'."% 3! * ON A J 131 A L HEAT m •^ ^'■■•iiii'i.i:!;. :'";.■!! !l:iii! i. m V3 .i!:i!ilrli! •.«; >\tii3,j'! ' c • ^ i, mm Mm J!'t; ■'"£& tit *• rtj.j^i.r ,i5iii :■: •.iili'i'Jilil. '■/&■« :iii'i. ifc *:'':!«fc.|i r ^ i iidii ikh ilb hi 11! 11 itiiK toi ■- \-Ac- ::■ r ^i.iii.n - ^;.:, ., j-ii ■, it. i> . * >!3 IM:!m. ,.'n'., ,:',-'!"M- ' -►fit, * ^ "l -ty 8657 VITAL CHEMISTRY. LECTURES ON ANIMAL HEAT. BY THOMAS SPENCER, M. D., Professor of the Institutes and Practice of Medicine ia the Medical Institution of Geneva College. PUBLISHED BY REQUEST OP THE CLASS. GENEVA, N. Y. I R A & STEPHEN H. PARKEB, PRINTERS 1845. Geneva Medical College, October 22, 1844. Prof. Spencer : Dear Sir:—At a meeting of the Medical Class, J. G. Pelton in the chair, it was unanimously resolved, that a committee be appointed re- spectfully to request a synopsis of your Theory which answers the question in Physiology, " Whence animal heat ?" Permit us to add, Sir, the pleasure it gives us individually, to pre- sent you the wishes of the Class. JOHN J. BROWN, "I ISRAEL PARSONS, C. H. HAMMOND, V Committee. ROBERT HUNTER, I DAVID BURTON, J Geneva, October, 1844. Gentlemen : Your line of 22d, in behalf of the Medical Class, asking for publication a copy of my Lectures on animal heat, has been received. As soon as pressing avocations will allow the neces- sary labor of preparation, I shall cheerfully respond to the wish of the Class, to whom convey, and accept for yourselves indiviaually, the assurance of au abiding interest in their welfare. Cordially your friend, THOMAS SPENCER. Messrs. Bhown, &c, Committee. PREFACE. The following Lectures are the results rather of occasional moments of leisure from the duties of an active professional life, than of a special devotion to the cultivation of the more inviting field of Chemistry and Physiology. For the facts upon which the discussion mainly depends, I am indebted to those who have more particularly de- voted their attention to these subjects, while the deductions are the results of my own reflections. An attempt to explain the vapor of the pulmo- nary excretion, led me by successive steps to a belief, not only in the intimate chemical relations of respiration and calorification, but of all the func- tions and phenomena of organic life. If every [step has been fortified by ascertained facts and the de- ductions have been legitimately drawn, a circle of vital affinities, uniting all the structures and functions of the organism, and making each set of capillaries mutually dependent on and balanced by others, in the chemico-vital changes produced up- on their passing currents of blood, has been deter- VI mined. That such a scries exists, and that the links in the chain may be demonstrated, can not be doubted ; but in view of the intricacy of the subject, and of my limited knowledge of experi- mental chemistry, a due distrust is still felt in the accuracy of the attempted determination. Much allowance is demanded upon the ground of the hasty manner in which (to answer the wishes of the class) it has been necessary to send these sheets to the press. Indeed the term must have closed without this being effected but for the assistance of a young friend, especially in the prep- aration of the Diagrams. I could have desired a more careful revision before submitting the re- sults of my inquiries to public criticism. If, however, they shall contribute in any degree to elucidate the hitherto obscure subject of Vital Chemistry, the end of their publication will be attained. Geneva, N. Y., January, 1845. CONTENTS. CHAPTER I. Mechanism and vital movements of the apparatus of respiration. (Omitted.) CHAPTER II. Chemico-vital changes produced by respiration UPON THE BLOOD AND RESPIRED AIR. § 1. Relations of atmospheric air to the pulmonary ap- paratus.—§ 2. Components of atmospheric air.—§ 3. Car- bonic acid and its use in animals.—§4. Old views of calor- ification.—§4. Established facts of physiology .-§5. Compo- sition of the dark pigment of venous blood, unknown.—§6. Laws of free and latent heat, why discussed.—§ 7. Three states of water : terms caloric and heat defined.—§ 8. Heat combines with gases.—§ 9. Different gases and liquids have unequal capacities for heat.—§ 10. Heat oombines in seve- ral proportions with water.—§ 11. Is the heat, passing off from the body in the vapor, derived from an external or in- ternal source 1—§ 12. Second fact (§ 5), that the blood is thinned by the lungs, examined.—§ 13. Pulmonic and sys- temic capillaries antagonists.—§ 14. Third and fourth facts (§ 5) examined : air loses Oxygen and gains Carbonic acid by respiration.—§ 16. Latent heat of pulmonary vapor and Carbonic acid derived from an external soure.—§ 15. What that source is.—§ 17. Oxygen has a greater capacity for heat than Carbonic acid.—§ 18. Burning of Carbon in the lungs.—§ 19. Heat moderated by the conversion of water Vlll and Carbon into the gaseous state.—§ 20. Is Carbon, before oxidation in the lungs, combined with other elements 1 Probably with water.—§ 21. Summary of conclusions.— Page 1—19. CHAPTER III. Changes of the blood in the systemic capillaries. § 22. Changes of color in the blood. Carbonic acid de- composed by the systemic capillaries and recomposed in the lungs. Dark pigment of the blood a compound of Car- bon with water.—§24. Proof.—§25. Carbon thrown off by the lungs and skin equals that used by the systemic ca- pillaries. Source of the Carbon in the venous pigment.— § 27. Carbonic acid universally diffused in nature. Analo- gy of vegetable to animal capillaries.—§ 29. Oxygen evolv- ed from leaves absorbes heat from water.—§ 30. Vegetable growth illustrated.—§ 31. Other proofs that Hydrate of Carbon is a solid.—§ 32. Origin of mineral coal.—§ 33. Other analogies between vegetables and animals.—$ 34. Dif- ferent uses of Hydrate of Carbon in vegetables and animals. § 35. Analogy of the pulmonic combustion of Carbon to the burning of wood.—§ 36. Analogy of pulmonic combustion to the decay of wood. Vegetables in mines, why luminous.— § 38. Comparison of this theory with that of Lavosier.— §39. Intimate connexion of respiration with the changes in the systemic capillaries. 20—35. CHAPTER IV. Function op calorification. § 40. Free heat of the lungs.—§ 41. Lungs not the only generators of heat.—$ 42. Old doctrines of calorification. —$ 43. Some facts already proved.—$ 44. Immediate cause of animal heat.—§ 45. Analogy and difference be- tween vegetables and animals.—§ 46. Harmony of all the ca- pillaries in calorification.—§ 47. Harmony of vital and inor- IX organic affinities.—§ 4S. Regulation of animal tempera- lure.—§ 49. Animal heat proportional to the development of the pulmonary apparatus.—§ 50. Heat proportional to the amount of Carbonic acid gasevolved.—§ 51. Spontane- ous combustion of drunkards explained.—§52. Two sets of systemic and pulmonic capillaries, and their functions.— $ 53. General summary of conclusions hitherto deduced. —§ 54. Questions still unsettled. 36—51. CHAPTER V. Source of the Carbonic acid and disposition of its Oxygen by the systemic capillaries. § 56. Source of the Carbonic acid, first views.—§ 57. Corrected views.—§ 58. Free Carbonic acid in food and drink insufficient to supply the pulmonic waste.—§ 59. Dis- position of the Oxygen. ; first surmises about.—§60. With what does the Oxygen unite 1—§ 61. Source of the Car- bonic acid.—§ 62. Hypothesis, that Carbonate of protox- ide of iron is an element of arterial blood.—§ 63. Perox- ide of iron and Hydrate of Carbon formed in the systemic capillaries. 52—60- CHAPTER VI. Chemico-vital changes produced by the lungs as an organ of he6mat0sis. § 64. What is the primary source of the oxides and Car- bonate of iron.—§ 65. Hydrated peroxide of iron decom- poses chyle and blood.—§ 66. Carbonate of protoxide of iron formed in the pulmonic capillaries.—§ 67. Summary and deductions.—§ 68. Questions still unsettled. 61—67. CHAPTER VII. Chemico-vital relations of the pulmonic and gas- tric FUNCTIONS. § 70. Connection between the formation of muriatic acid X in the stomach and Hydrate of Carbon in the systemic ca- pillaries.—§ 71. Muriatic acid, how formed in the stomach- —§ 72. Analogy of this to the decomposition of common salt by electricity.—§ 73. The soda secreted by the gas- ric capillaries does not enter the stomach ;—§74. But pas" aes through the liver into the bile and blood. The secre- tion of soda intermittent.—§ 75. Analogy of this to vegeta- ble physiology.- -§ 76. Source of iron in the blood.—§ 76' Formation of the Hydrated peroxide of iron in the lungs.— § 77. Red globule completed.—§78. Circle of affinities- completed. Summary. 67—77 CHAPTER VIII. CHEMIOO-VITAL CONNECTION OF DIGESTION, HEPATIC SE- CRETION, CALORIFICATION AND NUTRITION. § 79. Office of soda in the bile.—§ 80. Muriatic acid also a carrier of nutritive elements.—§ 81. Fibrin and albumen deposited for nutrition by the re-formation of salt and wa- ter.— §82. Source of the elements of water necessary to the formation of Hydrate of Carbon. 77--82. CHAPTER IX. Synopsis of the circle of chemical change in an- imal LIFE. § 83. Diagram 10. Gastric, hepatic and duodenic secre- tion and digestion.—§ 84. Diagram 11. Pulmonic capilla ries in the function of haematosis.—$ 85, Diagram 12. Sys- temic capillaries in the functions of calorification and nutri- tion.—$ 86. Pulmonic and cutaneous capillaries in the func- tions of excretion and calorification. 83—91. CHAPTER X. Physiological and pathological inferences. § 87. Coagulation explained.—5 88. Probable function IX ' of the mesenteric glands.—§ 89. Is there Carbonic acid in the blood ?—§ 90. Sudden death from air entering the jug- ular vein explained.—$ 91. Animal fat a reserve of fuel for calorification.—§ 92. Heat of fever.—§ 93. Foetal physiol- ogy.—$ 94. Red dots and vessels in the formation of new parts.—§ 95. Function of the liver.—* 96. Objection, that Carbonic acid is evolved in respiration of hydrogen and nitrogen answered. 92—102. CHAPTER XL Analogies and differences between animal and vegetable digestion and nutrition. § 97. Solution of nutritious matters effected by the roots of vegetables in a manner similar to that in the stomachs of animals. Why salt is aconstituent of vegetables.—§ 98. For- mation of Hydrate of Carbon in vegetables.—§ 99. Evolu- tion of oxygen by plants in the light, and of Carbonic acid by those in the dark.—$ 100. Why vegetables contain alka- lies and chlorides. 102—107. LECTURE I. CHAPTER 1. Of THE MECHANISM AND VITAL MOVEMENTS OF THE APPARATUS OF RESPIRATION. [Omitted.] CHAPTER II. OF THE CHEMICO-VITAL CHANGES PRODUCED DY RESPIRATION UPON THE BLOOD AND RESPIRED AIR. § 1. General remarks and facts. Atmospheric air is to the lungs, what food is to the stomach, except that it principally aids in withdrawing materials from, instead of becoming a nutrient addition to, the mass of circulating fluids. In the relation of the lungs and air tubes to the medium in which we live 2 o §2 and breathe, we observe an admirable adapta- tion. The air, by its elasticity and pressure, penetrates every cavity which communicates externally, and thus prevents a vacuum ; while a denser fluid could not penetrate into, and be in rapid succession expelled from, the compli- cated tubes and minute air cells of the lungs during inspiration and expiration. The speci- fic gravity of atmospheric air is 770 times less than that of water, and a column of it, about 40 miles high surrounding the earth, is equal to a column of water of the same diameter 32 feet, or of mercury thirty inches in height. The liv- ing man of ordinary size has, therfore, to sus- tain the enormous pressure of thirty or forty thousand pounds weight of atmosphere while life continues. § 2. I need hardly mention that atmospheric air is a compound of Oxygen, Nitrogen, and Carbonic acid, in about the proportion of 21, 78 and 1. It also contains the imponderable elements, light, heat and electricity ; watery vapor, and exhalations, holding in solution veg- etable and animal matters, with other acciden- tal admixtures. To the Oxygen, however, are we principally indebted for sustaining life. This gas not only sustains life, but is the great sup- §3 3 porter of combustion, and of chemical change in the operations of inanimate nature, and forms an important ingredient in a variety of com- pounds, such as oxides, acids, water, and vari- ous animal and vegetable substances. Nitro- gen, on the contrary, appears to be a kind of negative element of atmospheric air. It is, however, one of the elements of animal bodies, and experiments appear to prove that it is both absorbed by, and expelled from the lungs du- ring respiration. § 3. The other ingredient of atmospheric air, Carbonic acid, is one of the all-pervading sub- stances of nature-, is contained in the water we drink, forms an important ingredient in the food of plants, and, as I proceed, I shall assign to it, in the production of some vital phenomena, a higher agency than has hitherto been done. This agency J believe to be the evolution of animal heat at every point of the body by the decomposition and rccomposition of this gas. § 4. Old views of calorification. For a long period, the lungs were regarded as the seat of the evolution of animal heat, and it was believed that from this point it was dis- tributed to every part of the body. After the discovery of Oxygen, its absorption by the lungs, 1 §5 giving oil* the latent caloric, which thus be- came sensible in the various tissues of the body was supposed to be the immediate cause of animal temperature. But more rigid experi- ment and inquiry appear to prove, that instead of Oxygen entering the capillaries and combin- ing with blood in its transmission through the lungs, it is principally employed in converting the carbon of the blood into carbonic acid. Doctor Oliver says, " upon analyzing a por- tion of air which issues from the lungs in expi- ration, it is found that the proportion of its ele- ments has undergone a considerable change, and this change is found to consist in an in- crease of the carbonic acid, a diminution of the Oxygen, and an addition of a large quantity of watery vapor containing some animal matter in solution." §5. Established facts of physiology. It is now proposed to explain the changes produced by the vital Chemistry of the Pul- monic and systemic Capillaries upon the blood, as connected with the functions of Respiration and Calorification, from the following and oth- er well established physiological facts : 1. A considerable quantity of insensible wa- tery vapor is constantly evolved from the Lungs. §5 5 2. Notwithstanding this rapid vaporization from the blood in the Lungs, the blood returns from the Pulmonic, much thinner than from the systemic Capillaries. 3. Atmospheric air which has been respired is found to have lost about 7 per cent of its Oxygen. 4. The same air contains an increase of Car- bonic acid of about 7 per cent, containing, nearly, the 7 per cent of Oxygen. 5. The blood is freed of its darkening pig- ment, or, as usually expressed, the blood is de- carbonized by transmission through the Capil- laries of the Lungs. 6. By this depuration, the blood is changed to a vermilion color. 7. This coloring or carbonaceous pigment is incessantly formed in the entire mass of blood during its transmission through the systemic capillaries. 8. In vegetable physiology, the vital action of the Capillaries of the leaves, decomposes the Carbonic acid of the sap, and forms woody fibre, a triple compound of Carbon, Oxygen Hydrogen, generally in the proportions of wa- ter and called lignin or humus. 9. In the growth of trees, this compound, af- 2* (i §5 ter its formation, and while still suspended in water or sap, is carried back to the body of the tree, is deposited upon its exterior, beneath the bark, to contribute to its growth, constitutes almost the entire solid portion of this vegetable, and forms the annual layers or grains of wood. 10. Vegetables evolve from their leaves the Oxygen of the Carbonic acid, which their Ca- pillaries decompose. § 5. Composition of the venous pigment un- known. 