!■.•!'.(A'll'ill B' v. ■,.■/> 'Vi'. *-'^ ■» :r.t'.''!i'i«.'i't'Vl».\l \'rrff.'........,.............. 133 59. The Leech (Ilirudo officinalis) .......................................... 133 60. Suckers of Blue-Bottle Fly............................................... 133 61. " Yellow Saw Fly............................................... 133 62. " Great Water Beetle.......................................... 133 63. Motion of Fishes............................................................ 134 64. Vertebra? of Serpent....................................................... 136 65. Ribs of Serpent.............................................................. 136 66. Sucker of Lacerta Gecko.................................................. 137 67. Penguin........................................................................ 138 68. Tail of the Whale.....................................................'....... 139 69. Wing of Bat (Harpya Pallasii) .......................................... 140 70. Action of Leaping........................................................... 141 71. The Kangaroo................................................................ 141 72. The Podura................................................................... 142 73. Cray-Fish...................................................................... 143 74. Poulp or Octopus............................................................ 146 75. Head and Eyes of Bee..................................................... 147 76. Lateral and Full View of Eyeball of Owl.............................. 150 77. Ears of Peregrine Falcon, Day Owl, Tawny Owl, Long-eared Owl, and Barn Owl...................................................... 154 78. Sucking Tube of Nemestrina Longirostris............................ 155 79. Variously-formed Antennse of Insects.................................. 156 80. Bill and'Tongue of Wild Duck........................................... 158 81. Diagram of Sonorous Undulations...................................... 170 82, 83. Sonorous Undulations in Open Tube.............................. 171 84. Membranous Tongue........................................................ 173 85. Front View of the Larynx................................................ 174 86. Perpendicular View of the Larynx..................................... 174 87. Side View of the Larynx.................................................. 177 88, 89. Muscles of the Larynx................................................ 179 90. Organ-pipe.................................................................... 183 91. Action of Organ.............................................................. 183 92. Artificial Action of Dead Larynx....................................... 185 93. Section of Tongue, Pharynx, and Larynx of Porpoise............ 201 LIST OF ILLUSTRATIONS XI page Fig. 94. Larynx of Camel laid open............................................. 203 95. Larynx of Horse........................................................... 203 96. Lateral and Posterior View of Didelphis Opossum............... 204 97. Larynx of Cat.............................................................. 204 98. Lateral View of Larynx of Chimpanzee.............................. 205 99. Section of Inferior Larynx of Birds.................................. 206 100. Vocal Organs of Rana Temporaria.................................... 215 101. Thoracic Spiracle of Blue-Bottle Fly................................. 217 102. Thoracic Spiracle of Humble-Bee.................................... 217 ON THE NATURE, CONNEXIONS, AND USES OF THE GREAT DEPARTMENTS OF HUMAN KNOWLEDGE. Before man became a philosopher he was a discoverer; and in his capacity for discovery, and for reasoning on its results, he differs widely from all other beings. In the organic world there is no history but the history of man. The doings of one pair, or of one colony of inferior animals, however sagacious, are the doings of generation after generation. Birds build their nests in our gardens and shrubberies as they built their nests in Eden; the bees in our hives construct their honeycomb, as the bees of Samson's time did that which he took from the lion's carcase; and the beavers of Canada rear their dams, and huts, and burrows at this day as they have done ever since their species was created. How different is the account of man's proceedings from the time of his first appearance upon the earth ! What variety in his modes of clothing himself— of building habitations—of defending himself from beasts of prey— of transporting himself from place to place—of subjecting to his power the animate and the inanimate Creation ! In the first advances made by primitive man, his capacity for the attainment of knowledge shines forth almost as vividly as in the discoveries made during his most advanced state of civilization. To draw a distinction between the faculties of man and the faculties of the highest among the animal creation has always been a task of much difficulty; and yet how frivolous appear the attempts to trace a proximity between endowments but outwardly similar, the moment the actual fruits of man's faculties are contrasted with the nothing- ness of effect produced by any other species on the surface of the earth! It can hardly indeed be said with truth that man's mere 2 (13) 14 THE PROMINENT GROUPS OF HUMAN KNOWLEDGE. senses are more perfect than those of the animals which stand near him in the scale of being; but it is an obvious truth that he has a capacity to originate ideas which mould the observations of sense on a higher and more perfect type. In man's early progress, the rudiments of almost every branch of knowledge may readily be traced. His intellectual pre-eminence in the animal kingdom may be reduced to a few prominent heads — namely, to his great capacity, in the first place, for appreciating the abstract relations of number and quantity; secondly, to his exact perception of the resemblances and the differences of objects of sense; thirdly, to his inherent disposition to form objects and appearances, which agree even in one quality or mode of presenting themselves, into groups—which are afterwards to be recognised as possessed of a unity of character; fourthly, to his complete feeling of the distinct- ness of his bodily self from the rest of nature; to his instant percep- tion of its slightest change of position or attitude; and, to his almost unlimited voluntary power over its movements, so that it becomes an exact measure of the numerous relative properties of surrounding bodies; and, lastly, to his capacity for looking inwards upon himself, and taking note of the special effects produced on his internal nature by persons, and things, and circumstances. With these several heads the great departments of human knowledge, as we shall discover, intimately connect themselves. Science.—The systems of knowledge founded on intuitive con- victions of the human mind, to which the name of science is cur- rently given, are, in particular, the Abstract or Mathematical Sciences. Those collected from the perceptions of sense, with or without the aid of instruments and of the abstract sciences, and methodised by man's faculty of grouping individual appearances into compound unities, are the Inductive Sciences, under which falls the chief part of physical knowledge — namely, several branches of Natural Phi- losophy, the whole of the Electrical Sciences, Chemistry, and some parts of Physiology. Those founded in the same manner upon the organic kingdoms of nature, with the aid of certain fundamental intuitive convictions of the human mind, constitute the Physiological sciences. Those directly deduced from man's contemplation of the subjects of his consciousness, and the report of others as to the results of their reflections on what consciousness has taught them make up the Psychological sciences, Metaphysics, Ethics, &c. Those drawn from the contemplation of man in his social state, as bearing on the welfare of the community, are represented chiefly by Statistics and Political Economy. Those which rest on moral evidence in its three degrees of possibility, probability, and moral certainty,'rather than on the evidence of sense, are Government, Law, Medicine Taste, Criticism, &c. Those which are formed by comparing the VALUE OF THE TERM SCIENCE. 15 substances composing the exterior of our planet, and the individuals of the animal and vegetable kingdoms, and by marking their resem- blances and differences, constitute the Natural History of the three Kingdoms of Nature. And lastly, the systems of knowledge derived from the observation of the minute structure of minerals, plants, and animals, and the grouping of certain frequently recurring resemblan- ces into separate unities, each denoted by a single expression, con- stitute what have been termed the Descriptive Sciences, such as ZftCtasy, or Anatomy commonly so called, Phytotomy or Vegetable Anatomy, and Crystallography. Such, then, is an enumeration of the great branches of human knowledge, of which it is our intention in the present undertaking to treat. But, at present, let us examine more narrowly the resem° blances and differences of the evidence on which these several branches of knowledge depend, and endeavour to ascertain their con- nections and the precise uses to which each is subservient. We will premise, however, that although the name of science is currently applied to the more profound parts of man's studies, the term has no definite signification. In particular, it is employed indiscriminately to denote those systems of knowledge which are deduced from the inherent or intuitive convictions of the human mind, as well as those systems of knowledge which are built upon the perceptions of sense, variously grouped into a whole, because of the agreement of the members of each group in one mode of present- ing themselves. But vague as is the term science, it is too firmly rooted to be rejected. Geometry. — When any part of Mathematics, for example, Geo- metry, is compared with some one of the Inductive Sciences, such as Chemistry, it is discovered how loosely the term science must be used to apply equally to both. For this purpose, we select for con- trast the properties of the alkalies, on the one hand, and on the other the remarkable property of the right-angled triangle, that the square of its hypotenuse is equivalent to the sum of the squares of the two sides. The alkalies — that is, the pure caustic alkalies — are freely soluble in water and in alcohol; each saturates its owu proportion of every known acid; and were a new acid discovered, it would only be necessary to ascertain how much of it is required to saturate a given quantity of one of the alkalies, to pronounce how much of each of the others that same quantity would saturate ; the alkalies, besides, form soaps with oils; they change vegetable blue colours to green, and yellows to brown. By means of these properties, the chemist is able to detect the presence of any pure alkali in his analysis; and such is one of the great objects which the science of Chemistry has in view. But the point which we wish chiefly to be 16 VALUE OF THE TERM SCIENCE. borne in mind is, that from the whole history of Chemistry no reason can be elicited why an alkali should be soluble in water rather than insoluble, or soluble in alcohol rather than insoluble; why it should combine with oils or acids rather than resist combination with them; why it should change vegetable blues to green, and yellows to brown, rather than to any other colour. In the conception of properties, as belonging to the alkalies, opposed to all those just enumerated, there is nothing contradictory. In short, there is no reason why any pecu- liar property of an alkali, so far as the human faculties can compre- hend, should not, in the arrangement of nature, have been the oppo- site of what it actually is. And the same may be said of all those laws and properties in nature which are discovered solely by observation. On the contrary, when the several steps are considered by which an equality is proved between the square of the hypotenuse in a right-angled triangle, and the sum of the squares on its two sides, there is not discoverable, in the whole course of the demonstration, any single truth, the opposite of which does not involve a contradic- tion, so that, independently of any observation, the human mind is, by its very nature and constitution, compelled to extend to them an absolute and unconditional belief. The square described on the hypotenuse being cut by a straight FJQ> j# line in such manner as divides it into two distinct parallelograms, it is at once shown by the undeniable propo- sition, that if two equals have each an equal quantity added to them, the sums are equal; and then by the un- deniable proposition that the doubles of equals are equal to one another — that each of the two divisions of the square on the hypotenuse is equal to one of the squares on the two sides of the triangle. The proof of the theorem just re- ferred to, may readily be understood even by one unversed in the elements of geometry. With the meaning of parallel lines every one is familiar. Here are three pairs of parallel lines; one pair running from side to side, and Fig. 2. two Pau's between them, forming two parallelograms of rectilinear figures, the opposite sides of which are par- allel. These two parallelograms stand upon the same base, and lie between the same parallels; and when this is the ease parallelograms arc equal — that is, the area of the more EVIDENCE OF MATHEMATICAL TRUTH INTUITIVE. 