the atmosphere than with the water. " The diving-bell is a modern invention; and few facts excite our wonder more than the possibility of a man's being enabled to live and move at the bottom of the ocean. This triumph of reason over the unfriendly element, however, was anticipated by an insect,—the spider in question. This creature spins some loose threads, which it attaches to the leaves of aquatic plants; it then varnishes them with a glutinous secretion, which resembles liquid glass, and is so elastic as to admit of considerable distention and contraction. It next lays a coating of this same substance over its own body, and underneath this coating introduces a bubble of air. Naturalists conjecture, that it has the power of drawing this air in at the anus, from the atmosphere at the surface of the pool, but the precise mode in which it is separated from the body of the atmosphere, and introduced under the pellicle covering the insect's body, has not been clearly ascertained. Thus clothed, and shining like a ball of quicksilver, it darts through the waters, to the spot in which it had fixed its habitation; and, disengaging the bubble from under the pellicle, it dexterously introduces it into a web formed at the bottom. After repeatedly moving from the top to the bottom of the water, and, at each journey filling its habitation with a fresh bubble of air, at length the lighter, completely expels the heavier, fluid, and the insect takes possession of an aerial habitation,—com* modious and dry,—finished in the very midst of the waters. It is about the size and shape of half a pigeon's egg. From this curi- INSTINCT. 497 ous chamber the spider hunts, searching sometimes the waters, and sometimes the land, for its prey, which, when obtained, is trans- ported to this subaquatic mansion, and devoured at leisure. The male, as well as the female, exhibits the same instincts. Early in the spring the former seeks the mansion of the latter, and, having enlarged it by the introduction of a little more air, takes up its abode with its mate. About the middle of April, the eggs are laid, and, packed up in a silken cocoon in a corner of their habitation, are watched with incessant care by the female. In all our reasonings, then, on the subject of instinct, we must be compelled to admit, in the case of most animals at least, a union of intelligence which strikingly modifies those actions,—the impulse to which is doubtless laid in organization. The precise line of de- marcation between instinctive acts and reason cannot, however, be established, and this has led some philosophers to call in question the existence of the former:— " Tell me why the ant, 'Midst summer's plenty, thinks of winter's want, By constant journeys careful to prepare Her stores; and, bringing home the corny ear, By what instruction does she bite the grain, Lest, hid in earth, and taking root again, It might elude the foresight of her care ? Distinct in either insect's deed appear ^ The marks of thought, contrivance, hope, and fear. It is owing to this union of intelligence with instinct, that we find animals accommodating themselves to circumstances, so that if pre- vented from adopting the habits that belong to the species, they have recourse to others as similar as possible. Thus, if a bird is prevented from building its nest in a particular situation, or from obtaining the material which birds of its own species employ, it has recourse to other materials and to another situation, as like those that are appropriate to it as is practicable. The rook usually and instinctively builds its nest on the summit of the tallest trees: but Dr. Darwin,—who is one of those that call in question the influence of instinct,—asserts, that m Welbourn church-vard, a rookery was formed on the outside of the spire, and on the tops of the loftiest windows. There had formerly been a row or grove of high trees in the neighbourhood, which had been cut down, and, in consequence, the birds exhibited the union of intelli- gence with instinct, by building on the lotty spire and windows. E like manner, the jackdaw, of Selbourn according to Mr. White not finding a sufficiency of steeples and lofty houses, on which to hang their nests in that village, accommodated themselves to cir- cumstances, and built them in forsaken rabbit burrows. Bv Stahl, and the animists in general, as well as by more re- cent philosophers, the whole of the phenomena of instinct have been referred to experience, so obscure as not to be easily traceable, Vol. II. 63 498 LIFE. but not the less certainly existent. The insect tribes, however, fur- nish us with many cases where the young being can never see the parents,and can, of course, derive no benefit from the experience of its progenitors. Yet their habits are precisely what they have pro- bably ever been: so uniform, indeed, as to compel us to refer them to some constant impulse connected with their special organization, and consequently instinctive. In support of the existence of these natural impulsions, the com- mon occurrence of a brood of young ducks, brought up under a hen, has been adduced. These little beings, soon after they have broken the shell, and contrary to all the feelings and instincts of the foster mother, will seek the water, and suddenly plunge into it, whilst the hen herself does not dare to follow them. By what kind of experience or observation,—it has been asked,—by what train of thought or reasoning has the scarcely fledged brood been able to discern that a web-foot adapts them for swimming? Any experi- ence they can have derived must have taught them to shun the water, yet notwithstanding this, instinct points out to them the ha- bitudes to which they are adapted, and its indications are obeyed in spite of every kind of counter-experience. Our own country affords us an example of singular instinctive in- dustry in the Scarabaeus pilularis or tumble-turd, as it is vul- garly called. These common and remarkable beetles appear in April or May, and continue through the summer months, or till about September, when they disappear, and no more is seen of them until the following spring. Their constant employment, for the perpetuation of their, species, is in providing appro- priate nidi in which to deposit their eggs. This they effect by forming balls of dung, in the middle of which they deposit an egg. These balls are then buried in the earth, where they remain until the approach of spring, when the young are hatched, and make their way above ground. The industry and skill they exhibit, in forming and rolling these balls, is astonishing. One of the insects forces the ball onwards with his hind-feet, by raising himself on his fore-feet, whilst its companion draws down the ball on the opposite side with its fore-feet. In this manner, the ball is rolled until they come to a place where the ground allows the ball to be deposited, which is effected by the insect forming an excavation under it, and letting it fall downwards. Catesby says, that they convey their pellets three feet deep in the ground, but they are certainly satisfied with a less depth in Virginia. This insect has been considered peculiar to America. Aristotle and Pliny, however, mention a kind of beetle, which rolls large balls of dung with its feet backwards, and lodges within it,—to protect them from the rigor of winterj—small worms, which be- come its young. Dr. Good has adduced the singular instance of instinct exhibited by the Cancer ruricola or land-crab, an inhabitant of tropical INSTINCT. 499 climes, and especially of the Bahamas. It is gregarious, and associ- ates in large bodies, which seem to form an orderly society for the most part in the recesses of inland mountains, though they regular- ly once a year march down to the sea-side in an army of millions, to deposit their spawn in the ocean. The time, embraced for this expedition, is generally the month of May, when they sally forth from the stumps of hollow trees, the clefts of rocks, and subterra- neous burrows, in enormous multitudes. The whole ground is co- vered, and no geometrician, it would seem, could direct them to their destined station by a shorter route. No intervening obstacle arrests them. If they meet with a house, they will rather attempt to scale the walls than relinquish the direct path. Occasionally, however, they are constrained to conform to the surface of the country, and if it be intersected by a river, they pursue the stream to its fountain head. In great dearth of rain they are compelled to halt, when they seek the most convenient encampment, and remain there till the weather changes. A like halt is made when the solar heat is intense, and until the cool of evening, when they resume their progress. The journey often takes up three months before they reach the sea-coast. As soon as they arrive at the water, they plunge in, shake off their spawn upon the sands, and immediately direct their course back to the interior of the country. The soft sand is an appropriate nidus for the spawn, and, under the influence of the solar heat and of moisture, millions of little crabs are usher- ed into being, and are seen crawling to the shore, and exploring their way into the interior of the country; thus quitting their birth- place, for a state of existence entirely opposite, to which no expe- rience can have impelled them, and to which they are directed by an irresistible impulse situated within them. Instinct, then, is possessed by every organized body, animal and vegetable; whilst intelligence is the attribute of those only that are endowed with a certain nervous development. They are, therefore, manifestly distinct;—the former predominating over the latter in the lower classes of animals; whilst, in the upper classes, intel- ligence becomes more and more predominant, until ultimately in man it is so ascendant as to appear to be the main regulator of the functions; indeed, some have altogether denied the existence of in- stinct in man. Instinct is seated in every part of a living body; is to- tally independent of the nervous system; occurs in the vegetable and the zoophyte unprovided with nerves, or at least in which nerves have never been discovered; whilst intelligence is always accompanied by a nervous system, without which, indeed, its existence is incompre- hensible. How can we, consequently, accord with those physiologists who place the seat of instinct in the organic nervous system; whilst that of intelligence is in the brain? Where is the organic nervous system of the zoophyte, and a fortiori of the vegetable? Or how can we admit the seat of the various instincts, with Gall, to be in the brain, seeing that we have them exhibited where there is no 500 LIFE. brain nor any thing resembling one. The acephalous fcetus under- goes its full development in other respects, in utero, with the same regularity, as to shape and size, as the perfect fcetus, and can we deny it the existence of instinct? Yet, in the upper classes of animals especially, many of the ma- nifestations of instinct are effected through the nervous system, which, in them, as we have elsewhere seen, seems to hold in con- trol the various functions of the frame, and to be one of the two great requisites for the existence of vitality. The instinctive action in the appropriate organ, which gives rise to the internal sensations of hunger, thirst, &c, is communicated to the great nervous cen- tres by the nerves, and the brain responds to the impression, and excites, through the medium of the nerves, the various organs into ac- tion, which are calculated to accomplish the monitions of the instinct. What is the nature of this instinctive property ? Of this we know no more than we do of the principle of life, of which it is one of the manifestations. It is equally inscrutable with the impondera- ble agents, light, caloric, electricity, or magnetism, or with the mode of existence of the immaterial principle within us, which gives rise to the mental phenomena: we see it only in its results; which are, in many cases, as unequivocal as those produced by the agents just referred to. All, perhaps, that we are justified in con- cluding is, with Dr. Good, that instinct is the operation of the prin- ciple of organized life, by the exertion of certain natural powers, directed to the present or future good of the individual, whilst rea- son is the operation of the principle of intellectual life, by the ex- ercise of certain acquired powers directed to the same object; that the former appertains to the whole organized mass as gravitation does to the whole unorganized; actuating alike the smallest and the largest portions; the minutestparticles and the bulkiest systems; and every organ and every part of every organ, whether solid or fluid, so long as it continues alive; that, like gravitation, it exhibits, under particular circumstances, different modifications, different powers and different effects; but that, like gravitation, too, it is subject to its own division of laws, to which, under definite circumstances, it adheres without the slightest deviation; and that its sole and uni- form aim, whether acting generally or locally, is thatof perfection, preservation or reproduction. In this view, reason demands discipline, and attains maturity; instinct, on the contrary, neither requires the one, nor is capable of attaining the other. It is mature from the first, and equally so in the infant as in the adult. The great cause of all those mysterious phenomena, which cha- racterize living bodies, and distinguish them by such broad demar- cations from the dead, has been a theme of anxious inquiry in all ages; and has ever ended in the supposition of some special abstract force, to which the epithet vital has been assigned, and which has VITAL PROPERTIES. 501 received various appellations. Hippocrates designated it by the terms p^cvs, and evo^ov; Aristotle styled it the animating or motive and generative principle; Van Helmont, the archaeus; Stahl, anima; Barthez, Hunter, &c. vital principle, &c. &c. Yet, as Dr. Barclay has correctly observed, all physiological writers,—ancient and modern,—seem to be agreed, that the causes of life and organization are utterly invisible, whether they pass under the name of animating principles, (Aristotle, Harvey, &c.) vital principles, (Barthez,) indivisible atoms, spermatic powers, organic particles or organic germs, (Buffon,) formative appeten- cies or formative propensities, (Darwin,) formative forces, (Need- ham,) formative nisus or bildungstrieb, (Blumenbach,) pre-existing monads, (Leibnitz,) semina rerum, (Lucretius,) plastic natures, (Cudworth,) occult qualities, or certain unknown chymical affinities. " All seem agreed, that whatever they be, they have been operating since the world began, and throughout the world operating regularly, without intermission, in various places at the same time. All seem agreed, that their modes of operation are strictly methodical; that they seem to act on definite plans, and actually exhibit specific varieties of chymical combination, and mechanical structure, which human intelligence cannot compre- hend, much less explain. From their mutual dependence, and other relations subsisting between them, all seem to speak as if they were subjected to one great cause, which regulates and har- monizes the whole. All seem to speak of this great cause as if it were eternal, omnipotent, omnipresent: whether it be the element of fire, of air, or of water, or whether it be fate, nature, necessity, or a God." By virtue of this principle of life, every organized tissue is pos- sessed of certain properties, to which the term vital has been as- signed. Regarding the precise number of these properties, phy- siologists are not agreed. Whilst some have reckoned many; others have admitted but one. All the functions, which we have hitherto considered, are under the influence of life, and are products of the vital properties seated in the tissues; but we do not consider them to be directly caused by these properties. Digestion, for example, is executed by a se- ries of organs, all of which are conducive to a certain result, the aggregate constituting the function of digestion. The result of the action of the salivary gland is very different from that of the liver; yet both operations are vital, but modified by the different organi- zation of the two glands. We do not, however, ascribe the differ- ence to a difference in the vital properties of the glands. They are probably the same in both; and are seated in the primary tis- sues, of which all the more compound textures and organs are built up. They are primary or fundamental properties of living matter. Stahl, having observed obscure, oscillatory movements, alter- 502 life. nate contraction and expansion in certain parts of the body, either during the exercise of a function, or on the application of some external agent, conceived that every part of the frame is, at all times, more or less susceptible of similar movements. These movements he called tonic, their effect upon the organs tone, and the property by which they were induced he considered peculiar to organization, and termed it tonicity. This vital property, he conceived, influenced the progression of the fluids in the vessels; the phenomena of exhalation and absorption, and was totally dis- tinct from the properties possessed by inorganic bodies. Haller admitted two vital properties, very distinct from each other, which seemed to him to be equally elementary. The one of these is that by which a living part exhibits itself to be sensible, or transmits to the sensorium an impression made upon it, either by an extraneous body, or by its own internal and or- ganic action. The other is that by which a part contracts in a manner appreciable to the senses, either by the influence of the will, or of some external or internal stimulus. The first of these he considered to be a special vital property, which he termed sensibility; and the second to be another pro- perty, which he called irritability. Prior toTiis time, the word irritability had been adopted by Glisson, who had noticed the fact, that living matter was acted upon by irritations of various kinds, in a mode nowise analogous to physical and chymical mo- tions, and hence he concluded, that every organ of the human frame possesses an inherent and peculiar force, which presides over its movements, and is requisite for the exercise of its functions. This force he called irritability. Von Gorter subsequently ex- tended the views of Glisson, and applied them to the vegetable; affirming irritability to be the sole vital property of all organized bodies; vegetable as well as animal. The acceptation, given to the term by Haller, was conse- quently, more limited. He restricted it to those motions only of parts which fall under the observation of the senses; such as the contraction of the voluntary muscles, heart, &c. He made numer- ous experiments on living animals, for the purpose of discovering what parts are possessed or not of the two properties of sensibility and irritability, and he concluded, that the former resides exclu- sively in the nervous,—the latter in the muscular, system. This celebrated theory, which formed so large a part of physio- logical science at one time, and is still an interesting topic to the physiologist, has been referred to in so many parts of this work, as to require but few comments in this place. We have seen that many of the parts, regarded by Haller as insensible, are acutely sensible in disease, and that we cannot pronounce a part to be positively insensible until we have applied every kind of irritant to it without effect. We have elsewhere defined sensibility to be an exclusive property of the nervous system; and have attempted VITAL PROPERTIES. 503 to show that irritability is a property of the muscular tissue,—a vis insita—totally independent of the nerves, but of which the nervous fluid is an appropriate excitant. As, however, the vital properties of sensibility and irritability were restricted by Haller to the nervous and muscular systems, they were regarded to be insufficient for the explanation of the various living actions of the frame: the next step was, therefore, to extend them to every part and to every tissue. It was found, for example, that on investigating the most minute movements of parts, these movements were always preceded by an impression, to which they seemed sensible, and which appeared to excite their actions. This general property, common to every living part, of receiving an impression, was called sensibility; thus generalizing the property, which Haller had restricted to perceptivity by the mind. Every part was said to be sensible to the blood sent to it for its nutrition. Again, every part was observed to move in con- sequence of the impression it received, sometimes in an apparent manner,—-as the heart; at others too slightly for its movements to be recognised otherwise than by the results,—as in the case of the glandular organs; but always in a manner special to organized matter, and not analogous to any physical or chymical process. This motion was, therefore, referred to another force, called motility, which is nothing more than irritability generalized. These two properties are alone admitted by most modern writers. Every organ is said to feel and to move, after its manner, in the performance of its function;—the stomach in digestion; the heart in propelling the blood; the muscle in contracting, and the nerve in transmitting sensitive impressions to the brain. Many modern physiologists, whilst they admit the properties of sensibility and motility, have reckoned a greater number of vital properties; and this owing to their having observed that each part has its own peculiar mode of sensibility and motility, and when these modes have seemed to differ largely from each other, they have elevated them into so many special, vital properties. The chief modern theories on the vital properties are those of Barthez, Blumenbach, Chaussier, Dumas, and Bichat. Bar- thez admitted five, which we can do no more than enumerate: sensibility, force of contraction, force of expansion or active dilatation, force of fixed situation, and tonicity. Blumenbach also admitted five;—sensibility, irritability, contractility, vita propria or proper force of life, and nisus formativus, force of formation or bildungstrieb. Dumas referred all the living phenomena to four vital properties; sensibility, motility, force of assimilation, and force of vital resistance. The theory of Bichat on this subject requires a more detailed notice. He also admitted five vital properties; organic sensi- bility, insensible organic contractility, sensible organic con- tractility, animal sensibility, and animal contractility. 