1. Although generally admitted by modern physiologists that decarbonization is the prin- cipal vital office of the lungs, the nature of the carbonaceous substance pre-existing in ve- nous blood, seems by no means to have been satisfactorily determined. In attempting to set- tle this point, by proving that the same triple compound of Carbon and the elemments of water is formed by animal, as by vital vegeta- ble chemistry; and that its formation in the systemic capillaries, and its expulsion from the pulmonic, constitute the immediate cause of the vital function of Calorification, I shall endea- vor to conduct you through the same pathway by which I reached these conclusions. So do- ing, if I wander from the rule which should §6 7 guide all our medical inquiries,—that of having every step of our progress sustained by indubi- table facts,—the corrective may be applied by those who go with me in pursuit of physiologi- cal truth, if they rigidly scrutinize for them- selves the facts and reasonings. § 6. § III. Laws of free and latent Caloric. Preliminary to investigating the first fact stated, that vapor is thrown off from the lungs, it seems necessary to present a few remarks on the laws of caloric. This is considered necessary, in view of the facts, that many of my class are just commencing their medical studies, and that my able colleague in the chem- ical chair, has not reached this subject of his course. § 7. Water is capable of assuming three forms—the solid, fluid and aeriform, or that of vapor. These changes are produced by heat, or caloric. By caloric is meant the agent which produces in us the sensation of heat. The term heat is used in a two-fold sense; in the one implying the sensation produced up- on touching a hot body; in the other, it is sy- nonymous with caloric—that is, the agent, or cause of the sensation. Heat or caloric is sup- posed by most chemists to be a very subtil flu- 8 §8 id, and as such I shall now consider it. As I shall have occasion to use the term,—free heat, or caloric,—I would define it to be the heat which is readily transmitted from body to body, and which, hence, readily affects the thermome- ter. By latent heat is meant the kind which ap- pears to combine chemically with the atoms of bodies, and when so combined, it does not af- fect the thermometer. § 8. Latent heat combines with gases. In union with Oxygen, it holds it in the gaseous state, and remains chemically com- bined with it, until the Oxygen enters into new combinations, when it is set free, and, as soon as it is thus set free, it affects the thermometer. Again, Hydrogen gas is Hydrogen combined with latent heat which keeps it in the gaseous state till it enters into some new combination, when this heat is set free. § 9. Different gases as well as different fluids do not possess equal capacities for latent heat; that is, one will combine chemically with a larger amount than another of like bulk. This is proved by experiments which disengage this latent heat, and set it free from bodies ; that is, when thus set free, this free heat contained in a given bulk of one body, will raise the thermom- §11 9 eter two, three, or four times as much as the latent heat of another body of the same bulk. The body whose latent heat, on being set free, raises the thermometer most, is said to have the greatest capacity for latent heat. § 11. Latent heat combines variously with water. Water in its fluid state is combined with la- tent heat. Vapor is water combined with an additional proportion of latent heat, and when it condenses, the latent heat is again set free. Hence, in frosty weather, the vapor from the lungs loses its latent heat, and the water may be seen, as condensed on breathing upon win- dow-glass or other cold substances. Fluid water is held in that state by latent heat; but when it freezes, this latent heat is set free and becomes sensible. When, on the contrary, ice melts, the water again combines with free heat, which then becomes the latent heat of fluidity in the water. Heat, probably, unites in definite proportions, like the other elements of nature. When water is converted into vapor, it com- bines with the free heat of surrounding objects, and this heat then becomes latent in the vapor. But 10 § 12 § 11. § IV. Of THE PULMONARY VAPOR. To convert water into vapor, requires a large amount of heat. Is the source of animal heat the body, or is it external. When the water of the blood is converted into vapor, as it is in the lungs, there must either be a rapid absorption of free heat from the body, or heat must be ob- tained from an external source to supply the la- tent heat of the vapor. § 12. 2d Fact: Examined. Let us next examine the second fact, that the blood becomes thinner by its transmission through the lungs. This thinning occurs, not- withstanding the large amount of watery va- por and carbonic acid gas evolved. It seems fair to infer, from this fact, that the excretal substance thrown off" is composed of dense at- oms, mechanically suspended in the albumin- ous serum of venous blood, and that its expul- sion by the chemico-vital action of the air vesi- cles thus thins the sanguineous mass. The pul- monary vapor and gas thrown off would other- wise thicken the blood. § 13. The pulmonic and systemic capilla- ries antagonise each other. As no essential chemical change takes place § 14 11 in the blood in the large vessels, the vital pro- cess which forms these dense atoms must, ob- viously, be seated at the points where the blood passes from the systemic capillary arteries to their corresponding veins. The pulmonic and systemic red capillaries must hence antagonize each other; the systemic incessantly separating, the pulmonic throwing off* the carbonaceous matter into the atmosphere. After passing the systemic capillaries, as the blood, in every, the minutest portion, exhibits a like uniform change of color, all portions must receive a like ratio of coloring deposite. As no chemical change occurs in the large vessels, the element or elements which compose the coloring pig- ment of venous blood must, obviously, have pre- existed in every atom of arterial blood, before passing the systemic capillaries. That this ele- mental carbon of arterial and venous blood must be in different forms of chemical combi- nation, after having been subjected to the ac- tion of the respective vital laboratories of the antagonizing sets of pulmonic and systemic capillaries, cannot be reasonably doubted. § 14. But of the 3d and Ath Facts. (§ 5, above.) Before attempting to decide in what form, 12 §15 simple or compound, this eliminated carbon or pigment exists in each set of capillaries, let us examine the 3d and 4th facts stated, viz: that respired air loses about 7 per cent, of Ox- ygen and gains 7 per cent, of Carbonic acid gas. All substances, as well as water, in chang- ing from a fluid to a solid form, set their latent heat free, and in changing from a solid to a fluid, or from a fluid to an aeriform state, ab- stract heat from surrounding objects. § 15. It must hence be obvious, that to con- vert the solid carbonaceous pigment of the blood into the Carbonic acid gas, this must draw heat from the body as would the watery vapor, or there must be an external supply of caloric. There are then two substances thrown from or formed in the lungs—vapor and carbo- nic acid gas—both of which require a large amount of free heat to form and preserve them in the aeriform state in which they are expelled. There must therefore be a very rapid pro- duction of heat by the body to carry off this Carbonic acid and watery vapor, in respira- tion ; or an unceasing supply of Caloric must be drawn from some source exterior to the body. To throw off such a large amount of gaseous substances, this supply of heat must, §16 13 necessarily be so rapid that it appears hence reasonable to infer that it must be derived from some external source. § 16. What is this external source of Calo- ric . The atmospheric air respired loses, as I have before stated, about 7 per cent, of its Oxygen, and the blood its carbonaceous pigment by res- piration. Carbon and 0,xygen are the two ele- ments of carbonic acid gas, they are brought into contact in the lungs, and if an amount of OnXygen in the carbonic acid thrown off, is equal to that of the Oxygen lost from the air in res- piration, as stated in the 4th fact, it appears reasonable to infer that Carbon and Oxygen combine chemically to form the carbonic acid gas eliminated. The latent heat of the Oxygen in its chemical combination with the carbon of carbonic acid, would keep it in the aerial form. No heat would therefore require to be drawn from the body itself, for converting the carbon into the gaseous form, provided the OxjTgen en- tering into the composition of the carbonic acid gas contained a sufficent supply of latent calo- ric ; or in other words, if Oxygen has as great a capacity for latent heat as carbonic acid gas. 3 14 §17 § 17. Carbonic acid, and Oxygen gases, have different capacities for latent heat. Is the latent heat of the Oxygen taken from the atmosphere precisely sufficient, or is it more, or is it less, than is requisite for forming the carbonic acid gas evolved 1 Carbonic acid gas, you are aware, can be readily formed by the combustion of carbon in Oxygen gas. In this process, carbon combines chemically with Oxygen, and carbonic acid gas is the result. It accords with the well estab- lished chimical laws before refered to, that if the Oxygen contained less than the carbonic acid which was formed, the combination would cool the surrounding medium by absorbing its free heat; whereas, if the Oxygen gas employed contained more latent heat than the resulting carbonic acid, the caloric being set free, would raise the temperature. You are aware that a large amount of sen- sible heat is evolved, or set free, during the combustion of carbon, or charcoal, and its con- version into a gas; and hence, the irresistible conclusion, that the Oxygen gas employed in this chemical change contains more latent heat than the carbonic acid gas formed. From this §18 15 it must follow that there is an excess of latent heat set free in the air cells of the lungs by the conversion of the carbon of the blood into gas, in its combination with Oxygen. That is, Ox- ygen gas has a greater capacity for, and con- tains more, latent heat than carbonic acid gas. § 18. The combination of Oxygen and Car- bon in the lungs must produce an elevation of temperature in them, precisely as when we burn charcoal, and this icould cause a great evolu- tion of sensible heat in the air cells. This con- clusion drawn from the facts stated is fully con- firmed by Crawford, Dalton and other old chem- ists, who estimate the amount of latent heat contained in Oxygen at nearly four times that contained in Carbonic acid gas. The relative capacities for latent heat are not as dispropor- tionate according to more modern chemists, but all agree that Oxygen has the greatest ca- pacity for latent heat. Be the relative capaci- ty what it may, the oxydation of carbon always evolves heat, and sensibly raises the thermome- ter. The Carbon thrown off from the lungs, is, obviously, subdivided into its ultimate atoms, and hence spontaneously ignites on meeting at- mospheric air, and a large amount of free heat must consequently be set at liberty in the air cells 16 § 19 of the lungs, producing there a sort of combus- tion. What! combustion in the lungs ! This chemical change, but for a wise provision for disposing of this excess of caloric, would pro- duce inevitable death. § 19. What is this provision ? What is this safety-valve of the lungs . I have before stated that the pulmonary vapor must, necessarily, absorb a large amount of free heat from the body, or that there must be some external sup- ply of caloric. The oxydation of the carbon would abundantly supply the watery vapor with its needful latent heat, so that the vapori- zation of these two gaseous substances would not, as otherwise, cool the body, but would de- rive their caloric from the atmospheric Oxygen employed, and at the same time extra caloric would be set free to heat up the organism. That the necessary caloric for converting the water and carbon into the gaseous forms is ta- ken from the mass of blood in its transmission through the lungs, is entirely irreconcilable with the fact that the blood in the left cavities of the heart is warmer than that in the riffht. Again, the rapid absorption of heat by the rapid vaporization of water and conversion of carbon into carbonic acid gas must, inevitably, cool §20 17 the vital fluids, but for the supply of heat deri- ved from the Oxygen of the atmosphere. § 20. Is the carbon of the carbonic acid, be- fore oxydation in the lungs, in its simple, ele- mental state, or is it combined with other ele- ments 1 Simple, uncombined elements are not, generally, if ever, expelled from animals. Bi- nary compounds are those common to inor- ganic chemistry; while more complex com- pounds are peculiar to vital chemistry. If the carbonaceous pigment of venous blood be a triple compound, as probable, with what ele- ments is the carbon combined ? Oxygen and Hydrogen arc the elements of the watery va- por thrown off from the lungs, and if united with the carbon, would form a triple compound of water and carbon, like the lignin or humus of woody fibre as named by chemists and veg- etable physiologists. These facts render it probable that the carbonaceous pigment ex- pelled, is the same triple compound as in veg- etables, and if so, may hence be properly de- signated, Hydrate of Carbon. Although there are several theories of respiration, it seems sat- isfactorily established that the alteration of col- or in the blood in the pulmonic capillaries is essentially dependent upon the chemico-vital 18 §21 changes, I have detailed. An explanation, how- ever, of the chemical change altering the blood in the systemic capillaries from a vermilion to this dark color of venous blood, has perhaps never been satisfactorily made by any physiol- ogist. This I shall now attempt, and in con- nection with it, shall offer an explanation of the evolution of animal heat, called the func- tion of calorification. The fact that venous blood is reddened by exposure to atmospheric Oxygen, and carbonic acid given off precisely as when exposed in the lungs appears to settle the point, that carbonic acid gas is a product of, not an educt from, the blood of the pulmonic capillaries. §21. Let us now sum up the prominent points determined. 1. Carbonic acid gas is formed in the lungs by the oxydation of Carbon from the darkening pigment of venous blood. DIAGRAM 1. Elements of <\ ^ , become in the lungs atmospheric air i° }--------~Z^° ™' **' ***' Carbon of the ) n-^^' blood ) 2. The oxydation of the carbon imparts to §21 19 water free heat, which uniting with it, as latent heat, forms vapor. 3. The carbon of the coloring pigment which is cast off from the lungs, must be elemental atoms of carbon, or a compound of this element. 4. The pigment is probably a compound of the elements of water and carbon; and if so, the changes in the lungs may be thus illustra- ted: DIAGRAM 2. . -i • \ become in Atmospheric ) O \ Elements. \ q ?