17 upright of these two figures is equal to the area of the more slanting figure. And the truth of this will appear at once, by considering how the whole figure, composed of the two parallelograms taken together, is made up. If from this whole figure the more upright of the two parallelograms be taken, a triangle remains; and if from the whole figure the more oblique parallelogram be taken, another triangle remains. But these two triangles are equal, their corre- sponding sides and angles being equal; hence the parallelogram which remains, after one of these triangles is taken away, must be equal to the parallelogram which remains after the other triangle is taken away. Such, then, is the proof of the proposition, that par- allelograms between the same parallels, and standing on the same or an equal base, are of the same area; and as every parallelogram is divisible into two equal triangles by its diagonal, it follows that triangles standing on the same base, and between the same parallels, are of the same area. Let us now return to the figure on the preceding page, represent- ing the squares on the three sides of a right-angled triangle. In this figure there is a triangle standing on the same base, and between the same parallels as the square on the left-hand side of the triangle, and there is a triangle standing on the same base, and between the same parallels as the larger of the two parallelograms into which the square of the hypotenuse is divided ; but these two triangles are equal, owing to the equality of two sides, and the contained angle; heuce the square, which is equal to twice the area of one of these equal triangles, is equal to the parallelogram, which is equal to twice the area of the other triangle. And by the same mode of reasoning, the square on the right-hand side of the triangle is proved to be equal to the lesser of the two parallelograms into which the square of the hypotenuse has been divided. But in the whole range of Geometry the proposition holds good, that every stage of the proof is a truth, the opposite of which in- volves a contradiction ; and therefore, that it is itself a necessary article of belief. In short, it is incontrovertible that mathematical truths are necessary truths. Geometricians use various ways of con- vincing us of this: where two figures are necessarily equal, as a consequence of certain parts in one being known to be equal to corresponding parts in the other, the method of superposition is frequently employed; that is, we are required to fancy one figure placed upon the other, and then, mentally, to bring about their perfect adaptation : the parts, previously known to be the same m both being properly adjusted, the other parts, by this method, are shown to be necessarily coincident. There is, however, nothing of a mechanical or experimental character in this process. the figures are not bodily transported from one place to another; the whole is a 18 OBJECTS OF MATHEMATICAL SCIENCE. purely mental operation; and it is the mind, not the eye, that sees the complete adaptation of the two. Some superficial thinkers cavil at the peculiar character assigned to mathematical science, by reference to the very proposition above adduced; saying that the fact as to the equality of the squares, was discovered by observation, and the demonstration afterwards invented; as is proved, they further say, by the tradition, that Pythagoras sacrificed a hecatomb in gratitude to the gods, for having inspired him with its discovery. Thence, it may be sup- posed, they would infer, that all mathematical knowledge is founded on observation, and not on intuitive convictions of the human mind. It is evident, however, that many truths, susceptible of a mathe- matical demonstration, like that respecting the squares on the sides of a right-angled triangle, are discoverable by observation; and doubtless, in the early progress of geometry, this method was much employed to discover the course to be adopted for the extension of this branch of knowledge.' But had geometry, or any other part of mathematics, been confined to this method of investigation, would it ever have attained the rank of being the handmaid of inductive science—the very means by which observation has been made capa- ble of deciphering the system of the universe ? The distinction between mathematical truth and inductive science, so clearly pointed out by the contrast between the properties of the alkalies, and the remarkable properties of the right-angled triangle above referred to, is irrefutable. Magnitude. — We have not hitherto referred to the great object which mathematical science has in view, namely, to supply a mea- sure by which all magnitudes may be rendered commensurable. A few words will give the steps by which this is accomplished in a suf- ficiently clear light. By the propositions readily reducible to the truth, before referred to, that two triangles are equal, if their corresponding angles and corresponding sides be equal, any two rectilineal figures, however dissimilar, may be proved to be equal if they really be equal, or un- equal if they be unequal. And this may be described as the first great step in Mathematical Science; because, by means of the equi- valence of triangles, all rectilineal figures are rendered commensu- rable. The next step in Mathematics is to find the measure of figures bounded by curved lines. For example, to find the area of a circle in rectilineal measure. The attempts to find the area of a circle in rectilineal measure gave rise to the proof by the method of " exhaustions," as it is termed. OBJECTS OF MATHEMATICAL SCIENCE. 19 The area of a circle is a quantity intermediate between the area of a polygon circumscribing the circle, and that of a similar polygon inscribed within the circle. If the number of sides in each of these polygons be successively increased, the area of the interior polygon is continually aug- mented, while the area of the exterior polygon is continually diminished, — plainly, however, on this condition, that though the area of each conti- nually approaches nearer and nearer to the area of the circle, that of the exterior polygon can never fall short of the area of the circle, nor that of the interior polygon exceed the area of the circle. Thus, as the sides of these polygons may be increased without any limit, the difference between the area of the exterior polygon and the area of the interior polygon is continually becoming less and less, or con- tinually approaching, without reaching, to nothing; and though the rectilineal polygon cannot be made an exact measure of the curvi- lineal circle, yet it can be made to approach to its measure with any required degree of nearness. It may be remarked here, also, " that this operation enables the unlearned reader to understand what is meant when it is said that unity divided infinitely = 0. It was another step in Mathematics when the area of curvilineal figures came to be expressed exactly by the areas of rectilineal figures. What are called the "lunes" of Hippocrates, known to the ancients, afforded one of the earliest examples of this coincidence. To exhibit this property, a right-angled triangle is inscribed in a semicircle, and a semicircle described on its base and its perpendicu- lar. The portions of the two last semicircles which lie without the original semicircle, are found to be equal to the area of the triangle. The following is the kind of proof on which this proposition rests. It is found that if semicircles are de- FlQ 4_ scribed on the three sides of a right- angled triangle, the area of that de- scribed on the hypotenuse is equal to the joint areas of the semicircle on the base and that on the perpendicu- lar. But the greater semicircle in the annexed figure consists of the right- angled triangle and the two arches of that semicircle cut off by the sides of the triangle, and the joint areas of the two lesser semicircles consist of the two lunar spaces cut off by the greater semicircle and the two arches of that great semi- o ./^ 20 MEASURE OF CURVILINEAR MAGNITUDES. circle just mentioned; hence, if from each of these two equal quan- tities, the common quantity in both, namely, the arches of the great semicircle cut off by the sides of the triangle, be taken away, there remains on the one hand the triangle, and on the other the lunar spaces of the lesser semicircles, taken together, equal to each other. The propositions, on which the proof of this correspondence in equality depend, are easily understood. The circumference of a circle is proportional to its diameter — a proposition which may easily be shown to be a necessary consequence of the geometrical definition of proportion. It is not, howevei", so obvious that the area of one circle is to the area of another circle, as the square of the diameter of the first circle to the square of the diameter of the second circle. It is, however, a very im- portant proposition, for, if a person supposed that the areas of circles are simply proportionate to their diame- ters, he might commit many serious errors. For ex- ample, if he wished a tube, as a gas-tube, twice the capacity of an- other tube, and desired it to be made of equal length, but twice the diameter, it would turn out to have four times the capacity; for the square of a line eight inches long consists of sixty-four square inches, while that of a line four inches long consists of only sixteen square inches. That the areas of circles are not to one another as their diameters, is a truth of which the learner may easily sat- FlG' 6# isfy himself without any knowledge of Geo- metry ; thus : let a circle be described with any diameter, and within it let two circles be described, with the diameter of each only half that of the outer circle; then if a circle, with double the diameter of another, were no more than double that of the other in area or surface, it is plain that the two inner circles would just fill up the outer, which is at once seen to be impossible. It is, however, worthy of remark, that the circumference of the outer circle would be exactly equal to the two circumferences of the inner circles, which is only one among the many interesting and unexpected truths that Geo- metry presents. But the great progress made in this part of Mathematics has arisen from the investigation of the areas produced by the higher order of curves, as of the conic sections, exemplified in the ancient EVIDENCE OF THE PROPERTIES OF NUMBER. 21 discovery that a parabola is equal to two-thirds of its circumscribing parallelogram. ° But it would be superfluous to carry these illustrations further, since it already sufficiently appears what is the proper object of Mathematics, and that the evidence employed in this Science uni- formly consists of propositions, the reverse of which, according to the constitution of the human mind, involves a contradiction. Number. — Our observations have been confined hitherto to what rdates to magnitude; but the doctrine of number is in no respect different. That 2 and 2 make 4, and that 2 taken from 4 leave 2, are unquestionably intuitive truths —they must be believed; they are necessary truths, because the opposite propositions involve a con- tradiction. But the truth that 10 times 10 make 100, rests on the same kind of evidence. One repeated a hundred times makes 100. Observation is not required to prove 10 times 10 to be 100; it is merely required to discover if what is called 100 be 100. If, in the primitive state of our race, one man, on giving another figs or dates, held up the fingers of both hands ten times, he who received them would count them, not to ascertain if 10 times 10 were 100, but to discover if he who gave the fruit had spoken truly as to the number. Mathematical Evidence. — All Arithmetic, then, rests on the same evidence — all its truths are necessary; and the same may be said of Algebra, Logarithms, and the Differential Calculus. Alge- bra may be described as Arithmetic carried on by symbols; so that the kind^ of operation is constantly indicated, but not actually per- formed till the relation between the given quantities and the quantity sought, be reduced to its simplest possible form. Logarithms depend on what seems a singular property of numbers; yet that property is as certainly deducible from necessary truths as any truth in Mathe- matics. If two series of numbers stand respectively in Geometrical and Arithmetical ratio, it is found that the product of any two num- bers in the Geometrical series may be found by adding the corres- ponding numbers in the Arithmetical series, and then taking the number in the Geometrical series which stands opposite: and this is the product sought. Logarithms.