504 LIFE. First. Organic sensibility is the faculty possessed by every living fibre of receiving an impression, or of being modified by contact, so that the modification is restricted to the part that ex- periences it, and is not transmitted to the brain. The term sensibility was adopted by Bichat because already established, and the epithet organic was added, to affirm, that it is the exclusive attribute of organized bodies, and common to all. This property is not only modified in each organ, as the difference in their nutrition and functions demonstrates, but it adapts each organ to its appropriate external stimulant, so that the salivary gland shall be specially influenced by mercury; the upper part of the small intestine by calomel; the lower by aloes, &c. &c. Its exercise is continuous, involuntary, known only by its results, and is more marked as we descend in the scale of animal life; whilst animal sensibility is the contrary. Secondly. Insensible organic contractility is the faculty posses- sed by every living part, of moving in an imperceptible manner, in consequence of an impression immediately received, without either the mind having consciousness of the motion, the will participating, or the brain in any manner directing it. We have an example of this in the action of the stomach during digestion; and of every part of the body on the blood sent to it for its nutrition. Bichat applied the term insensible organic contractility to this property for the following reasons;—contractility, because contraction is the kind of motion which constitutes it; organic, because it is common to all living beings; and insensible, because the brain has no consciousness of it. Like organic sensibility, it is modified in each organ. Its exercise is likewise continuous and involun- tary; and it also exhibits itself more intensely as we descend in the scale of beings. It always co-exists with organic sensi- bility. Thirdly. Sensible organic contractility is the same motive faculty as the last, with this difference, that the movements induced by it fall under the senses, and are recognised independently of their results. This property is likewise modified in each organ; its exercise is also involuntary, and it only differs from the last in degree,—the movement that constitutes it being apparent. Thus, the heart contracts independently of the will, but its motions are not imperceptible, as in the cases which belong to the second vital property of insensible organic contractility. Fourthly. Animal sensibility is the property possessed by cer- tain organs of transmitting to the mind, through the medium of the brain, the consciousness of impressions which they have re- ceived. It is sensibility in the restricted acceptation of Haller. The epithet animal was given to it by Bichat to distinguish it from the other variety of sensibility, which belongs to all orga- nized bodies, whilst this is exclusively possessed by animals. The whole of the attributes of this property have been detailed, at much VITAL PROPERTIES. 505 length, in the first volume of this work. Fifthly. Bichat ad- mitted a fifth vital property, under the name animal contrac- tility, which comprised voluntary muscular contraction;—treated of elsewhere as one of the functions of the body. It differs from organic contractility, in its exciting cause not being seated in the organ in which it is developed, that is, in the muscle, but in the brain; and, moreover, whilst the other varieties of contractility are irresistibly connected with, and proportioned to, the kind of sensibility correspondent to them, this is not the case with animal sensibility, and its play is never continuous. From the distinction we have endeavoured to draw, between the fundamental vital properties and the functions, it will be obvious, that the ingenious division of Bichat is susceptible of farther cur- tailment by analysis. A vital property must be one possessed by all living bodies; it is fundamental in the tissues, and differs according to the precise structure of the tissue. It is found in the vegetable, as well as in the animal. Neither of the two last properties of Bichat, how- ever, corresponds with this definition. They do not exist in the vegetable. They require not only a nervous system, but a brain that can conceive and will. They are both, indeed, complicated functions, and as such have been considered at great length, else- where. By ultimate analysis, therefore, the five vital properties of Bichat may be reduced to the two we have previously men- tioned:—sensibility, and motility. Perhaps we ought to rest satisfied with the admission, that every primary tissue is ca- pable of being acted upon by appropriate stimuli, or is sensible; and that it possesses the additional property of moving, in conse- quence of such impression. Physiologists have, however, attempted to simplify the subject still farther, and to reduce the vital proper- ties to one only. Such is the view of Broussais, who considers contractility to be. the fundamental vital property of all the tis- sues. We have elsewhere shown, however, that even in the mus- cular fibre it is by no means clear, that positive contraction of the fibres occurs, and that the two extremities of a muscle are con- ceived, by some late physiologists, to be brought into approxima- tion by their fibres assuming a zigzag arrangement. In the pri- mary nervous, and cellular tissues, the existence of such contracti- lity is yet more doubtful. Adelon, again, considers that sensibility is the only living property that must be admitted. " Hitherto," he remarks, "phy- siologists have separated the susceptibility of receiving the impres- sion that excites the movement, from the faculty of producing it, and have admitted two vital properties under the names sensibility and motility. Supposing an instant, however short, between the moment of impression, and that of the motion which follows it, they have looked upon the act of receiving the impression as distinct from that of moving in consequence of it. But these acts Vol. II. 64 50G LIFE. are really but one. It is the movement executed by a part, in con- sequence of an impression, which proves that the part has been sensible to such impression. To feel, as Chaussier and Bichat have remarked, is merely to vary the mode of existence in conse- quence of an impression. It is merely moving in a manner which is neither physical nor chymical. This is evident where the move- ments are occult: without the results induced by these movements, sensibility would not have been manifested." For these and other reasons he concludes, that " the two properties, sensibility and mo- tility, are reducible to one only, which may be called sensibility, if desired, but which must carry with it the idea of motion, and is the active, motive faculty of living matter." The term sensibility is, however, unfortunate, in consequence of its conveying the no- tion of mental perception, and of such acceptation having been re-% ceived into physiology, as designating a function. It has, conse- quently, been proposed to substitute the term excitability, insta- bility, or irritability, but with the same signification. Rudolphi prefers incitability, (E r r e g b a r k e i t,) as not liable to the ob- jection that may be urged against the others, of having been em- ployed in other significations. This incitability differs in the dif- ferent organs and tissues; in the muscles it is termed irritability, (Mus kelkraft, Reizbarkeit;) in the nerves, sensibility, (Nervenkraft, Em pfindlichkeit;) and by some physio- logists, iii the membranous parts it is called contractility, (S p a n n- kraft, Zusammen ziehungskraft.) Such are the phenomena which indicate the existence of the vi- tal principle, and such the laws by which it seems to be governed. By certain physiologists, it is considered to influence solids only; by others, it has been considered to reside in the fluids also, and es- pecially in the blood. The notion of the vitality of this fluid was espoused by the celebrated John Hunter, and to him we are in- debted for many of the facts and arguments, adduced in its favour, and which have impelled the generality of modern physiologists to admit its existence. The analogy of the egg had demonstrated that life is not restricted to substances which are solid and visibly organized. The fresh egg, like other living bodies, possesses the ordinary counteracting powers communicated by vitality, and re- sists those agents which act upon the dead egg as on other animal substances deprived of the living influence. The fresh egg may be exposed for weeks, with impunity, to a degree of heat, which would inevitably occasion the putrefaction of the dead. During the time of incubation, the egg of the hen is kept at a heat of 105° for three weeks; yet, when the chick is hatched, the remaining yolk is perfectly sweet. The power of resisting cold is equally great. Hunter per- formed several experiments, which show the power of the vital principle in resisting cold, and the influence of cold in dimi- nishing the energy of the vital principle. He exposed an egg to LIFE. 507 the temperature of 17° and of 15° of Fahrenheit, and found that it took about half an hour to freeze it. When thawed, and again exposed to a cold atmosphere, it was frozen in one-half the time, when exposed to a temperature of 25°. He then put a fresh egg, and one that had previously been frozen and again thawed, into a cold mixture at 15° ; the dead egg was frozen twenty-five minutes sooner than the fresh. These experiments led to the le- gitimate inference, that the egg possessed the principle of life, and although fluid, must have enjoyed the properties, which we have described as characteristic of vitality;—of being acted upon by an appropriate irritant, and of moving responsive to such irri- tation. Similar results to those obtained with the egg followed analo- gous experiments with the blood. On ascertaining the degree of cold, and the length of time necessary to freeze blood taken imme- diately from the vessel, he found that, as in the egg, a much shorter period, and a much less degree of cold, were requisite to freeze blood that had been previously frozen and thawed, than blood re- cently taken from the vessel. The inference, deduced from this, was, that the vitality of recent blood being comparatively unimpair- ed, it was enabled to resist the cold longer than blood, whose vital energy had already been partly exhausted by previous exposure. The fluidity of the blood, whilst circulating in the vessels, has been regarded as an additional evidence of its vitality. It is obvious that such fluidity is indispensable, seeing that it has to circulate through the minute vessels of the capillary system, and that the slightest coagulum, forming in them, would lead to morbid derangements. Yet the blood is peculiarly liable to become solid by its constitution, and whenever it is removed from its vessels, coagulates. This is not owing simply to the cessation of its circu- lation, for if it be kept at the same temperature as in the living body, and be made to circulate with equal rapidity through a dead tube, it equally becomes solid. The cause, consequently, that maintains its fluidity, is presumed to be the vital agency. Another argument in favour of the vitality of the blood is drawn from the facts connected with its coagulation,—facts, which show, that the process is but little influenced by physi- cal agents, and which have induced Magendie to infer,—with many other physiologists, who are but little disposed to invoke the vital agency,—" that the coagulation of the blood cannot be ascribed to any physical influence, but that it must be esteemed essentially vital, and as affording a demonstrative proof that the blood is en- dowed with life." It has, indeed, been attempted to show, that there are certain phenomena which demonstrate that the vitality of this fluid increases or diminishes with the vitality of other parts of the body. When blood is drawn from a vessel it does not in- stantly coagulate or die; and, by observing the length of time con- sumed in the process, it has been thought, that we might be, in 508 LIFE. some measure, able to estimate the degree of vital energy it pos- sesses. In diseases, where the vital action is exalted,—as in in- flammation, the blood is found to coagulate much more slowly than in a state of health, and the coagulation itself is more perfect, whilst in diseases that are dependent upon a diminution of the vital energy, the opposite is the fact; because, in the first case, it is presumed, the blood possesses the vital principle in a higher de- gree than natural, and consequently resists, for a longer period, the influence of the physical agents to which it is exposed; whilst, in the second case, it possesses the vital principle to a less degree than natural, and therefore yields sooner to the influence of those agents,—the coagulation, however, in all instances being analogous to the rigidity of the muscles which takes place after dissolution, and indicates the final cessation of vitality. The buffy coat or inflammatory crust of the blood, called, also, corium phlogisticum, and crusta pleuretica, is a circum- stance connected with the blood's life, which has been invoked by the supporters of this view of the subject. The terms are applied to an appearance of the crassamentum, which is owing to its upper portion containing no red particles, but exhibiting a layer of a buff- coloured coriaceous substance lying at the top, owing to the red particles, during coagulation, sinking to the lower portion of the clot, before coagulation is completed; hence the colourless state of the upper surface. At the same time, the whole of the coagulated portion is much firmer than usual. The red particles, in such case, have time to subside before the coagulation is com- plete, which takes place more slowly than in health; and this is conceived to be owing to the blood's possessing a higher degree of vitality,—a view which is confirmed by some experiments of Mr. Thackrah. These consisted in receiving blood, taken from the vessels of a living animal, in a full and uninterrupted streamy into different cups, and noting the time at which coagulation commenced in each. Blood, for example, was taken from a horse at four pe- riods, about a minute and a half being allowed to intervene between the filling of each cup. In the first cup, coagulation began in eleven minutes and ten seconds; in the second cup, in ten minutes and four seconds; in the third cup, in nine minutes and thirty-five se- conds; and in the fourth cup, in three minutes and twenty seconds. In another experiment, blood was drawn into three separate cups, from the veins of a slaughtered ox, the first of which was filled in the first flow ; the second about three minutes afterwards; and the third a short time before the death of the animal. Coagulation commenced in the first cup in,two minutes and thirty seconds; in the second, in one minute and thirty-five seconds; and in the third, in one minute and ten seconds. In a similar experiment, coagula- tion commenced, in the first cup, in two minutes and ten seconds; in the second, in one minute and forty-five seconds; and in the third, in thirty-five seconds. LIFE. 509 Similar phenomena are found to occur in the human subject. Blood, to the amount of about a pint and a half, was taken from the arm of a female labouring under fever. A portion of this, re- ceived into a cup on its first effusion, remained fluid seven mi- nutes; a similar quantity, taken immediately before tying up the arm, was coagulated in three minutes and thirty seconds. Of blood, taken as in the last experiment, from the arm of a man, the first portion began to coagulate in seven minutes; the last in four. The vitality of the system, and with it the vitality of the blood, being diminished by each successive abstraction of that fluid, it coagulated or died sooner and sooner in proportion as it was pre- viously more and more enfeebled. It is obvious, however, that if these and other arguments lead to a belief in the vitality of the blood, they are equally favourable,— many of them at least,—to the life of the chyle; which, we have seen, accurately resembles the blood in every property, except in that of coloration; and if we admit the blood to be possessed of life, a question arises, respecting the part at which the nutritive substances, taken into the system, become converted into the nature of the being they are destined to nourish, and receive the principle of life. This must be either through the admixture of the fluids poured out from the supra-diaphragmatic portions of the alimentary canal, from those of the stomach or small intestine, or owing to the mysterious and inappreciable action exerted by the chyliferous radicles themselves, which separate the same fluid, chyle, from every substance that may be submitted to their action. These are the only fluids that have been suspected to be endow- ed with vitality. None of the others exhibit analogous phenomena, when exposed to similar agencies. On the whole, we are led to the conclusion, that, the vital prin- ciple animates both solids and fluids, but all that we seem to know regarding it is—in the language of Dr. Barclay, "that all the organisms of animals and plants are formed out of fluids, and that in a certain species of fluid, secreted from the parent, and after- wards inclosed in a very thin and transparent vesicle, there is a living organizing principle, which also acts upon the fluid in a way which we know not, forming out of it a regularly organized sys- tem of solids, and forming not only the rudiments of that system, but causing it afterwards to be nourished, and to grow through the medium of fluids, which are moved and distributed under the in- fluence of this organizing animating principle." Our knowledge being limited to this category, we are compelled to study life in its results or manifestations. These,as we have seen, constitute the science of biology or physiology. 510 death. OF DEATH. It has wisely entered into the views of Providence, that the existence of all organized bodies should be temporary. Yet we find considerable difference amongst them, in this respect. Whilst some of the lower classes of animals and vegetables are no sooner ushered into being than a process of decay appears to commence; others require the lapse of ages for their various developments and declensions; and, as a general principle, those, in which the attain- ment of growth has been slow, have the period of decrease pro- portionably protracted; whilst, where maturity has been rapidly attained, decay as rapidly supervenes. The ages of man, we have seen, are numerous and protracted. For a time, the parts of the frame, that are concerned in his deve- lopment, unceasingly deposite the necessary particles by a process as beautiful and as systematic, as it is mysterious, until ultimately the growth, peculiar to the species and the individual, is attained. At this point, the preponderance, which previously existed in the action of the exhalants over the absorbents, appears to cease. All is equality; but ere long, the exhalants fall off in their wonted activity; the fluids decrease in quantity; the solids become more rigid; and all those changes supervene that we have described as characterizing the decline of life, and the approach of that phe- nomenon which has now to be considered. Death is the necessary, total, and permanent cessation of those functions, by which the presence of life is characterized. This cessation may happen at all ages, from accident or disease; a few only ceasing gradually to live by the effects of age alone. Hence a distinction has been made into that kind of death, which is produced by the gradual wear and tear of the organs, and that which cuts off the being prematurely from existence. The former has been termed, by some physiologists, senile or natural, the latter accidental. These differ considerably in their physiology; and will, therefore, require a distinct consideration. 1. Beath from old age. The natural period of life is different in different individuals. It varies according to numerous appreci- able and inappreciable circumstances;—the original constitution of the individual; the habits of life; the locality in which he maybe situated, &c. Whilst some countries are remarkable for their lon- gevity, others surprise us by the short period that is allotted for the natural duration of life. Blumenbach asserts, that by an accurate examination of numer- ous bills of mortality, he has ascertained the fact, that a considera- ble proportion of Europeans reach their 84th year, but that few DEATH. 