-------------T^ car< ac-gas. Hydrate of Carbon the lungs H vapor. LECTURE II. CHAPTER III. OF THE CHANGE OF COLOR AND CHEMICAL PROPERTIES, PRODUCED UPON THE BLOOD BY THE SYSTEMIC CAPILLARIES. Facts to be examined, [§5, 5 to 10.] Questions to be answered: 1, Is the car- bonaceous pigment formed by the systemic ca- pillaries in form of elementary atoms . Or 2, Is it a compound of carbon and water . § 22. § V. Of the change of color in BLOOD. The 5th and 7th Facts that the blood is red- dened in the lungs by parting with a carbona- ces pigment; and is darkened in the systemic capillaries by its formation there, seem conclu- sively to show that the elemental Carbon there- of undergoes changes in its chemical relations or combinations, with the other simple elements §22 21 of the blood at both these points of the organ- ism. The fact, also, that Carbonic acid gas applied to arterial blood out of the body dark- ens it, precisely as when the blood passes the systemic capillaries, appears fully to establish the same point. This fact seems also to justify the belief that Carbonic acid is decomposed, in passing such capillaries to form the carbonaceous pigment sent from this point to the lungs and skin for elimination. The farther facts, that out of the body, arterial blood is darkened by applying to it Carbonic acid, and that it is again reddened by applying to it Oxygen, precisely as when the venous pigment unchanged reaches atmospher- ic air in the lungs, seem to prove that the Car- bonic acid is—First, decomposed by the action of some of the elements of blood upon it, and— Second, recomposed by the after application of Oxygen to the darkening pigment. Now it is obvious that as the carbonaceous pigment, in being sent from the systemic to the pulmonic capillaries undergoes no chem- ical change or change of color, the conclu- sions seem irresistible that the same chemical changes occur in arterial and venous blood, by the application to them respectively of Car- 22 §24 bonic acid and Oxygen out of the body as in it; and that hence the systemic and pulmonic capillaries must antagonise each other, by the one set decomposing, the other rccom- posing Carbonic acid. But these facts and deductions do not settle the undetermined point left in our last Lecture, whether the pigment is elemental Carbon, or a compound of it. That directly opposite chemical changes take place in the pulmonic and systemic capillaries; that Carbonic acid is recomposed in the pulmonic capillaries, as already explained, while the same gas is decom- posed in the systemic, and that these two sys- tems of vessels are thus the counterparts or antagonists of each other, seem alike inferable from the following facts : while they also show that water is chemically combined as a triple compound of carbon, by the vital action of the systemic capillaries, to form the pigment of ve- nous blood; §24. 1. Directly opposite changes of color take place in the pulmonic and systemic capillaries, the one changing the blood from dark to red ; the other from red to dark. If the expulsion of a carbonaceous substance, whatever its che- mical composition, changes the blood from a §25 23 dark to a vermilion color in the lungs, it is most obvious that the formation of this very sub- stance in the systemic capillaries changes the blood from vermilion to dark. It appears to be a generally admitted physi- ological fact that the serous capillaries are the ingenious architects which select the materials and build up the various parts of the organism, while, on the contrary, the red capillaries have been considered only in the light of common carriers. But it is believed that they are not restricted to this humble office; but are con- nected with the function of calorification. § 25. 2. The change of color produced by the transmission of the blood from every min- ute capillary artery to its corresponding sys- temic vein, to a dark color, is just as uniform as is the change to a vermilion color between the minute, pulmonic vessels ; and there must, ob- viously, be as unceasing a supply of the elemen- tary Carbon in the systemic capillaries, as there is expulsion of it from the pulmonic and cutaneous capillaries. In health the elimina- tion of carbon from the lungs and skin thus con- stantly balances the amount supplied in the systemic red capillaries, and thus darkens eve- ry atom of the venous blood. But 24 § 25 3. What is the source of the elemental car- bon of the venous pigment I It is obvious that to supply the atoms of carbon, for the inces- sant formation of the carbonaceous pigment, a large amount of this element must pre-exist in the blood as free carbonic acid gas, or that it exists in some of its compounds ; it being esti- mated by Lavoisier, and several subsequent ex- perimenters, that at least twelve ounces of pure carbon, or charcoal, are required to be thrown off' by the lungs every twenty-four hours, to form the whole volume of Carbonic acid gas expelled. Davy, Allen, and Pepys think that more than twelve ounces are expelled ; Muller thinks this an over estimate ; while Liebig esti- mates it at 13. 9 ounces. This elementary Carbon combined with Oxy- gen, forming the Carbonic acid gas, of whose many important offices in nature I have before spoken, is readily, when set free in the stom- ach, assimilated by the digestive organs, and like water it is rapidly conveyed into the mass of circulating fluids. In addition to free Carbonic acid in arterial blood, it is also combined with various com- pounds found in this fluid, such as carbonated alkalies. §27 25 " Mr. Brande (says Dr. Good) has established by experiments, that Carbonic acid does exist, and that, too, in a considerable quantity, in the blood of animals, while circulating through both arteries and veins; and that it is so largely poured forth by blood placed while warm un- der the receiver of an air pump, as to give the appearance of effervescence, a fact familiar to Boyle two hundred years ago." The venous and arterial blood, according to Mr. Brande's experiments, seem to contain a equal proportion of this gas, and he calculated that not less than two cubic inches were extri- cated from every ounce of blood thus experi- mented upon. The works of Muller, Carpen- ter and other able writers of modern date, abound in the proof that both arterial and ve- nous blood contain Carbonic acid. From all the sources referred to, it seems probable that there would always be in the mass of circula- ting fluids, a sufficient supply of Carbonic acid from which could be abstracted the uninterrup- ted supply of Carbon for the carbonaceous pig- ment first formed in the systemic capillaries. § 27. 4. No carbonaceous substance so uni- versally pervades nature, as Carbonic acid. 5. Vegetable physiology furnishes an analo- 4 86 §29 gy which sustains the belief that Carbonic acid is decomposed in the systemic capillaries of animals, to furnish the Carbon of the carbona- ceous pigment of venous blood. Carbonic acid is regarded as an essential food of plants; its decomposition furnishes the Oxygen evolved from their leaves, while the elementary Carbon is depoaited to form a part of the body of the plant. The systemic capillaries are the vessels which perform the vegetative or vital growth of animals ; and analogy would lead to the be- lief that the capillaries of vegetables and ani- mals may alike decompose Carbonic acid. As already noticed, [Fact 8, § 4 plus 1,] it is a generally admitted fact that Carbon in veg- etables combines with water, in form of woody fibre ; in other words, wood is a triple com- pound of Carbon, Hydrogen and Oxygen, call- ed humus or lignin; and this, upon analysis in some kinds of wood, is found to be a compound of Carbon in union with Oxygen and Hydro- gen in the definite proportions of water. § 29. Oxygen evolved from leaves, absorbs heat from water. . I have already stated the estimate of Dalton and other old Chemists, that Oxygen contains four times as much latent heat as Carbonic acid §30 27 gas. I have myself furnished the proof that it contains a much larger amount; and modern Chemists agree in the general fact, that Oxy- gen has a greater capacity for latent heat than Carbonic acid, although the difference is not as great as estimated by Dalton. In the formation of Hydrate of Carbon, there- fore, by the capillaries of the leaves in vegeta- bles, there must be some other source of Calo- ric than the latent heat of the Carbonic acid, to convert its Oxygen into the gaseous state in which it is evolved. This requisite amount of heat must hence be supplied from the water which, in combining with the Carbon, gives off its latent heat of fluidity to the Oxygen thrown off* from the Carbonic acid. If so, it follows that the atoms of Hydrate of Carbon, as depos- ited for the growth of vegetables, are minute solids. § 30. Thus illustrated: DIAGRAM 3. s Heat---___ Elements of j ^) ~~ ——... n Carbonic acid. \ O § W~^ f Heat,--'' ^""^^^ Elements of \ q >. ^"^^^ water. \h)-----"---"---"—^C- H- °- 28 §31 The water and Carbon, on assuming the so- lid form in the Hydrate of Carbon, furnish to the Oxygen the heat necessary to its existence in the gaseous state. §31. Other proof that C. H. O. is a solid. That Hydrate of Carbon is a solid, may also be fairly inferred from these facts : 1. That this compound of Carbon forms the basis of the so- lid wood we burn; and 2. That the driest wood, upon combustion, yields Carbonic acid gas and watery vapor by the oxydation of the Carbon. If Hydrate of Carbon in these aggre- gated masses, be a solid, its minutest elemen- tary subdivisions are also, obviously, solids. § 32. Not only does Carbonic acid play an important part in the formation of the vegeta- bles which cover the surface of our globe, but it enters into the composition of numerous min- erals in the bosom of the earth, and also fur- nishes, by slow process, through the medium of vegetable growth, the elementary Carbon of our extensive coal mines. The modern theory of the formation of these is, that the layers of coal were of vegetable origin, and that the wa- ter of the Hydrate of Carbon of the vegetable fibre being gradually separated by heat and va- porization from the Carbon, this is left in the §33 29 form of coal; that is, the earth here becomes a large coal pit. All of you, young gentlemen, must be famil- iar with a coal pit. In this, wood is subjected to heat without atmospheric air being admitted, in order to vaporize the water of the wood, leaving the Carbon in porous masses of coal. So the bosom of the earth, by its internal heat, slowly drives off the water from the vegetable layers, converting them into mineral coal. § 33. Other analogies of animals and veg- etables. 6. There are numerous other striking analo- gies between animal and vegetable life; both possess a living principle by means of which they convert the elements of extraneous sub- stances to their own uses and growth ; Carbo- nic acid constitutes an important ingredient in the food of both, and vegetables, by a vital pro- cess of their minute vessels, decompose this gas, appropriating its elementary Carbon to their use and growth. The experiments of Muller, and the facts of Liebig and other physiologists, appear to prove conclusively, that free, as well as combined Carbonic acid, exists in the arterial blood of animals from which this compound could be 30 §34 formed, as in vegetables ; and it appears fair to infer that, as the minute vessels of animals pos- sess like vital properties as those of vegetables, they may also decompose this gas, and form the Hydrate of Carbon. Admit this inference from analogy to be true, and it must be obvious that the atoms of Hydrate of Carbon in the blood must be as much minute solids, as when deposited in vegetables, or as congregated in masses in the wood we burn ; facts before pro- ved. § 34. Co-miiaralice uses of C. II. O. in veg- etables and animals. This Hydrate of Carbon, as soon as formed in vegetables, is deposited to contribute to their growth ; there being no return circulation. On the contrary, this compound docs not contrib- ute to the growth of animals, but as soon as it is formed in them, it becomes an excretal sub- stance, requiring to be immediately eliminated from the body by the lungs and skin, in the manner already explained. The facts, that the blood loses its dark color, and becomes thinner in passing the lungs, are readily explained upon this theory, the dense atoms of the darkening pigment obviously thick- ening and coloring venous blood. The vapori- §35 31 zation of the water, and the Carbonic acid gas evolved, would, inevitably, thicken the blood, unless their elements pre-existed in a more so- lid form in the venous blood brought to the lungs, than in arterial blood. You may say, from what has been advanced, that these dense atoms of Hydrate of Carbon, being the components of woody fibre, must be infinitesimal blocks of wood, floating in the sanguineous mass. This is, doubtless, true; and let us now see if we can trace any analogy between the burning of aggregated atoms in form of blocks of wood, and the combustion of these atoms of Carbon in the lungs. § 35. Of the analogy of pulmonic combus- tion of Carbon and the burning of wood. When the driest baked wood is set on fire, and the attraction of cohesion is thus overcome, it burns rapidly ; Carbonic acid gas, and a large amount of watery vapor are generated. Here the Oxygen of the atmosphere combines with the Carbon, forming Carbonic acid gas, and the excess of latent heat of the Oxygen gas, over and above what is necessary to con- vert the Carbon into the gas, combines with the water of the Hydrate of Carbon and con- verts it into watery vapor. In this process the 32 §36 heat overcomes the attraction of aggregation of the wood, when the Carbon becomes at once oxydized and the water vaporized. § 36. Analogy of pulmonic oxydation and that of decay in wood. But, have we any analogy in the natural de- composition of solid lignin, or Hydrate of Car- bon . Decaying wood, called, in popular no- menclature, spunk, may be cited. This is lu- minous in the dark, owing to the gradual oxy- dation of the Carbon; and the evolution of Carbonic acid gas and watery vapor slowly go- ing on, as the attraction of cohesion is over- come by decay. In the lungs, the Hydrate of Carbon, in its condition of molecular solids, alike burns spon- taneously. Why vegetables growing in mines are luminous, is explicable from their having no bark, and from the small amount of Hydrate of Carbon formed by them, hence coming in di- rect contact with atmospheric Oxygen. A thought here maybe worth remembering: Hydrate of Carbon or wood, seems to be about intermediate in density between the extreme density of its pure element of Carbon, as formed in diamond, and water as a fluid; a medium to be expected in such compounds of the two §36 33 elements. In the formation of the two gaseous compounds in the lungs and on the surface, the latent heat of the Oxygen of the atmosphere must, in like manner, as in burning wood, con- vert the water of the Hydrate of Carbon into the insensible respiratory and perspiratory vapor. From the facts and analogies examined, find- ing as we do, not only identity of phenomena, but of cause, we may fairly infer that the vital chemistry of vegetables and animals in the for- mation of Hydrate of Carbon, is identical. It seems alike true that the laws in both harmo- nise with the chemical laws of inorganic chem- istry. If so, exposing arterial blood out of the body to Carbonic acid should, obviously, dark- en its color, and form Hydrate of Carbon as in the systemic capillaries; while Oxygen ap- plied to venous blood should, as in the lungs, redden it, and produce Carbonic acid ; both well observed facts, as stated by Liebig, and as before noticed. If to these facts, as direct de- ductions from our analogies, we add the fur- ther facts, first, that arterial blood, darkened by Carbonic acid out of the body, is again red- dened by Oxygen ; and second, that Carbonic acid and vapor are given off upon exposure to 34 §38 Oxygen, precisely as in respiration, the proof 6eems again indubitable that the pulmonic and systemic capillaries perform the antagonist functions of composition and decomposition of Carbonic acid. The Hydrate of Carbon on coming into con- tact with Oxygen, ignites, and forms Carbonic acid gas, and the excess of Caloric in the Ox- ygen converts the water of the hydrate of car- bon into vapor, or halitus, and the blood hence becomes reddened out of the body precisely as in passing through the lungs. From all these facts and analogies, I cannot resist the conclu- sion, that carbonic acid gas is decomposed in the systemic red capillaries, that there is form- ed precisely the same triple compound in ani- mals, as in vegetables; the hydrate of carbon. §38. This theory of respiration differs es- sentially from that of Lavoisier, La Place and Prout, which supposes Carbon and Hydrogen, or hydro-carbon, to exist in the blood, and that Hydrogen and Carbon both become oxydised by respiration. Hydro-carbon is a mere im- aginary compound, which was necessary to complete their theory, while hydrate of Carbon as just