—The most difficult and complicated arithmetical operations may be performed with ease and expedition by means of Logarithmic tables; and thus multiplication is reduced to addition, division to subtraction, evolution to multiplication, and the trouble- some process of involution, or the extraction of roots, to simple division. Astronomy owes much of its pre-eminence, as an exact science, to the discovery of Logarithms, as, without their aid, it would have been almost impossible to have made the calculations necessary to confirm its laws. The astronomer reduces his algebrai- 22 MEASUREMENT OF INACCESSIBLE HEIGHTS. cal formulae to a form adapted for logarithmic computation; and his assistants, by the simplest rules of arithmetic, are thus enabled to compile the Nautical Almanac, without which the commerce of our great nation would be nearly destroyed — the Nautical Almanac and a table of logarithms being as essential to the mariner as his chart and compass. Proportion. — To exhibit a tithe of the uses to which the sciences of quantity and number can be applied, would fill a volume. Still the only practical use of these important sciences, is the measurement of quantities before unknown. The great instrument in all the de- partments of abstract science is proportion; thoroughly to under- stand which is to possess an instrument of knowledge applicable to almost every situation in life. When Thales of Miletus travelled into Egypt, 600 years before Christ, and saw the Great Pyramid, he Fig. 7. was curious to determine its height, which hitherto it had been deemed impossible to ascertain. Observing the shadow of the pyra- mid as the sun shone upon it, stretching far in the opposite direction, he struck his staff upright in the sand; and finding the shadow which it cast to be exactly its own length, he rightly concluded that the shadow, measured from the middle of the base of the pyramid, must equal in length the height of the pyramid. He paced the shadow, and found its length to be 270 paces, or about 500 English feet. Pliny, who relates this anecdote (lib. xxxvi. 17), expressly says that Thales measured the shorter shadow at the time when it was of the same length as the staff. But although equality in length of the shadow and the body may be allowed to be necessary for the discovery of this mode of mensu- * MEASUREMENT OF HEIGHTS WITHOUT PROPORTION. 23 ration, it would quickly appear without any necessity for experiment, that whatever relation the shadow bore to the staff, the same relation of magnitude would the shadow bear to the height of the pyramid. The three things requisite are, the measure of the shadow of the staff, the measure of the shadow of the pyramid, arid the measure of the staff itself. But, to solve this more complex problem, the knowledge of proportion is necessary: namely, that when of four numbers the first two bear the same analogy to each other as the last two to each other, the first of the four, multiplied by the last of the four, is equal to the second multiplied by the third; or, as it is usually expressed, the product of the extremes is equal to the pro- duct of the means:—or 4 : 16 : : 20 : 80—that is, 4 is to 16, as 20 to 80; but the product of the extremes, 4 and 80, is 320; and the product of the means, or middle numbers, 16 and 20, is also 320. But when three numbers are known, and a fourth is sought in the same relation to the third which the second holds to the first, it is plain that the product of the means can be obtained, and that that product being also the product of the extremes when both these come to be known, and being divided by the first extreme, the second extreme will be obtained : that is, if in the above formula 16 and 20 be multiplied together, and the product divided by 4, the fourth number, the second of the two extremes, or 80, will be obtained. And this rule of proportion prevails throughout the whole range of the sciences of magnitude and number. In every kind of mea- surement proportion plays its part, with the exception of that which is of the rudest kind. In the measurement of the height of the Fig. 8. Great Pyramid by Thales, the idea of proportion is involved, al- though hardly brought out into relief. We will cite another example of the measurement of a height without distinct reference to propor- tion. The height of a tower or pillar—no matter how high—which 24 MEASUREMENT OF HEIGHTS WITHOUT PROPORTION. stands on a level plain, and the foot of which is accessible, can be measured as soon as men have discovered that in a right-angled tri- angle, the sides of which are equal, each of the other two angles is equal to half a right angle, and the perpendicular equal to half the hypotenuse. If the perpendicular line in a right-angled triangle re- present a tower, it is evident that its height is equal to half the hy- potenuse, or side opposite to the right angle at A. Thus, if a person setting out from the foot of the tower pace the distance to the point at which the top of the tower is seen at an elevation of 45°, or half a right angle, the number of paces he has taken indicates the height of the tower. Trigonometry. — The usual mode of determining heights is by the rules of Trigonometry, without any necessity for the angle of elevation being of a particular number of degrees. When a tower is accessible, the angle BC A is measured, and the base of the triangle C B; the angle at B is known, being a right angle, and the angle at A is found by subtracting the angle at C from 90° or a right angle; because since the three angles of every triangle are to- gether equal to two right an- gles, the angles at C and A are together equal to one right angle. When the foot of the tower is inaccessible, the angle G F E is measured, then the space FDand the angle FDE; the angle EFD is found by sub- tracting G F E from two right angles, since every straight line falling on another straight line forms with it two angles, to- gether equal to two right an- gles. But when the angles D and F in the triangle EDF are known, the angle at E is easily found by subtracting the sum of the angles D and F from two right angles. But as a general rule in Trigonometry, when out of the three sides and three angles of a triangle, any three, except the three angles, being given, the remaining three can be determined. Hence the length of the'line AB in the triangle ACB, or the height of the tower, can be so dis- Fig. 10. LAWS OF MOTION. 25 covered; and in the triangle FDE the length of EF can be disco- vered, as preliminary to the same steps. Motion. — The laws of motion, which make up so important a part of Natural Philosophy, stand at once on a different footing from mathematical truth, and from the principle of gravitation. ° It is common to enumerate three laws of motion. The first is, that a body under the action of no external force will remain at rest, or move uniformly in a straight line. The second, that when a force acts upon a body in motion, the change of motion in magnitude and direction is the same as if the force acted upon the body at rest. The third law of motion is, that when pressure communicates motion to a body, the momentum generated in a given short time is propor- tional to the pressure, or, as given by Newton in a more general form, action and reaction are equal and opposite. In order to form a correct notion of these laws, we must have definite ideas of bulk, force, velocity, motion, and pressure, as well as the modes of measuring them. Newton defines the mass of a body to be the product of its density and its volume; and he deter- mines the mass by its weight, because he found, by most accurate experiments with pendulums, that the mass is proportional to the weight. We see that all bodies placed above the earth's surface have a tendency to fall, and exert a force upon whatever support prevents them from falling; this force we term pressure, and the measure of this pressure is weight—bodies being said to be of equal weight, if they produce equal pressure on their support; consequently weight is a measure of the earth's attraction for heavy bodies; but, in assuming weight to be a measure of mass, or the quantity of matter contained in a body of given volume, we clearly assume that the earth's attraction is the same for all kinds of matter; and that a cubic inch of gold weighs more than a cubic inch of copper, because the former contains more particles of matter than the latter, and not because the earth has a more powerful attraction for gold than copper — an assumption abundantly confirmed by experiment. Hence weight becomes a measure of pressure, and consequently of force producing pressure. We can also estimate force, in another way, without reference to mass, pressure, or weight. According to the first law of motion, a body can only move by the action of some ex- ternal force; now, the space through which it passes in a given time will afford us a measure of its velocity, which is only a term for the quickness or slowness of its motion; and the velocity acquired in any given time will afford us a measure of the force which produces the motion of the body. Neglecting the resistance of the air, it is found that all heavy bodies, how different soever in weight, fall through the same space, and acquire the same velocity at the end of any given interval of time. It is clear, therefore, that the measure 3 26 LAWS OF MOTION. of a force, by the velocity it generates in a given time, in no way involves any consideration of the mass, and must therefore differ from our previous measure of force. Force, measured by the velocity generated in a given time, is called accelerating force; force, measured by weight or pressure, is termed moving force. Now, though we can conceive, as a conse- quence of what jve have said, that two equal accelerating forces, acting separately on two different masses, would cause them to acquire the same velocity, at the end of a given time, it does not follow that these different bodies would produce the same effect on any body which might oppose their motion. In order that they should do so, it is necessary that the product of the mass and the acquired velocity, should be the same for both moving bodies. Thus a ball of 2 lb. weight, moving with a velocity of 50 feet per second, will cause a ballistic pendulum, when struck by it, to vibrate through the same arc as when struck by a ball of 50 lb. weight, with a velocity of 2 feet per second, or a ball of 100 lb. with a velocity of 1 foot per second. The product of a body's mass, and its velocity, is called its momentum, or quantity of motion. If we conceive two equal weights, W and W', suspended from the extremities of a string passing over a pully P, supposed to be destitute of friction, the weights will remain at rest. If we place ever so small a, weight, x, on the weight W, the weight on which we place it must immediately descend; and, as long as x is placed on W, by the first law of mo- tion, the velocity of its descent will continually increase. If we remove x the weight W will still descend, but with the velocity constant, which it had acquired at the instant of x's removal. Now in this case the weight x is called the moving force, or pressure producing motion; the two i W weights W and W, together with x, the mass moved: the velocity of W's motion will be a measure of the accelerating force produced by x. Now it is found, by numerous careful experiments, that this accelerating force, multi- plied by the mass moved, 2W + a:, is always proportional to the pressure-producing motion x: and this is the third law of motion. The laws of motion cannot be proved by any series of experi- ments, however extensive — these experiments only suggest the laws; and perhaps our firmest conviction of their truth arises from the wonderful manner in which, by combining these laws with the principle of gravitation, Astronomers have been able to predict the motions of the heavenly bodies with such marvellous exactness, and even to point out with certainty the precise spot in the heavens Fig. 11. HOW MATHEMATICAL AND PHYSICAL LAWS DIFFER. 