511 exceed it; whilst, according to Foder^, in the insalubrious region of Brenne, in France, nature begins to retrograde, at from 20 to 30; and 50 years is the usual term of existence. Haller noted one thousand cases of centenarians; sixty-two of from 110 to 120 years; twenty-nine of from 120 to 130; and fifteen who had attained from 130 to 140 years. Beyond this advanced age, examples of longevity are much more rare and less sufficiently attested; yet we have some well authenticated cases of the kind. Thomas Parr was born in 1635; married when at the age of 120; retained his vigour till 140; and died at the age of 152, from plethora —it was supposed—induced by change of diet. Harvey dissected him and found no appearance of decay in any organ. Henry Jen- kins, who died in Yorkshire, in 1670, is an authentic instance of the greatest longevity on record. He lived 169 years. It would not seem, that the natural period of life has differed much in postdiluvian periods. The Psalmist writes:— " The days of our years are threescore and ten; and if by rea- son of strength they be fourscore years, yet is their strength labour and sorrow, for it is soon cut off, and we fly away." And when Barzillai excused himself for not visiting the royal palace at Jerusalem, he observed to the king:— " I am this day fourscore years old, and can I discern between good and evil? can thy servant taste what I eat or what I drink? can I hear any more the voice of singing men or singing women? wherefore, then, should thy servant be yet a burden unto my lord the king?" It is not easy to indicate the character of organization which is most conducive to longevity and to health. It has been supposed, however, and with some probability, that the state of the nervous system is greatly concerned ; for the pathologist looks to this part of the frame as the commencement of many fatal maladies. Generally, the aged individual sinks silently to death, in the manner we have described under decrepitude, totally unconscious of all that surrounds him. At other times, however, he preserves his sensorial powers to the last, and may be capable of locomotion; until, owing to some oppression of one or other of the vital func- tions during sleep, it becomes the sleep of death;—the elasticity of the organs being insufficient to throw off the oppression and re- sume their functions. At other times, a slight febrile irritation will be the prelude to dissolution. The great characteristic of this kind of death—as pointed out by Bichat in one of the best of his excellent productions*—is, that animal life terminateslong before organic life. Death takes place in detail;—the animal functions, which connect the aged with the objects around him being anni- hilated, long before those that are concerned in his nutrition. Death, in other words, takes place from the circumference towards * Eecherches physiologigues sur la vie et la mort. 512 death. the centre, whilst, in accidental or premature death, thc annihila- tion of the functions begins in the centre and extends to the circumference. As vitality gradually recedes, in the aged, from the exterior, one of the great centres of vitality—brain, heart or lungs—stops for an instant. The powers are insufficient to re- store the action, and total death necessarily ensues. It has been an interesting inquiry with physiologists to deter- mine the cause of death, thus naturally occurring. The opinions have been various, but such causes as affect the three great vital functions seem to be most entitled to consideration. These have been supposed to be, First, ossification of the arteries, occa- sioning an obstacle to the free circulation of blood in the parts; Secondly, ossification of the cartilages of the ribs, and diminution of the capillary system of the lungs, preventing sanguification; and Thirdly, shrivelling and gradual induration of the nervous system, ultimately rendering it unfit for innervation, &c. These are the physical circumstances or changes, which may give occa- sion to the final cessation of the vital phenomena, but, after all, the difficulty remains,—and one that is insolvable,—to explain the cause why these changes themselves occur in the organs essential to vi- tality. We say it is insolvable, for until we have learned the na- ture of life, which seems far beyond our comprehension in the present state of our knowledge, it is obviously impracticable to un- derstand the phenomena that arise from its gradual declension and final extinction. It is not common, however, for death to occur in this quiet and gradual manner. Man is liable to numerous diseases, from the earliest to the latest period of existence, many of which are of an extremely fatal character. It was admitted by Sydenham, whose estimate cannot be regarded as more than an approximation, that two-thirds of mankind die of acute diseases; and that of the re- maining one-third, two-thirds, or two-ninths of the whole, die of consumption, leaving, consequently, only one-ninth to perish from other chronic maladies, and from pure old age. How small, then, must be the number of those that expire from decrepitude simply? 2. Accidental death.—This term has been used, by many phy- siologists, to include all kinds of death that befal mankind in the course of their career, and before the natural term ; the cause con- sisting in the supervention of some accidental, organic lesion, which arrests the vital movements before they would cease of themselves. This kind of death differs essentially from that we have been considering. The individual is here, perhaps, in the full possession of all his faculties; his organs have been, previously, to all appearance, in the most favourable condition for the pro- longation of vitality, and his death, instead of being natural, and unperceived in its approaches by the individual himself, is usually forced and violent. Every species of sudden death commences by the interruption death. 513 of the circulation, respiration, or the action of the encephalon. One of these three functions first ceases, and the others die in suc- cession. Each will demand a few remarks. 1. Beath beginning in the heart.—When,—owing to fatal syn- cope, to wounds of the heart or great vessels, or to the rupture of an aneurism,—the heart is struck with death, the cessation of the functions is speedy. Sensation and motion are lost; respiration is arrested, and death occurs,—if the cause of the cessation of the heart's action be suddenly smd sufficiently applied,—almost in- stantaneously. The order, in which death takes place in the dif- ferent organs, is as follows. The heart failing to propel its blood, the brain no longer receives the necessary impulse for the conti- nuance of its functions; it therefore ceases to act; the consequence of this is the death of all those organs that receive their nervous influx from it; all voluntary motion is annihilated, as well as the action of the respiratory muscles. The mechanical phenomena of respiration are, therefore, arrested ; and air is no longer received into the chest. From this cause, then, the chymical phenomena of respiration would cease, were they not previously rendered un- necessary by the cessation of the heart's action. The phenomena of nutrition and calorification,—the functions of the capillaries,— yield last. 2. Beath beginning in the brain.—In this case, owing to the loss of innervation,—as in severe injury done to the head, or in the worst cases of apoplexy,—the sensorial functions first cease, and the individual lies deprived of all sensation, volition, and men- tal or moral manifestation. Respiration becomes progressively more irregular and laborious, and ultimately ends. The order of death is here as follows:—the interruption of the brain's action de- stroys that of the voluntary and mixed muscles; the mechanical phenomena of respiration therefore cease, and then the chymical. This is followed by cessation of the heart's action, owing to the united loss of nervous influx from the brain,—and to the blood being no longer aerated in the lungs, but returned to it in a con- dition not adapted for the maintenance of its contractility. To the cessation of the heart's action succeeds the loss of the general circulation ; and lastly, that of the functions of nutrition. 3. Beath beginning in the lungs.—The action of the lungs may be destroyed in two ways: either the mechanical phenomena of respiration may first cease, as in hanging, strangulation, &c, where the air is prevented from reaching the lungs; or the chymi- cal phenomena may be first arrested, as where air is breathed, which does not contain oxygen, but yet can be respired for a lfIn the first case, the order of death is as follows:—the mechani- cal phenomena cease; to this succeeds cessation of the chymical phenomena, owing to the supply of air being cut off; the blood is Vol. II. 65 514 DEATH. now returned to the heart without being aerated, and therefore un- fit for supporting that organ in action. It continues to beat, how- ever, for a time; black biood is consequently sent to the brain and to every organ; the brain dies, and the other parts in succession. Where the chymical phenomena first cease, the suspension of the action of the brain follows for the cause already assigned; and the mechanical phenomena of respiration are not arrested, until the nervous influx is cut off by the death of that organ. The immediate phenomena of death and the order of their suc- cession are easily understood, where one of the great centres of vi- tality is suddenly destroyed, either from accident or disease, but where death does not follow immediately, and time is allowed for a series of morbid phenomena to be established, the problem be- comes much more complicated. Some organ or structure is first deranged; and, owing to the intimate connexion, which we have elsewhere seen to exist between the various functions, general de- rangement or irritation follows, and the individual dies, worn out by such irritation, but without our being exactly able to under- stand on which of the great centres that dispense vitality, the ma- lign influence has been exerted, or whether it may not have affected all equally. In inflammation of the brain, heart, or lungs, we may presume, that the functions of these organs have been respectively an- nihilated by the diseased action; and that as such functions are essential to the existence of vitality, death may arise in the manner we have already described; but we frequently find the bowels affected with inflammation, or the peritoneum lining the interior of the abdomen; and the case, if neglected, is as surely attended with fatal consequences as the same morbid affection of the organs termed vital; and this in a space of time so short, as not to enable us to understand the nature of the mode of action of the lethiferous agent. But that it must exert its influence on one or more of the great centres of vitality is manifest. Perhaps in every case, the heart yields first, not suddenly but gradually; the brain failing to receive its due impulse, becomes progressively unfit for transmitting the nervous influence to the muscles; insensibility gradually supervenes, until it has attained such an extent, that no nervous influence is sent to the respiratory muscles, when cessa- tion of their action naturally ensues. Of the nature, however, of the morbid condition of the heart, thus induced by disease, we are totally ignorant. It is fashionable to say, that death is produced by irritation, but this is merely concealing our deficiency of know- ledge under a term, the explanation of the agency of which com- prises the whole difficulty. Adelon thinks, that the brain gene- rally gives way first in these cases; in consequence of which the respiration is disturbed, the lung becomes engorged, the respira- tion difficult, and death occurs as in a case of gradual asphyxia. DEATH. 515 There is something extremely obscure in these cases. The author has recently left the bedside of a deceased friend, fifty-one years of age, where the intellectual manifestations and the nervous dis- tribution to the muscles of voluntary motion were executed, even vigorously, until a short time prior to dissolution. For several days previously, the heart had acted feebly, irregularly, and inter- mittingly ; and the chest had heaved laboriously, yet without the existence of pain or the usual signs of inflammation, although sueh had been previously present. In this case, the first source of mis- chief was seated, probably, in the respiratory organs, and the diffi- culty of transmitting the blood through them occasioned the failure of the powers of the heart. Finally, its action ceased first, and the other functions failed in due succession. These remarks are chiefly applicable to death, as it arises from the numerous acute affections, which are so fatal to mankind; but it may occur also from those, that persist for a great length of time, and destroy after months or years of morbid irritation, as in cases of calculi of the bladder, enlargements of the viscera, &c. In these cases, also, death must result ultimately from destruction of one or other of the vital functions,—respiration, circulation or inner- vation ; but in a manner so gradual, that it takes place nearly in the same manner as in old age; except that, in all cases, it pro- ceeds from the centre to the circumference; the great internal functions first ceasing, and afterwards their dependencies,—a dif- ference, which explains why we are justified in attempting means of resuscitation in sudden death, whilst it would be the height of absurdity to have recourse to them where, "Like a clock worn out with eating time, The wheels of weary life at last stand still." The renovation could only be effected by the substitution of new, for the worn out, machinery. For some time before dissolution, both in death from old age and from disease, the indications of the fatal event become more and more evident. The speech grows embarrassed, the ideas are incoherent, the hands, if raised by the effort of the will, fall inertly into their former position, the laboured respiration occasions in- sufficient oxygenation of the blood, and the distress excites an at- tempt at respiration which the debility renders nearly ineffectual; distressing yawnings and gaspings occur to remedy the defective pulmonary action, and the whole respiratory system is in forcible and agitated motion; the teeth at times gnashing, and convulsive contractions occurring at the corner of the mouth. The heart be- comes °radually unable to propel the blood with the necessary force into the arteries, so that it ceases to reach the extremities of the body,—as the hands, feet, nose and ears,—which grow cold, and a cold clammy moisture oozes from the vessels. In experiments 516 DEATH. on animals, the blood is found to be driven no farther than to the feet; then to the groin; afterwards, it reaches only to the kidneys, and a kind of reflux occurs through the space along which it had previously been urged forwards. The flux and reflux now reach no farther than the diaphragm, and gradually retreat, until the blood flows back upon the heart itself, which now stops for a time, and then makes an effort to free itself from the contained fluid. The heart's action and respiration are imperfectly performed for a few times at irregular intervals, till at length the contractility of the organ is entirely gone. Respiration ceases by a strong expul- sion of air from the chest,—often accompanied with a sigh or a groan, and probably arising, partly from the relaxation of the in- spiratory muscles, and still more from the elasticity of the carti- lages of the ribs. Hence it is that, in common language, to expire is synonymous with to die. In cases of sudden death, the heart will continue to beat for some time after innervation and respiration have entirely ceased. Un- der such circumstances the left ventricle dies first, the obstruction to respiration cutting off its supply of blood. For some time immediately preceding dissolution, there is usually a peculiar mixed expression of countenance,—a compound of apparent mental and corporeal suffering,—which has given oc- casion to its being called the agony. It is characterized by facial indications, which were first well described by Hippocrates, and from him called Fades Hippocratica. The nose is pinched, the eyes are sunken, the temples hollow, the ears cold and retracted, the skin of the forehead tense, the lips pendent, relaxed and cold, &c. The eye, during this condition, especially when dissolution approaches, is fixed and slightly elevated, being kept in that posi- tion, according to Sir Charles Bell, by the power of the brain over the voluntary muscles of the eye being lost, and the organ ,being given up to the action of the oblique or involuntary mus- cles. In this view, the state is one of insensibility, not of suf- fering. Although, from the moment that respiration and circulation permanently cease, the body may be regarded as unquestionably dead, vital properties yet remain in some of the organs, the pre- sence of which is an evidence that vitality has previously and re- cently existed. The functions, which persist after the animal has become dead to surrounding objects, are those that belong to the organic class. Animal heat, for example, may still be elicited for a time, in the internal organs more especially, and it may require several hours, in death caused suddenly or speedily, by accident or disease, before the whole body is cold. Absorption is, also, said to have occurred after death, and the beard and hair to have grown; it is more probable, however, that, in the last cases, the apparent elongation may have been owing to the shrinking of the integu- DEATH. 517 ments. The rectum is very frequently evacuated after dissolution; and cases have occurred where a child has been born by the contrac- tion of the uterus after the death of the mother. The most sensible evidence, however, of the continuance of a vital property after dis- solution, is in the case of the muscles, which, as we have mention- ed in another place, can be made to contract powerfully on the application of an appropriate stimulus, even for an hour or two after death. The case, cited from Dr. Ure, under muscular mo- tion, is full of interest in this and other respects. Nysten, from his experiments, inferred, that the parts cease to contract in the following order:—the left ventricle, the large intestine, the small intestine, the stomach, the bladder, the right ventricle, the oesopha- gus, the iris, the different voluntary muscles, and lastly, the auri- cles, particularly the right auricle. The body cools gradually at the surface and especially towards the extremities, with a rapidity proportionate to the privation of fluids, and the coldness of the atmosphere. Whilst refrigeration is going on, the blood remains more or less fluid; and, owing to the arteries emptying themselves, by virtue of their elasticity, of their contained blood, the fluid generally accumulates in the venae cavae, the auricles of the heart, and the vessels of the lungs. By virtue of its gravity, it collects also in the most depending parts, occa- sioning sugillations or livid marks, which might be mistaken for bruises inflicted during life; but may be distinguished from them by attention. It will be readily understood, that the situation of the blood in the vessels may differ somewhat according to the vital organ which first ceases its functions. If the action of the heart stops, the lung is empty; if the lung or heart ceases, the lung and the right side of the heart—with the vessels communicating with it—are surcharged with blood, whilst the organs of the cor- poreal circulation are almost empty. During the progress of refrigeration, and especially soon after death, the muscles are soft and relaxed, so that the limbs fall into that position to which the force of gravity would bring them; the eyes are half open; the lips and lower jaw pendent, and the pupil dilated. When the body, however, is cold, the blood is coagulated, and white or yellowish coagula exist, es- pecially in the cavities of the heart, which were at one time supposed to be morbid formations, and termed polypi. They take the shape, more or less, of the cavity in which they are found. Lastly, the muscles become firmly contracted, so that no part can now be moved, without the application of considerable force; and, in this state, they continue until the natural progress towards pu- trefaction again softens their fibres. This has been regarded by physiologists as arising, like the coagulation of the blood, from the last exertion of that residue of vital power which the body retains after the period of apparent dissolution. With more propriety, 518 death. perhaps, it may be assigned to physical alterations taking place in the organs, owing to the total loss of those powers, which were previously antagonists to such changes. It might seem from the previous enumeration of the signs of death, that no difficulty could possibly arise in discriminating be- tween a living and a dead body. Cases have, however, occurred, where such difficulty has been great and perplexing. Many of the signs may exist, and yet the person be merely in a state of sus- pended animation; and in certain instances it has even been con- sidered advisable to wait for the manifestations of the putrefactive process, before the body should be consigned to the grave. The fol- lowing case, given by Dr. Gordon Smith, strongly exhibits the embarrassment that may occasionally arise. A stout young man had been subject to epilepsy, which became combined with mad- ness. On this account it was necessary to remove him to a privato asylum in the neighbourhood of London, where he died suddenly, in a violent epileptic paroxysm. The body was removed to the residence of his friends, soon after death, when the necessary pre- parations for interment were made. On paying attention to the corpse it was found, that the limbs were quite pliable; that the eye was neither collapsed nor glazed; and that the whole features re- tained their full natural appearance as during life. A surgeon, who for years had been in the habit of attending him, was sent for; and although he could find no indications of vitality, he prudently recommended that the interment should not take place until de- composition had began to manifest itself. In the course of two or three days, appearances still continuing the same, a physician was called in, who concurred in the recommendation that had been already given. Fifteen days from the supposed time of his death had elapsed, when Dr. Smith's informant had an opportunity of inspecting the body. At this time the countenance retained the appearance described, but the eye seemed beginning to sink, and some degree of lividity had commenced on the surface of the abdo- men. The joints were still flexible. At this time a very eminent professor of anatomy viewed the body, and considering the hesita- tion that had prevailed to be altogether groundless, he appointed the following day to examine it internally. The head was accordingly opened, and a considerable extravasation of blood found in the posterior part of the cranium, between the skull and dura mater and between the membranes and substance of the brain. No serum was detected in the ventricles; but the brain itself was remarkably hard. This was sixteen days after death. On the following day, the body was interred. A clamour now arose amongst the neigh- bours, that he had been prematurely handed over to the anatomist. The body was exhumed; an inquest was held; and the evidence of the medical gentlemen demanded. The jury, of course, returned a verdict of " apoplexy." DEATH. 