shown is an extensive triple compound. § 39. From the facts already considered, and §39 35 the fact that respiration can be but for a mo- ment suspended without inducing death, is not the conclusion irresistible that the impor- tance of the lungs to life is dependent upon the pulmonic capillaries preserving the balance, by throwing off hydrate of carbon as fast as it is formed by the systemic capillaries . If so, can we doubt, that such formation is, itself, connected with some important office of vitali- ty 1 In vegetable physiology, hydrate of Car- bon fulfils the important office of contributing to the growth of plants, and as it serves thia useful purpose, and since it does not help build up the organism of animals, it can hardly be doubted, that it contributes in animal life to some important function not found in vegeta- bles. With what function is it connected . This leads me in the next place to speak CHAPTER IV. Of the function of calorification. § 40. In burning wood, the Carbon and wa- ter are not only converted into gaseous forms, but a large amount of free heat is thrown off. The same thing must, obviously, occur in the lungs to some extent from the like chemical changes, and this chemical combination would, hence, tend to elevate the temperature of the blood. This may, obviously, be one source of animal heat, and accounts for the blood in the left cavities of the heart being one degree or more higher than in those of the right. § 41. Moreover, although the chemico-vital process going on in the lungs would be an in- cessant source of animal heat, yet the universal and'equal diffusion of temperature throughout all parts of the body appears to disprove its be- ing the only source, and, indeed, conclusively to show, that animal heat must, in some way, be measurably, if not principally, generated in the systemic, instead of the pulmonic capilla- ries. The experiments of Dulong show that more heat is generated by animals than could be done by this conversion of Carbon into Car- §42 37 bonic acid gas by the lungs, and that hence some additional mode of generating heat must exist in the functions of the systemic capilla- ries. (Hare's Chem., 507.) § 42. From the earliest records of science, respiration and calorification have been be- lieved to be intimately connected; and ancient theories made the lungs the centre, from which heat radiated to every part of the organism; but the simple fact of the equal distribution of heat to every point, overturns, I think, this doc- trine. A second doctrine taught, that the OnXygen absorbed by the blood in the lungs, gave off its latent heat in all parts of the body, and thus preserved the elevated temperature of animals. § 43. As already explained, rigid experiment and induction appear to prove that the Oxygen employed in respiration, is principally used in decarbonizing the blood. We have heretofore proved, that water, in uniting with Carbon in vegetables, gives oft* its latent heat of fluidity in forming a solid atom of the Hydrate of Carbon. Facts also justify the conclusion, that the form- ation of solid atoms of Hydrate of Carbon in the systemic capillaries of animals, results from the like decomposition of Carbonic acid. 5 38 §44 § 44. Immediate cause of animal heat. As fluid and gaseous substances, like water and Carbonic acid, on becoming solid must part with latent heat, it hence follows that, wher- ever the capillaries form these atoms of Hydrate of Carbon, latent heat must be set free, and thus furnish an incessant supply of this life- imparting agent. § 45. Analogy and difference of vegetable and animal life. The latent heat set free in forming solid Hy- drate of Carbon, (C H O) in animals, may be illustrated by recurrence to the Diagram for illustrating the decomposition of Carbonic acid by vegetables. [See § 31.] This will also show the difference, as well as strict analogy, between vegetables and animals, in forming this triple compound. DIAGRAM 4. In the systemic capillaries, Heat,______-T?_theBloo_d_____ Elements of Carbon- ic acid, ( c ) To the Blood in a new compound. o. o. Elements of water, C.H.O. To the Blood §45 39 In vegetables, the heat of the Carbon and water converts the Oxygen of the Carbonic acid into atmospheric Oxygen gas. [§ 31, Diag. 3.] In animals, the heat of the Carbon and water are both set free in the blood, because the Oxy- gen is not converted into and thrown off as a gas. Casting the eye upon the Diagram, it shows that in this formation the Oxygen of the Car- bonic acid is thrown to the atmosphere while it is retained in the system of animals. To dispose of this surplus Oxygen in animals, has proved a difficult problem. It was at first surmised that it was in some way connected with the decomposition of muriatic acid, the Oxygen of the Carbonic acid uniting with the Hydrogen of the acid, to form water ; a hypo- thesis surrendered in view of facts to be here- after noticed. Physiologists have demonstrated that the surface of the body, as well as the lungs, is con- stantly evolving Carbonic acid gas ; and this fact accounts alike for the aqueous discharges occurring from both pulmonic and cutaneous surfaces, in the form of an insensible vapor. It also shows what ample provision the Archi- 40 §46 tect of our bodies has made for the elimination of this effete Carbon, and aids our other proofs of the high importance of this function of the skin and lungs. § VI. Harmony of vital and inorganic Chemistry in Nature. § 46. Harmony of all the Capillaries in Ca- lorification. This view accounts for the universal diffu- sion of heat wherever red blood circulates, and connects by indissoluble links the cutaneous, respiratory and calorific functions ; the interior capillaries of the body antagonising those ex- terior, in the formation and combustion of Hy- drate of Carbon; and yet all unite as one har- monious ichole in imparting heat to the swift currents of the vital fluids. ^ 47. Harmony of vital and inorganic af- finities. Controlled by the vitality infused into both sets of capillaries by the function of innerva- tion, the laws of their vital chemistry and con- sequent animal heat are hence strictly accord- ant with the Chemical laws of inorganic nature. § 48. Regulation of animal temperature. Thus far we have confined our inquiries to §49 41 the question, how heat is generated. But a word upon the regulation of animal tempera- ture seems to be here demanded. Like the chemico-vital office of generating heat, its regulation is obviously dependent upon the life-imparting influence infused into the ca- pillaries at every point of the organism, by the nervous filaments, all uniting in the universal function, both of generating and regulating ani- mal heat. While the- nerves and capillaries are the vital agents, water is the great instru- ment of this function of graduating animal temperature. Moreover, water performs a most important part in all the vital and chemical phe- nomena of animated nature; for it is not only in its simple but compound state, the great sol- vent of the nutrient elements, for repairing and building up the various tissues; but is the me- dium for suspending, conveying, and, by its ele- ments, forming the Hydrate of Carbon ; while it also carries off the other waste matters by the excretory outlets. §49. It follows, as a deduction from the views I have presented, that the degree of ani- mal temperature, cater is paribus, in each class of animals, should bear a direct ratio to the ex- 5* 42 §50 tent of the pulmonary apparatus, as compared with the bulk of their bodies. This deduction is fully sustained by Dunglinson, Muller, and, indeed, by every physiologist. § 50. Heat also proportionate to amount of Carbonic acid evolved. It must also be obvious that the degree of heat in animals would be proportionate to the amount of Carbonic acid evolved, as compared with the bulk of their bodies ; a fact fully sus- tained by the rigid experiments and observation of modern physiologists. These conclusions are also fully borne out by other facts from comparative anatomy and physiology. In cold-blooded animals, there is but a com- paratively slight apparatus for the decarboni- zation of the blood; a fact readily explicable upon these physiological views, as there is lit- tle necessity for the decomposition of Carbonic acid, for the elevation of animal temperature, and, of course, no necessity for an extensive decarbonizing apparatus. In birds, on the con- trary, the pulmonic apparatus is, comparatively, very extensive, occupying a large proportion of their bodies, and we find their temperature a- bove that of man and the other animals of the §51 43 same class, and they give off nineteen times more Carbonic acid gas than the cold-blooded animals. {Muller.) This elevation of temperature in birds, ap- pears to be a provision of nature for expanding the gases extensively distributed in their cellu- lar and pulmonary structures, and by adding to their specific levity, facilitating their accustom- ed movements. In the polar fox, the heat of whose body is at 106° or '7°, the lungs are ve- ry capacious. These facts appear most fully to prove, that the evolution of animal heat is, in some way, dependent upon the office of the lungs; physi- ologists formerly supposed, directly so; but modern investigations, while they appear to disprove any direct connection, have failed to illustrate, as I have assumed to do, not only the direct, but the indirect, yet indissoluble links, uniting the functions of the cutaneous and res- piratory surfaces, with the interior and univer- sal generation of caloric. §51. An explanation of the spontaneous com- bustion of the body in habitual drunkards, may be founded upon these physiological views. The experiments of Beaumont conclusively show that both water and alcohol are promptly 44 §52 absorbed from the stomach. Alcohol has of- ten been found distilled into the closed cavities of the brain, instead of passing off by the lungs, the usual safety-valve. These, and various other facts, prove that alcohol may enter the blood without decompo- sition. From long habit of drinking, the blood becomes surcharged with this inflammable poi- son, as the breath indicates, even when the drunkard is most sober. This poison deranges all the functions of life, and if the lungs failed to throw off all the Hydrate of Carbon, and still absorbed Oxygen, as they constantly do, the blood having both Hydrate of Carbon and al- cohol as inflammables, the Oxygen might ignite the Carbon and alcohol, and thus set up a spon- taneous combustion in every part of the body where red blood circulates. § 52. It will be perceived that I have as- signed to the lungs and surface of the body sim- ilar offices, the expulsion of Carbon and other excretal matters; while it is to the deeper seated, red capillaries, that the function of ca- lorification is mainly assigned. It is in those capillaries carrying red blood that the decom- position of Carbonic acid takes place, while the serous capillaries are engaged in the more §53 45 elaborate office of depositing the nutritious ele- ments which build up and repair the waste of our bodies, and which also furnish the materi- als for secretion. While in the lungs there are two sets of capillaries, the systemic for nu- trition, and the pulmonic for decarbonization, so of the systemic we also find, upon these views, the same double set of capillaries, to wit: the serous for nutrition, and the red, or carbonizing capillaries, for calorification. § 53. General summary of the first two Lectures. The following summary may be presented upon the reciprocal chemical changes of the blood in the capillaries of the lungs and sys- tem, and the connection of respiration with ca- lorification : 1. The lungs perform an excretal office on which life constantly depends, because directly and indirectly aiding calorification. 2. The substance thrown oft* is Hydrate of Carbon. 3. The Carbon, on coming in contact with atmospheric Oxygen combines with it, forming Carbonic acid gas, which is thrown off from the lungs and skin by expiration and perspiration. 4. The amount of latent heat of the Oxygen 46 §53 gas* employed, is much greater than that of the Carbonic acid gas formed in the lungs, and, hence, caloric is set free, imparting heat to the blood and surface. 5. This free heat also combines with the wa- ter of the Hydrate of Carbon, and converts it into vapor. 6. The lungs and cutaneous surface aid in regulating animal temperature by the conver- sion of water into vapor, thus conveying off' any excess of free caloric in the system by com- bining with it in the form of latent heat. 7. The water of the Hydrate of Carbon is converted into vapor in the lungs and upon the surface, precisely as when wood is burned, and hence assumes the form of insensible respira- tory and perspiratory transpiration. 8. Facts appear to show that the chemical change in both venous and arterial blood may occur, independent of the vital principle, by applying to the venous, Oxygen gas, and to the arterial, Carbonic acid gas. 9. The systemic red capillaries are the an- tagonists of the pulmonary, and are constantly decomposing Carbonic acid, and, with water, forming Hydrate of Carbon ; or, in other words, carbonizing the blood. §53 47 10. From this union, water and Carbonic acid are transformed into a solid substance, and, hence, latent, becomes free heat, at every point where red blood circulates. 11. The function of the systemic red capil- laries of the body in decomposing, and that of the small vessels of the lungs and skin in rccam- posing Carbonic acid gas, reciprocally depend upon and balance each other; in other words, one set carbonizes, the other decarbonizes the blood. 12. In consequence of this indissoluble link which connects the functions of respiration and calorification, the degree of temperature, the Carbonic acid evolved, and the size of the lungs as compared with the bodies of animals, al- ways bear a direct ratio to each other. 13. There is a beautiful analogy between an- imals and vegetables, in the decomposition of Carbonic acid by the minute vessels of each. 14. This explanation shows that the great end and function of respiration is, both directly and indirectly, to aid in the all-important office of the generation and diffusion of animal heat. 15. The undetermined questions left in clos- ing our last Lecture (§ 21.3,4,) have been set- tled by proving, first, that the coloring pigment £8 §54 of venous blood is not elemental Carbon, but second, is a compound of Carbon and water. § 54. Unsettled questions. While the foregoing summary appear to be legitimate deductions, to be henceforward treated as physiological facts, it seems also proper, as in closing my last lecture, (Lee. 1.) to state what we have left unaccomplished. 