27 where a planet hitherto unknown would be found. To some minds these laws may appear objects of intuitive belief, when once we have acquired correct ideas of matter, force, and motion; but on this point some metaphysical difficulties clearly exist. Our natural be- lief in the laws of motion certainly differs from that which prevails in regard to mathematical truths; for the opposite of mathematical truths at once presents a contradiction, while the opposite of the laws of motion may not exhibit itself at first as a contradiction to every mind. Moreover the human mind cannot conceive that even Omnipotence can make two and two anything but four. Nevertheless, if we con- template a heavenly body at perfect rest, on the assumption that it is for the time the only body in space, that heavenly body, in the language of the first law of motion, will remain at rest for ever, unless some cause of motion come into operation. In this case who will dare to say that it is impossible for Omnipo- tence to move that heavenly body without applying a cause of motion? Such an assertion would be wholly inadmissible, unless, among the causes of motion, it is understood that the Fiat of the Almighty is included. The Balance. — The principle of the Balance seems at first sight self-evident; for it is self-evident—at least to a person of ordinary Fig. 12. Fig. 13. intelligence — that if a rod of uniform material and dimension be fixed by its middle point on a pivot, and two bodies equal in weight be suspended one from either extremity, they will be in equilibrium. But to render this proposition intelligible, the nature of gravity, as a property of bodies at the earth's surface, must be clearly seen. That being understood, the proposition will then stand thus: — Equal causes" applied exactly in the same manner, must produce equal effects; the causes being the like number of particles tending downwards on either side of the fulcrum. And, by an easy de- 28 LAW OF GRAVITATION DISCOVERED BY OBSERVATION. monstration referable to self-evident principles, it can be shown that when the weights differ, there is, nevertheless, an equilibrium, if the fulcrum be at the point in the rod which divides it inversely in the ratio of the weights. This case, however, plainly differs from the convictions afforded by the necessary truths of mathematics, since the reasoning is mixed up with principles ascertained by experience, — the gravity of bodies, for example. And the same thing may be said of the demonstra- tions respecting the mechanical powers in general, — the lever, the wheel and axle, the pulley, the incliped plane, the wedge, and the screw. In Hydrostatics it is self-evident that a solid and insoluble body, immersed in a liquid, must displace a quantity of the liquid equal to its bulk. The discovery of this fact cost Archimedes a great effort; but the moment it occurred to his mind, it was self-evident, and required no proof to obtain universal assent. That a solid floating body, like a ship of the line, displaces a quantity of water equal to its weight, is equally true, but not, at first sight, quite so obvious. " The refraction of light, to which so many phenomena can be re- ferred, admits of no explanation. The evidence of the truth of this law is as yet derived solely from observation; and a wholly opposite condition of the law could be as readily received upon the same evidence as its actual form. Gravitation. — The law of Universal Gravitation rests ultimately on observation. It is the greatest achievement of Inductive Science. It is expressed in the language of Mathematics; but it has nothing of the character of a mathematical truth. This law declares the mutual gravitation of all bodies, with forces directly as their quantities of matter, and inversely as the squares of their distances. In the expression of this law bodies are conceived to consist of minute particles, more or less closely aggregated or packed together. In Physics, all such component particles of matter (differing from the laws on Chemistry) are regarded as made up of the same small portions of matter; that is to say, it is a part of the law that any two particles, at whatever distance from each other, exert the same mutual attraction. Thus the attraction of one body or mass of matter for another if the sum of the attractions of all the particles of the one towards the sum of all the particles in the other; and if the attraction be equal on both sides, that is, if the attraction exerted by the one be as great as the attraction by the other, it is determined in the abstract, that the number of particles in the one is exactly the same as the number of particles in the other. But these two bodies, which are thus conceived to contain equal quan- ATTRACTION OF MATTER. 29 titles of matter, may be either of the same magnitude, or may con- siderably differ in magnitude. A cubic foot (that is 1728 cubic inches of water.) contains no more matter than 128 cubic inches of mercury, which is the same thing as to say there is the same number of particles of matter in 128 cubic inches of mercury as in 1728 cubic inches of water. The law of Gravitation is expressed in its simplest form, as re- spects particles of this kind — namely, the particles of matter attract each other inversely as the squares of their distances. For example, to make the violent supposition that there is previously no matter in the universe, let two particles of matter be called into existence, and observed first at the distance of five miles, and then at three miles from each other. Their attraction for each other is greater at the distance of three miles than at the distance of five miles; but the greater attraction is not represented by 5 and the less by 3, but by the squares of those numbers, that is, by the one and the other of these numbers mnltiplied each into itself, the products of which multiplication are 25 and 9. Thus the attraction between these two particles at five miles' distance is represented by 9, and at the distance of three miles by 25. The law does not indicate the velocity with which two such particles will approach each other; but did we know what proportion each bore to the whole mass of the earth, then it might be discovered by reference to the velocity of bodies falling near its surface — sixteen feet in the first second. We may here remark how the laws of motion mix themselves up with the law of gravitation, — the same supposition being continued as to the absence of all other matter in space. If, after these two particles had approached to within three miles of each other, one of them were annihilated, all attraction would of course cease ; but the other particle, in accordance with the first law of motion, would con- tinue to move onwards in a straight line with the velocity which it had acquired at the moment of the extinction of the other. Attraction. — To express the attraction exercised by the particles of the sun over the particles composing each of the planets, numbers must be fixed upon which express, in some kind of dimension, the distances of each of these from the sun, and these numbers being squared we shall obtain a series denoting their relative attractions. To keep down the number of figures, it is best to choose some large measure, for example, the distance of the moon from the earth, or 240,000 miles. In the following table are set down the squares of the distances of the old planets from the sun, expressed in numbers, denoting how many times each planet is more distant from the sun than the moon is from the earth. 3* 30 MOMENTUM AND VELOCITY. Mercury ..................... 25,600 ! Jupiter........................ 4,410,000 Venus ..................... 7S,400 I Saturn......................... 12.91)0,000 The Earth .......................160,000 Uranus........................ 57,700,000 Mars............................... 360,000 I These numbers, however, do not express the actual attraction be- tween the sun and these several planets; but only what their relative attractions would be; if each contained the same number of particles. But where an estimate is already formed of the quantity of matter in any planet, and that quantity is considered in connection with the estimate of the quantity of matter itf the sun, and the actual velocity in bodies falling near the surface of the earth, then the elements are afforded for calculating the actual force of gravity between the sun and that planet. The roots corresponding to the numbers in the above table denote the actual distances of the planets from the sun, as measured by the distance of the moon from the earth, — namely, for Mercury, 160; for Venus, 280; for the Earth, 400; for Mars, 600; for Jupiter, 2,100; for Saturn, 3,600; for Uranus, 7,600; or nearly as 1, 2, 3, 4, 15, 28, 54. It is easy to see that the law of gravitation is sufficiently stated, when made to refer to particles of matter, by simply saying that the particles attract each other inversely as the squares of the distances. For it follows, as a necessary consequence, when a number of par- ticles are collected into one mass, and a less number of particles into another mass, that the sum of the attractions in the one shall be to the sum of the attractions in the other directly as the number of particles in the one is to the number of particles in the other. Again, when two bodies of the same bulk exhibit exactly the same attraction the one for the other, and under the same circumstances, we conclude that the number of particles in each is the same; and this is what is signified when it is said that two bodies have the same density. Moreover it can be proved that the attraction between the centres of two spherical masses of matter is the same as if the whole particles of each mass were collected within their respective central points. The attraction between two bodies, or masses'of particles, is mea- sured not by the mere velocity acquired by each, but by the amount of motion, or the momentum which each exhibits. When two masses of matter, different in the number of their particles, are supposed to come into existence in free space at some distance from each other, the quantity of motion produced in each is the same. That which contains the greatest number of particles would move with less ve- locity ; that which contains the less number of particles with greater velocity; but the momentum, cr quantity of motion, in each will be the same. It is easy, then, to understand, on the principle of gravitation, why two bodies — for example, a pillow and a piece of lead equal to the pillow in weight — were there no atmosphere, w->iil i fall to the PHYSICS. — ELECTRIC SCIENCES. 31 ground from a given height in the same time. Both would have the same momentum : but the momentum or impulse of the piece of lead would be impressed on a small portion of the surface, while that of the pillow would extend over a large surface, so that each point of that surface would be less affected. At first consideration, it may be somewhat difficult to see clearly that this great law of gravitation essentially differs from a mathe- matical proposition, as resting not on intuitive convictions but on observed facts. But a closer view of the whole subject satisfies the inquirer that no law of this kind could have been predicted d priori; that is, from any natural or intuitive conviction of the human mind' Such knowledge has no other foundation than observation. What confuses the mind is the large extent to which mathematical investi- gation is employed for the assistance and perfection of observation. Here, however, mathematical investigation serves merely the office of an instrument, by which, indeed, the dominion of the senses over nature is almost immeasurably increased. Physics. —The several subjects just noticed fall strictly under the head of Natural Philosophy or Physical Science, and indeed merely afford examples for the kind of knowledge which belongs to that great department. But when we consider that Natural Philoso- phy is ancillary to the great objects of Mechanical Science —to the construction of Time-keepers, the Hydraulic Press, the Steam Engine, Artesian Wells, Gunnery, the Pendulum, Telescopes, Microscopes' the Barometer, the Tides, Kailways, &c. — we shall be able to esti- mate the vast importance of a knowledge of its various subdivisions to men, particularly to those living in countries newly settled, and where the division of labour has not yet been carried sufficiently far to save every man from the necessity of being his own engineer and overseer. Even in the long-established social communities of modern Europe, we have but to glance the eye over the career of individuals of great activity of mind rather than of solid education, to discover how much time and money are annually wasted in the vain hope of accomplishing what is unattainable. Many a man of genius in former times, unenlightened by the knowledge this work is intended to convey, has wasted his life and fortune in fruitless efforts to discover the perpetual motion. And although this is not often now the object to which uninstructed ingenuity is directed, there is still as much health, as much genius, as much industry, as much wealth consumed on things unattainable as in former ages. Electric Sciences. — The fact that amber, after being rubbed upon woollen cloth, first attracts light bodies and then repels them, and upon which the Science of Electricity rests, derives all the evidence of its truth from observation. The same may be said of all the dis- coveries hiiherto made in Electricity. There is no principle in the 32 CHEMISTRY AN INDUCTIVE SCIENCE. whole subject which could have been inferred independently of ob- servation. It is purely a science of induction; and the same remark may be made of Galvanism. It was as impossible to predict, a priori, the decomposition of water, and the other surprising effects of Galvanism, by the mere approximation of two metallic plates im- mersed in an acid solution, as it is to establish, a priori, after the effect is witnessed, that it is really due to the apparatus employed. Of Magnetism, what more can be said than that certain facts have been ascertained by observation ? And although it is now sufficiently apparent that Electricity, Galvanism, and Magnetism are merely dif- ferent forms of one more general science, that conclusion has been deduced, not from any « priori reasoning, but simply from the accu- mulation of facts, and the inference of principles from these by the common process of induction. Under the heads just noticed, together with those of heat and light, how many subjects fall, of surpassing interest and of the most direct use to men in every situation of life ! Some years ago, when the number of steam-boat accidents in the United States attracted public attention, an American writer successfully showed that as many persons every year lost their lives by lightning, within the Union, as by the bursting of steam-boilers. Increased knowledge and attention on the part of engineers have very much diminished the amiual mortality from steam-boat accidents; and surely it is not too much to expect that the great annual loss of life by lightning may be materially circumscribed by a better acquaintance with the nature of the electric fluid, and the precautions which such a know- ledge may suggest for avoiding danger during the violence of a thunderstorm. Chemistry. — But Chemistry supplies the best example of a purely inductive science; and the progress which Chemistry has al- ready made is sufficient to make known the final composition of the bodies which man sees on every side around him. It teaches that, out of sixty-three simple substances, all these bodies are constituted. It shows him how to obtain each of those simple substances in a state of purity; and, when it is required, it points out how these simple substances are to be converted into such compound bodies as are necessary to the arts and conveniences of life. ( In Chemistry there are no original a priori rules. There are no facts or laws discoverable by the mere light of thought, independ- ently of experiment and observation. All that the exercise of genius < can do in Chemistry is to suggest new paths to be explored. Che- mistry, therefore, is a science which enables us to understand both the extent and the limits of the Baconian precepts. It is wholly in- ductive; and yet the principles which induction has here afforded, RELATION OF ART TO CHEMISTRY. 