519 It may hence, become a matter of medico-legal inquiry to verify the existence of death, in cases where doubt prevails, from the per- son being in a state of apparent death,—natural or assumed. Perhaps the most singular case on record, of suspension of two of the most important of the vital functions, occurred to the dis- tinguished John Hunter. In the year 1769, being then forty-one years of age, of a sound constitution, and subject to no disease ex- cept a casual fit of the gout, he was suddenly attacked with a pain in the stomach, which was speedily succeeded by a total suspen- sion of the action of the heart and of the lungs. By violent exer- tion of the will he occasionally inflated the lungs, but over the heart he had no control whatever; nor, although he was attended by four of the chief physicians in London from the first, could the action of either be restored by medicine. In about three-quarters of an hour, however, the vital actions began to return of their own ac- cord, and in two hours he was perfectly recovered. " In this attack," says his biographer, Sir Everard Home, "there was a suspension of the most material involuntary actions, even involun- tary breathing was stopped; while sensation, with its consequences, as thinking and acting, with the will, were perfect, and all the voluntary actions were as strong as ever." At one period it was universally credited, that substances could be administered, which might arrest the whole of the vital func- tions or cause them to go on so obscurely as to escape detection. This erroneous popular notion is exhibited, in the description of the action of the drug, administered by Friar Lawrence to Juliet:— " Take then this phial, And this distilled liquor drink thou off; When presently thro' all thy veins sball run A cold and drowsy humor, which shall seize Each vital spirit; for no pulse shall keep His natural progress, but soon cease to beat. No warmth, no breath shall testify thou lives!; The roses in thy lips and cheeks shall fade To paly ashes; the eyes windows fall Like death, when he shuts up the day of life; And in this borrow'd likeness of shrunk death, Thou shalt continue two-and-forty hours, And then awake as from a pleasant sleep." Death may also be feigned for sinister purposes. The author recollects a body having been brought in a sac to the house of Mr. Brookes, the distinguished anatomist of London, the vitality of which was detected by the warmth of a protruded toe. It was that of a robber, who had chosen this method of obtaining admis- sion within the premises. The celebrated case of Colonel Townshend exhibits the power occasionally possessed over the vital functions; and Dr. Cleghorn of Glasgow knew an individual, who could feign death, and had 520 DEATH. so completely the power of suspending or at least of diminishing the action of the heart, that its pulsations were imperceptible. Lastly, the character of the death, as to violence or gradual ex- tinction, is often exhibited in the physiognomy of the dead. Where it has taken place during a convulsion, or by agents that have forcibly and suddenly arrested respiration or innervation, the countenance may be livid, the jaws clenched, the tongue protruded and caught between the teeth, and the eyes forced, as it were, from their sockets; but usually in death from old age or even from acute and tormenting disease, whatever distortion or mark of suf- fering may have existed prior to dissolution, subsides after the spirit has passed, and the features exhibit a placidity of expres- sion, singularly contrasting with their previously excited condi- tion. For effect, however, the poet and the painter suit their de- scriptions of death to the character of the individual whom they are depicting. The tyrant falls convulsed and agonized, whilst the tender and delicate female is described to have progressively withered, till " At last, Without a groan, or sigh, or glance to show A parting pang, the spirit from her past: And they who watch'd her nearest could not know The very instant, till the change that cast Her sweet face into shadow, dull and slow Glazed o'er her eyes—the beautiful, the black, Oh! to possess such lustre, and then lack." Brnox, Don Juan, Canto IV. Warwick's description of the frightful physiognomy of Duke Humphrey,after death from suffocation, is scarcely overdrawn:— " But see his face is black and full of blood; His eyeballs farther out than when he liv'd, Staring full ghastly like a strangled man: His hair uprearM, his nostrils stretch'd with struggling: His hands abroad display'd, as one that grasp'd And tugg'd for life, and was by strength subdu'd. Look on the sheets, his hair you see is sticking.- His well-proportion'd beard made rough and rugged, Like to the summer's corn by tempest lodg'd. It cannot be but he was murder'd here: The least of all these signs were probable." King Henry VI. p. 2. Act. III. How different is this picture from that of the countenance of the young being, who has gradually sunk to death in the manner above described. The beauty is unextinguished, and the paleness and lividity of death have taken the place of the colours of life; yet the wonted physiognomy may remain. " Hush'd were his Gertrude's lips! but still their bland And beautiful expression seem'd to melt With love that could not die!" Cami>bei.l. DEATH. 521 Perhaps one of the most beautiful and accurate pictures, drawn by the immortal Byron, is his description of the serenity of coun- tenance observable in most fresh corpses; an expression which, by association, is deeply affecting, but not without its consolation to the friends of the departed. He, who hath bent him o'er the dead, Ere the first day of death is fled; Before decay's effacing fingers Have swept those lines where beauty lingers: And mark'd the mild, angelic air, The rapture of repose that's there: The fix'd yet tender traits, that streak The languor of the placid cheek; And but for that sad, shrouded eye, That fires not,—wins not,—weeps not now: And but for that chill, changeless brow, Where cold obstruction's apathy Appals the gazing mourner's heart, As if to him it could impart The doom he dreads, yet dwells upon: Yes but for these and these alone, Some moments, ay, one treach'rous hour, He still might doubt the tyrant's power. So fair, so calm, so softly seal'd The first, last look by death reveal'd. Vol. II. 66 INDEX.* A. Aberration of refragibility, 148. -------- of sphericity, 148. Abortion, II. 332. Absence of mind, H. 426. Absorption, II. 1. ---------accidental, H. 61. ---------cutaneous, H. 62. ---------of drinks, II. 17. ---------of excrementitial secre- tions, II. 24. ——------internal, II. 58. ---------interstitial, n. 58, n. 166. ---------of lymph, II. 25. ---------of recrementitial secretions, II. 24. 1 of solids, H. 166. ---------venous, II. 35, 53. Abstinence, deaths from, 465. ■ effects of, 464. Academia del cimento, experiments of the, on the gizzards of birds, 428. Acid, acetic, where found, 19. ----benzoic, where found, 19. ----lactic, where found, 19. ----lithic, where found, 17. ----muriatic, where found, 14. ■ nutritive properties of, 448. -----oxalic, where met with, 19. ----phosphoric, where met with, 13. -----sulpho-cyanic, where met with, 18. -----uric, where met with, 17. -----xanthic, where met with, 17. Adipocire, how formed, 288. Adipous exhalation, II. 206. Admiration, expression of, 407. Adolescence, age of, H. 397. Affections, what, 252. African race, II. 467. Age, critical, II. 279, H. 401. Ages, the, II. 384. Air, atmospheric, properties of, H. 73. ---expulsion of, from the intestines, 513. --- in the intestines, nature of the, 506, 511. — in the stomach, nature of the, 499. Albino, state of the eyes of the, 171. Album grxcum, what, 509. Albumen, where met with, 15. 1 concrete, where met with, 15. ------- liquid, where met with, 15. ------- nutritive properties of, 449. Aliments, classification of, 447. Alphabet, how formed, 389. Anaphrodisia, H. 184. Androgynous being, H. 256. Angle, facial, 256. -----occipital, 258. Anguish with bodily suffering, expres- sion of, 406. Anhelation, II. 93. Animalcules, spermatic, H. 267. Animalculists, II. 306. Animality, what, 7. Animals and vegetables, differences be- tween, 7. ------cold-blooded, what, H. 171. ------warm-blooded, n. 171. Appetite, physiology of the, 461. American race, H. 468. Anatomie vivante, referred to, 27. Antipathies, II. 439. Apparatus, what, 26. Arsenuretted hydrogen, effects of the respiration of, H. 113. Arteries, circulation in the, II. 139. -------- described, II. 123. —---- locomotion of, II. 154. Asiatic race, H. 468. Association, effects of, II. 460. Atrabiliary capsules, II. 29. Attitudes, 340. --------- erect, 340. ---------horizontal, 347. ---------on one foot, 346. --------- on the knees, 346. --------- sitting, 346. Audition, 113, 125. Aura seminis, what, II. 267. —---------insufficient for effecting fecundation, II. 292. Australian race, II. 469. Axis, cerebro-spinal, 91. Azote,effects of the respiration of, 11.112. ------protoxide of, respiration of the, H. 110. ------source of, in the food, 443. ------where found, 13. * II. refers to the Second Volume. 524 INDEX. B. Bearing a load, physiology of, 358. Beastings, what, n. 337. Belching, 517. Bewegungssinn, what, 318. Bier-right, II. 440. Biffin, Miss, her case, 84. Bile, colouring principle of the, 21. —— secretion of the, II. 225. ----use of, in digestion, 505. ----yellow colouring principle of the, 18. Biliary apparatus, II. 225. Black man of Gmelin, II. 467. Blood, agency of the, in health and dis- ease, II. 159. -----coloration of the, II. 199. ■ coagulation of the, II. 50. -----fibre of the, II. 47. -----forces that propel the, n. 148. -----forces that retard the, II. 153. -----globules of the, II. 40. -----infusion of substances into the, II. 161. -----life of the, II. 52, II. 507. red colouring principle of the, 17. 117. transfusion of, II. 160. velocity of the, II. 155. venous, H. 39. venous, inspiration of, II. 148. weight of the, in the body, II. Body, human, specific gravity of the, 354. Bones, 289. ------spongy, use of, in olfaction, 107. Borborygmus, what, 513. Bosjesman female, generative organs of the, H. 269. ---------------, nates of the, II. 208. Brace, Julia, deaf, dumb and blind, 242. Brain, convolutions of the, an index of the mind, 261. -----decussation of the, 306. -----fatty matter of the, 18. -----insensible, 63. -----movements of the, 62. -----the organ of the mind, 232. -----a plurality of organs, 263. ■ protections of the, 42. 1 ratio of the weight of the, to other parts, 254. Byron, admiral, effects of prolonged hunger on, 462. -----lord's, picture of suffering from shipwreck, 464. Calcium, where found, 14. Caloric, laws of, II. 170. Cahridti of Chaussier, II. 183. Calorification, II. 170. --------seat of, II. 183. theories of, II. 184. Capillary circulation, II. 144. Carbon, where found, 13. Carbonic acid, effects of the respiration of, II. 112. oxide, effects of the respira- tion of, II. 112. Cartilages, 294. Caseine, where met with, 17. Catalini, Madame, her extent of voice, 398. Catamenia, what, II. 279. Caucasian race, II. 465. Chabert, M., his resistance to heat, 79, U. 180. Cheese, nutritive properties of, 449. Cheselden's case of the boy restored to sight, 219. Childhood, age of, II. 393. Chinese race, U. 468. Chlorine, where found, 14. Chyle, description of the, II. 8. where formed, 500. Chylification, 500. Chyliferous apparatus, II. 4. Chylosis, II. 4. Chyme, 476, 482. Chymification, 476. Circulation, H. 116. ---------in arteries, H. 139. ---------in birds, II. 163. ---------capillary, II. 144. ---------in fishes, II. 163. ---------in the heart, II. 129. ---------in insects, II. 163. ----——— in mammalia, II. 162. ---------in reptiles, H. 163. ---------in veins, II. 147. Circulatory apparatus, II. 118. Circumcision in the female, II. 270. Clay, as an article of diet, 438. Climacteric years, H. 404. Coenaesthesis, 226. Cold, effects of severe, II. 176. Colouring matter of organs, exhalation of the, II. 210. Colustrum, what, II. 337. Colours, accidental, 188. —— complimentary, 189. - harmonic, 189. ————- insensibility to, 210. opposite, 189. Combustibility, preternatural, II. 47. Combustion, spontaneous, H. 47. Commodus, his feats, 295. Composition of man, 12. Conception at different ages, II. 318. ' at different seasons, U.318. INDI Conception, physiology of, II. 288. ---------signs of, II, 317. Concord, what, 124. Condiments, 459. Consonants, 449. Contractility de tissu, 33. ---------par defaut d''extension, 33. Cookery, effects of, 457. Copulation, H. 285. Corpus luteum, H. 295, n. 298. Coughing, II. 89. Cowper, Spencer, his case, 356. Craniological system of Gall, 268. Craniology, 267. Cranioscopy, 267. Cranology, 267. Cretinism, H. 455, H. 474. Cry, 384. Crying of animals, H. 193. Crypsorchides, H. 261. Crypts, sebaceous, 73. Cutaneous exhalation, H. 211. Cutis anserina, 409. Cutting, Margaret, her case, 382. D. Deaf, dumb, intelligence of the, 240. ----------and blind, 241. Death, H. 510. Declamation, 398. Decreptitude, II. 403. Defecation, 512. Deglutition, 472. --------- of air, 476. Dentition, first, II. 389. -------second, II. 393. Depuration, cutaneous, II. 217. ---------urinary, H. 232. Derivation, H. 148. Desires, instinctive, 228. Diastole of the heart, II. 130. Diet regulated by the Egyptians, He- brews, &c. 440. ----variety of, necessary for man, 445. Differences, acquired, amongst man- kind, H. 451. ---------individual, H. 445. ---------natural, H. 451. Digestibility, comparative, of aliments, 455. Digestion, 414. -------- buccal, 470. -------in the large intestine, 507. -------- in the small intestine, 500. -------- oral, 470. ------— physiology of, 460. --------physiology of, of liquids, 514. -------- physiology of, of solids, 461. -------■ of the stomach after death, 493. -------- theories of, 484. sx. 525 Digestion, theories of, by chymical so- lution, 486. -------theories of, by coction, 484. ------- theories of, by fermentation, 485. -------theories of, by maceration, 486. -------theories of, by putrefaction, 484. -------theories of, by trituration, 485. Digestive organs, 474. --------------of birds, 426. --------------of ruminant animals, 424. Dislodging a stake, physiology of, 358. Diverticula, II. 157. Docimasia pulmonum, H. 86. Dragging a weight, physiology of, 358. Dreams, H. 410. ------waking, n. 416. Drinks, 450. E. Ear, external, physiology of the, 125. ----internal, physiology of the, 131. ----middle, physiology of the, 127. ----musical, 134. ----trumpet, 122. Echo, 122. Egg, incubation of the, n. 340. Elasticity of tissue, 33. Elements, inorganic, 3, 21. --------organic, 4, 15. -—■-----organic, containing azote, 15. --------organic, not containing azote, 18. Emboitement des germes, II. 311. Emotions, 253. ------- instinctive expressions of the, 411. Endosmose, 34, II. 482. Engastrimism, 379. Epigenesis, II. 302. Epiglottis, use of the, in deglutition, 474. Erection, II. 284. Eructation, 517. Ethiopian race, II. 467. Evolution, doctrine of, II. 305. Exhalants, H. 165. Exhalations, n. 205. --------- areolar, II. 211. --------- external, II. 211. Exosmose, 34, n. 482. Expectoration, II. 91. Expiration, II. 84. Expression, 359. —--------depressing, 403. -- exhilarating, 403. 526 INDEX. Extract of meat, 16. Extractive of meat, 16* Eye, achromatism of the, 169. ----accessory organs to the, 160,176. ----accommodation of the, to distances, 192. ----coats of the, 171. ----dimensions of the, 159. ----insensibility of the, to colours, 209. ----refracting power of the, 167. ----transparent parts of the, 150. Eyes, corresponding points of the, 203. ---- unequal foci of the, 204. F. Face, muscles of the, 400. Faculties, affective, 231, 252. -------- emotive, 231. -------- intellectual, 249. --------intellectual and moral, phy- siology of the, 247. -------- mental, 230. -------- moral, 252. --------• of the heart, 231. Faeces, properties of the, 509. Fat, exhalation of the, II. 206. ----nutritive properties of, 449. Fear, expression of, 406. Fecula, nutritive properties of, 447. Fecundation, H. 288. Feeling, common, sense of, 226. -------of life, 226. Female, characteristics of the, II. 452. ------ standard, II. 453. Fibre, what, 26. -----albugineous, 25. -----cellular, 24. -----elementary, 24. -----laminated, 24. -----medullary, 25. -----muscular, 24, 282. -----nervous, 25. —----pulpy, 25. Fibres, primary, 24. Fibrils with formative appetencies, H. 304. Fibrine, nutritive properties of, 449. -------where met with, 16. Filament, what, 24. Fish, poisonous, 454. Flexors, preponderance of the, 339. Fluid, nervous, 69. -----of the human body, 26. Flying, 357. Foetal existence, II. 339. Foetus, anatomy of the, II. 339. ------animal functions of the, II. 364. ■------calorification of the, II. 382. ------circulation of the, II. 376. ■------dependencies of the, II. 346. Foetus, digestion of the, II. 375. effect of maternal imagination on the, II. 380. -----expression of the, n. 365. -----external senses of the, II. 364. — increment of the, II. 352. intellectual and moral faculties of the, II. 364. -----internal senses of the, II. 364. -----motion of the, II. 365. -----nutrition of the, II. 365. nutritive functions of the, II. 365. peculiarities of the, II. 358. physiology of the, II. 364. reproductive functions of the, H. 383. ------respiration of the, II. 375. secretions of the, II. 382. Follicle, II. 195. sebaceous, 73. Follicular secretions, n. 221. Food, animal substances used as, 450. -----birds used as, 452. -----Crustacea used as, 452. -----effect of baking on, 458. -----effect of boiling on, 457. -----effect of broiling on, 458. -----effect of cookery on, 457. -----effect of frying on, 458. -----effect of roasting on, 458. -----fish used as, 454. -----insects used as, 455. -----molluscous animals used as, 454. -----of man, 438. -----prehension of, 467. -----reptiles used as, 453. vegetables used as, 455. Force, vital, H. 480. Forces, motive, seat of the, 297. Foreshortening, 213. Free-martin, 278. Functions, animal, 41. ---------classification of the, 37. --------- correlation of, H. 428. ---------nutritive, 414. ---------of man, 37. ---------reproductive, II. 251. ---------table of the, 38. --------- vegetative, 7. G. Galvanism, effects of, on the dead body, 315. Ganglions, nervous, 57. Gas animale sanguinis, II. 45. Gases, deleterious, II. 113. -----irrespirable, II. 113. permeability of tissues by, 35. Gastric juice, 482, 487. Gelatine, nutritive properties of, 449. INDEX. 527 Gelatine, where met with, 15. GemeingefUhl, 226. Generation, H. 251, -----■---- ab animalculo maris, II. 312. ---------animalcular, theory of, II. 312. ——------by spontaneous division, H. 256. ■ ----equivocal, n. 251. ---------fissiparous, H. 256. ---------gemmiparous, II. 256. ---------oviparous, II. 256. ---------ovo-viviparous, II. 257. ---------regular, H. 251. ---------spontaneous, H. 251. ---------theories of, II. 302. ---------univocal, II. 251. ---------viviparous, II. 257. Generative apparatus, II. 258. Genital organs of the female, II. 268. ----------- of the male, II. 258. Germs, dissemination of, II. 310. ------encasing of, II. 311. ------vital, Darwin's notion of, n. 304. Gestation, H. 325. Gestures, 399. Girandelli, Madame, her resistance-to heat, 79. Gland, described, H. 195. Glandular secretions, II. 222. Globuline of the blood, H. 49. Gluten, nutritive properties of, 449. Goitre, n. 28, H. 455. Gras des Cimetiires, 288. Growth of the body, n. 167. Gum, nutritive properties of, 448. Gustation, 87- H. Habit, H. 456. Hjematosis, H. 66, H. 94. Hair, 73. Halitus of the blood, H. 45. Hallucinations, n. 416. Hand, advantages of the, as an organ of touch, 83. Harmony, what, 114. Hawking, II. 90. Hearing, immediate functions of, 133. ------improved by cultivation, 140. ------organ of, 113. -------sense of, 113. Heart, n. 119. ------a double organ, II. 117. ------circulation through the, II. 129. .-----suction power of the, II. 148. Heat, sense of, 73, 225. Hematine, n. 48. Hermaphrodism, II. 276. Hermaphrodite, II. 256, II. 276. Honeywell, Miss, her case described, 84. Hunger, 226, 461. Hunter, Mr. case of, *519. Hybrids, doctrine of, II. 308. Hydrogen, effects of the respiration of, II. 111. --------where found, 13. -------- carburetted, effects of the respiration of, II. 112. I. Idiosyncrasy, II. 449. Illusions, mental, II. 416. -------optical, 211, 222. Imagination, effects of the, II. 437. ---------maternal, influence of the, on the fcetus, II. 380. Imbibition, 34, II. 56. Imitation, effects of, II. 461. Impressions, external, 239. Impulses, cerebral, 302. Incubation of the egg, II. 341. Individualitatssinn, 226. Infancy, II. 384. -------first period of, II. 384. ------second period of, II. 389. ------third period of, II. 393. Inorganic bodies, 1. Inspiration, H. 84. ---------first, II. 385. Instinct, II. 492. Intellect, 248. Iron, where found, 14. Irritability, 312, II. 503. Irritation, constitutional, II. 430. Itching, 227. J. * Joints, 292. Joy, expression of, 407. K. Kalmuck race, II. 468. Kissing, 402. L. Labour, II. 332. ------premature, II. 232. Lachrymal apparatus, 164. Lacteals, II. 4. Lactation, II. 336. Language, 359. —-------artificial, 386. -----—- natural, 384. ■ origin of, 387. Laughter, II. 92. -------broad, 403. ■-------of animals, II. 93. Leaping, 352. LebensgefUhl, 226. 