16. The new compound into which the Ox- ygen of the Carbonic acid enters, remains to be investigated; 17. Whether it befree Carbonic acid de- composed by the systemic capillaries ; or is derived from some compound containing it; 18* Whether the Carbonic acid passes through the organism unchanged to be cast off from the lungs ; or \sformedby some vital pro- cess ; 19. Whether the elements of water, which enter into the Hydrate of Carbon, are taken from the free water of the blood, or are derived from some compound of water; or 20. Whether the elements of the water are taken from different compounds containing such elements, when these are combined with the Carbon. In our inquiries thus far, I have attempted to r* §54 49 give you a birds-eye view of the organs of res- piration, of their important offices in the ani- mal economy, and of the links which connect them with the nervous and circulating systems, and with the function of calorification. No rational mind that understands and con- templates this complicated piece of mechanism in its infinity of movements, can fail of being filled with admiration at the silver cords, which unite respiration with the other vital functions; or be less mindful of the unrivalled symmetry, and wonderful adaptation of all, to the great purposes for which they were created. Nor can we be less impressed with the important part carbonic acid plays, in the wide range of na- ture's operations. In the mineral kingdom, the important element of this substance is separa- ted from the organic remains of vegetables which are transformed by a slow but unfalter- ing process, into the extensive coal mines found in the bosom of the earth. So on the deep foundation of the soundless Ocean, by vital in- sect chemistry combining Carbonic acid with lime, and by insect labor placing upon each rising summit, successive layers of this com- pound, there is begun and consecutively reared the coral island, till slowly lifting its 5 50 §54 spray-capped head, it proudly towers above the mountain wave. In the vegetable kingdom, by the decompo- sition of this gas and the deposit of its atoms, it forms the growing substance of every plant, from the humble violet, spreading its epheme- ral beauties to the sunbeam, to the lofty oak bearing its arms and defying, for centuries, the howling blast, and raging tempest; while in the animal creation, the same carbonaceous gas, by its rapid compositions and decompositions, imparts to all the vivifying stimulus of heat, alike spreading the wing of the insect, and aid- ing the eagle in his lofty flight; alike rousing the glow-worm from his humble bed, and feed- ing the lamp of life in man, and lighting up the fire of genius. In contemplating the all-perva- ding influence of this agent, the conviction is strongly forced upon the mind, that the unseen Hand that guides its affinities, " Acts by general, not by partial laws." And, however humble have yet been the ef- forts of mind in unraveling the mysteries of its own " fearfully and wonderfully made," but frail earthly tenement, sufficient is already known to justify the conclusion, that the laws which con- §54 51 trol the rapid compositions and decompositions among the elements of animated beings, are as general and immutable as those stamped by the hand of Omnipotence upon the atomic changes of inanimate nature, or upon the cycling move- ments of the planetary system. LECTUEE III. Of other chemico-vital changes connect- ed with Respiration and Calorification. CHAPTER V. § 55. Of the source of the Carbonic acid, and disposition of its Oxygen by the systemic capillaries. Questions to be answered: Whence the Car- bonic acid for forming the Hydrate of Carbon . Whence its Carbon . Whence its Oxygen . How is the Oxygen disposed of. § 56. Source of Carbonic acid; first views. In my last Lecture, I stated that Carbonic acid gas is an all-pervading compound in na- ture ; that all water we drink contains it; that it is an ingredient of both arterial and venous § 57 53 blood; that it is combined with the alkalies and other compounds of venous blood; and hence, that from some, or all these sources, suf- ficient Carbonic acid might be perpetually sup- plied for decomposition in the systemic capilla- ries, to furnish Carbon for the Hydrate of Carbon. These were, briefly, my first views on this point; they have for several successive years been presented in this form to the Medi- cal Classes ; and I have again presented them in like form for the purpose of examining them more critically than heretofore, and if wrong, to show how errors should always be corrected in such inquiries. We are always prone to take wrong roads in such investigations, and well settled facts should always be the guides to aid us back, and put us again on the right track. § 57. Sources of Carbonic acid; corrected views. The sources already indicated for the need- ful and incessant supply of Carbonic acid for the formation of Hydrate of Carbon, are obvi- ously reducible to the water and the food we swrallow. Are these sources sufficient to fur- nish twelve ounces of Carbon from the Carbo- nic acid gas thrown off from lungs and skin in 6* 54 §58 twenty-four hours ; such amount being well set- tled as a physiological fact. This Carbonic acid must be either supplied already formed, or be manufactured in the animal body, while its elements, if previously uncombined, must be perpetually supplied from the food and drinks, to preserve the balance of waste and supply. The supply of Carbon must hence be equal to the pulmonic and cutaneous waste, or soon leave the lungs nothing to do in their function of decarbonizing the blood. § 58. Free Carbonic acid in the food and drink insufficient to supply the pulmonic waste. It being clear that all the Carbonic acid, or its Carbon used in the systemic capillaries to form Hydrate of Carbon, must come from our food and drink, let us inquire whether these contain sufficient free Carbonic acid to furnish the supply. The sum of our drinks in twenty- four hours can by no means be sufficiently charged with Carbonic acid to supply any thing like the needful amount, because many gallons if not barrels of water, would be needed for the purpose. The solid food usually contains but a small amount of Carbonic acid, while it a- bounds in Carbon. We must hence believe that the sources of Carbonic acid first named, §59 55 (§ 56) are utterly inadequate to the requisite supply, and that the Carbon of the food must be somewhere in the organism oxydised by a chemico-vital process, before it is used to form Hydrate of Carbon. §59. Disposition of the Oxygen. But before we attempt to show where this oxydation occurs, let us try to clear up a diffi- culty which, for a long time, beset our inqui- ries, viz : the disposition of the Oxygen of the Carbonic acid. (§ 45.) In vegetables, as I have before explained, the Carbon unites with the elements of water to form the Hydrate of Car- bon, while the Oxygen is thrown to the atmos- phere. (#ee§45.) When the Hydrate of Car- bon is formed in the systemic capillaries of ani- mals, it must, as when formed in vegetables, part with its Oxygen. It was at first surmised that the disposition of the Oxygen was connect- ed with the decomposition of Muriatic acid, the Hydrogen of which united with this surplus Oxygen to form water. This surmise was surrendered in view of these facts: (1.) That free muriatic acid does not exist in the blood ; (2.) That if it did, its decomposition would set chlorine free in the 56 §60 circulating mass, and thus prove a suddenly fa- tal agent, unless simultaneously entering into some new combination as the antidote; and (3.) that no such combination could be explained upon any known facts and laws of organic or inorganic chemistry. That Oxj'gen gas is not thrown off from animals as from the leaves of vegetables, is a fact well determined. This surplus Oxygen must hence, obviously, unite in some new solid or fluid form. § 60. With what does the Oxygen unite ? Some well known facts stated by Liebig, seem to show that this surplus Oxygen unites with the Oxide of Iron, which is always a con- stituent of the red globules of blood. He re- marks, " The globules of blood contain a com- pound of iron. From the never-failing pres- ence of iron in red blood, we must conclude that is unquestionably necessary to animal life." To this remark of Liebig all will subscribe. Oxide of Iron, though a constituent of vegeta- bles, is not contained in their sap or circulating fluids, while it is found in the fluids, or blood of animals. From these facts, it appears fair to infer, that the Oxide of Iron in the blood of animals is employed in aid of some functions §61 57 not found in vegetables, and that, hence, it may probably be connected with the functions of re- spiration and calorification. Liebig has the further remarks, that" the com- pound of iron in the globules of blood has the characters of an oxydized compound;" that " no other metal can be compared with iron for the remarkable properties of its compounds;" and adds, "the compounds of protoxide of iron possess the property of depriving other ox- ydized compounds of Oxygen ; while the perox- ide of iron, under other circumstances, gives up Oxygen with the utmost facility." Admit that the protoxide of iron exists in the blood, it might readily absorb the Oxygen giv- en off from the Carbonic acid decomposed in forming the Hydrate of Carbon, and thus con- vert the iron into the peroxide. The peroxide thus formed, would be carried along in the cir- culation from the systemic to the pulmonic ca- pillaries. But the same difficulty would be en- countered in the lungs as in disposing of the sur- plus Oxygen of the Carbonic acid in forming Hydrate of Carbon, while it would leave the source of Carbonic acid undetermined. § 61. Source of Carbonic acid; Law of iron. 58 §62 A fact, or law, as stated by Liebig, will not only show the source of supply of Carbonic acid for forming the Hydrate of Carbon, but will also enable us to dispose of this surplus Oxygen,—the two objects of this part of our in- quiry, (§ 55.) He says : " Carbonate of protox- ide of iron, in contact with water and Oxygen, is decomposed ; all the Carbonic acid is given off, and by absorption of Oxygen it passes into the Hydrated peroxide, which may again be converted into a compound of the protoxide." The existence, however, of this compound of iron in the blood is by no means established. § 62. Hypothesis : Protoxide and Car- bonate of Protoxide of Iron in blood. But let us admit as hypothesis, to be after- ward proved as fact, that arterial blood con- tains protoxide and Carbonate of the protoxide of iron. If the laws of vital chemistry in the systemic capillaries are the same as those of inorganic chemistry just stated, the following must be the results : The blood always contains water. The Car- bonic acid itself contains Oxygen, and these two conditions of the law quoted (the presence of water and Oxygen,) existing, the Carbonate of the protoxide of iron would be resolved into §63 59 the Hydrated peroxide, and the Carbonic acid set free to combine in a new form. Carbonic acid out of the body darkens arterial blood, and it must do so in the systemic capillaries. But what chemical changes occur \ The fol- lowing diagram will illustrate : DIAGRAM 5. § 63. Showing the formation of the hydrated Peroxide of Iron, and of the Hydrate of Car- bon, in the systemic capillaries: Fc--~^Z^~~^Fe2 03+Aq\ f Hydrated > Peroxide of Iron. yFe2 03\Aqy Carbonate | O ~] of Protoxide <{ O of Iron, Water, £ } ---------^ C H O { ^^ of The Carbon (C.) of the Carbonic acid goes to unite with the elements of water to form Hy- drate of Carbon. The Oxygen of the Carbonic acid passes to the protoxide of iron to convert it into the peroxide. The peroxide unites with 60 §03 the water of the blood, and thus becomes Hy- drated peroxide. We have thus deoxydised the blood through the instrumentality of the Oxides of Iron, and furnished the Carbonic acid. This completes the circle of affinities informing Hydrate of Carbon for calorification ; but it has been done by assuming as hypothesis that the protoxides and Carbonate of protoxide of iron are constit- uents of blood. The elements of water are also used in the diagram hypothetical Iy, with- out previously settling the question whether the water of the blood is taken to form Hydrate of Carbon, or whether its elements are derived from other compounds containing them. The Hydrated peroxide of iron formed upon this hy- pothesis, would, obviously, go on in the circu- lation from the systemic to the pulmonic capil- laries ; but the protoxide of iron must obvi- ously have been sent through the arteries from the lungs. Let us therefore follow the track of the arteries back to the pulmonic organs, and see if these, in completing haematosis, furnish the compounds of iron supposed.- §64 61 CHAPTER VI. § 64. Of the chemico-vital changes pro- duced by the lungs as an organ of hamatosis. Questions to be answered. What the pri- mary source of the per and protoxides of iron . What the source of Carbonate of protoxide of iron ! The chemico-vital laws thus far determined show, that if Carbonate of protoxide and pro- toxide of iron are constituents of arterial blood, the peroxide must necessarily be formed in the systemic capillaries in the function of calorifi- cation. The Hydrated peroxide of iron so formed in the systemic capillaries, upon our hypothesis, (§ 62,) was sent via the veins to the lungs ; but the pre-existence of this Oxide of Iron in the blood does not rest upon the hy- pothesis assumed, (§ 62.) It is next proposed to show, not only the pre-existence of the peroxide of iron in blood ; but, that the other two forms of iron assumed in the hypothesis, (§ 62,) as constituents of arterial blood, must both be formed by the capillary chemistry of the lungs. This done, it will show the protOnX- ide of iron on the one hand, and the hydrated 62 §64 peroxide on the other, reciprocally dependent upon and balancing each other in their forma- tion respectively by the pulmonic and systemic capillaries, and in oxidizing and deoxidizing Carbon for calorification. Recurrence to the facts of the indefatigable Liebig, show peroxide of iron to be a constituent of blood. He states that " the compound of iron in the globules has the characters of an oxidized compound; for it i.j decomposed by sulphuretted hydrogen exactly in the same way as oxides, or other analagous compounds of iron. By means of diluted mineral acids, peroxide (sesquioxide) of iron may be extracted, at the ordinary tempera- ture, from the fresh or dried coloring matter of the blood." [The manner in which the Hydrated perox- ide of iron in the blood is formed by the capil- laries of the lungs, from the elements sent from the stomach, will be hereafter explained.] If from the fact that Hydrated peroxide of iron exists in blood, and from the law of its af- finities, that " Hydrated peroxide of iron in contact with organic matters, destitute of sul- phur, is converted into the Carbonate of pro- toxide," (Liebig,) we can show the formation of protoxide and Carbonate of protoxide of §64 63 iron by the pulmonic capillaries, the chemico- vital changes of the systemic capillaries for ca- lorification, as explained by the hypothesis, (§ 62,) will be fully established. § 65. Hydrated peroxide of iron decompo- ses chyle and blood. Let us apply this law to the vital changes produced by the lungs upon the elements of blood. The chylous fluids, after their per- fection in the apparatus for their formation, and their entry into the left subclavian vein, pass through, as the first set of capil- laries,—those of the lungs. The chylous flu- ids are, obviously, not only organic matters, but they are in the best possible condition of minute subdivision to facilitate chemical change. The same principle holds true as to the debris of the tissues, or any other constituents of blood. It cannot be reasonably doubted that the Hy- drated peroxide of iron would act in, as out of the body, on being brought in contact in the pulmonic capillaries with the chylous fluids and other constituents of blood. If so, the blood would be decarbonised, the Carbon would be oxidised by the surplus Oxygen of the Hy- drated peroxide of iron, and this would thus be 64 §66 converted into the Carbonate of protoxide by union with the Carbonic acid formed. The formation of the Carbonate of protoxide in the pulmonic capillaries, must hence be a physio- logical truth. § 66. Diagram. Protoxide and Carbon- ate of protoxide of iron formed by the pulmo- nic capillaries. This fact may be thus illustrated : DIAGRAM 6. The Oxygen of the peroxide of iron oxidises the Carbon of the nutritive fluids ; the Car- bonic acid and protoxide of iron thus formed, unite as the Carbonate of protoxide. Moreo- ver, there is formed not only the equivalent of protoxide in union with Carbonic acid, but three other equivalents of simple protoxide are §67 65 formed to go out from the lungs in arterial blood. This fully verifies the facts assumed in the hypothesis, (§ 62,) and as displayed by the diagram for illustration, (§ 63.) The truth of the explanation of chemical changes produced by the vital action of the systemic capillaries for calorification is hence established, and the circle of affinities perform- ed by iron in calorification, is fully displayed. § 67. Summary. Deductions from the facts examined. The lungs are not only employed in the func- tions of excretion and calorification in expelling and oxidizing the Carbon of the Hydrate of Carbon, but are the last of the organs of hm- matosis, viz : 1. In decarbonizing the chylous and other constituents of blood, thus fitting them for nu- trition. 