33 while they are numerous and most available, are, as laws of nature, neither free from exception nor very comprehensive. It is by the study of the mere properties of substances that che- mists have achieved most of their success. The early progress of Chemistry was tardy in the extreme, until gaseous bodies fell under rigid examination ; and from that date its progress has been almost incredible. Chemists for ages knew of several sorts of air; but they seem never to have arrived at the idea, that by determining the seve- ral peculiar properties of these airs they might be able to distinguish them from each other. Hydrogen gas has been known from time immemorial as an inflammable vapour, which played about the appa- ratus whenever sulphate of iron was directly made by the addition of dilute sulphuric acid to iron filings. But although its peculiar inflammable character was known, and even its smell in this way of producing it, and also that it did not appear unless a large propor- tion of water was added to the acid; yet no one thought of seeking the means of identifying it when otherwise produced, until Caven- dish noticed its extreme levity. There was no deficiency of genius or industry among chemists during the period of this slow progress; but with all their solicitude to pursue the precepts of Bacon, they do not appear to have suffi- ciently felt the necessity of an exact knowledge of the peculiar pro- perties of every substance, and the means of its identification when present in minute quantity. The only efficient aid which chemistry has derived from exact knowledge is the homely aid of the balance. Until recently, chemical operations were too rude to admit of much advantage from the nice determination of the weights of the sub- stances employed in experiments; otherwise, how many difficulties of former times might have been solved without delay ! In the experiment of burning hydrogen gas with oxygen gas, it was remarked, at an early period, that the apparatus became bedewed with moisture. The gases shrank into nothing, and moisture was found upon the apparatus. Yet it was a long time before the con- clusion was drawn, that the water was the product of the combustion. The balance would at once have settled this point, by showing that the water produced equalled the sum of the weights of the two gases exploded. * * The subjects which Chemistry embraces are so many necessities of man in his social life. A few examples of the departments of art founded on Chemistry will suffice to show how desirable a know- ledge of Chemistry is to every man,, whatever his occupation in life. Among these stand prominent the extraction of metals from their ores- the subject of artificial light, or the various modes of artificial illumination; the arts of dyeing and bleaching; the^ substances fit for fuel- the nature of fire-damp and choke-damp in mines; the 34 OBJECTS OF PHYSIOLOGY. artificial production of ammonia, in reference to agriculture; gun- powder; artificial minerals; chemical tests, and the detection of poisons; ventilation, and disinfecting agents; cements; artificial minerals; pigments; metallic alloys; and other subjects which it is needless here to enumerate. Physiology. — Next in order to Chemistry stand the Physiologi- cal Sciences. The discoveries in this science are to a great extent peculiar laws of nature, while many of the phenomena of living bodies are physical, chemical, and electrical. When the muscular fibre shortens itself on the application of a stimulus, it is in obedience to a pure Physiological law. When the impression conveyed from the surface of the body by a reflex nerve is succeeded by an influence transmitted to an organ of motion, it is in obedience to another dis- tinct physiological law. Certain laws of nature acting together with the laws of motion produce the planetary movements, so strikingly remarkable for sym- metry and harmonious union with each other. On the other hand, certain laws of Physiology, in apparent opposition to the laws of physical nature, and to the ordinary laws of Chemistry, produce effects in every way so surprising, as to have engaged the attention of men in all ages, upon the very peculiar nature of the influences by which such effects can be called forth and sustained with an almost unerring uniformity, during the various limited periods to which the existence of individuals in the two organic kingdoms extends. There is nothing, in the whole character of physiological science, more at variance with the general economy of nature than the limited duration, in each individual, of the phenomena which constitute animal or vegetable existences;—and the complete isolation, through- out its whole existence, of each individual from other portions of the organic world, after the first separation from the parent organism, is another most striking and peculiar feature of physiological science. The innumerable forms which organism assumes, in the varieties of animal and vegetable species, set at nought every possible idea of their source being a mere physical force of development, under the limitation cf a few overruling influences. And what is not less re- markable* than the characters already stated, is the manifestation, at every step, of the nice accommodation of means to peculiar ends, in the structure and economy of organic bodies, which renders it im- possible to seize the mere inductive laws of Physiology, without a perpetual reference to final causes. If it be said that the animal or plant could not have existed with- out certain organs adequate to certain ends—and therefore that such contrivances are merely indispensable conditions of existence,— OBJECTS OF PHYSIOLOGY. 35 the answer is, that organic nature is not a necessary part of the economy of the universe; that the material world, without the organic, was complete in itself; and therefore it is to be concluded, because the organic world exists with marks of design, such as characterise the works, of man on earth, as distinguished from the works of nature, that in the origin and maintenance of the organic world there is manifested a special intelligence and wisdom, without continual reference to which Physiology will fail to make the pro- gress of which it is susceptible. The knowledge of Physiology opens up a new field of human thought. In it we trace the wisdom of the Creator, as in Astronomy we discover manifest proofs of his power. Galen said with truth,—" The study of Anatomy is the use of a hymn in praise of the wisdom of God." This is, indeed, the most dignified office of Physiology; and it is in this light that it exhibits its greatest glory. But to how many subordinate uses is it also subservient! Under Physiology, in its largest sense, stand Medicine and Surgery. In proportion as the knowledge of even a rude Physiology has diffused itself has the value of human life increased. Both Medi- cine and Surgery are but handmaidens of Nature; but how ineffec- tual— nay rather, how pernicious — were man's natural modes of treating diseases and injuries, until Physiology had enlightened him ! One great use of a knowledge of Physiology is to teach men what they should avoid doing when diseases have arisen, or injuries have been sustained. He who understands something of the animal economy, knows with what precaution he should employ less known remedies; while he knows also, that even good remedies are only good when seasonably used. And this knowledge, so far from unfitting him for finding new remedies among the natural productions of a strange place, affords him an infinite advantage over every one who, without such knowledge, ventures to experiment upon a disease. Let a man understand the general scope of Physiology, and he becomes, under sickness or injury, a safe guide in the wilds of Australia; while he who is ignorant of the animal economy, if he uses remedies at all, uses them as much at random as in the days of spells, amulets, and charms. If he has studied Botany, he knows, as we shall presently see, from which families of the vegetable king- dom safe drugs may be taken, and from which poisonous substances may be feared. Man, in every country, acquires the most part of his knowledge by experience; but in every complex kind of knowledge, like that which relates to man, animals, and plants, his experience deceives him unless he be previously acquainted with the general scope of nature in that department. Hence a new settler in a strange country, who understands Physiology, has an immense advantage 36 PSYCHOLOGY. — STATISTICS. over one whose ignorance does not allow him to interpret the things which daily come under his notice. Psychology. — The vast recent progress of the physical sciences has cast into shade those important branches of knowledge which rest on thought retroverted upon itself. Such are the Psychological sciences,— Metaphysics, Logic, Ethics, etc. However little has been the progress of an exact kind hitherto made in those sciences, there can be no doubt that man is both capable of making, and destined to make, great advances in those all-important departments of knowledge. If it be asked to what end ? The answer is, that it is solely by the general diffusion of these sciences that language can be made an exact medium for the interchange of thought and opinion on all subjects which are not represented by sensible objects. In no distant time the activity of mankind must require new occupation of mind. The career of physics, astronomy, and chem- istry, must begin to slacken, if such a slackening has not already commenced. The world at present stands amazed at the successful application of the discoveries, not quite of recent date, in the physi- cal and chemical departments, to the arts of life—steam navigation, gas illumination, railway communication, the electric telegraph, the advance of agriculture; but even these wonders must lose their novelty, and the time will arrive when the sciences of mind will have their turn of popular favour and cultivation, from which the most important fruits may be anticipated. The stagnation of the psychological sciences extends to all those which rest upon moral evidence; in short, to all those which depend for their progress on precision of nomenclature, while the subjects of inquiry are not fully represented by sensible objects. There are, indeed, numerous departments of human knowledge which seem to depend on mere observation, in which general principles are con- tinually deduced from apparent facts, while the progress made is very little commensurate with the labour bestowed upon them. This defect of progress arises chiefly from the so-called principles or inferences being deduced from particulars called by the same name, without being, as is necessary for a perfect induction, exactly identi- cal in character. The Science of Government, the Science of Law, the Science of Medicine, and many other departments of human knowledge, come within this description. Statistics. — Statistics have of late assumed the character of a separate branch of knowledge. It is rather an art than a science, and when unskilfully practised, is subject to the greatest possible fallacies in its deductions. The evidence of statistics is apt to be represented as equivalent to that of demonstration. But the slightest consideration will show that the evidence of statistics, though capable in some IMPORTANCE OF NATURAL HISTORY. 