528 INDEX. Lebemsinn, 226. Lenses, various, 147. Letters, how divided, 390. Life, II. 480. Light, 141. -----colours and decomposition of, 147. -----diffraction of, 206. -----duration of the impression of, on the retina, 224. -----intensity of, 142. -----reflection of, 143. -----refraction of, 144. -----velocity of, 142. Likeness of child to parent, remai'ks on the, II. 315. Line, facial, 256. ----occipital, 258. Liquor amnii, n. 348. Locomotion, nervous system of, 300. Locomotive influx, 300. Longsightedness, 198. Lungenprobe, II. 86. Lymph, II. 29. -----coagulable, II. 47. Lymphatic apparatus, II. 25. Lymphosis, II. 30. M. Magnesium, where found, 15. Malaria, II. 75. Malay race, II. 469. Manganese, where found, 14. Manhood, age of, II. 400. Mankind, varieties of, II. 462. Marks, mother's, II. 380. Marrow, exhalation of the, II. 209. Matiere extractive du Bouillon, 16. Meat, effect of mode of killing on, 451 ----influence of age on, 450. ----influence of food on, 451. ----influence of sex on, 450. Mechanical principles, 324. Meconium, II. 383. Medulla oblongata, 50. ------spinalis, 51. Melody, 125. Membrane, nictitating, 163. Menses, II. 279. Menstruation, II. 279. -----------vicarious, II. 281. Milk, II. 338. Mind, not proportionate to the state o the senses, 240. ----seat of the, 280. Miscarriage, n. 332. Mitchell, the boy, case of, 241. Molecules, organic, of Buffon, 303. Mongolian race, H. 468. Monorchides of the Cape of Good Hope, II. 261. Monstrosities, II. 379. Moral acts, 247. Morbus cseruleus, II. 50. Motility, II. 503. Motion, muscular, 282, 294. -----voluntary, 282. Motive apparatus, 282. ——— forces, seat of the, 297. Movements, locomotive, 349. ---------partial, 347. Mucilage, nutritive properties of, 448. Mucous membranes, exhalation of the, II. 220. Mucus, where met with, 16. Muscles, 282. ------analysis of, 287. ------colour of, 310. ------contraction of, 309. ------mixed, II. 79. ------relaxation of, 318. ------simple and compound, 337. Muscular contraction, duration of, 320. -----------------extent of, 323. -----------------force of, 318. -----------------velocity of, 321. Musical tone, 124. Muskelsinn, 318. Muteosis, 399. Myopy, 198. N. Nsevi materni, II. 380. Nails, 73> Natural bodies, 1. -----state of man, 440. Nausea, 519. Negro race, II. 467. Nerves, 52. -----fatty matter of, 18. -----pneumogastric, effects of the section of the, on digestion, 495. -----on respiration, II. 107. -----sensible and insensible, 63. Nervi-motion, Dutrochet's views of, 32, H. 482. Nervous system, 41. Norma verticalis of Blumenbach, 259. Nose, blowing the, II. 90. ----use of, in smell, 107. Nutrition, II. 165. Nutritive principle, peculiar, does not exist, 443. Nyctalopes, eyes of, 171. O. Odours, 101. -----classification of, 104. disengagement of, 101. divisibility of, 103. medicinal properties of, 105. nutritious properties of, 105. INDEX. 529 Odours, vehicles of, 103. Oils, nutritive properties of, 449. Oleine, where met with, 18. Olfaction, 97, 106. Onomatopoeia, 387. Optic nerves, decussation of the, 158. Organ, 26. Organization, 5. -----;-----compounds of, 4, 18. Organized bodies, characters of, 1. Organology, 267. Osculation, 402. Osmazome, nutritive properties of, 449. ---------where found, 16. Ovarists, doctrine of the, II. 306. Oxygen, respiration of, II. 109. ——— where found, 13. P. Pain, 230. ----bodily, expression of, 406. Painting, a variety of expression, 413. Palsy, theory of, 306. Pancreatic juice, secretion of the, II. 223. ——^—-------use of in digestion, 506. Pandiculations, II. 92. Panspermia, II. 310. Panting, H. 93. Parturition, H. 332. Passions, 252. . expression of the, 411. ------seat of the, 237. Pectoriloquy, 379. Periosteum, 292. Peristaltic action, 480. Peristole, 480. Perceptivity of plants, 9. Perspective, 214. ---------aerial, 215. Perspiration, II. 211. Phosphorus, where found, 13. Phrenologist, cerebral organs of the, 268. Phrenology, 267. Physiognomy, 407. Physiology, general, of man, 12. Picromel, where found, 20. Pneumogastric nerves, effect of the sec- tion of the, on digestion, 495. ___________-------on respiration, II. 107. Poetry, a variety of expression, 413. Point, visual, 197. Potassium, where found, 15. Power, sensorial, 281. Pregnancy, II. 325. ._____----duration of, H. 330. _________. signs of, n. 329. Prehension of food, 358, 467. ------——of liquids, 515. Vol. II. ( Presbyopy, 198. Presentations, various, II. 335. Principle, nutritive, peculiar does not exist, 443. Principles, mechanical, 329. --------proximate of animals, 15. Propelling a body, how effected, 358. Property, hygrometric of tissues, 34. -------physical of organs, 33. --------vital, II. 501. Protogala, II. 3S7. Puberty, II. 397. Pulse, doctrine of the, II. 157. —---venous, II. 130. Purgations, II. 281. Pylorus, use of the, 478. R. Bacofnissement, 34. Rage, expression of, 406. Redman, II. 468. Regurgitation, 517. Rennet, 490. Reproduction, desire of, II. 283. -----------functions of, II. 251. -----------instinct of, II. 283. Respiration, II. 66, II. 79. ---------effects on the circulation, n. 148. --------of animals, H. 114. ---------of gases, II. 109. Respirations, number of, II. 87. Respiratory organs, H. 66. Reverie, II. 426. Rumination, 518. Running, 353. S. Saliva, n. 222. Sapidity, cause of, 90. Sanguification, II. 94. Savours, 89. -----— classification of, 91. Schurze of the Bosjesman female, II. 269. Seasickness, 519. Secretion, II. 195. --------follicular, II. 221. --------glandular, H. 222. Secretory apparatus, II. 195. Selbstgefhul, 226. Self-feeling, 226. Semen, secretion of, II. 266. ■------properties of, II. 267. Seminists, II. 306. Sensations, 41, 64. --------external, 70. --------internal, 228. --------morbid, 229. --------organic, 228. Sense, muscular, 225, 318. 67 530 INDEX. Sense of individuality, 226. -----of locality, 226. -----of life, 226. -----of motion, 318. ---— pneumatic, 226. -----sixth of Buffon, 225. Senses, additional, 225. —■---secondary instruments, 240. Sensibility, 41, 64. --------less in the lower animals, 235. --------vital property of, H. 502. Serous exhalation, II. 205. ---------------of the cellular mem- brane, II. 206. Sexes, differences between the, H. 452. -----proportion of the, born, H. 318. Sheep, fat-buttocked, II. 208. Short-sightedness, 198. Sighing, II. 91. -------sound of, 384. Sight, sense of, 140. Silicium, where found, 14. Singing voice, 398. Sinuses, nasal, use of in smell, 107. Skeleton, living, exhibited, 27. Skin, 73. ----goose, 409. Skull, 43. Sleep, II. 405. .----complete, II. 409. -----incomplete, II. 409. -----walking, II. 412. -----want of, II. 406. Slumber, II. 407- Smell, 97. -----acuteness of, in animals, 110. ----- acuteness of, in the blind, 112. -----immediate function of the, 109. -----improved by education, 112. -----mediate functions of, 110. -----nerves of, 108. -----organs of, 97. Sneezing, II. 89. Sobbing, II. 93. Sodium, where found, 14. Solander, effects of severe cold on, II. 176. Solids, 21. -----compound, 25. Somnambulism, II. 412. Soul, seat of the, 280. Sound, 120. -----acute, malappreciation of, 137. ----- intensity of, 124. -----reflexion of, 122. -----sympathetic, 121. -----timbre of, 124. -----tone of, 124. -----vehicle of, 120. -----velocity of, 121. Spaying, method of effecting, II. 291. Spectra ocular, 189. Speech, 386. Sperm, n. 266. Spermatic animalcule, II. 267. Spermatists, IT. 306. Spinal marrow, protection of the, 46. -----------structure of, 51. Spirits, animal, 68. Spitting, II. 90. Spleen, II. 245. Spontaneity of plants, 9. Squeezing, 358. Squinting, 204. Standing, 340. Stansfield, case of, II. 440. Starch, nutritive properties of, 447. Stearine, where met with, 18. Stethoscope, 123. Stomach, digestion of the, after death, 493. Stout, Mrs. her case, 356. Strabismus, 204. Straining, II. 88. Structure, elementary of animal sub- stances, 29. Study, brown, II. 426. Succus intestinalis, 503. Sugar, nutritive properties of, 448. -----of diabetes, 20. -----of milk, 19. Sulphur, where found, 14. Sulphuretted hydrogen, effects of the respiration of, II. 113. Superfoetation, II. 323. Supra renal capsules, II. 29. Suspicion, expression of, 408. Sweat, what, II. 211. Swimming, 354. Sympathetic, great, 57. Sympathy, II. 433. -------cerebral, II. 442. --------direct, II. 442. --------morbid, II. 430. -------of contiguity, II. 435. -------of continuity, II. 434. Synergies, II. 429. Synovia, II. 209. System, 26. -----nervous, of locomotion, 300. Systole of the heart, H. 130. T. Tablier of the Bosjesman female, II. 269. Tact, 73. Taste, 87. -----diversity of, in animals, 96. -----immediate functions of, 95. ----- improvement of, by education, 96. -----mediate functions of, 95. INDEX. 531 Taste, organs of, 88. Tapetum, 171. Tattooing, II. 168. Tawny man, II. 469. Tears, 164. -----secretion of the, II. 222. -----use of the, 180. Teeth, shedding of the, II. 393. Temperament, athletic, II. 447. ■----------- atrabilious, H. 447. ■-----------bilious, H. 447. -----------choleric, II. 447. ——------influence of, on the mind, 236. .-----------lymphatic, II. 448. .-----------melancholic, II. 447. .-----------muscular, n. 447. ___________nervous, II. 448. -----------phlegmatic, II. 448. ___________pituitous, II. 448. __----------sanguine, H. 446. Temperature, animal, n. 170. -----------depressed, effects of, II. 175. -----------elevated, effects of, H. 177. ___________of animals, table of, H. 172. of bodies, H. 170. Tractors, metallic of Perkins, II. 437. Transpiration, cutaneous, II. 211. pulmonary, II. 218. Transudation, 34, II. 56 Travail, II. 333. Tutamina cerebri, 42. oculi, 160 Twins, proportion of cases of, II. 320. U. Understanding, 248. Urea, where met with, 17. Urinary organs, II. 232. Urine, 511. secretion of, II. 232. Terror, expression of, 406. Testes, descent of the, II. 362. Thaumatrope of Paris, 224. Thigh-bone, neck of, advantage of the, 344. Thirst, 514. -----sense of, 226. Thymus gland, II. 28. Thyroid gland, II. 28. Tickling, 227. Tingling, 227. Tissue, 26. -----albugineous, 25. -----cellular, 24, 29. ------compound, 25. -----laminated, 24. ------medullary, 25. ------muscular, 24, 30. -----nervous, 25, 30. ------primary, 24. ------pulpy, 25. Tissues, permeability of to gases, 35. Titillation, 227. Tone, 33. Tonicity, 33. ________of Parry, II. 144. Touch, 73, 79. . .______immediate functions ot, 83. ______mediate functions of, 85. ______regarded the first of the senses, 84. Townshend, Col. his case, U. 134. Utero-gestation, II. 325. Uvula, use of the, 472. Varieties of mankind, II. 462. Vasa vasorum, II. 38. Vegetables and animals, differences be- tween, 7. Veins, II. 35. -----circulation in the, II. 147; Vena porta, II. 39. Venous system, H. 35. Ventrale cutaneum of the Bosjesman female, II. 269. Ventriloquism, 379. Venus, Hottentot, II. 208. Vestiges of the French, what, 115. Virility, age of, II. 400. Vis insita of Haller, 312. ---mortua, 36. Vision, 140, 165. ______advantages of to the mind, 208. direction of bodies appreciated by, 211. ----distance appreciated by, 211. ----distinct, point of, 190. —---distinct, requisites for, 187. ----,double, 201. ----erect, 185. ____immediate functions of, 208. ----■ improved by education, 225. ----indirect, 190. ----magnitude, appreciated by, 211. mediate functions of, 211. ------motion, appreciated by, 218. -----multiple with one eye, 206. ------nerves of, 173. -----oblique, 190. ------organs of, 150. .------phenomena of, 182. ------position, appreciated by, 211. seat of, 183 ------surface of bodies appreciated by, 211. Visual angle, 212. Vital force, II. 480. 532 INDEX. Vital principle, H. 480. ----properties, H. 501. Vitality, II. 480. Vocal apparatus, 360. Voice, 360. -----intensity of, 366. -----native, 384. -----quality of the, 378. -----timbre of the, 378. ——— tone of the, 366. Volition, seat of, 294. Vomiting, 518. -------at pleasure, 518. Vowels, 390. W. Walking, 349. Wants, 228. Weeping, n. 93. --------expression of, 404. --------of animals, II. 93. Whispering, 384. Whistling, 384. Writing, art of, 389. Y. Yawning, II. 91. THE END. MEDICINE, &c. LIBRARY OF THE MEDICAL SCIENCES. NOW PUBLISHING, THE CYCLOPEDIA OF PRACTICAL MEDICINE AND SURGERY, A DIGEST OF MEDICAL LITERATURE. EDITED BY ISAAC HATS, MI. D. TERMS OF PUBLICATION. The work will be published in parts averaging 112 pages each, and embellished with numerous wood cuts. It is expected that the work will be completed in forty parts, making eight large volumes. A part will be published every month, if practicable. Price to Subscribers 50 cents each part. Gentlemen who are desirous to have the work for- warded to them, will please transmit their orders to [he publishers, or to any of the Agents for the Amer- ican Journal of the Medical Sciences, accompanied by a remittance of five dollars, which will pay for the first ten numbers. In order that the postage on thisrwork may not in- terfere with its extensive circulation, it is printed on a very large sized paper, so that no one part will con- tain more than five sheets of paper, thus making the postage within one hundred miles, 7J cents; or over that distance, 12J cents. MANUAL of GENERAL, DESCRIPTIVE, and PATHOLOGICAL ANATOMY. By J. F. Meckel, Professor of Anatomy at Halle, &c. &e. Translated from the French, with Notes, by A. Sidney Doane, A. M. M. D. 3 vols. 8vo. " It is among the irilst classical, learned, and authori- tative treatises on Anatomy."—American Journal of Med. Science. SURGICAL MEMOIRS of the CAM- PAIGNS of RUSSIA, GERMANY, and FRANCE. Translated from the French of Baron Larrey. In 8vo. with Plates. A MANUAL of MEDICAL JURISPRU- DENCE, compiled from the best Medical and Legal Works ; comprising an account of—I. The Ethics of the Medical Profes- sion ; II. Charters and Laws relative to the Faculty; and III. All Medico-legal Ques- tions, with the latest Decisions: being an Analysis of a course of Lectures on Foren- sic Medicine. By Michael Ryan, M. D., Member of the Royal College of Physi- cians in London, &c. First American edi- tion, with Additions, by R. Eglesfield Griffith, M. D. In 8vo. MEDICINE, &c. A PRACTICAL TREATISE ON MEDI- CAL JURISPRUDENCE, with so much of Anato- my, Physiology, Pathology, and the Practice of Medicine and Surgery, as are essential to be known by Members of the Bar and Private Gentlemen; and all the laws relating to Medical Practitioners; with explanatory plates. By J. Chitty, Esq. First American edition : with Notes and Additions, adapt- ed to American works and Judicial Decisions. 8vo. DIRECTIONS for MAKING ANATOMI- CAL PREPARATIONS, formed on the basis of Pole, Marjolin, and Breschet, and in- cluding the new method of Mr. Swan. By Usher Parsons, M. D., Professor of Anato- my and Surgery. 1 vol. 8vo. with Plates. " It is compiled and prepared with judgment, and is the best and most economical companion the student can possess to aid him in the pursuit of this delightful department of his labors "—Bost. Med. % Surg. Jour. "This is unquestionably one of the most useful works on the preparation of Anatomical Specimens ever pub- lished. It should be in the hands of every lover of anatomy; and as.attention now is more directed to the formation of museums, it will be found a very valuable book. Nothing is omitted that is important, and many new formula; are introduced, derived from the author's experience, and from rare books, which he has had the industry to collect."—JV. Y. Med. Journal, Aug. 1631. A PRACTICAL GUIDE to OPERATIONS on the TEETH. By James Snell, Dentist In 1 vol. 8vo. with Plates. "Those of our readers who practise in the department of Surgery, on which Mr. Snell's essay treats, will find some useful instructions on the mode of extracting teeth."—Med. Qaictte. "This is an excellent practical work, and will be found generally useful."—Alltenceum. " This is the best practical manual for the dentist we have seen in the English language."—Gaz. of Health. PRINCIPLES of PHYSIOLOGICAL MED- ICINE, including Physiology, Pathology, and Therapeutics, in the form of Proposi- tions, and commentaries on those relating to Pathology, by F. J. V. Broussais, &c.; translated by Isaac Hays, M. D. and R. E. Griffith, M. D. In 8vo. "The present work will form an indispensable addi- tion to the library of every physician. It is a very im- portant and necessary companion to the Treatise on Physiology as applied to Pathology, by the same au- thor."—American Journal of Med. Science. PRINCIPLES of SURGERY. By John Syme, Professor of Surgery in the University of Edinburgh. In 8vo. HUMAN PHYSIOLOGY, illustrated by numerous Engravings; by Robley Dungli- son, M. D., Professor of Physiology, Pathol- ogy, &c. in the University of Virginia, Mem- ber of the American^ Philosophical Society, &c. 2 vols. 8vo. * " It is tha most complete and satisfactory system of Physiology in the English language. It will add to the already high reputation of the author."—American Jour- nal of Med. Science. " A work like this, so abounding in important facts, so correct in its principles, and so free from errors aris- ing from a prejudiced adherence to favorite opinions, will be cordially received and extensively'consulted by the profession, and by all who are desirous of a know- ledge of the functions of the human body; and those who are the best qualified to judge of its merits, will pronounce it the best work of the kind in the English language."—Silliman. t "This is a work of no common standing, it is char- acterized by much learning and research, contain*1 a vast amount of important matter, and is written tr a scholar and a man of taste. We think it will be placed by general consent at the head of the systems of PL 'si- ology, in the English language."—Transylvania Journ. > XVEEDZ CINE. The PRACTICE of PHYSIC. By W. P. Dewees, M^ D. Adjunct Professor of Mid- wifery, in the University of Pennsylvania, 2d edition, complete in 1 vol. 8vo. " We have no hesitation in recommending it as deci- dedly one of the best systems of medicine extant. The tenor of the work in general reflects the highest honor on Dr. Dewees's talents, industry, and capacity for the exe- cution of the arduous task which he had undertaken. It is one of the most able and satisfactory works which mod- ern times have produced, and will be a standard authori- ty."—London Med. and Surg. Journal, Aug. 1630. DEWEES on the DISEASES of CHIL- DREN. 5th ed. In 8vo. The objects of this work are, 1st, to teach those who have the charge of children, either as parent or guar- dian, the most approved methods of securing and im- proving their physical powers. This is attempted by pointing out the duties which the parent or the guar- dian owes for this purpose, to this interesting, but helpless class of beings, and the manner by which their duties shall berfulfilled. And 2d, to render available a long experience to these objects of our affection when they become diseased. In attempting this, the author has avoided as much as possible, " technicality;" and has given, if he does not flatter himself too much, to each disease of which he treats, its appropriate and designating characters, with a fidelity that will prevent any two being confounded together, with the best mode of treating them, that either his own experience or that of others has sug- gested. DEWEES on the DISEASES of FEMALES. 4th edition, with Additions. In 8vo. A COMPENDIOUS SYSTEM OF MID- WIFERY ; chiefly designed to facilitate the Inquiries of those who may be pursuing this Branch of Study. In 8vo. with 13 Plates. 6th edition, corrected and enlarged. By W. P. Dewees, M. D. The ELEMENTS OF THERAPEUTICS and MATERIA MEDICA. By N. Chap- jian, M. D. 2 vols. 8vo. 5th edition, cor- rected and revised. MANUAL of PATHOLOGY: containing the Symptoms, Diagnosis, and Morbid Char- acter of Diseases, &c. By L. Martinet. Translated, with Notes and Additions, by Jones Quain. Second American Edition, 12mo. We strongly recommend M. Martinet's Manual to the profession, and especially tojjuderft's; if the latter wish to study diseases to advantaf^. they should always have it at hand, both when ai ihe bedside of the patient, and when making post mortem examinations."—American Journal of the Medical Sciences, JVu. /. CLINICAL ILLUSTRATIONS of FEVER, comprising a Report of the Cases treated at the London Fever Hospital in 1828-29, by Alexander Tweedie, M. D., Member of the Royal College of Physicians of London, &c. 1 vol. 8vo. " In short, the present work, concise, unostentatious as it is, would have led us to think that Dr. Tweedie was a man of clear judgment, unfettered by attachment to any fashionable hypothesis, that he was an energetic but judicious practitioner, and that, if he did not dazzle his readers with the brilliancy of theoretical speculations, he would command their assent to the solidity of his didac- tic precepts."—Med. Chir. Journal. The ANATOMY, PHYSIOLOGY, and DIS- EASES of the TEETH. By Thomas Bell, F.R.S., F.L.S. &c. In 1 vol. 8vo. With Plates. " Mr. Bell has evidently endeavored to construct a work of reference for the practitioner, and a text-book for the student, containing a ' plain and practical digest of thc information at present possessed on thc subject, and results of the author's own investigations and expe- rience.'" * * * "We must now take leave of Mr Bell, whose work we have no doubt will become a class-book on the important subject of dental surgery."—Medico-Chi- rurgical Review. " We have no hesitation in pronouncing it to be the best treatise in the English language."—North American Medical and Surgical Journal, JVV». 19. AMERICAN DISPENSATORY. Ninth Edition, improved and greatly enlarged. By John Redman Coxe, M. D. Professor of Ma- teria Medica and Pharmacy in the Univer- sity of Pennsylvania. In 1 vol. 8vo. %* This new edition has been arranged wilh spe- cial reference to the recent Pharmacopoeias, published in Philadelphia and New-York. ELLIS' MEDICAL FORMULARY. The Medical Formulary, being a collection of prescriptions derived from the writings and practice of many of the most eminent Phy- sicians in America and Europe. By Benjamin Ellis, M. D. 3d. edition. With Additions. " We would especially recommend it to our brethren in distant parts of the country, whose insulated situations may prevent them from having access to the many autho- rities which have been consulted in arranging the mate- rials for this work."