2. This decarbonization of the elements originally entering the animal as food, furnishes the Carbon of Carbonic acid, and the Hydrate of Carbon employed in the function of calorifi- cation. 3. That the Oxides of Iron are the first in- struments for oxidizing and deoxidizing Car- bon as the important agent in calorification, 7* 66 §68 while atmospheric Oxygen is the last agent. 4. The protoxide of iron is the carrier of the carbonic acid from the lungs to the systemic ca- pillaries. 5. The affinities of the iron in its circle for calorification show, that if either Oxide exists as a constituent of blood, the other Oxide must necessarily be formed ;—the pulmonic and sys- temic capillaries antagonizing and balancing each other, in oxidizing and deoxidizing these compounds. § 68. While the foregoing deductions fully answer the first four questions stated as the ob- jects of inquiry in this lecture, the primary source of the iron and its oxides remains unexplain- ed, as does the inquiry " whence the elements of water in the Hydrate of Carbon." That both find their way into the blood from the stomach, is obvious. But what chemico-vital changes their elements undergo in reaching their points of destination in the organism as the aids of the functions of respiration and ca- lorification, should be determined before our circle of vital affinities can be considered as complete. Preliminary to doing this, however, it is necessary to consider, § 70 67 CHAPTER VII., The chemico-vital relations of the pul- monic AND GASTRIC FUNCTIONS. § 70. It will be remembered that I stated, as my first surmise for disposing of the Car- bonic acid in the formation of the Hydrate of Carbon, that the change was connected with the decomposition of muriatic acid. Upon this hypothesis, the surplus Oxygen would combine with the Hydrogen of the muriatic, or Hydro- chloric acid, to form water. This hypothesis was surrendered for reasons already given, (§ 59.) Although this disposition of the Oxygen proved an untenable hypothesis, we are now to attempt the proof that the formation of the Hydrate of Carbon by the systemic capillaries is indirectly, but remotely, connected with the formation of muriatic acid by the capillaries of the stomach. It is an admitted fact in physi- ology, that the muriatic acid is the essential solvent of the gastric juice, but the strict anal- ogy between the vital chemistry of the capilla- ries of the stomach, in secretion, and some of 68 §70 the chemical changes of inorganic nature, seems never to have occurred to physiologists. The examination of a few facts will illustrate this analogy. It is a well known fact that animals soon die, unless supplied with salt, which is the only extensive ingredient of blood containing chlo- rine. Neither do animals live long if entirely deprived of water. Salt is a compound of chlorine and sodium. Muriatic acid is com- posed of hydrogen and chlorine, and hence the more modern designation is Hydrochloric acid. Soda is a compound of Sodium and Oxygen, and is an ingredient of blood, while muriatic acid is not. As muriatic acid constitutes the active solvent of the gastric fluid, and as it does not exist in a free state in blood, the muriatic acid of the gastric juice cannot be an educt from blood, but must be formed from the chem- ical transformation of some compounds con- taining its elements ; because animal chemistry creates no new elements. Leibig says : " The presence of free muri- atic acid in the stomach, and that of soda in the blood, prove beyond all doubt the neces- sity of common salt for the organic processes ;" § 71 69 but how salt is transformed into muriatic acid, this able chemist and physiologist has failed to explain. This shows that he was led to the very threshhold of the explanation of gastric secretion, I am now to offer. § 71. Muriatic acid of the gastric solvent; how formed. It is proposed to determine at what point of the organism this chemico-vital process occurs ; and also show its strict analogy to a process of inorganic chemistry. Upon careful examina- tion of the chemical compounds of the blood, it will be found that the two elements of muriatic acid can only be derived from common salt and water; and hence the free muriatic acid secre- ted by the stomach, must be formed by the un- ion of the chlorine of salt and the hydrogen of water. This would leave the Oxygen of the water and the sodium of the salt to unite, and the compound would be oxide of sodium, or free soda. There is consequently double decompo- sition bchceen the elements of water and salt in the capillaries ichich secrete the gastric fluid. § 72. What analogy to inorganic chemistry ? On applying the galvanic apparatus to a so- lution of salt and water, double decomposition occurs; the chlorine of the salt unites with the 70 §73 hydrogen of water, forming muriatic acid ; (7/ CI.) while the union of the Oxygen of the wa- ter and sodium of the salt forms free soda. Al- though most obvious that the nervous appara- tus and intimate nervous filaments which pre- side over the organic action of capillary gastric secretion, perform in this vital process the very same double decomposition as the galvanic trough, I will not stop to insist that the proxi- mate cause of this change is alike electric in both, although apparently sustained by the ar- tificial digestion performed by exposing food to the influence of salt and animal membranes, connected with the galvanic apparatus. § 73. But what becomes of the soda manu- factured by the gastric capillaries ? The soda does not enter the interior of the stomach for digestion, as does the muriatic acid, and it must hence pass on in the gastric veins. This would supply the free soda found upon analysis in the blood, as also this important el- ement of bile. A fact stated by all physiolo- gists is, that bile is rapidly secreted during the digestion of a meal, while the liver is nearly quiescent in the intervals. Precisely the same with the stomach, which, according to Beau- mont, generally secretes gastric juice only while §74 71 a meal is digesting, when rapid secretion oc- curs. As the soda formed, constitutes an im- portant ingredient of both bile and blood, let us inquire by what avenues does it reach the heart and liver . Evidently through the veins of the stomach. § 74. But where do these empty ? The veins of the stomach help make up the vena porta, which goes to the liver. Part of the soda formed by the capillaries of the stomach would therefore be used in the secretion of the bile, of which soda is an important element; while the residue would pass directly through the vena cava hepatica into the general mass of blood, and supply it with its free soda. This explanation connects, by indissoluble chemico- vital links, the functions of the stomach and liver, soda being manufactured by the stomach for the secretion of the bile at the very time needed to complete digestion. This physical union of the stomach and liver fully accounts for the rapid secretion of both organs during the digestive process, and their simultaneous quiescence in the intervals of digestion. In the intervals of meals, it must be evident that the salt and water of the blood pass un- changed through the vessels which secrete the 72 § 75 gastric juice ; but salt and water being natural constituents of blood, this intermittent action of the gastric vessels would by no means derange the organism. So in the liver, the portal blood would pass nearly or quite unchanged in the intervals of meals. The stimulus of a meal seems to rouse the nervous influence imparted to the capillaries of the stomach and liver, in- ducing their respective secretions. § 75. We have a striking analogy to this in- termittent secretion of the stomach and liver, in vegetable physiology. The Carbonic acid, which constitutes a prin- cipal nutritive element for the growth of veget- ables, is decomposed at one period of the day, while at another, it passes unchanged from their leaves. When the stimulus of the sun is imparted, the Carbon forms a union with wa- ter, forming Hydrate of Carbon for their growth, while the Oxygen is evolved from the leaves. Withdraw the sun's influence, and the carbonic acid passes off unchanged, thus cut- ting off this important source of their nutrition, until the sun again imparts its life-infusing stim- ulus. This is beautifully illustrated by water vegetables under ice. When the sun's influ- ence is withdrawn, bubbles of Carbonic acid §76 73 gas collect under the ice ; when the sun shines, bubbles of Oxygen gas rise in like manner. § 76. Source of iron in the blood. That peroxide of iron is a constituent of the red globules of blood is proved by the most careful analyses, and hence our reasonings heretofore founded upon this fact are legiti- mate. But while this is an admitted fact in organic chemistry, the chemico-vital process, which forms this constituent of blood, has nev- er been explained. This I shall now attempt, by showing the relation between the stomach and lungs as the first and last organs for the formation of blood in the function of ha?mato- sis. That the oxides of iron are the essential coloring ingredients of the red globules, is the general belief of physiologists and chemists. It must, obviously, be in the minutest state of subdivision ; these minute solid atoms being mechanically suspended by the adhesive pro- perties of blood. The oxide of iron is found as a constituent of vegetable and animal food, and being a solid, and insoluble in water, it is plain that it must be rendered soluble by digestion before it can be absorbed by the lacteals. Its not coloring the chylous fluids, is an evidence that it has united with some other element. 74 §76 According to Beck, peroxide of iron digested in muriatic acid, forms the perchloride. This acid being the active solvent of the stomach, must form there the same soluble compound of iron; thus: I Ft ) Elements of Per-<( O DIAGRAM 7. {Fc oxide of Iron and Muriatic Acid. Fe2 ClZ HZ OB The chloride of iron thus formed passes in colorless solution with water, through the lac- teals into the blood. § 76f. After the lacteals, the next capilla- ries through which the chyle has to pass, are those of the lungs. The perchloride of iron decomposes the free soda, the sodium combin- ing with the chlorine to form salt, and the Ox- ygen with the iron, which with the water of the blood, forms hydrated peroxide of iron, the very compound needed in the lungs to decarbonize the nutritive fluids, as before proved ; thus : §77 75 DIAGRAM S. § 77. Red globule completed. This diagram will readily call to mind the facts, that the salt and water are decomposed in the stomach, forming muriatic acid and so- da, which thence take different directions. The soda travels via the liver and heart, to form the free soda of the blood, while the muriatic acid goes as the carrier of the iron, and the two again meet in the pulmonic capillaries. Usual affinities being here restored, would form the hydrated pel oxide of iron, and thus complete the red globule. The lungs are, hence, the last of the organs of hamatosis. This is the very point of the organism where we before proved, that the organic matters of chyle and blood were decarbonized, and the Carbon oxydized by the hydrated peroxide of iron to form the Carbonate of the protoxide. § 78. The circle of affinities completed. We have traced all the connecting links of vital chemistry in the changes of the Carbon 76 §78 and iron from the lungs, through each set of capillaries back to the stomach; thus comple- ting the circle of affinities, which these impor- tant agents perform in healing the furnace of the living locomotive. The answers to the unsettled questions at the head of the chapter, as to the source of the iron and its oxides in blood, may be briefly summed up— 1. The iron is originally derived from veget- ables, in the form of oxide of iron. 2. This oxide of iron is converted into per- chloride of iron by the muriatic acid of the gas- tric juice, and thus rendered soluble. 3. The perchloride of iron is reconverted in the lungs into the hydrated peroxide of iron by the free soda of the blood. 4. The hydrated peroxide is converted into the protoxide in the lungs, by oxydizing the Carbon of the nutritious fluids. 5. The protoxide carries Carbonic acid thus formed to the systemic capillaries for calorifi- cation, and is there reconverted into hydrated peroxide. 6. In the series of chemical compositions and decompositions of iron and Carbon, as explain- ed, an exact balance is preserved in the amount §79 77 of each at all points of the organism where em- ployed for calorification. 7. The oxides of iron are, probably, employ- ed in oxidizing and deoxidizing various other compounds than those already considered, as 8. In deoxidizing sugar, &c, to form animal fat, and in oxidizing the Carbon of the fat for calorification. CHAPTER VIII. Of the chemico-vital connection of di- gestion, HEPATIC SECRETION, CALORIFICATION AND NUTRITION. Question still unsettled : Whence the water, or its elements, to form Hydrate of Carbon . §79. Soda, and its uses in bile. Having traced one portion of soda formed by the stomach, by a direct channel, through the vessels of the liver into the blood, let us fol- low the track of the other portion, which enters as an important element of bile, in its chemi- co-vital uses. In the hepatic secretion, soda forms one of the leading elements, and as soon 8* 78 §80 as bile enters the duodenum, it begins to part with its soda, which combines with albumen, forming a soluble compound in the serum of chyle and blood. The proportion, which this compound of soda and albumen bears to the other ingredients of chyle, goes on increas- ing in traversing the intestinal canal and lac- teal apparatus, until it enters the left subcla- vian vein ; and the soda must hence attract the albumen from the other elements of the chyme. It is an admitted physiological fact, that the soda remains the solvent of the albumen, not only in chyle, but in the mass of blood, until the albumen is needed for nutrition, secretion, or other vital uses in the systemic capillaries. § 80. Of Muriatic acid as a carrier of nutri- tive elements. Having traced the soda used in bile, through the digestive apparatus, as a solvent and car- rier of albumen into the blood, to fit it for nutri- tion in the systemic capillaries, let us go back to the stomach and follow the free muriatic acid of the gastric juice in its ultimate uses, as another carrier of nutritive elements. Besides the iron and albumen, as important elements of vegetable and animal food, as already noticed, the leading ones are fibrin and casein, which §81 79 arc first formed by vegetables, and then trans- ferred by the chemico-vital action of animals, and appropriated to building up their structure. The more essential elements, hence, of animals and vegetables are those named. It is obvious that all and every atom of nutriment, whether in form of iron, albumen, casein, fibrin, or oth- er nutritive element, must be subjected to, and combined with, the gastric solvent to form the chyme, and disposed of in the manner ex- plained in the function of hsematosis. Physiol- ogy has furnished no evidence that the process of chylification has, at any point of its progress, separated the fibrin, casein, and other nutri- tive elements from their primary solvent in the the stomach ; and we may from this conclude, that when they reach the mass of blood in the left subclavian vein, they continue soluble from their union with muriatic acid. The fibrin or casein so held in solution by muriatic acid, would go the round of the circulation to the systemic capillaries, to which point we have just followed and left its fellow carrier, Soda, still joined to albumen. § 81. Nutrition, by re-formation of salt and water dropping albumen and fibrin. As the usual affinities of inorganic nature, 80 §81 between the elements of salt and water, had been broken up by the vital chemistry