37 circumstances of being demonstrative, also ranges through every degree of moral evidence — the possible, the probable, and the morally certain. Hence the source of the great errors just referred to, as often as the evidence of statistics is assumed to possess one uniform demonstrative character. It is manifest that in all kinds of induction the principles arrived at can have no higher authority than the evidence bearing on the identity of the several particulars out of which these principles have been drawn. It seems unnecessary to go farther in illustration of the proposi- tion that the various departments of knowledge, resting on moral evidence, cannot make effectual progress until the psychological sciences have gained a larger share of popular favour, and have become generally cultivated and understood. Natural History.—Between Natural History and the descriptive sciences, a strict alliance has been closely cemented. In the advantages of this alliance both departments participate. Natural History was originally very rudely arranged, owing to the various mineral, vegetable, and animal species being grouped together, in accordance merely with their most obvious external characters. What are termed natural systems of Natural History have arisen out of its alliance with the descriptive sciences, — the knowledge of the minute structure of plants and animals, and of the structure and composition of mineral bodies being made subservient to the group- ing together those individuals of the three kingdoms which are most closely related to each other in internal as well as in external characters. Mineralogy. — What a field of profit to the student does Natural History present! In the inorganic kingdom, how precious is the knowledge by which he can, figuratively at least, convert dross into gold! If a man has become acquainted with the characters of mineral substances, he may discover that which is regarded as worthless to be often of the greatest value for some purpose in the arts. A recent action at law exhibited one of the parties as having obtained a lease for upwards of twenty years of a coal-mine, —• one of bituminous shale, which yields many times the price of coal for the manufacture of gas. The lease was found valid. Now, had the proprietor known a little of minerahTgy, instead of entering upon a costly law-suit, he might have enriched himself by selling his own stratum at its actual value. But numerous instanccs^ could easily be cited, in which similar ignorance of natural objects is tantamount to loss; and where, on the other hand, even a slight knowledge leads to great pecuniary benefit. Knowledge 'of the Mineral Kingdom implies an acquaintance with the characters by which the precious stones are recognised; with the indications of the mineral forms of the useful metals; with 4 38 IMPORTANCE OF NATURAL HISTORY. those of marbles, spars, alabasters, and ornamental minerals in general; with building stones, and their relative value; and with the minerals which characterise the several geological formations. All these subjects we propose to introduce in due time into our Treatises; and on how many occasions may Fig. 14. our expositions of this description of know- ledge prove of the utmost service in many positions of life ! Let us state a case, as re- lated by Professor Tennant in his Fifteenth Lecture, on the results of the Great Exhibi- tion. For want of the knowledge of the crystalline form of the diamond, a gentleman in California offered £200 for a small speci- men of quartz. The gentleman knew nothing of the substance, except that it was a bright, shining mineral, excessively hard, not to be touched by the file, and which would scratch glass. Presuming that these qualities belonged only to the diamond, he conceived that he was offering a fair price for the gem. The offer was declined by the owner; who, had he known that the diamond was never found crys- tallized in the form of a six-sided prism, terminated at each side by a six-sided pyramid, as seen in the larger cut, which is the exact size and shape of the stone, he would have been able to detect the fact, that that for which he was offered £200 was really not worth more than half-a-crown ! The larger figure represents the piece of quartz in question; the smaller, one of the more common forms of the diamond. Zoology. — Again, as to the Animal Kingdom, how large the mine of knowledge it embraces, and that of interest and importance Fig. 15. not confined to the naturalist! The merchant, the manufacturer, the agriculturist, the traveller, the sportsman have all to seek aid, in UTILITY OF ZOOLOGICAL KNOWLEDGE. 39 their several pursuits, from a knowledge of this department of natural history. Look to the value of our fisheries, and judo-e how available to the commercial world becomes this knowledge of animal nature. Nay more, but for our knowledge of natural history, one of our most important articles of food would in time have entirely disappeared from our waters. We allude to the salmon, the fry of which, and the parr, are now universally acknowledged to be identical. Our cut (No. 15) shows the fish so well known by the trans- verse dusky bars which mark its sides. Under the name of parr, it abounds in all salmon rivers; and, until the researches of Mr. Shaw, Sir Wm. Jardine, and others, proclaimed it to be the young of the salmon, it fell in thousands before the strategies of every village boy who possessed a crooked pin and a yard or two of line. Science has now established its value, and invoked regulations for its preservation. The angler too, — how much more successful is he in his sport who has studied the circumstances which influence the humours of his prey ? Is it less true of the sportsman who un- weariedly paces the moors in autumn that his success is intimately dependent on his knowledge of the habits of the game ? The wild- goose chase is proverbial; but, besides the actual chase of the bird, in which no one succeeds who does not understand its habits, there are many figurative wild-goose chases in the animal kingdom in which success fails from ignorance of particulars, which the study of Natural History could easily have supplied. A practical illus- tration of the benefits even of a slight knowledge of Zoology, pre- sents itself in the case of a traveller or emigrant in some unknown country. He has pitched his tent, or raised his hut; and then he finds the locality infested by serpents. He is all anxiety and fear. He knows not what to do : whether to proceed to another spot, or to remain and brave the danger. Some acquaintance with the structure of reptiles would at once have decided his plans; for with the first he killed he could decide whether they were venomous or Fig. 16. Fig. 17. harmless. The former— and the common viper is one — possesses, on either side of the head, glands which secrete their venom ; and, to conduct it to the wound they inflict upon their prey, they are 40 UTILITY OF BOTANY. furni.-hcd with .two hollow but long, recurved, and sharply pointed teeth in their upper jaw. The harmless serpents have no such apparatus; and thus the two genera are at once distinguished by the absence or presence of the fang in question. Our cut, (Figs. 16, 17,) after Professor Owen, exhibits the skulls of the two families with their dental peculiarities. Botany. — A treatise might be written on the benefits which an acquaintance with the Vegetable Kingdom is capable of affording. Of how great use is it in strange countries to be able to distinguish the plants fit for food, from such as are poisonous; and to recognise those which have been employed in medicine, or in any one of the numerous arts to which the Vegetable Kingdom is subservient! Even an Elementary knowledge of Botany is of exceeding interest and importance. Travellers in unknown lands know full well that life or death often depends upon their acquaintance with the science — an acquaintance, it may be, not derived from learned treatises, but simply from little more than the ordinary observation of those edible plants with which all persons are familiar. But even this is still a knowledge of Botany. An all-wise Providence has so arranged that plants may be associated into families from their external resem- blances; and, further, tint plants possessing such resemblances to each other, have many prrperties in common. One of the great families of Fig. 18. plants is the Cruciferae, or Tur- nip tribe, every member of which, marked by very obvious characters, is easily recognised, and scarcely to be mistaken ; and all are remarkable for edi- ble and antiscorbutic properties. The crew which accompanied Vancouver in the expedition of 171)2, suffered severely from scurvy, from want of vegetable food. The surgeon advised that they should make for the first land; and at Cape Horn he found a plant resembling spinach, which he directed to be used as food, with the hap- piest effects. This is not a rule without an exception; but it is of such universal application that the traveller may in his necessity, safely trust himself to its guidance. UTILITY OF BOTANY. 41 The Icosandrous plants, or such as have an indefinite number of stamens attached to the ca- lyx, are remarkable for their Fig. 19. fidelity to this law. They are all edible, and are repre- sented by the apple and pear tribes, the cherry, the straw- berry, &c. There is also another great family — the grasses, the members of which exceed those of any other class, in number and in their essen- tial importance to the whole animal creation. This fam- ily comprehends the grasses, commonly so called — the wheat, oat, barley, rye, &c, of our temperate climate, and the sugar canes of tropi- cal regions; and all possess the common properties of being nutri- tious and healthful. During Lord Anson's voyages, on the failure of provisions, the mariners landed and found vegetables, which, although unknown, were recognised as belonging to this great family, and proved to be highly beneficial. But while the value of this law is indisputable, a further know- ledge of Botany is necessary to the traveller; since he will frequently find associated together edible and poisonous plants. Thus, the deadly Upas tree is placed with the delicious fig. The magnificent Euphorbias of tropical forests yield, on the one hand, the refreshing juice of the E. Balsamifera of the Canaries, and the Yuca Dulce, the nutritious farinaceous meal of Mexico; and, on the other, furnish to the warlike inhabitants of Ethiopia the poisonous juices in which they dip their arrows. The splendid Cactuses, also, produce the delicious milk of the Hya-hya, in British Guiana, and that of the Cow tree in Ceylon, and also furnish the strychnine of medicine, and the far-famed wouralie poison of the banks of the Orinoco. Lastly, it frequently happens that, while one part of the plant yields an article of food, another is laden with noxious properties. Thus, if the starch furnished by the Euphorbias and Cactuses were eaten before the juices of the plants were expelled, speedy death would ensue; and, as a more familiar example, the tubers of the potatoe plant form a valuable article of diet, while its green-coloured fruit is poisonous. 4* 42 LESSONS TAUGHT BY GEOLOGY. Geology.—Geology, again, is no longer a merely curious specula- tion. On the contrary, it is one of the sciences which most surely leads to practical results. It has methodised the crust of the earth, and taught us to look for certain minerals almost as we look for certain books upon certain shelves of a library. Coal is nowhere found but in the coal-measures; and a knowledge of the position of the coal or ironstone strata, and of the rocks usually associated with them, has guided the capitalist to the spot where he might engage in the search for these products with the least chance of disappoint- ment ; and, in many instances, had the directions of Science been sought and followed, vast sums would have been saved * to the community. 3 Deceived by appearances, 5 or misled by designing indi- * viduals, persons have sought 3 coal at a great expense in the * _2 wealden formation of Sussex, i'^ the oolites of Oxfordshire and \u Northamptonshire, and among \'% the Silurians of Radnorshire; \a whereas attention to the sim- ]L~ plest principles of Geology ' „i would have shown the folly = ^ of such attempts. Because [«* Pennsylvania is rich in coal, \ g it was imagined, in the neio-h- = -2 bouring state of New York, \ a that the precious gift might ^ also be found there; and the ;^ resemblance of certain silu- . % rian rocks, on the banks of \* the Hudson, to the bitumi- f nous shales of the true coal ' formation, appeared to sanc- | tion the surmise. Accord- » , ingly, mining .idventurers | squandered away a large amount of capital; until Geol- ogy, at the invitation of the Legislature, authoritatively declared the futility of the attempts. Our cut exhibits a section of the Great Bristol Coal-field, extend- ing from the Mendip Hills to the north-west of Bath, a distance of about twenty miles. OBJECT AND EFFECTS OF EDUCATION. 