—Phil. Med. and Phys. Journal. MANUAL of MATERIA MEDICA and PHARMACY. By H. M. Edwards, M. D. and P. Vavasseur, M. D. comprising a con- cise Description of the Articles used in Medicine; their Physical and Chemical Properties; the Botanical Characters of the Medicinal Plants; the Formulae for the Prin- cipal Officinal Preparations of the American, Parisian, Dublin, &c. Pharmacopoeias; with Observations on the proper Mode of combin- ing and administering Remedies. Trans- lated from the French, with numerous Ad- ditions and Corrections, and adapted to the Practice of Medicine and to the Art of Phar- macy in the United States. By Joseph Too- no, M. D. Member of the Philadelphia Med- ical Society, and E. Durand, Member of the Philadelphia College of Pharmacy. "It contains all the pharmaceutical information that the physician can desire, and in addition, a larger mass of information, in relation to the properties, &c. of the dif- ferent articles and preparations employed in medicine, than any of the dispensatories, and we think will entirely supersede all these publications in the library of the phy- sician."—Am. Journ. of the Medical Sciences. MEMOIR on the TREATMENT of VENE- REAL DISEASES without MERCURY, employed at the Military Hospital of the Val-de-Grace. Translated from the French of H. M. J. Desruelles, M. D. &c. To which are added, Observations by G. J. Guthrie, Esq. and various documents, showing the results of this Mode of Treatment, in Great Britain, France, Germany, and America. PHYSIOLOGICAL MEDICINE, ANATOMY, &c. HISTORY OF CHRONIC PHLEGMASIA, OR INFLAMMATIONS, founded on Clin- ical Experience and Pathological Anatomy, exhibiting a View of the different Varieties and Complications of these Diseases, with their various Methods of Treatment. By F. J. V. Broussais, M. D. Translated from the French of the fourth edition, by Isaac Hays, M. D. and R. Eglesfeld Griffith, M. D, Members of the Am. Philosophical So- ciety, Acad, of Nat. Sc, &c. &c. 2 vols. 8vo. THE MEDICAL COMPANION, or FAMILY PHYSICIAN : treating of the Diseases of the United States, with their symptoms, causes, cure, and means of prevention; common cases in Surge- ry, as fractures, dislocations, &c.; the management and diseases of women and children; a dispensato- ry of preparing family medicines, and a Glossary explaining technical terms. To which are added, a brief Anatomy and Physiology of the Human Body, showing, on rational principles, the cause and cure of diseases. An essay on Hygiene, or the art of preserving health, without the aid of medicine. An American Materia Medica, pointing out the virtue and doses of our medicinal plants. Also, the Nurse's Guide. The 8th edition. By James Ewell, M. D. In one large vol. 8vo. *** This edition has undergone a complete revision, and is brought up to the present time. A TREATISE ON PHYSIOLOGY, Applied to Pathology. By F. J. V. Broussais, M. D. Translated from the French, by Drs. Bell and La Roche. 8vo. Third American edi- tion, with additions. " We cannot too strongly recommend the present work to the attention of our readers, and indeed of all those who wish to study physiology as it ought to be studied, in its application to the science of disease." " We may safely say that he has accomplished his task in a most masterly manner, and thus established his reputation as a most "excellent physiologist and profound pathologist." —North American Med. and Surg. Joum. Jan. 1827. A TREATISE ON DENTAL SURGERY Second edition, revised, corrected, and im- proved, with new plates. By S. S. Fitch, M. D. 1 vol. 8vo. THE PRACTICE OF MEDICINE, upon the Principles of the Physiological Doctrine. By J. G. Coster, M. D. Translated from the French. An EPITOME of the PHYSIOLOGY, GENERAL ANATOMY, and PATHOL- OGY of BICHAT. By Thomas Hender- son, M. D. Professor of the Theory and Practice of Medicine in Columbia College, Washington City. 8vo. PHYSIOLOGICAL PYRETOLOGY; or, A Trka- tise on Fevers, according to the Principles of the New Medical Doctrine. By F. G. Boisskau, Doctor in Medicine of the Faculty of Paris. &c. &«•. r rom the fourth French edition. Translated by J. R. Knox, M. D. 1 vol. 8vo. " Bnis^eau's Pyretoloey is not merely the most remarkable performance Mill ha.'*, yet appeared among the disciples of Broussais, but i. realty the Met "idI n/ost satisfactory exposition of the pjtholoyj'of Fevers w..,,,vh,ch we are acquaiutal.,'-v4"«ncaji Journal of Medical Sciences, iSo. X.1V. ON THE INFLUENCE OF VARIOUS PHYS- ICAL AND MORAL AGENTS; Climate and Lo- cality, Change of Air, Food, Clothing, Bathing, Ex- ercise, Professions, &c., on Healthy Man: constituting elements of private Hygiene, or the art of preserv ing health. By Robley Dunglison, M. D., Profes sor of Materia Medica, &c, in the University of Maryland, Author of a Treatise on Human Physi- ology, &c. &c. 1 vol. 8vo. (In the press.) A TREATISE on PATHOLOGICAL ANATOMY. By William E. Horner, M. D., Adj. Prof, of An-1 atomy in the University of Pennsylvania. "We can conscientiously commend it to the members of the profession, as a satisfactory, interesting, and instruc- tive view of the subjects discussed, and as well adapted to aid them in forming a correct appreciation of the dis- eased conditions they are called on to relieve.''—American Journal of the Medical Sciences, No. 9. By the same Author. A TREATISE on SPECIAL and GENERAL ANATOMY. Third edition, revised and corrected, in 2 Vols. 8vo. THE HAND; ITS MECHANISM, AND VITAL ENDOWMENTS, AS EVINCING DE- SIGN. By Sir Charles Bell. 1 vol. 12mo. Being a part of the Bridgewater Treatises. SYSTEM of ANATOMY, for the use of Stu- dents of Medicine. By Caspar Wistar. Sixth edition, revised and corrected, by W. E. Horner, Adjunct Professor of Anatomy in the University of Pennsylvania. In 2 Vols. 8vo. ELEMENTS of GENERAL ANATOMY, or a description of the Organs comprising the Human Body. By P. A. Beclard, Pro- fessor of Anatomy to the Faculty of Medi- cine at Paris. Translated by J. Togno. TREATISE on SURGICAL ANATOMY. By Abraham Colles, Professor of Anatomy and Surgery, in the Royal College of Sur- geons in Ireland, &c. Second American edition, with notes by J. P. Hopkinson, De- monstrator of Anatomy in the University of Pennsylvania, &c. &c. A TREATISE ON DISEASES OF THE HEART AND GREAT VESSELS. By J. R. Bertin. Edited by G. Bouillaud. Translated from the French. 8vo. ON THE INFLUENCE of ATMOSPHERE AND LOCALITY; Change of Air and Climate; Seasons; Food; Clothing; Bath- ing ; Exercise; Sleep; Corporeal and Intel- lectual Pursuits, &c. &c. on Human Health: constituting Elements of Hygiene. By Robley Dunglison, M. D., Author of a Treatise on Human Physiology. 1 vol. 8vo. BXX.B2CINE AND SURGERY. A TREATISE on FEVER. By Southwood Smith, M. D, Physician to the London Fever Hospital. •' No work has been more lauded by the Reviews than the Treatise on Fevers, by Southwood Smith. Dr. John- son, the editor of the Medico-Chirurgical Review, says, ' It is the best we have ever perused on the subject of fever, and in our conscience, we believe it the best that ever flowed from the pen of physician in any age or in any country.' "—Am. Med. Journ. An ESSAY on REMITTENT and INTER- MITTENT DISEASES, including generic- ally Marsh Fever and Neuralgia—compris- ing under the former, various Anomalies, Obscurities, and Consequences, and under a new systematic View of the latter, treating of Tic Douloureux, Sciatica, Headache, Ophthalmia, Toothache, Palsy, and many other Modes and Consequences of this gene- ric Disease; by John Macculloch, M. D., P. R. S. &c. &c. "In rendering Dr. Macculloch's work more accessible to the profession, we are conscious that we are doing the state some service."—Med. Chir. Review. 1 We most strongly recommend Dr. Macculloch's trea- tise 10 the attention of our medical brethren, as present- ing a most valuable mass of information, on a most im- portant subject."—JV. A. Med. and Surg. Journal. A PRACTICAL SYNOPSIS OF CUTANE- OUS DISEASES, from the most celebrated Authors, and particularly from Documents afforded by the Clinical Lectures of Dr. Biett, Physician to the Hospital of St. Louis, Paris. By A. Cazenave, M. D. and H. E. Schedel, M. D. Second edition. " We can safely recommend this work to the attention of practitioners as containing much practical informa- tion, not only on the treatment, but also on the causes of cutaneous affections, as being in fact the best treatise on Uncases of the skin that has ever appeared."—Ameri can Journal of the Medical Sciences, No. i. LADY'S MEDICAL GUIDE. By Richard Reese, M. D. 18mo. of Baron Larrey. LECTURES ON INFLAMMATION, exhib- iting a view of the General Doctrines, Pa- thological and Practical, of Medical Sur- gery. By John Thompson, M. D., F. R. S. E. Second American edition. THE INSTITUTES AND PRACTICE OF SURGERY; bein? the Outlines of a Course of Lectures. By W. Gibson, M. D. Profes- sor of Surgery in the University of Pennsyl- vania. 4th edition, revised, corrected, and enlarged. In 2 vols. 8vo. PRINCIPLES OF MILITARY SURGERY, comprising Observations on the Arrange- ments, Police, and Practice of Hospitals, and on the History, Treatment, and Anoma- lies of Variola and Syphilis; illustrated with cases and dissections. By John Hennen, M. D., F. R. S. E. Inspector of Military Hospitals—first American from the third London edition, with the Life of the Author, by his son, Dr. John Hennen. "The value of Dr. Hennen's work is too well appreci- ated to need any praise of ours. We v> pre only required then, to bring the third edition before the notice of our readers; and'having done this, we shall merely add, that the volume merits a place in every library, and that no military surgeon ought to be without it."—Medical Oai, american journal op the medical science-;*. Published Quarterly. And supported by the most distinguished Physician! in the Unnod States, among which ure Professors Bigelow, Channing, Chapman, Coxe, De Butts, De- wees, Dickson, Dudley, Francis, Gibson, I lure, Henderson, Horner, Hosack, Jackson, Macneven, Mott, Mussey, Physick, Potter, Sewall, Warren, and Worthington; Drs. Daniell, Drake, Emerson, Fearn, Geddings, Griffith. Hale, Havs, Hayward, Ives, Jackson, Moultrie, Ware, and Wright. It is published punctually on the first of November, February, May, and August. Each No. contains about 280 large 8vo. pages, and one or more plates —being a greater amount of matter than is fur- nished by any other Medical Journal in the United States. Price §5 per annum. The following Extracts show the estimation in which this Journal is held in Europe:— "Several of the American Journals are before us. * * * Of these the American Journal of the Medical Sciences is by far the better periodical; it is, indeed, the best of the trans-atlantic medical publications; and, to make a com. parison nearer home, is in most reelects superior to the great majority of European works of the same det-irip tion."—The Lancet, Jan. 1831. " We need scarcely refer our esteemed and highly eini nent cotemporary, [The American Journal of the Medical Sciences.] from whom we quote, to our critical remarks on the opinions of our own countrymen, or to the princi- ples which influence us in the discharge of our editorial duties." " Our copious extracts from his unequalled pub- lication, unnoticing multitudes of others which come be- fore us. are the best proof of the esteem which we enter- tain for his talents and abilities."—London Medical and Surgical Journal, March, 1830. "The American Journal of the Medical Sciences is one of the most complete and best edited of the numerous periodical publications of the United States."—Bulletin des Sciences Medicates, Tom. XIV. PATHOLOGICAL and PRACTICAL RE- SEA RCHES on DISEASES of the BRAIN and SPINAL CORD. By John Abercrom- bie, M. D. " We have here a work of authority, and one which does credit to the author and his country."—North Amir. Med. and Surg. Journal. By the same Author. PATHOLOGICAL and PRACTICAL RE- SEARCHES on DISEASES of the STO- MACH, the INTESTINAL CANAL, the LIVER, and other VISCERA of the ABDOMEN. "We have now closed a very long review of a very valuable work, and although we have endeavored to con- dense into our pages a great mass of important matter, we feel that our author has not yet received justice."— Medico-Chirurgical Review. A RATIONAL EXPOSITION or the PHYSICAL SIGNS of DISEASES of the LUNGS and PLEURA; Illustrating their Pathology and facilitating their Diag- nosis. By Charles J. Williams, M. D. In 8vo. with plates. " If we are not greatly mistaken, it will lead to a better understanding, and a more correct estimate of the value of auscultation, than any thing that has yet appeared." —Am. Med. Journal. CABINET CYCLOPAEDIA, CONDUCTED BY THE REV. DIONYSIUS LARDNER, LL. D. F. R. S. L. & E. M.R.I. A. P.L.S. F.Z.S. Hon.F.C.P.S. M. Ast. S. &c. &c. ASSISTED BY EMINENT LITERARY AND SCIENTIFIC MEN. Now publishing by Carey, Lea, % Blanchard, and for sale by all Booksellers. This work will form a popular compendium of what ever is useful, instructive, and interesting, in the circle of liuman knowledge. A novel plan of publication and ar- rangement has been adopted, which presents peculiar advantages. Without fully detailing the method, a few of Iheee advantages may be mentioned. Each volume will contain one or more subjects uninter- rupted and unbroken, and will be accompanied by the corresponding plates or other appropriate illustrations. Facility of reference will be obtained without fettering the work by a continued alphabetical arrangement. A subscriber may omit particular volumes or sets of vol- umes, without disintegrating his series. Thus each pur- chaser may form from the -'Cabinet " a Cyclopjedia, more or less comprehensive, as may suit bis means, taste, or profession. If a subscriber desire to discontinue the work at any stage of its publication, the volumes which he may have received will not lose their value by separation from the rest of the work, since they will always either be complete in themselves, or may be made so at a trifling expense. The purchasers will never find theii property in this work destroyed by the publication of a second edition. The arrangement is such that particular volumes may be re-edited or rewritten without disturbing the others. The "Cabinet Cyclopaedia" will thus be in a state of continual renovation, keeping pace with the never-ceas- ing improvements in knowledge, drawing within its circle from year to year whatever is new, and casting off whatever is obsolete, so as to form a constantly modern- ized Cyclopaedia. Such are a few of the ad vantages which the proprietors have to oner to the public, and which they pledge themselves to realize. Treatises on subjects which are technical and profes- sional will be adapted, not so much to those who desire to attain a practical proficiency, as to those who seek that portion of information respecting such matters which is generally expected from well-educated persons. An interest will be imparted to what is abstract by copious illustrations, and the sciences will be rendered attractive, by treating them with reference to the most familiar ob- jects and occurrences. The unwielrily bulk of Encyclopaedias, not less than the abstruse discussions which they contain, has hitherto consigned th°m to the library, as works of only occasional reference. The present work, from its portable form and popular style, will claim a place in the drawing-room and the boudoir. Forming in itself a Complete Library, af- fording an extensive and infinitely varied store of in- struction and amusement, presenting just so much on every subject as those not professionally engaged in it require, convenient in size, attractive in form, elegant in illustrations, and most moderate in expense, the "Cabinet Cyclopaedia" will, it is hoped, be found an object of para- mount interest in every family. To the heads of schools and all places of public educa- tion the proprietors trust that this work will particularly recommend itself. It seems scarcely necessary to add, that nothing will be admitted into the pages of the " Cabinet Cyclopjedi a" which can have the most remote tendency to olfend public or private morals. To enforce the cultivation of religion and the practice of virtue should be a principal object with all who undertake to inform the public mind; but with the views just explained, the conductor of this work feels these considerations more especially pressed upon his attention. Parents and guardiaus may, therefore, rest assured that they will never find it necessary to place a volume of the " Cabinet " beyond the reach of their chil- dren or pupils. interest which may present itself from time to time can claim a place. Its subjects are classified accord- ing to the usual divisions of literature, science, and art. Each division is distinctly traced out, and will consist of a determinate number of volumes. Al- though the precise extent of the work cannot be fixed with certainty, yet there is a limit which will not be exceeded; and the subscribers may look forward to the possession, within a reasonable time, of a complete library of instruction, amusement, and general refer- ence, in the regular form of a popular Cyclopaedia. The several classes of the work are—1, NATURAL PHILOSOPHY; 2, The USEFUL and FINE ARTS; 3, NATURAL HISTORY; 4, GEOGRAPHY; 5, POLITICS and MORALS; 6, GENERAL LITE- RATURE and CRITICISM; 7, HISTORY: 8, BI- OGRAPHY. In the above abstruse and technical departments of knowledge, an attempt has been mads to convey to the reader a general acquaintance with these sub- jects, by the use of plain and familiar language, ap- propriate and well-executed engravings, and copious examples and illustrations, taken from objects and events with which every one is acquainted. The proprietors formerly pledged themselves that no exertion should be spared to obtain the support of the most distinguished talent of the age. They trust that they have redeemed that pledge. Among the volumes already published in the literary department, no less than four have been the production of men who stand in the first rank of literary talent,—Sir James Mackintosh and Sir Walter Scott. In the sci- entific department, a work has been produced from the pen of Mr. Herschel, which has been pronounced by the highest living authority on subjects of general philosophy, to contain " the noblest observations on the value of knowledge which have been made since Bacon," and to be " the finest work of philosophical genius which this age has seen." The following is a selection from the list of Contributors. The Right Honorable Sir JAMES MACKIN- TOSH, M. P. The Right Rev. The Lord Bishop of Cloyne. Sir WALTER SCOTT, Bart. JOHN FREDERICK WILLIAM HERSCHEL, Esq. THOMAS MOORE, Esq. J. B. BIOT, Member of the French Institute. ROBERT SOUTHEY, Esq. Poet Laureate. The Baron CHARLES DUP1N, Member of the Royal Institute and Chamber of Deputies. THOMAS CAMPBELL, Esq. T. B. MACAULEY, Esq. M. P. DAVID BREWSTER, LL.D. J. C. L. SISMOIS DI, of Geneva. Capt. HENRY KATER, Vice President of the Royal Society. The ASTRONOMER ROYAL. DA VIES GILBERT, Esq. M. P. S. T. COLERIDGE, Esq. JAMES MONTGOMERY, Esq. The Right Hon. T. P. COURTENAY, M.P. J. J. BERZELIUS, oi Stockholm, F. R. S.( &c. The Rev. G. R. GLEI3. T. PHILLIPS, Esq. Prof, of Painting R. A. Rev. C. THIRLWALL, Fellow of Trinity Colkfje, Cambridge. ANDREW URE, M. D. F. R, l\, &c. &c. <*c. DR. LARDNERS CABINET CYCEOPyEBIA. VOLUMES PUBLISHED. I. II.—HISTORY of SCOTLAND. By Sir Walter Scott. III. VI.—HISTORY of ENGLAND. By Sir James Mackintosh. In 8 Vols. Vols. I. and II. IV.—OUTLINES of HISTORY. V —HISTORY of the NETHERLANDS. By T. C. Grattan, Esq. VII. VIII. XII.—HISTORY of FRANCE. By Eyre Evans Crowe. In 3 Vols. IX.—MECHANICS. By Caft. Kater and Dr. Lardner. X.—A PRELIMINARY DISCOURSE on the 0B: JECTS, ADVANTAGES, and PLEASURES of the STUDV of NATURAL PHILOSOPHY. In 1 Vol. By J. F. W. Herschel, Esq. XI.—BIOGRAPHY of EMINENT BRITISH STATESMEN. XIII.—HYDROSTATICS and PNEUMATICS. By Dr. Lardner. XIV.—HISTORY of the PROGRESS and PRE- SENT SITUATION of the SILK MANUFAC- TURE. XV.—HISTORY of the ITALIAN REPUBLICS. By J. C. L. Sismondi. XVI.—HISTORY of the PROGRESS and PRE- SENT STATE of the MANUFACTURE of PORCELAIN and GLASS. XVII.XVIII. XX. XXI. XXII.—HISTORYofSPAIN and PORTUGAL 5 vols. XIX—HISTORY of SWITZERLAND. XXIII—HISTORY of ENGLAND. By Sir James Mackintosh. Vol. III. Volumes in immediate preparation. THE HISTORY OF IRELAND. By Thos. Moore. Vol. I. is nearly ready, and the re- mainder in progress. HISTORY OF ENGLAND. Vol.4. Being a continua tion of Mackintosh. A PRELIMINARY DISCOURSE on the USEFUL ARTS and MANUFACTURES. By the Baron Charles Dupin, Member of the Institute of France and of the Chamber of Deputies. A HISTORY of the MOORS. In 3 vols. By Rob- ert Southey, Esq. LIVES of the MOST EMINENT LITERARY MEN of ALL NATIONS. In 8 vols. By Scott, Southey, Moore, Mackintosh, Montgomery, Cunningham, and all the principal Literary and Scientific Contributors to the Cyclopaedia. GEOGRAPHY In 4 vols. By W. Cooley, Esq. author of the " History of Maritime Discovery." LIVES of the MOST DISTINGUISHED BRITISH NAVAL COMMANDERS. By R Southey, Esq. LIVES of the MOST DISTINGUISHED BRITISH MILITARY COMMANDERS. By the Rev. G. R. Gleig. The HISTORY of GREECE. In 3 vols. By the Rev. C. Thirlwall. FALL OF THE ROMAN EMPIRE: Com- prising a view of the Invasion and Settle- ment of the Barbarians. By J. C. L. De Sismondi. Nearly ready. " BOOKS THAT YOU MAY CARRY TO THB FIRK, AND HOLD READILY IN YOUR HAND, ARK THE MOST USEFUL AFTER ALL. A MAN WILL OFTEN LOOK AT THEM, AND BI TEMPTED TO OO ON, WHEN HE WOOI.D HAVE BEEN FRIOHTENED AT BOOKS OP A LARGER 8IZE, AND OF A MORE ERUDITE APPEARANCE."