of the stomach when the soda and muriatic acid started as carriers, it is obvious, if the elements of salt and water, which had been separated at the stomach, resume in the systemic cappilla- ries their usual affinities, the soda and muriatic acid, by a double decomposition, would reunite to form salt and water, and drop their albumen and fibrin, as molecular solids. This would, obviously, carry and drop the atoms of these essential elements of the animal structures at all points of the organism, to contribute to its growth, and to supply its waste. Now albu- men being the animal element of the nervous system, and fibrin of the muscular; and these two systems being always intermingled in the intimate structures, and combined in the same functions, especially in those of motion, these two essential elements of their growth would be deposited side and side in the nervous and fibrous filaments. The salt and water thus formed, would proceed directly onward in the general mass of blood, carrying with them the refuse atoms displaced by the new, to be dis- charged by the kidneys and other excretory outlets. It will be perceived that the muriatic §82 81 acid and soda are, upon this physiological view, mere carriers of the nutritious particles from the stomach to the solids of the tissues; and that as soon as they have done this, they resume the affinities of inorganic chemistry, form salt and water, and become again carri- ers of the waste molecules out of the body. This deposition of nutritive elements must be at those points where the systemic capillary ar- teries terminate in the correspondent veins; the very points, as before shown, where calor- ification occurs from the formation of Hydrate of Carbon. § 82. Let us, by a Diagram, endeavor to an- swer the deferred question: " Whence the ele- ments of water to form the Hydrate of Car- bon 1" DIAGRAM 9. Carbon from / An---■—----------Fn and An The muriatic acid (HC1) of the soluble fibrin and the soda (NaO) of the soluble albu- 82 §82 men react on each other, and, depositing fibrin (Fn) and albumen (An) for nutrition, form common salt (NaCl) and evolve Oxygen (O) and Hydrogen (H), the very elements of water (HO), which are required to convert the Car- bon (C) into Hydrate>f Carbon (CHO). (It will be remembered that water was assumed hypothetical^ in § 63.) This answers the re- served and last question, " AYhence the ele- ments of water to form the Hydrate of Carbon." We have now shown how are united by chemico-vital union, all the important func- tions of animal life, how each is reciprocally dependent upon every and all others, and how all are again balanced in one harmonious se- ries of vital affinities by the function of inner- vation. This series may now be presented in the order of nature by a brief synopsis of the more important conclusions from our inquiries. LECTUEE IV. GENERAL SUMMARY AND INFERENCES FROM PRECE- DING LECTURES. CHAPTER IX. Synopsis of the circle of chemical chan- ges IN ANIMAL LIFE. DIAGRAM 10. Gastric, hepatic and duodenic secretion and digestion. GASTRIC CHYMIFICATION. Fe?__ __Fe2Cl3 Oil CI- H_______Zi^^.HO ^HClFn DUODENIC CHYI.IFICATION. N'a An. .NaAn §83 85 DIAGRAM 10.--EXPLANATION. Gastric Secretion.—Double decomposition of the wa- ter and salt is effected by the organism of the stomach, in a manner analagous to the action of electro-galvanism on the same compounds. Jn this decomposition the oxygen (O) of the water unites with the sodium (Na) of the salt to form soda (Na) : the hydrogen (H) of the water unites with the chlorine (CI) of the salt to form (HCl) the free muriatic acid of the gastric secretion. Gastric Chymification.—Free muriatic acid, as a gen- eral solvent of the food, unites with peroxide of iron, (Fe203) one of the constituents of the food, and forms by double de- composition water (HO) and the perchloride of iron (Fe2Cl3). Another portion of the muriatic acid unites with^6n» (Fn) forming a soluble compound, (HClFn). Hepatic Secretion.—The soda (Na) is carried to the liver by the gastric veins. A part goes thence, by the ve- na cava hepatica, to the heart : this is the free soda of the blood. Another part of the soda is incorporated with the bile. Duodenic Chylification.—This soda of the bile, pas- sing into the duodenum, unites with albumen (An) render- ing it soluble (NaAn). The various components of the chyle, perchloride of iron (Fe2CP), water (HO), soluble fibrin (HClFn), soluble al- bumen (NaAn), &c. pass by the lacteals and the left subcla- uan vein, through the heart, to the pulmonic capillaries. 9 DIAGRAM 11. Pulmonic capillaries in the function of h&matosis. Sol. Fibrin HClFn Sol. Albumen NaAn Soda Perchloride of Iron Pass unchanged. _________NaCl Protoxide of Iron, \ Carb. Protox. of Iron. 2 §81 87 DIAGRAM 11.--EXPLANATI0N. Soluble fibrin (HClFn) and soluble albumen (NaAn) pass through the pulmonary capillaries unchanged. The free soda (Na) of the blood and the perchloride of iron (FeeCl!), by double decomposition, become common salt (NaCl) and peroxide of iron (Fe203); the latter, in contact with the carbonaceous compounds of the blood, is converted into protoxide of iron (Fe) and carbonate of protoxide of iron (FeC). These pass on to the systemic capillaries to- gether with the sohble fibrin and albumen. 88 §85 CIRCLE OF VITAL AFFINITIES. DIAGRAM 12. Systemic capillaries in the functions of calorifica- tion and nutrition. Fe_ d° ) Protoxide J Fe \ of Iron \0 ) Carb. of Protox. of Iron Soluble Fibrin Soluble Albumen _Fe203 Fe203 ( CHO \ Heat set free. NaCl Fn&An §85 89 DIAGRAM 12.-EXPLANATION. Protoxide of iron (Fe) and carbonate of protoxide of iron (FeC) are converted into the peroxide of iron (Fe203), the carbon (C) being set at liberty. Double decomposition takes place between the muriatic acid (HCl) of the soluble fibrin (HClFn) and the soda (Na) of the soluble albumen (NaOAn) : the elements of water (HO) go to unite with the carbon (C), set free from the carbonate of protoxide of iron (FeC), to form hydrate of carbon (CHO), while the chlo- rine and sodium form common salt, which, with other waste molecules, passes off from the system through the excretory organs. The fibrin and albumen are simultaneously de- posited for nutrition. The change of the carbon from carbonic acid (C) into the 6olid hydrate of carbon (CHO) gives rise to an evolution of heat; and this process, taking place at all points of the organism where red blood is converted into venous, produ- ces universal calorification. 9* 90 §86 CIRCLE OF VITAL AFFINITIES. DIAGRAM 13. Pulmonic and cutaneous capillaries in the func- tions of excretion and calorification. Oxygen of the £0.---------__C Atmosphere ) ^^^-""Heat set free. Hydrate of Carbon )Q ---H Vapor. §86 91 DIAGRAM 13.--EXPLANATION. In the lungs and skin the oxygen (O) of the air, meeting with the hydrate of carbon (CHO), forms carbonic acid (C) and watery vapor (H), both of which pass off as excre- tions. As in burning wood, the formation of the same products is attended with the evolution of heat more than sufficient to disengage the carbonic acid and water in the aeriform state, so from the lungs and skin the carbonic acid and wa- ter escape in the gaseous form and leave still a large sur- plus of heat to warm the passing currents of the blood and unite with the systemic capillaries in the function of uni- versal calorification. 92 §87 CHAPTER X. Physiological and pathological inferen- ces. § 87. Coagulation explained. It has already been explained how the vital chemistry of the stomach overcomes the usual affinities of the elements of salt and water; how the new formations, soda and muriatic acid, become the carriers of the new elements for calorification and nutrition ; and how the diversified processes of vitality use the elements carried by them to the organism, and how, by the restoration of the usual affinities of chlorine and sodium, salt and water are re-formed. It must be quite intelligible how fibrin, in union with muriatic acid, like iron so combined, may have its carrier taken from it by soda, whether this be united with albumen, or free in the blood. The fibrin may be employed separ- ately from albumen when fibrin only is wanted in any organic process, by its muriatic acid uniting with the free soda of the blood. When death occurs, the rotary motion of the globules, observed during life, soon ceases, the control of vitality over chemical changes must also cease; §88 93 the congregation is broken up, and each ele- ment finds its old associate in the wide world of inorganic nature. So, also, to arrest the vi- tal fluid in a blood vessel, or to draw it from the body, suspending the usual rotary move- ments of its globules, breaks up the vital, and subjects it to inorganic affinities. While the albumen still remains dissolved in the serum, the soluble fibrin becomes solid; its muriatic acid combines with the free soda precisely as in the vital process just explained. § 88. Probable function of the mesenteric glands. Soda is the solvent of albumen. That mu- riatic acid is the solvent of fibrin and other an- imal elements, has been drawn as a deduction from the facts noticed in the progress of our present inquiries, (§ 80.) Not only does this explain coagulation, but considered in connec- tion with two facts noticed by physiologists, it seems to shed some light upon the hitherto un- determined function of the mesenteric glands. One fact is, that fibrin is decomposedby mu- riatic acid. If so, the muriatic acid of the stomach should have a like effect in digestion. A second fact is, that fibrin cannot be detect- ed in chyle until this has passed the mesenteric 94 §89 glands. The first fact would seem to show that the stomach must change the arrangement of the elements of fibrin; and the second, that the function of the mesenteric glands in restor- ing fibrin as a constituent of chyle, must be analagous to the function of vegetables in pri- marily forming fibrin from inorganic elements. It would from these facts, considered in con- junction with that of coagulation, seem proba- ble, that the function of the mesenteric glands may be to recombine the elements of fibrin de- composed by the stomach, and restore them to their primary arrangement, to be subsequently held in solution by the muriatic acid. §89. Is there free Carbonic acid in blood, both arterial and venous ? The affirmative of the question is maintained by Muller, Carpenter, and numerous other phy- siologists of eminence. While coagulation is one of the prompt chemical changes of blood withdrawn from the vital influence, others still more prompt occur ; such as the reddening of venous blood by oxygen, and the darkening of arterial, by Carbonic acid. It has been al- ready shown that the very same chemical chan- ges result from the application of these gases to arterial and venous blood in, as out of the §89 95 body, (§ 22.) If venous blood be acted upon by atmospheric air out of the body, the ignition of the Hydrate of Carbon produces Carbonic acid gas, and reddens it, as when passing the lungs. This may exhibit all the appearances of preexisting Carbonic acid in the blood. So of arterial blood ; the Carbonate of protoxide of iron formed by the function of hsematosis in the lungs, if exposed out of the body to the in- fluence of oxygen, would evolve the Carbonic acid, (§ 61) giving to the arterial blood all the appearance of containing free Carbonic acid. From the well known affinity of free soda for Carbonic acid it seems fair to infer, that if this acid entered the blood vessels by the stomach, the two would at once combine as Carbonate of soda ; thus accounting for this compound as a constituent of blood. Moreo- over, facts show Carbonic acid gas to be a nox- ious agent in blood, as when absorbed in respi- ration. It may be objected that this result is produced by excluding Oxygen, which is the usual stimulus of the lungs. But the fact that Carbonic acid gas produces death much more suddenly than many other non-respirable gases, even when largely diluted by atmospheric air, seems to show that its absorption must con- 96 §90 tribute to its suddenly fatal effects. These facts and considerations seem to show, that free Carbonic acid is not a constituent of blood. § 90. Sudden death from air entering the jugular vein, explained. The Oxygen ignites the Hydrate of Carbon, and evolves Carbonic acid, which almost in- stantly reaches the pulmonic capillaries. This, as when entering from the pulmonic air vesi- cles, produces the like noxious influence, and accounts for sudden death. § 91. Animal fat a reserve of fuel for ca- lorification. Animal fat abounds in Carbon, and Liebig thinks it a reserve supply connected in some way with respiration and calorification ; al- though he has not explained how its Carbon is ignited. This is sufficiently shown by the pre- vious explanation of the manner in which Car- bon, derived from other sources, is employed in calorification. The large amount of fat which hybernating animals take into their retirement, supplies the necessary fuel for their long period of slumber. § 92. Heat of fever. In fever, the source of Carbon, by way of food, is mainly cut off. Emaciation is rapid, §93 97 showing prompt absorption of the fat. There is a constant correspondence of activity in the three great functions of respiration, circulation and calorification. The larger proportion of Carbon in animal fat than in ordinary food and the hurried respi- ration and calorification, constitute a combina- tion of causes, which could not fail of produc- ing a morbid degree of animal heat. As this store of Carbon becomes exhausted, the febrile heat necessarily moderates. § 93. Fecial physiology, as usually taught, comes in direct conflict with the views of re- spiration and calorification which have been offered. It has been handed down from phy- siologist to physiologist, as a settled principle, that the placenta of the foetus performs the usual office of the lungs in the adult; but, either this principle, or our whole theory of respira- tion and calorification, must be founded in er- ror. The single circulation of the foetus be- fore birth, and the anatomical structure of the placenta, show no provision but for veg- etable life; that is, to furnish and deposit, but not to carry off the refuse elements of the nutriment. There are no excretions,—no pul- monary or cutaneous vapors,—no Carbonic 10 98 94 § acid discharged, nor is there any change of color in the foetal blood as it goes to, and re- turns from the placenta. There can, conse- quently, be no formation of Hydrate of Carbon, as in the adult, for calorification, no necessity for any pulmonary apparatus to decarbonize the blood. The elements of growth must, hence, be prepared by the maternal vessels and furnished through the medium of the placenta, in office analagous to the roots of vegetables ; while the heat is furnished from the mother or from some other exterior source, as in incuba- tion. Until the lungs are set in play, the sys- temic capillaries cannot form, or send on for ignition to the pulmonary capillaries, the Hy- drate of Carbon for calorification. The capil- laries of the lungs in the foetus may, doubtless, as in the adult, perform the function of ha3ma- tosis, converting, by double decomposition, the free soda of the blood and perchloride of iron formed ia the mother's stomach, into the hy- drated peroxide of iron, that this may be in readiness for decarbonizing the vital fluids as soon as respiration commences. § 94. The sudden appearance of dots of red globules in the formation of new parts and vessels as these permeate the coagulable §95 99 lymph, admits a like explanation. The free soda and perchloride of iron being at the ex- tremities of the previously colorless vessels brought together, there undergo a double de- composition, and thus complete the red globule. § 95. The liver principally an organ of h&matosis. Physiologists have expressed very different views of the function of the liver, many believ- ing it principally an organ of excretion ; others that it is also an organ of hsematosis. That so- da is furnished by the gastric capillaries for the hepatic secretion, renders it probable