43 Arrangement of Knowledge. — Besides the Sciences and the Liberal Arts, which last will obtain a due share of our attention, there are, among the subjects of human knowledge, the Arts and Manufactures, which contribute to the convenience and comfort of life; and which may be classed under the general head of Social Economy. The various branches of knowledge of a practical kind connect themselves with corresponding branches of Science. Some arts are mechanical; some chemical; some physiological, and some purely intellectual. In all these departments there arc practical branches of knowledge which deserve the attention of every one who desires to be accounted liberally educated; while there are others too tech- nical to admit of any proficiency except on the part of those who devote their lives to the pursuit. Arts of this latter description will not enter into our plau; but, in other respects, we shall exclude no branch of study which belongs to the educatiou of an accomplished citizen. It is thus seen that the mode in which wre design to treat our subjects is such as best conduces to exercise and improve the human faculties, and to open and expand the mind. Uses of Knowledge. — The acquisition of knowledge has two great objects; namely, to obtain information for its own sake—that is, for the sake of the uses to which that information may be applied; and also, by the varied exercise of apprehension, memory, reasoning, judgment, and other powers of the intellect, to render those faculties available for the purposes, however great, in which, one time or other, a man's position in life may require their utmost service. The effect of education upon the individual is easily understood. It makes him what he actually is, as respects the. particular stores of knowledge he possesses, and the command of mind which he can bring to bear on every crisis of his life. But man in society does not stand insulated, either as respects his knowledge or his powers of exertion. Every man possessed of knowledge and of ability, natural or acquired, sheds around him gifts of incalculable value. He is a centre or focus from which light is diffused on every side.. A person who is himself uneducated, by living among those who are educated, obtains no small share of the advantages which they pos- sess. He picks up fragments of their knowledge; but by far the greatest of his gains arises from the circumstance that, by the imi- tative power with which our species is so largely gifted, he catches the spirit of the acquired modes of thinking possessed by those around him; so that, although his knowledge may remain rude and disjointed, he begins to think like one who has received a liberal education. Thus, like charity, knowledge carries with it a double blessing—blessing him that offers, and him that receives. 44 OBJECT AND EFFECTS OF EDUCATION. Perhaps no people as a body ever exceeded the Athenians in acuteness. This we may justly infer from the style of the orations addressed to them, particularly from the stern, direct character of those of Demosthenes. To the immediate education of the Athe- nian youth no very great attention appears to have been paid. We are told that their first instruction was in swimming and the rudi- ments of literature. As for those whose abilities were but mean, they were to learn husbaudry, manufactures, and trades. Those who could afford the education of a gentleman were to learn to play upon musical instruments, to ride, to study philosophy, to hunt, and practise gymnastics. Whence, then, did the Athenians as a body acquire that reputation for acuteness, for which, undoubtedly, they were pre-eminent ? The portion of the people to which this charac- ter applied, probably at no period exceeded thirty thousand, if, in- deed, that be not too high an estimate; since it only excludes the servants and bondmen, by far the most considerable proportion of the inhabitants, and makes allowance for about ten thousand foreigners, who were permitted to listen, but not to take part in public affairs, or in public amusements. The signal acuteness of the Athenians arose, unquestionably, not from any remarkable superiority in their early education, but from the public life which they lived, continually listening, in their public assemblies and courts of justice, to orators; in the schools of phi- losophy, to discourses on human nature rather than on physical science; and in the theatres, to the unrivalled dramas of their tra- gedians and comic writers. Thus an Athenian, when Athens was at the height of its fame, could not be otherwise than acute. He took part in the deliberations regarding public affairs ; he was pre- sent whenever instruction or amusement was going forward ; and, if war arose, he fought,—sometimes by sea, sometimes by land. He had occasion for no language but his own ; his instruction was chiefly oral; he required no books but those written almost in his own time; and he could not but know his own language in all its minute- ness and shades of meaning. He was a statesman, a legislator, a lawyer, a soldier, a philosopher, and a man of taste; he was there- fore master of all the technicalities which had as yet arisen in the language; and nothing could be spoken of, or even hinted at, which he did not at once perceive and understand. How different is the case in modern times ! How much more must be learned to be on a level with the age than was necessary in Athens! At Athens the knowledge and acuteness by which an accomplished citizen was distinguished, came to him as easily as an acquaintance with town life now comes to those hopeful scions who spend their nights and days in the metropolitan streets. EDUCATION DESTROYS DELUSION. 45 V e citp the superior acuteness of the Athenians to illustrate the effect of the spread of intelligence from mind to mind, by which the improvement of a small proportion of the population becomes a sort of leaven to the whole mass, which, under favourable circumstances, may quickly become similarly affected. But the history of the Athenian people affords us another lesson, by showing how much the world has changed since their time, and how much more labo- rious is now the task -of acquiring knowledge, and a character for intelligence and acuteness; for, in our day, owing to the rapid extension of new departments of knowledge, and the consequent increase of new terms, there is no longer that general acquaintance with the meaning of words which prevailed among the ancient inhabitants of Athens. Popular Errors. — We admit that, in the course of time, society, merely by having included within it a small sprinkling of persons imbued with exact knowledge, has come to think correctly upon a great number of subjects, on which formerly the grossest errors pre- vailed. But this very circumstance affords the strongest inducement to promote education, with the utmost speed, through every rank of the community. There are still many evils more or less latently devastating the social fabric, which an improved state of knowledge, and the consequent more exact mode of thinking, would go far to correct. It is an undeniable fact, that within the last two or three hundred years a vast amount of positive delusion, by which the human faculties, moral and intellectual, were for ages kept in thral- dom, has almost wholly disappeared from western Europe. Now, if men in general no longer seek to discover the coming incidents of a man's life, or distant events in the history of a people, by studying the course of the stars or to prefigure the future in the direction of a thunder-clap, or in a shower of stones from the air, or in the flight of a bird, or in some peculiarity of an animal's entrails,—and that less from any profound or widely-diffused knowledge bearing on such subjects, than from a more exact mode cf thinking on the course of nature derived from the increasing, though still small proportion of educated minds influencing society — surely there is ground to anticipate that many of the evils still left behind — the fruits of ignorance and unsound thinking — would be eradicated by the general diffusion of education throughout the masses of the com- munity. Ignorance of Natural Laws. — How slight is the knowledge of the laws of nature, which for the last two or three hundred years has fallen to the lot of each individual, even among the educated orders of society ! And yet that mere sprinkling of knowledge in such sciences as Astronomy, Meteorology, Natural History, and 46 NECESSITY OF INSTRUCTION TO GUARD AGAINST ERROR. Anatomy, has sufficed to banish from this part of the world astrology, divination, sorcery, witchcraft, and magic. What an encouragement does this fact afford to perseverance in that course which, within the narrowest limits, has proved so successful! But there are still delu- sions remaining to be banished by the extension of sound knowledge. Does the favour extended by the public to clairvoyance, table-turning, and spirit-rapping tell of the advancement of our age beyond the standard of a former one ? The age should* blush for itself, and take to study. Such study would not only teach what to believe in mat- ters of science, but put it fairly on its guard against blind guides, who every now and then arise, like ignes fatui, to mislead the unwary. There are two brilliant examples of these in the present day, who may serve as lessons to the public in the time to come, as having led many astray from the simplicity of truth. They are dis- tinguished men, too — the one an eminent chemist of Germany, the other, one of the greatest men Scotland has produced. The public should prize both these men much, but truth more. It is melan- choly to think that such men should outlive their faculties; but it is still more melancholy to think that the public should be so little instructed as not to distinguish true from false science. Statistic Fallacies. — The tendencies of the present age have caused exactness, where men must think without sensible forms before them, to be so generally neglected, that authors who would lose caste and reputation for bad spelling, and still more, for errors in grammar, may violate with impunity the rules of logic, so essen- tial to the teaching of truth. In no department are these rules so often grossly violated as in statistical subjects, where we should cer- tainly expect something like mathematical accuracy. Mr. Farr, the able medical assistant of the Registrar-General, has pointed out a most ludicrous mistake of a logical kind, which cannot be too widely exposed in an age when every man appeals to statistics, and deems himself competent to deal with them. The annual mortality in prison-life being required, the statist takes the number of persons who have sojourned in a particular prison during the year, and also the number of deaths that have occurred. He then divides the former by the latter, and points to the result. Such logic is the 6ame as if an innkeeper should boast of the healthiness of his bouse, 'as compared to the rest of the town, on the ground that he had, during the year, entertained a thousand guests, of whom only one had died; whereas, the mortality for the rest of the town had been at the rate of twelve per thousand. On this kind of logic, however, Mr. Farr tells us that a French minister pronounced prisons to be the healthiest places in the world; and an English inspector gravely affirmed, that in very few situations in life is an adult less likely to die than in a well-conducted prison! OBSERVATION TO . BE GUIDED BY KNOWLEDGE. 47 False Induction. — In the ridiculous book of one of the persons to whom we have referred, translated by an eminent professor of chemistry, there is a most unpardonable abuse of the term " induc- tion." One of the purposes of the work is to maintain that some people can see lights assuming the form of human bodies in church- yards, and other places where persons have been buried; and we are told that the evidence on which the German author rests this state- ment is an induction of particulars. Now, what is this so-called induction of particulars? A lady repeatedly says that she sees luminous forms over the graves of the newly-buried. Each repetition of the assertion is gravely set down as one of such a series of particulars, as upon which it is allowed to found an induction. In the first place, there is no evidence of even one of her assertions being founded upon anything but a vagary of the imagination. It is a correct induction, from the particular instances referred to, to say that the lady in question asserts such things; but here the induction ends, and, as regards the reality of the things seen, one assertion is as good as a thousand. It is melancholy to think that such credulity should exist araon" men of eminence in special departments of human knowledge; but still more melancholy to reflect that the very terms of exact logic should be misunderstood by an eminent professor of an important department of Physical Science. Education. — The sentiment, so long tolerated in this country, that education might prove hurtful to the masses of societv, and unfit them for their ordinary occupations, has long since either died a natural death, or, if not dead, is content to hide its diminished head in some unvisited corner of the land. Nevertheless it is not alto- gether a settled point what kind of education should be provided for the public. Some simple-minded people limit their notion of educa- tion to the humble acquirements of reading and writing; and persons of this stamp are often heard to express their surprise when they discover that a large portion of our criminal population are masters of these accomplishments. Beading and writing are but the instru- ments by which education is acquired. And it has been a strange oversight that so much pains have been bestowed in providing our population with the instruments of education, while so few have taken thought to put within their reach the books from which the knowledge yearned after could be reached. To supply in part this want is the great purpose of our present undertaking; and if those who express their surprise that there are among public criminals persons who can read and write, would extend their ideas of educa- tion to what includes some acquired knowledge of God, of Man, and of Nature, they would confess that crimes are seldom committed by sound-minded and educated people. 