—Dr. Johnson. "We advisedly call the Cabinet Cyclopedia a great undertaking, because we consider, that in its effects on the tone and habits of thought of what is known by the phrase, ' the reading public,' it will be, if carried through in the spirit of its projection and commencement, one of the most invaluable productions of modern literature. * * "But these advantages, eminent as they undoubtedly are, are not the sole nor the chief recommendations of the Cabinet Cyclopaedia. Neither is it on the extreme cheapness of the publication, nor the federal independence —if we may so speak—of its several volumes, that we rest our prediction of its influence on the tone of think- ing of the present, and on the literature of the next gen- eration—but on the promise, amounting almost to a moral certainty, of the great excellence of its execution. A mul- titude of persons eminent in literature and science in the United Kingdom are employed in this undertaking; and, indued, no others should be employed in it; for it is a truth that the profound and practised writer alone is capable of furnishing a ' popular compendium.' " What parent or guardian that throws hiseye over the list of its contributors but must be rejoiced by meeting the names of those who are in themselves a guarantee of intellectual and moral excellence?"—Literary Oaiette. "The plan of the work appears well adapted to the pur- pose it is proposed to fulfil—that of supplying a series of publications, embracing the whole range of literature and science, in a popular and portable form; while the excellence of the execution is guarantied by the judgment displayed in the selection of writers. The list of authors employed in this ambitious undertaking comprises some of the most eminent men of the present age."—Atlas. " The Cyclopaedia, when complete, will form a valuable work of reference, as well as a most entertaining and in- structive library. It is an essential principle in every part of it, that it should be clear and easily understood, and that an attempt should everywhere be made to unite accurate information with an agreeable manner of con- veying it. It is an experiment to try how.much science may be taught with little crabbed or technical language, and how far the philosophical and poetical qualities of history may be preserved in its more condensed state. It possesses also the most indispensable of all the qualities of a work intended for general instruction—that of cheap ness. Whatever the plan might be, it was evident that ihe grand difficulty of Dr. Lardner was to unite a body of writers in its execution, whose character or works af forded the most probable hope that they were fitted for a task of which the peculiarity, the novelty, and even the prevalent relish for such writings greatly enhance the dif- ficulty. We do not believe, that in the list of contribu- tors, there is one name of which the enlightened part of the public would desire the exclusion. " In science, the list is not less promising. The names of the President, Vice-Presidents, and most distinguished Fellows of the Royal Society, are contained in it. A treatise on astronomy, by Herschel; on optics, by Brews- ter; and on mechanics, by Lardner; need be only recom- mended by the subjects and the writers. An eminent Prelate, of the first rank in science, has undertaken a noble subject which happily combines philosophy with religion. Twelve of the most distinguished naturalists of the age, Fellows of the Linnxan and Zoological So- cieties, are preparing a course of natural history. Others not less eminent in literature and science, whose names it is not needful yet to mention, have shown symptoms of an ambition to take a place among such fellow-laborerf,"— Times. " The topics, as may be supposed, are both judiciously selected and treated with ability. To general readers, and as part of a family library, the volumes already pub- lished possess great recommendations. For the external beauties of good printing and paper they merit equal com- mendation."—Bait. American. " The uniform neatness of these volumes, their very moderate price, and the quantity of information which they contain, drawn from the best and most attractive sources, have given them deserved celebrity, and no one who desires to jwssess such information, should hesitate a moment to add them to his library."—Fed. Oaiette. " This excellent work continues to increase in public favor, and to receive fresh accessions of forc« to it* corps of contributors. —Lit. Oazette. LARDNERS CABINET CYCLOPAEDIA. OF THE MANY WORKS WHICH HAVE BEEN LATELY PUB- LISHED IN IMITATION, OR ON THE PLAN ADOPTED BY THE SOCIETY FOR THE DIFFUSION OF USEFUL KNOWLEDGE, DR. LARDNERS CYCLOPAEDIA IS BY MUCH THE MOST VALUA- BLE, AND THE MOST RECOMMENDED BY DISTINGUISHED ASSISTANCE, SCIENTIFIC AND LITERARY." Edinburgh Review. HISTORY OP ENGLAND. By Sip James Mackintosh. In 8 Vols. Ill Vols, pub- lished. " I" tfie first volume of Sir James Mackintosh's His- tory of Lngland, we find enough to warrant the antici- pations of the public, that a calm and luminous philoso- phy will diffuse itself over the long narrative of our Brit- ish History."—Edinburgh Review. " In this volume Sir James Mackintosh fully developes those great powers, for the possession of which the public have long given him credit. The result is the ablest com- mentary that has yet appeared in our language upon some of the most important circumstances of English History." -Atlas. " Worthy in the method, style, and reflections, of the author's high reputation. We were particularly pleased with his high vein of philosophical sentiment, and his occasional survey of contemporary annals."—National Oaiette. "If talents of the highest order, long experience in po- litics, and years of application to the study of history and the collection of information, can command superi- ority in a historian. Sir James Mackintosh may, without reading this work, be said to have produced the best his- tory of this country. A perusal of the work will prove that those who anticipated a superior production, have not reckoned in vain on the high qualifications of the author."—Courier. " Our anticipations of this volume were certainly very highly raised, and unlike such anticipations in general, they have not been disappointed. A philosophical spirit, a nervous style, and a full knowledge of the subject, ac- quired by considerable research into the works of pre- ceding chroniclers and historians, eminently distinguish this popular abridgment, and cannot fail to recommend it to universal approbation. In continuing his work as he has begun, Sir James Mackintosh will confer a great bene- fit on his country."—Land. Lit. Oaiette. "Of its general merits, and its permanent value, it is impossible to speak, without the highest commendation, and after a careful and attentive perusal of the two vol- umes which have been published, we are enabled to de- clare that, so far. Sir James Mackintosh has performed the duty to which he was assigned, with all the ability that was to be expected from his great previous attain- ments, his laborious industry in investigation, his excel- lent judgment, his superior talents, and his honorable principles "—Inquirer. " We shall probably extract the whole of his view of the reformation, merely to show how that important topic has been handled by so able and philosophical a writer, professing Protestantism.—National Oaiette. "The talents of Sir James Mackintosh are so justly and deeply respected, that a strong interest is necessarily ex- cited with regard to any work which such a distinguished writer may think fit to undertake. In the present instance, as in all others, our expectations are fully gratified."— Gentleman's Magazine. " The second volume of the History of England, form- ing the sixth of Carey & Lea's Cabinet Cyclopedia, has been sent abroad, and entirely sustains the reputation of its predecessors. The various factions and dissensions, the important trials and battles, which render this period so conspicuous in the page of history, are all related with great clearness and masterly power.'— Boston Traveller. HISTORY OF SCOTLAND. By Sir Walter Scott. In 3 Vols. " The History of Scotland, by Sir Walter Scott, we do not hesitate to declare, will be, if possible, more exten- sively read, than the most popular work of fiction, by the same prolific author, and for this obvious reason: it com- bines much of the brilliant coloring of the Ivanhoe pic- tures of by-gone manners, and all the graceful facility of style and picturesqueness of description of his other charming romances, with a minute fidelity to the facts of history, and a searching scrutiny into their authenti- city and relative value, which might put to the blush Mr. Hume and other professed historians. Such is the magic charm of Sir Walter Scott's pen, it has only to touch the simplest incident of every-day life, and it starts up invested with all the interest of a scene of romance; and yet such is his fidelity to the text of nature, that the knights, and serfs, and collared fools with whom his in- ventive genius has peopled so many volumes, are regarded by us as not mere creations of fancy, but as real flesh and blood existences, with all the virtues, feelings and errors of common-place humanity."—Lit. Gazette. BIOGRAPHY OP BRITISH STATESMEN\ containing thc Lives of Sir Thomas More, Cardinal Wolsey, Archbishop Cranmcr, and Lord Burleigh. " A very delightful volume, and on a subject likely to increase in interest as it proceeds. * * * We cordially commend the work both for its design and execution. — Lend. Lit. Gazette, HISTORY OF FRANCE. BY EYRE EVANS CROWE, Esa. In 3 vols. " The style is concise and clear; and events are sum- med up with much vigor and originality."—Lit. Gazette. " His history of France is worthy to figure with the works of his associates., the best of their day, Scott and Mackintosh."—Monthly Mag. " For such a task Mr. Crowe is eminently qualified. At a glance, as it were, his eye takes in the theatre of centuries. His style is neat, clear, and pithy; and his power of condensation enables him to say much, and effectively, in a few words, to present a distinct and perfect picture in a narrowly circumscribed space "—La Belle Assemblee. "The style is neat and condensed; the thoughts and conclusions sound and just. The necessary conciseness of the narrative is unaccompanied by any baldness; on the contrary, it is spirited and engaging."—Bait. Ameri- can. "To compress the history of a great nation, during a perioil of thirteen hundred years, into three volumes, and to preserve sufficient distinctness as well as interest in the narrative, to enable and induce the reader to possess himself clearly of all the leading incidents, is a task by no means easily executed. It has, nevertheless, been well accomplished in this instance."—JV. Y. American. "Written with spirit and taste."— U. S. Gazette. "Could we but persuade our young friends to give these volumes a careful perusal, we should feel assured of their grateful acknowledgments of profit and pleas- ure."—JV. Y. Mirror. " At once concise and entertaining."—Saturday Bui letin. THE HISTORY OF THE NETHERLANDS, to the Battle of Waterloo. By T. C. Grat- tan. " It is but justice to Mr. Grattan to say that he has executed his laborious task with much industry and pro- portionate effect. Undisfigured by pompous nothingness, and without any of the affectation of philosophical pro- fundity, his style is simple, light, and fresh—perspicuous, smooth, and harmonious."—La Belle Assemblee. " Never did work appear at a more fortunate period. The volume before us is a compressed but clear and im- partial narrative "—Lit. Gaz. " A long residence in the country, and a ready access to libraries and archives, have furnished Mr Grattan with materials which he has arranged with skill, and out of which he has produced a raoBt interesting volume."— Gent. Mag. LARDNER'S CABINET CYCLOPAEDIA. ' IT IS NOT EASY TO DEVISE A CURE FOR SCCH A STATE OF THINGS (THE DECLINING TASTE FOR SCIENCE;) BUT THE MOST OBVIOUS REMEDY IS TO PROVIDE THE EDU- CATED CLASSES WITH A SERIES OF WORKS ON POPULAR AND PRACTICAL SCIENCE, FREED FROM MATHEMATICAL SYMBOLS AND TECHNICAL TERMS, WRITTEN IN SIMPLE AND PERSPICUOUS LANGUAGE, AND ILLUSTRATED BY FACTS AND EXPERIMENTS, WHICH ARE LEVEL TO THE CAPACITY OF ordinary minds."—Quarterly Review. LARDNER'S CABINET CYCLOPAEDIA PRELIMINARY DISCOURSE ON THE OB- JECTS, ADVANTAGES, AND PLEAS- URES OP THE STUDY OF NATURAL PHILOSOPHY. By J. T. W. Herschel, A. M. late Fellow of St. John's College, Cambridge. "Without disparaging any other of the many interest- ing and instructive volumes issued in the form of cabinet and family libraries, it is, perhaps, not too much to place at the head of the list, for extent and variety of condensed information, Mr. Herchel's discourse of Natural Philoso- phy in Dr. Lardner's Cyclopaedia."—Christian Observer. " The finest work of philosophical genius which this age has seen."—Mackintosh's England. "By far the most delightful book to which the existing competition between literary rivals of great talent and enterprise has given rise."—Monthly Review. " Mr. Herschel's delightful volume. * * * We find scattered through the work instances of vivid and happy illustration, where the .fancy is usefully called into action, so as sometimes to remind us of the splendid pictures which crowd upon us in the style of Bacon."—Quarterly Review. " It is the most exciting volume of the kind we ever met with."—Monthly Magazine. " One of the most instructive and delightful books we have ever perused.'— U. S. Journal. A TREATISE ON MECHANICS. By Capt. Kater, and the Rev. Dionysius Lardner. With numerous engravings. "A work which contains an uncommon amount of useful information, exhibited in a plain and very intelli- gible form."—Olmsted's Nat. Philosophy. "This volume has been lately published in England, as a part of Or. Lardner's Cabinet Cyclopaedia, and has re- ceived the unsolicited approbation of the most eminent men of science, and the most discriminating journals and reviews, in the British metropolis.—It is written in a popular and in elligible style, entirely free from mathe- matical symbols, and disencumbered as far as possible of technical phrases."—Boston Traveller. " Admirable in development and clear in principles, and especially felicitous in illustration from familiar sub- jects."—Monthly Mag. "Though replete with philosophical information of the highest order in mechanics, adapted to ordinary capaci- ties in a way to render it at once intelligible and popu- lar."— Lit. Gazette. " A work of great merit, full of valuable information, not only to the practical mechanic, but to the man of sci- ence."—JV*. Y. Courier and Enquirer. A TREATISE ON HYDROSTATICS AND PNEUMATICS. By the Rev. D. Lardner. With numerous engravings. " It fully sustains the favorable opinion we have already expressed as to this valuable compendium of modern sci- ence."—Lit. Gazette. " Dr. Lardner has made a good use of his acquaintance with the familiar facts which illustrate the principles of science."—Monthly Magazine. " It is written with a full knowledge of the subject, and in a popular style, abounding in practical illustra- tions of the abstruse operations of these imporant sci- ences."— U. S. Journal HISTORY of the RISE, PROGRESS, and PRESENT STATE of the SILK MANUFACTURE; with numerous En- gravings. ' It contains abundant information in every depart- ment of this interesting branch of human industry—in the history, culture, and manufacture of silk."—Monthly Magazine. " There is a great deal of curious information in this little volume."—Literary Gazette. HISTORY of the ITALIAN REPUBLICS; being a View of the Rise, Progress, and Fall of Italian Freedom. By J. C. L. De Sismondi. "The excellencies, defects, and fortunes of the gov- ernments of the Italian commonwealths, form a body of the most valuable materials for political philosophy. It is time that they should be accessible to the American people, as they are about to be rendered in Sismondi'a masterly abridgment. He has done for his large work, What Irving accomplished so well for his Life of Colum- bus."—National Gazette. HISTORY of the RISE, PROGRESS, and PRESENT STATE of the MANUFAC- TURES of PORCELAIN and GLASS. With numerous Wood Cuts. " In the design and execution of the work, the author has displayed considerable judgment and skill, and has so disposed of his valuable materials as to render the book attractive and instructive to the general class of readers."—Sat. Ev. Post. " The author has, by a popular treatment, made it one of the most interesting books that has been issued of this series. There are, we believe, few of the useful arts less generally understood than those of porcelain and glass making. These are completely illustrated by Dr. Lardner, and the various processes of forming differ- ently fashioned utensils, are fully described." OUTLINES OF HISTORY, from the earli- est Records to the present time. ' To concentrate in one comparatively small volume, a complete epitome of the entire history of the world, ancient and modern, so treated as to present a correct image of it, would fceom to be an object to be wished for, rather than expected; the 'Outlines of History,' however, realize this object."—Asiatic Journal. The HISTORY of SPAIN and PORTU- GAL. In 5 vols. " A general History of the Spanish and Portuguese Peninsula, is a great desideratum in our language, and we are glad to see it begun under such favorable aus- pices. We have seldom met with a narrative which fixes attention more steadily, and bears the reader's mind along more pleasantly." ' In the volumes before us, there is unquestionable evidence of capacity for the task, and research in the execution."—CA 5. Journal. HISTORY OF SWITZERLAND. "Like the preceding historical numbers of this valu- able publication, it abounds with interesting details, illustrative of thc habits, character, and political com- plexion of the p««pie and country it describes; and af- ford*, in the small space of one volume, a digest of all the important facts which, in more elaborate histories occupy five times the tpace."—Evening Post. EDUCATION, &c. ELEMENTS OF THE INTEGRAL CAL- CULUS ; with its Applications to Geometry, and to the Summation of Infinite Series, &c. Revised and corrected by Michael O'Shan- nessy, A. M. One vol. 8vo. " The volume before us forms the third of an analyti cal course, which commences with the • Elements of Analytical Geometry.' More elegant text-books do not exist in the English language, and we trust they will speedily be adopted in our Mathematical Seminaries. The existence of such auxiliaries will, of itself, we hope, prove an inducement to the cultivation of Analytical Science; for, to the want of such elementary works, the indifference hitherto manifested in this country on the subject is, we apprehend, chiefly to be ascribed. Mr. Young has brought the science within the reach of every intelligent student, and, in so doing, has contributed to the advancement of mathematical learning in Great Britain."—Presbyterian Review, January, 1832. " We remember the time when such a work as this would have been invaluable, and we do not think that any late publication has superseded the necessity of it." ■—Spectator, September 34, 1831. ELEMENTS OF THE DIFFERENTIAL CALCULUS; comprehending the General Theory of Curve Surfaces, and of Curves of Double Curvature. Revised and corrected by Michael O'Shannessy, A. M. One vol. 12mo. " The whole Elements of the Differential Calculus, comprehending all that is most valuable in the large works of the most celebrated Analysts, are contained in one volume, beautifully printed on a fine paper, and neatly bound in cloth. It appears to be in every respect well fitted for a Class.Book, and can scarcely fail to be very generally adopted "—Presbyterian Review, Septem- ber, 1831. " There are no affected changes of method : there is no parade of original plan, or of novelty of principle; and yet there is much original matter, much original reasoning, and, what is of more value than all questions about originality in an elementary treatise, there is a perspicuity, a unity of method prevailing in all its parts, that renders it more than any book we have seen pecu- liarly adapted to instruction. " It is not, however, as an elegant and perspicuous development of the first principles of the Calculus, mere- ly, that we have admired, and therefore recommended Mr. Young's little work. We have also found much to commend in it of a more profound character—much that we look for in vain in larger works, and indeed in all English books. "The paralogisms of some other writers, distinguished ones too, are pointed out in the preface, and in the body of the work; and many steps which have hitherto been deemed unquestionable, have been shown by Mr. Young to be altogether fallacious. We wonder, indeed, when we see them pointed out, why they did not occur to our- selves nor to any body else till now ; and we look upon the aptitude displayed in these detections to be highly characteristic of a mind which looks with a laudable anxiety to the purity of the fundamental principles of science."—Philosophical Magazine, October, 1831. ELEMENTS OF PLANE AND SPHER- ICAL TRIGONOMETRY; with its appli- cations to the Principles of Navigation and Nautical Astronomy, with the necessary logarithmic and Trigonometrical Tables. By J. R. Young. To which is added, some Original Researches in Spherical Geometry. By T. S. Davies, Esq. Revised and correct- ed by John D. Williams. One vol. 8vo. "In the Spherical Trigonometry, the fundamental Theorems are laid down with great clearness and per- spicuity, and the subsequent formula* are derived both briefly and elegantly. " We hope, therefore, that the account we have been able to offer of this unpretending volume, will have the effect of calling the attention of younger students, (and still more of professional tutors,) to it, as a book emi- nently calculated to insure an early intimacy with thc practice as well as the principles of Trigonometry, and of attracting the notice of Geometers generally to the curious results that appear in the supplemental chapters, and inducing them to attempt the extension of a branch of science, which apparently admits of almost unlimit- ed cultivation."