that not only this important constituent of bile, but that various other materials are sent from the stom- ach and bowels to the liver for combination, during the process of chymification and chyli- fication. Moreover, the diversity of elements constituting bile, the slow secretion thereof during the intervals of meals and its rapid se- cretion during digestion, appear to indicate that various alimentary substances may be ab- sorbed for direct conveyance through the por- tal vein to the liver for new elaboration. That almost all the soluble parts of bile enter into the chylous fluids and are absorbed into the circulation, strengthens the belief that the prin- 100 §96 cipal function of the liver is to combine in the globule of bile, the materials from the food to fit them for the subsequent formation of chy- lous fluids and blood. § 96. An objection that Carbonic acid is evolved in the respiration of hydrogen and ni- trogen, answered. An objection to this theory of respiration and calorification has been offered, at first view very formidable, viz : that of the evolution of Carbonic acid gas when nitrogen and hydro- gen are respired. This fact seems to have confirmed Muller, Carpenter, and other distin- guished physiologists, in the belief that Car- bonic acid gas is an educt from the blood, in- stead of a chemical product of respiration. Muller expresses the belief that the experiments of Sir H. Davy and others upon warm blooded animals " are of no value," because they " can be kept in Hydrogen but a short time," and that their lungs " contain Carbonic acid at the commencement of the experiment." He thinks a long time necessary to such experiments, and cold blooded animals are accordingly made the subjects, because of their tenacity of life. But are experiments upon these more conclusive . This class of animals evolve far less Carbonic §96 101 acid than warm blooded, and live far longer without the presence of Oxygen ; while in some, respiration appears mainly performed by the skin. The amphibia remain submerged for a considerable time, the whale about an hour, without a new supply of atmospheric air. It can hardly be doubted that frogs and all such animals, can carry in the air cells a sufficient supply of Oxygen to last them during their stay under water. Upon breathing hydrogen or nitrogen, it is fair to infer that respiration would alike go on for some time, before the supply of Oxygen would be exhausted, when the same effects would occur as in warm blood- ed animals. Until these occurred, the Oxygen would oxydize the Hydrate of Carbon and form Carbonic acid to be thrown off from the lungs. But Muller also states that " frogs fall into a state of asphyxsia, when made to respire in hydrogen and nitrogen." Can it be reason- ably doubted that the asphyxsia occurs in both classes of animals from the like cause, the ex- haustion of the air cells of Oxygen 1 If not, oxydation of Hydrate of Carbon might obvi- obviously go on, till asphyxia suspended the re- spiratory movements in the cold bloded ani- mals. 10* 102 $97 CHAPTER XI. Analogies and differences between ani- mal and vegetable digestion and nutrition. § 97. We find in vegetable and animal flu- ids and solids the same compounds as the pro- ducts of their vital movements, viz : albumen. fibrin, casein, and compounds of iron. As ani- mals derive their food from vegetables, these compounds must be of primary vegetable ori- gin. Organic compounds arc all found in soils, especially in those rich in decaying ani- mal and vegetable substances. In vegetables. as in animals, their elements must be rendered soluble in order to ascend in their capillaries; whether or not vegetable digestion and nutri- tion consist wholly in an original elaboration of elements from inorganic nature. That some vegetables are essentially constituted from a primary elaboration of inorganic el- ements, is doubtless true ; but there can be lit- tle doubt that they also digest and deposit for nutrition, vegetable and animal compounds. In order to effect the necessary solution of the oxide of iron found in vegetables, some solvent like muriatic acid of the gastric juice of animals is indispensable. Common salt and water are $ 97 103 as necessary to vegetable as to animal life, and hence the wise Creator has provided that they shall always be in apposition in rain water, which contains common salt as a uniform con- stituent. The fact that fruit trees, which have been unproductive, will often yield abundantly by digging around them and depositing salt near their remote roots, is an evidence that salt is as necessary to vegetable as to animal di- gestion. Admit the truth of this deduction, and the explanation of the manner in which iron finds its way through the vegetable capil- laries to form a constituent of their solid or- ganism, becomes obvious. Double decomposi- tion of salt and water by the radicals of the roots of vegetables, would, as in animals, fur- nish muriatic acid to dissolve the iron, convert- ing it into the soluble perchloride, fitted for ca- pillary ascent; while soda would be simulta- neously formed, ready to reconvert the chlor- ide of iron into the peroxide, and also to re- form salt as soon as the iron reached the point of destination. The reason of salt being a uni- form constituent of vegetables, must be obvi- ous ; since when thus re-formed, there is no re- turn circulation, as in animals, to carry it off as an excretion. 104 §98 § 98. Formation of Hydrate of Carbon in vegetables. To form Hydrate of Carbon, according to all analogy, should require a like chemical ac- tion in vegetables and in animals. In animals we have shown (§ 82, Diag. 9) that each of three binary compounds yields an element by, what may be properly designated, triple de- composition, to form this compound for calori- fication. So in vegetables, carbonic acid (C), muriatic acid (II CI) and soda (Na O) each yields an element to form Hydrate of Carbon ; thus, DIAGRAM 14. Carbonic \ n \______________ I Oxygen to th* ■ i CHO jTLr^in-or acid \ Cl-^^^^ * H-v<1- Car" C A S O^" ^"^\^ Soda \ Na----------—^>Na CI Salt. This is what may be called triple, or vital decomposition; each of three binary inorganic compounds yielding an element to form the first and simplest triple compound of vital che- mistry. We have shown by former facts that the very same carbonaceous combustible i§ §99 105 formed by diffusing carbonic acid in arterial blood, out of, as in the animal; and that this combustible Hydrate of Carbon must in both instances have been formed by the triple de- composition just stated. Muriatic acid and soda formed by the radi- cles of vegetables, carry up in solution the ele- ments of vegetable growth, and evolve them where their double decomposition furnishes the elements of water to form the Hydrate of Car- bon, as in animal nutrition (Diag. 9, §82). Here also, there being no return circulation (as in animals) the Hydrate of Carbon is de- posited as the essential, solid structure of plants (analagous to the bones of animals,) while in animals, the Hydrate of Carbon is used in their functions of calorification and respiration. These functions in animals, as compared with vegetables, seem to be superadded and interme- diate between those of digestion and nutrition. § 99. Another difference of animal and veg- etable physiology has already been noticed, that of the Oxygen of the Carbonic acid being thrown to the atmosphere in vegetables, but not in animals. This triple decomposition of Soda, Muriatic and Carbonic acids does not occur except when the vegetable is subjected 106 §99 to the influence of the sun's rays, while Car- bonic acid, undecomposed, passes at other times from the leaves. This is beautifully il- lustrated in the growth of water plants under ice, as before noticed (§75). Vegetable growth takes place even where the sun's rays arc not admitted as in mines; and it is doubtless true that it continues during the night, although the Carbonic acid is not then decomposed to form Hydrate of Carbon. This growth of vegeta- bles in the absence of light, may be illustrated thus : DIAGRAM 15. Carbonic \ .-. f y. _, , . acid j l----------" ° atmosphere. Muriatic ( H____________H The Carbonic acid (C) instead^ of yielding Carbon to form Hydrate of Carbon at the leaves, as when the sun shines (Diag, § 98), is given off unchanged to the atmosphere, while the water (H) and salt (NaCl) recom- posed, remain as constituents of the plant. Any organic elements, such as fibrin, albumen, §100 107 or casein found in soils, or the inorganic ear- thy elements, such as iron, lime, &c, are ren- dered soluble by the muriatic acid and soda at the roots (§ 83 Diag. 10). After ascending in the sap they would be deposited for the nu- trition of the vegetable after the recomposition of salt and water, as in the nutrition of animals (Diag. 12, § 85). The water thus re-formed, remaining fluid, instead of helping, as when the sun shines, to compose solid Hydrate of Carbon, accounts for such vegetables as grow in the dark being more suculent and less solid, than others. § 100. These analogies of animal and veg- etable digestion and nutrition, show why vege- tables contain the alkalies or chlorides, as con- stituents of their solid organism, while animals do not ; these throwing them off as excretions, after the soda and muriatic acid have served their office of carriers. INDEX. Alkaliet, why found in vegetables, 107. Analogies, between animal and vegetable digestion and nutrition, 102. Animal heat, functibn of, 36. immediate cause of, 38. old views of, 3, 37. proportional to the development of the pulmo- nary apparatus, 41. proportional to the amount of Carbonic acid evolved, 42. pulmonic and cutaneous capillaries in, 90. regulation of, 40. systemic capillaries in, 88. Atmospheric air, composition of, 2. ----change of by respiration, 12. Bile, contains soda, 71, 77. Blood, arterial thinner than venous, 5. ----to what owing, 10. changes produced in by respiration, 1. changes in the systemic capillaries, 20. change of color in, 5. ----to what owing, 20. carbonaceous pigment of formed in the systemic capillaries, 5. decarbonized by transmission through the lungs, 5. pigment of venous blood, 20. 11 no Capillaries, harmony of in calorification, 40. pulmonic antagonists of systemic, 10. two sets of, and their functions, 45. Caloric, sec heat. Calorification, see animal heat. function of, 36. Carbon, burned in the lungs, 15, 31, 32. amount thrown off from the lungs, 24. source of in the venous pigment, 24. Carbonic acid, agency in vital phenomena, 3. decomposed by vegetables, 5, 104. decomposed in the systemic capillaries and re- composed in the lungs, 21. disposition of its oxygen by the systemic ca- pillaries, 55. evolved in the respiration of hydrogen and ni- trogen, objection answered, 100. evolution by plants in the dark, 106. in food and drink, 54. in the atmosphere, 2. source of in the systemic capillaries, 52, 53, 58, 64. Chlorides, why found in vegetables, 107. Coagulation, explained, 92. Coal, mineral, 28. Combustion, in the lungs, 31, 32. spontaneous of drunkards explained, 43. Death, from air entering the jugular vein explained, 96. Diagram 1. Carbonic acid formed in the lungs by the oxi- dation of Carbon, IS. 2. Carbonic acid and water formed, in the Ill lungs, by the oxidation of the Hydrate of Carbon, 19. 3. Latent heat heat of oxygen how supplied in the growth of vegetables, 27. 4. Heat evolved in the systemic capillaries in the formation of Hydrate of Carbon, 38. 5. Formation of Hydrated peroxide of iron and Hydrate of Carbon in the systemic capilla- ries, 59. 6. Protoxide and Carbonate of protoxide of iron formed by the pulmonary capillaries, 64. 7. Perchloride of iron formed in the stomach,74. 8. Perchloride of iron and soda, converted into 6alt and Hydrated peroxide of iron, in the pulmonary capillaries, 75. 9. Source of the elements of water to form the Hydrate of Carbon, 81. 10. Gastric, hepatic and duodenic secretion and digestion, 84. 11. Pulmonic capillaries in the function of hs- matosis, 86. 12. Systemic capillaries in the function of ca- lorification and nutrition, 88. 13. Pulmonic and cutaneous capillaries in the functions of excretion and calorification, 90. 14. Formation of Hydrate of Carbon and dis- engagement of oxygen by vegetables, 104. 15. Vegetable growth in the dark, 106. Digestion, 84. Excretion, pulmonary and cutaneous capillaries in, 90. Facts, in physiology, 1. 112 Fat, use in calorification, 96. Fatal physiology, 97. Fever, heat of, 96. Functions, relation of gastric and pulmonic, 67. of digestion, hepatic secretion, calorification and nutrition, connection of, 77. of the liver, 99. Hatmatosis, function of pulmonary capillaries in, 86. Heat, absorbed by the oxygen evolved from leaves and source of, 26. absorbad in the formation of watery vapor and Carbonic acid in the lungs, 12,16. capacity for, 8. latent and free defined, 8. latent heat of gases, 8. ----of water, 9. laws of, 7—9. Hydrate of Carbon, 17. density of, 28, 32. formed in the systemic capillaries, 59. formation in vegetables, 104. a solid, 28. uses in vegetables and animals, 30. Inferences, physiological and pathological, 92. Iron, in blood, 56. carbonate formed ia the pulmonary capillaries, 64. hydrated peroxide formed in the lungs, 74. peroxide formed in the systemic capillaries, 59, ----decomposes chyle and blood, 63. primary source of, 73. perchloride formed in the stomach, 74. 113 Lignin, composition of, 5. Liver, function of, 99. Lungs, not the only generators of heat, 36. changes produced by as an organ of hsemato- 613, 61. Mesenteric glands, probable function of, 93. Muriatie acid, analogy of its formation to the decomposi- tion of common salt by electricity, 69. composition of, 68. connection between its formation in the stom- ach and that of hydrate of carbon in the sys- temic capillaries, 67. a carrier of nutritive elements, 78. formed in the stomach, 67, 68, 69. Nutrition, 79. systemic capillaries in, 88. Oxygen, a component of the atmosphere, 2. capacity for heat, 14. evolution of, by plants, 104. disposition of in the systemic capillaries, 55,56. Physiological and pathological inferences, 92. Pulmonic capillaries, antagonists of systemic, 10. Red dots of blood, in the formation of new parts, 98. Red globule completed, 75. Roots of vegetables, how they effect the solution of nutri- tive matters, 102. Salt, why a constituent of vegetables, 103. Secretion, gastric, hepatic and duodenic, 84. of muriatic acid in the stomach, 68. of soda by the stomach, 69. 114 Soda, analogy of its intermittent secretion to a fact in veg- etable physiology, 71, 72. secreted by the gastric capillaries, does not en- ter the stomach, 70. passes through the liver into the bile and blood, 71. uses in bile, 77. Synopsis, of the circle of chemical changes in animal life, 83. Systemic capillaries, antagonists of pulmonic, 10. Vapor, pulmonary, 4, Vegetables, action upon carbonic acid, 5, 104. analogies to animals, 29, 38, 102. differences from animals, 38, 102. growth of illustrated, 27. how take up nutritious matters, 102. Venous blood, pigment of, 6, 20. Woody fibre, 5. Water, source of in the formation of hydrate of carbon, 81. ERRATA Page 9, line 6, for § 11 read $ 10. Page 38, line 15, for $ 31 read § 30. Page 103, line 15, for radicals read radicles. 1 ll " 'J .• V* ■ 1 *.' Spencer, Thomas, Lectures on animal heat WZ270S7461 1845 Condition before treatment: The book was in fair condition. The cloth casing had failed along the entire length of both spine hinges. The front cover was detached; however, sewing of the text block was intact. There was moderate foxing throughout. A small fragment of the spine label was found inside the book. Conservation treatment: The spine was lined with tengujo Japanese paper using wheat starch paste. A second lining of acrylic-toned sekishu Japanese paper was then applied using an approximate 1:1 mixture of methyl cellulose (Bookmakers) and polyvinyl alcohol (University Products). The edges of the covers were lifted and the tongues of the spine lining paper were inserted in order to secure the hinges. 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