—Philosophical Magazine. A TREATISE ON ASTRONOMY. By Sir John F. W. Herschel, F. R. S., &c. One vol. 12mo. "The present treatise is in no wise inferior to its pre- decessor : it is characterized by the same agreeable and elegant style, the same facility of illustration—added to which it possesses unrivalled precision and accuracy of demonstration. Avoiding, therefore, the abstruse nice ties and the transcendental mathematics of the subject, the author has nevertheless produced a volume calculat- ed, we are fully persuaded, to impress upon his readers the magnitude and importance of the science, and to in itiate them in no mean degree into its mysteries Lit Gazette. A GEOLOGICAL MANUAL. By Henry T. de la Beche, Esq., F. R. S., F. G. S., Member of the Geological Society of France, &c. In one vol. 8vo., with 104 wood cuts. "The management of the work is clever, while there is great merit in the original remarks, and a vast fund of information throughout."—Atlas. " Mr. De la Beche's Geological Manual is the first and best work of the kind, and he has performed his task with a perfect knowledge of all that has been ascertain- ed in Geology, and with considerable judgment and taste in the manner of doing it. So much Geological science was never before compressed in so small a space."— Spectator. " A work of first-rate importance in the science to which it relates, and which must henceforth take its place in the library of every student of Geology."—Phi- losophical Magazine. " Even those who cultivate this most fascinating branch of science only in their Cabinet and Library, will rind that they cannot be without it."—Jameson's Edinburgh Philosophical Journal. A COLLECTION OF ITALIAN COLLO- QUIAL PHRASES, on every subject ne- cessary to maintain Conversation, the whole so disposed as considerably to facilitate the acquisition of the Italian language. By an Italian Gentleman. One vol. 18mo. NOVELLE ITALIANE.—Stories from Ital- ian Writers, with a literal, interlinear trans- lation, on Locke's plan of Classical Instruc- tion, illustrated with Notes. First American from the last London edition, with additional translations and notes. 1 vol. 12mo. DIALOGHI DISPOSTI PER FACILI- TARE LO STUDIO DELLA LINGUA ITALIANA, Scritti m Francese da A. G. Collot. Tradotti da F. Mancinelli Ro- mano. One vol. 18mo. THE NATIONAL SCHOOL MANUAL: a regular and connected Course of Element- ary Studies, embracing the necessary and useful Branches of a Common Education. In Four Parts, with a quarto Atlas. Compiled from the latest and most approved Authors, by M. R. Bartlett. The plan of this work was the suggestion of the late Governor Clinton, whose zeal and efforts in the cause of our Public Schools, will be cherished with grateful re- membrance to the latest posterity; and this work, so far as it had advanced, up to the time of his lamented death, received his favorable regard and patronage. The object of the National School Manual, is to fur- nish a System of instruction, for a thorough English ed- ucation, in :t plain, practical, and progressive Series of Lessons, collaterally arranged. EDUCATION. A New Abridgement of AINSWORTH'S DICTIONARY, English and Latin, for the use of Grammar Schools. By John Dymock, LL D., with Notes, by Charles Anthon. 1 vol. 18mo. In this edition are introduced several alterations and improvements, for the special purpose of facilitating the labor and increasing the knowledge of the young scholar. GREEK and ENGLISH LEXICON. By D. Donnegan. Abridged for the use of Schools. In 1 vol. royal 18mo., containing above 800 pages. This work is printed on a handsome distinct type, and contains as much matter as many of the larger lexi- cons ; but owing to the form in which it is printed, it is sold at such price as to be within the'reach of all stu- dents. It offers more advantages to the young student than any other lexicon now in use. The vocabulary is more extensive and complete—comprising not only words found in the classics, but also such as are found in the writings of Hippocrates and the Greek physicians. The meanings attached to words by the several writers are also given. Words are given in alphabetical order in every poeti- cal and dialectic variety. The conjugation of verbs and flection of nouns are more complete than in other lexicons;—the meanings of words fuller and more correct—there being first a primary and then a secondary meaning, each distin- guished from the metaphorical and idiomatical. Phrases are also given when they note any peculiarity in signi- fication. The etymology of words is only omitted where it is confused or disputed. There is nothing left out which the young student would find necessary in study- ing the classics, and which would enable him to under- stand the true meaning of a word. In short, in this work the essential advantages of a good Dictionary are combined with those of a good Grammar—advan- tages not found in any Greek and English lexicon now used. ELEMENTS of MECHANICS. By James Renwick, Esq., Professor of Natural and Experimental Philosophy, Columbia College, N. Y. In 8vo. with numerous Engravings. " We think this decidedly the best treatise on Me- chanics, which has issued from the American press, that we have seen; one, too, that is alike creditable to the writer, and to the state of science in this country."— American Quarterly Review. ELEMENTS of OPTICS. By David Brew- ster. First American edition, with Notes and Additions, by A. D. Bache, Professor of Natural Philosophy and Chemistry in the University of Pennsylvania. 18mo. "The author has given proof of his well-known in- dustry, and extensive acquaintance with the results of science in every part of Europe."—Monthly Mag. " The subject is, as might be expected, ably treated, and clearly illustrated."—U. S. Jour. A TREATISE on HYDROSTATICS and PNEUMATICS. By the Rev. Dionysius Lardner, LL. D. F. R. S. &c. First Amer- ican from the first London edition, with Notes by Benjamin F. Joslin, M. D., Pro- fessor of Natural Philosophy in Union Col- lege. "It fully sustains the favorable opinion we have al- ready expressed as to this valuable compendium of mod- ern science."—Lit. Gaz. "Dr. Lardner has made a good use of his acquaintance with thrt familiar facts which illustrate the principles of science."—Monthly Mag. " It is written with a full knowledge of the subject, and in a popular style, abounding in practical illustra- tions of the abstruse operations of these important sciences."— U. S. Jour. An ESSAY on MORAL CULTURE, ad- dressed to Parents and Teachers. By M. M. >• Carll. 18mo. An ELEMENTARY TREATISE on AL- GEBRA, Theoretical and Practical; with attempts to simplify some of the more diffi- cult parts of the science, particularly the demonstration of the Binomial Theorem, in its most general form; the Solution of Equations of the higher orders; the Summa- tion of Infinite Series, &c. By J. R. Young. First American edition, with Additions and Improvements, by Samuel Ward, Jun. 8vo. "A new and ingenious general method of solving Equations has been recently discovered by Messrs. H. Atkinson, Holdred, and Horner, independently of each other. For the best practical view of this new method and its applications, consult the Elementary Treatise on Algebra, by Mr. J. R. Young, a work which deserves our cordial recommendation."—Dr. Gregory's edition of hut- ton's Mathematics. " For the summation of Infinite Series the author gives a new and ingenious method, which is very easy and extensive in its application."—Newcastle Mag. By the same Author. ELEMENTS of GEOMETRY; containing a new and universal Treatise on the Doc- trine of Proportions, together with Notes, in which are pointed out and connected several important errors that have hitherto remained unnoticed in the writings of Ge- ometers. Also, an Examination of the vari- ous Theories of Parallel Lines that have been proposed by Legendre, Bertrand, Ivory, Leslie, and others. " His observations on the theory of parallel lines, the labor he has bestowed on the doctrines of proportion, as well as his corrections of many errors of preceding Ge- ometers, and supplying their defects, together with his minute attention to accuracy throughout, may be justly considered as rendering his performance valuable, espe- cially to the learner."—Philosophical Magazine. " We have never seen a work so free from pretension and of such great merit. Various fallacies latent in the reasoning of some celebrated mathematicians, both of ancient and modern date, are pointed out and discussed in a tone of calm moderation, which we regret to say i not always employed in the scientific world."—Monthly Magazine. " This is a work of valuable information, the concep- tion of a most enlightened mind, and executed with a simplicity which cannot but carry the important truth it speaks of home to the conviction of every under- standing."— Weekly Times. The ELEMENTS of ANALYTICAL GE- OMETRY ; comprehending the Doctrine of the Conic Sections, and the General Theory of Curves and Surfaces of the sec- ond order, with a variety of local Problems on Lines and Surfaces. Intended for the use of Mathematical Students in Schools and Universities. " If works like the present be introduced generally into our schools and colleges, the continent will not long boast of its immense superiority over the country of Newton, in every branch of modern analytical science." —Atlas. THE ELEMENTS OF MECHANICS, com- ' prehending Statics and Dynamics, with a co- pious Collection of Mechanical Problems, in- tended for the use of Mathematical Students, in Schools and Universities; with numerous Plates. Revised and corrected by John D. Williams. 1 vol. 8vo. EDUCATION. LESSONS on THINGS, intended to improve Children in the Practice of Observation, Re- flection and Description, on the System of Pestalozzi, edited by John Frost, A. M. The publishers request the attention of teachers, school committees, and all who are desirous of improving the methods of instruc- tion, to this work, which is on a plan hitherto unattempted by any school-book in this coun- try, and which has been attended with extra- ordinary success in England. The following remarks on the work are ex- tracted from the " Quarterly Journal of Edu- cation." " This little volume is a 'corrected and re-corrected' edi- tion of lessons actually given to children, and, therefore, possesses a value to which no book made in the closet can lay claim, being the result of actual experiment. The work consists of a number of lessons, divided into live series; beginning with subjects the most easy and elementary, it gradually increases in difficulty, each suc- cessive step being adapted to the mind of the child as it acquires fresh stores of knowledge. " Every part of these lessons is interesting to the child, both on account of the active operation into which his own mind is necessarily called by the manner in which the lessons are given ; and also by the attractive nature of many of the materials which form the subject of the lessons. In the first and most elementary series, the pupil is simply taught to make a right use of his organs of sense, and to exercise his judgment so far only as relates to the objects about him; and accordingly the matter brought before him at this stage, is such that its obvious properties can be discovered and described by a child who has acquired a tolerable knowledge of his mother tongue." OUTLINES of HISTORY, from the Earliest Records to the Present Time. Prepared for the Use of Schools, with Questions, by John Frost, A. M. " The main object of the work is, by giving a selection of interesting and striking facts from more elaborate his- tories, properly and carefully arranged, with chronological tables, to render the study of general history less dry and repulsive than it has been heretofore. This, we think is fully accomplished. Very great care appears to have been bestowed on the selections, and in arranging the chrono- logical tables, as well as in the classification of the his- torical matter into parts and chapters. The work will sufficiently recommend itself to all who examine it."— Sat. Evening Post. "To concentrate in one comparatively small volume, a complete epitome of the entire history of the world, an- cient and modern, so treated as to present a correct image of it, would seem to be an object to be wished for, rather than expected; the ' Outlines of History,' however, realize this object."— Asiatic Journal. "We consider that Mr. F has done a service to schools, by the time and labor which he has bestowed upon this work; the marginal dates will be found of great service, but the chapters of questions upon the text, and upon the maps, to illustrate the geography of the history, will es- pecially recommend the work to^he attention of teach- ers."— U- S. Gazette. Philadelphia, July Kit A, 1831. "The 'Outlines of History,' I consider an excellent class-book of general history for the use of schools. The questions added by Mr. Frost, are a most valuable auxili- ary for the teacher as'well as the pupil. I shall use the 'Outlines' in my school, and cordially recommend it to parents and teachers. S. C. WALKER." Philadelphia, April 30th, 1831. "Dear Sir,—I have just received a copy of your edition of the 'Outlines of History.' From a cursory perusal, I am disposed to give it a high rank as a school-book. So well satisfied am I with the arrangement and execution of the work, that I intend to put it immediately into the hands of a class in my own school. " Very respectfully, your obedient servant. " Mr. John Frost." " LEVI FLETCHER. FRENCH. BY A. BOLMAR. A COLLECTION of COLLOQUIAL PHRASES on every Topic necessary to main- tain Conversation, arranged under different heads, with numerous remarks on the peculiar pronunciation and use of various words—the whole so disposed as considerably to facilitate the acquisition of a correct pronunciation of the French. By A. Bolmar. One vol. 18mo. A SELECTION of ONE HUNDRED PERRIN'S FABLES, accompanied by a Key, containing the text, a literal and free trans- lation, arranged in such a manner as to point out the difference between the French and the English idiom, also a figured pronunciation of the French, according to the best French works extant on the subject; the whole preceded by a short treatise on the sounds of the French language, compared with those of the English. Les AVENTURES de TELEMAQUE par FENELON, accompanied by a Key to the first eight books; containing like the Fa- bles—the Text—a Literal—and Free Trans- lation ; intended as a Sequel to the Fables. The expression ' figured pronunciation,' is above em- ployed to express that the words in the Key to the French Fables are spelt and divided as they are pronounced. It is what Walker has done in his Critical Pronouncing Dic- tionary ; for instance, he indicates the pronunciation of the word enough, by dividing and spelling it thus, e-nuf. In the same manner I indicate the pronunciation of the word comptaient thus, kon te. As the understanding of the figured pronunciation of Walker requires the student to be acquainted with the primitive sounds of the English vow- els, he must likewise, before he can understand the figured pronunciation of the French, make himself acquainted with the 20 primitive sounds of the French vowels. This any intelligent person can get from a native, or from anybody who reads French well, in a few hours. A COMPLETE TREATISE on the GEN- DERS of FRENCH NOUNS; in a small pamphlet of fourteen pages. This little work, which is the most complete of the kind, is the fruit of great labor, and will prove of immense service to every learner. ALL THE FRENCH VERBS, both REG- ULAR and IRREGULAR, in a small volume. The verbs lire to be, avoir to have, parler to speak, finir to finish, recevoir to receive, vendre to sell, se lever to rise, se bien porter to be well, s'en alter to go away, are here all conjugated through—affirmatively —negatively—interrogatively—and negatively and i'»- terrogativety—an arrangement which will greatly fa- cilitate the scholar in his learning the French verbs, and which will save the master the trouble of explain- ing over and over again what may be much more easily learned from books, thus leaving him more time to give his pupil, during the lesson, that instruction which cannot be found in books, but which must be learned from a master. NEUMAN'S SPANISH and ENGLISH DICTIONARY. New Edition, in one vol. I6mo. (Sliemfotrg, Natural Htstorg, antr $lulosoi)hj>. THE: CHEMISTRY OF THE ARTS, on the basis of Gray's Operative Chemist, being an Exhibition of the Arts and Manufac- tures dependent on Chemical Principles, with numerous Engravings, by ARTHUR Ii. PORTER, M. D. late Professor *of Chemistry, &-C. in the University of Ver- mont. In 8vo. With numerous Plates. The popular and valuable English work of Mr. Gray, which forms the groundwork of the present volume, was published in London in 1829, and de- signed to exhibit a systematic and practical view of the numerous Arts and Manufactures which involve the application of Chemical Science. The author himself a skilful, manufacturing, as well as an able, scientific chemist, enjoying the multiplied advantages afforded by the metropolis of the greatest manufacturing nation on earth, was eminently qualified for so arduous an undertaking, and the popularity of the work in Eng- land, as well as its intrinsic merits, attest the fidelity and success with which it has been executed. In the work now offered to the American public, the practical character of the Operative Chemist has been preserved, and much extended by the addition of a great variety of original matter, by numerous correc- tions of the original text, and the adaptation of the whole to the state and wants of the Arts and Manu- factures of the United States. Among the most con- siderable additions will be fottnd full and extended treatises on the Bleaching of Cotton and Linen, on the various branches of Calico Printing, on the Manufac- ture of the Chloride of Lime, or Bleaching Powder, and numerous Staple Articles used in the Arts of Dying, Calico Printing, and various other processes of Manufacture, such as the Salts of Tin, I^ead, Man- ganese, and Antimony; the most recent Improve- ments on the Manufacture of the Muriatic, Nitric, and Sulphuric Acids, the Chromatis of Potash, the latest information on the comparative Value of Dif- ferent Varieties of Fuel, on the Construction of Stoves, Fire-Places, and Stoving Rooms, on the Ven- tilation of Apartments, &c. &c. The leading object has been to improve and extend the practical charac- ter of the Operative Chemist, and to supply, as the publishers flatter themselves, a deficiency which is felt by every artist and manufacturer, whose processes f involve the principles of chemical science, the want of a Systematic Work which should embody the most recent improvements in the chemical arts and manu- factures, whether derived from the researches of sci- entific men, or the experiments and observations of the operative manufacturer and artisans themselves, CHEMICAL) MANIPULATION. Instruction to Students on the Methods of perforin ing Experiments of Demonstration or Research, with accuracy and success. By MICHAEL FARADAY, F. R. S. First American, from the second London edi- tion, with Additions by J. K. MITCHELL, M.D. " After a very careful perusal of this work, we strenu- ously recommend it, as containing the most complete and excellent instructions for conducting chemical experi ments. There are few persons, however great their ex- perience, who may not gain information in many impor- tant particulars; and for ourselves, we beg most unequiv- ocally to acknowledge that we have acquired many new and important hints on subjects of even everyday occur- rence."—.PAtiosoyAicai Mag. " A work hitherto exceedingly wanted in the labora- tory, equally useful to the proficient and to the student, and eminently creditable to the industry and skill of the author, and to the school whence it emanates."—Jour- nal of Science and Arts. GEOLOGICAL MANUAL, by II. T. De la Beche, F. R. S., F. G. S., Mem. Geol. Soc. of France. In 8vo. With 104 Wood Cuts. ELEMENTS of PHYSICS, or NATURAL ) PHILOSOPHY, GENERAL and MEDI- £ CAL, explained independently of TECH- ^ NICAL MATHEMATICS, and containing New Disquisitions and Practical Sugges- tions. By Neill Arnott, M. D. Second American from the fourth London edition, with Additions by Isaac Hays, M. D. " Dr. Arnott's work has done for Physics as much as Locke's Essay did for the science of mind."—London Uni- versity Magazine. We may venture to predict that it will not be surpass- ed."—Times. Dr. A. has not done less for Physics than Blackstone did for the Law."—Morning Herald. " Dr. A. has made Natural Philosophy as attractive at Buffon made Natural History."—French Critic. " A work of the highest class among the productions of mind."—Courier. CUVLER'S ANIMAL KINGDOM, arranged in conformity to its organization. Trans- lated by H. M'Murtrie, M. D. 4 vols. 8vo. Same work, abridged for the use of Schools, &c. 1 vol. 8vo. A FLORA of NORTH AMERICA, with 108 colored Plates. By W. P. C. Barton, M. D. In 3 vols. 4to. ARNOTT'S ELEMENTS of PHYSICS. Vol. II. Part I. Containing Light and Heat. " Dr. Arnott's previous volume has been so well receiv- ed, that it has almost banished all thc flimsy productions called popular, which falsely pretend to strip science of its mysterious and repulsive aspect, and to exhibit a holy- day apparel. The success of such a work shows most clearly that it is plain, but sound knowledge which the public want."—Monthly Review. AMERICAN ORNITHOLOGY, or NATU- . RAL HISTORY of BIRDS, inhabiting the UNITED STATES, by Charles Lu- cien Bonaparte; designed 8 a continua- tion of Wilson's Ornithology, Vols. I. IL III and IV. %* Gentlemen who possess Wilson, and are de- sirous of rendering the work complete, are informed that the edition of this work is very small, and that but a very limited number of copies remain unsold. A DISCOURSE on the REVOLUTIONS of the SURFACE of the GLOBE and the Changes thereby produced in the ANI- MAL KINGDOM. By Baron G. Cuvier. Translated from the Frer.cb, with Illustra- tions and a Glossary. In 12mo. With Plates. ' One of the most scientific and important, yet plain and lucid works, which adorn the age------Here is vast Rid to the reader interested in the study of nature, and the lights which reason and investigation have thrown upon the formation of the universe."—Next Monthly Mag. azine. t i \<«^ VjLN <^^m^T\ NLM032067313