48 OBSERVATION TO BE GUIDED BY KNOWLEDGE. We have asserted that reading and writiqg are not education, but rather the instruments by which knowledge is to be acquired. It must be admitted, however, that some limitation may be required to this sentiment; since it might be contended that reading and writing stand, in some measure, on the same footing as the several branches of what has been termed " industrial education." But although industrial education, in its special sense, signifies merely that sort of training by which a person may be rendered more apt to learn the kind of occupation which is to be his calling throughout life, and more capable of attaining excellence in it; yet such an education has an additional influence in developing the faculties, both intellectual and moral, far beyond what the mere accomplishments of reading and writing can produce. Important as industrial education is, for the simple purpose of aiding the development of industry, we must never lose sight of its subsidiary effect in exalting the intellectual and moral character of the individual; nor is it to be doubted that the very best effects may be anticipated from mingling in all schemes of industrial education such studies as belong to Physiology and Psychology, together with those of a directly industrial character, in order to secure a more immediate influence upon the moral character. There can be no doubt that it is possible so to direct industrial education as to destroy much of the benefit which it is capable of conferring. There is nothing in the study of abstract science and physical knowledge which should withdraw the mind from an ac- knowledgment of the existence of the Spiritual in the economy of nature. But there is a mode of studying these subjects which makes the properties and laws of matter terminate too much in themselves, without sufficient reference to the power of the Infinite Intelli- gence by which they are maintained and supported. In all systems of industrial education it should be a first principle ■ that the power which operates in the workings of nature should stand forth acknowledged as the Power of God; and that man's power of thinking should be confessed as being the foundation of all that his mere senses seem to have discovered of the course cf nature. The term observation is likely to mislead the unwary, who are so often told that all human advancement depends upon observation that they are apt to forget that observation may serve to perpetuate error as readily as to advance truth. They lose sight of the essential maxim that it is instructed observation that at once discards error and establishes truth. It is indeed difficult for an enthusiastic stu- dent, amid the• profusion of knowledge now set before him, not to believe that all that is necessary to enable an unprejudiced person to understand the order and course of nature, is simply to open his eyes OBSERVATION TO BE GUIDED BY KNOWLEDGE. 49 and look around him. It is, then, an instructive lesson for him to discover that, by the same exercise of the senses which seems at once to have laid open the secrets of the universe, all those phantoms, which for so many centuries deluded the human mind, took their origin. What we here desire to insist upon is, the paramount influence of the state of man's spiritual development at any one time upon his capability of apprehending the economy of nature, with regard to the axiom—that the study of the agency by which knowledge is acquired should never be severed from the study of the things which are made the objects of knowledge. It is a common idea that the rapid progress of modern science has arisen entirely from a diligent use of the senses, in obedience to the precepts of the Baconian Philosophy. The vast progress of human thought, previous to the possibility of this advantageous use of the senses, is too often altogether overlooked. Thus sense is exalted at the expense of the higher faculties of the mind, and the conclusion arrived at, that the education of the sentient part of our nature is all in all. How erroneous is this idea, will at once appear from the briefest retrospect of the history of man's progress. In man's rudest state there is no want of what passes for knowledge; and his mind is so far from being barren in that stage of progress, or his memory destitute of ideas, that he positively bends under the burden of his thoughts and recollections. Nevertheless, the greater part of this profusion of apparent knowledge with which his mind is filled is en- tirely false. In a somewhat later stage of progress, this early mass of delusion is represented by the more refined but equally worthless products of sorcery, magic, witchcraft, divination, and astrology. When we look to the history of man in the first rude ages, we discover an appalling amount of delusion, which we admit has arisen from this tendency to account for what he sees; but, side by side with this heap of rubbish, we find surprising proofs of the exactness with which he has gathered up such laws of nature as are most essential to his every-day well-being. It is when the phenomena are of rarer occurrence, or when they are complex, or when they seldom arise under exactly the same form, that he falls into error. On the contrary, when phenomena come frequently under his notice, if he has erred at first, he commonly obtains the means of rectifying his error. As soon as he discovers distinctly that the succession is not invariable, he ceases to regard the two events as standing in the relation of cause and effect. # It would be 2asy, then, to show that no just reproach can be thrown against this principle of man's mental constitution. All that he knows of cause and effect he has acquired by a reliance on this 5 50 FUTILITY OF HYPOTHESIS part of his mental endowments; and we may justly remark thit, in the early stages of his progress, he must have been led to expect, through this principle, the discovery of things placed beyond his reach, owing to the great success with which he had applied the same to the acquisition of knowledge fit for the supply of his every- day wants. Astrology, divination, sorcery, witchcraft, and magic, are all pur- suits seeking to attain a knowledge and power forbidden to man. To these pursuits, doubtless, he was led by this belief, that when two events stand in immediate succession, the first is the cause of the second. By these studies he sought an unattainable knowledge of the future, and an unattainable power over the future ; he was dealing with obscure phenomena; he could not readily discover the test afforded by a distinct failure in the succession; and hence these subjects grew to the extent in which history exhibits them. But, during all that while, the knowledge of real causes and real effects was accumulating; and as this real knowledge successively laid open the true order and course of nature, the supposed means of gaining knowledge and power, as respects the future, began to decline. What we contend for is, the necessity of directing education to the knowledge of the workings of the human mind, as well as to the study of the laws of nature. This we must repeat in season and out of season; and we think we have just shown, by a sufficient detail of facts, that man's knowledge of the course of nature is correct only in so far as he understands the real character of that intelligent agency, his own mind, by which alone, upon earth, the operations of nature are fathomed. It is a great error to attempt to reduce popular education to a low standard. The power of thinking, and even of thinking deeply, naturally belongs to all sound-minded men. It is the complexity of many subjects of knowledge that have risen up among men which creates the chief difficulty in popular education; and that difficulty is, above all, aggravated by the technicalities of words and symbols, which have been perhaps unnecessarily affected, particularly by those who ridicule the idea of popular education in the profounder parts of knowledge. It is quite true that access to the most profound and exact parts of Physical Science can only be obtained through the abstruse means of mathematical investigation. But there is no room for despair. Although it is impossible, without the application of more time and labour than can be spared by the busy world, to gain a practical acquaintance with th^e profound means of mathematical investigation, it is within the reach of every one to gain tolerably just ideas of the nature of those powerful instruments of research. All mathematical truth rests, as we have seen, on intuitive principles WITHOUT THE REQUISITE KNOWLEDGE. 51 of the human mind, independently of all experience; and by ap- proaching Mathematics on this side, that is, by considering the funda- mental principles of Mathematics in their logical form, not only are the mental faculties enlarged and expanded, but the want of an inti- mate knowledge of its details is, in no slight degree, supplied to the student of the general economy of nature. To present the various departments of Mathematics in what may be termed their metaphy- sical form, should be an object with all those concerned in devising the means of placing an enlarged education within the reach of the public. It is not to be wished that men engaged in active pursuits should immerse themselves in the deep cultivation of modern mathe- matics. Geometry, in the prosecution of which every step is made clear to the mind, cannot but serve to expand the faculties; but the higher departments of Mathematics render the operator too much of a machine, and, unless when the mind is happily constituted, are very apt to spoil the faculties for use in the ordinary concerns of life. Opinions and Principles. — At the commencement of an under- taking which involves so wide a range of discussion, it is incumbent upon us to make a profession of the rule by which we are to be governed on all those occasions when, in the capacity of instructors, we have to enter upon certain momentous questions that cannot be better indicated than as falling under the heads of opinions and PRINCIPLES. Our paramount rule will be the love of truth. We repudiate the materialism which at present contaminates so much of our popular literature on subjects of science. We shall endeavour to show how groundless—how unphilosophical—are such views of the economy of the universe. We shall take pains, as often as an opportunity occurs, to make it clear to our readers that the faculties of the human mind are qualified to discover something greater than mere law in the economy of nature. We do not fear to promise that the proof of the operation and superintendence of an Infinite and Personal Intelligence will be as completely exhibited as that of the existence of any of the laws of nature which man has discovered. We shall, on all proper occasions, combat the erroneous notion, now so generally inculcated, that the discovery of a law includes all that the human mind can derive from the contemplation of nature. We know how plausible this notion may be made to appear; and how fascinating it is to think that all the complex operations of nature can be reduced within the limits of a few general laws. But we know also how many are deceived into the belief that such an explanation of the phenomena is satisfactory to the human mind, as including all which, by its constitution, it desires in the search into 52 OUR OPINIONS AND PRINCIPLES. nature. But do the popular writers who have adopted those views tell their disciples that this specious system of law is designed to supersede all idea of cause—all idea of efficiency—all idea of power —all idea of an overruling Intelligence ? It will be easy to show that such is the case, notwithstanding that some may protest that, while they insist upon the universality of law, they never fail to profess their belief in an Omnipotent Creator. We admit that it is so; but we say that it requires but small penetration to see that their logic leaves no room for that God in whom their lips alone profess a belief. Further, we affirm, and challenge contradiction, that the great apostle of such views, from whose works the ideas and reasonings of these writers are chiefly drawn, makes no such limitation in his doctrines; but, on the contrary, he explicitly declares that the age of theology in human science is gone by—meaning, by that expression, that the doctrine of universal law has superseded the idea of a Creator. We know that some persons cherish the notion that the light of nature cannot carry men to the knowledge of God. We will not, however, enter into debate on this point at present; we will only remind those to whom our argument may suggest this sentiment, that what we are contending against is altogether different—namely, the proposition latent in many popular treatises, that human science is positively adverse to the belief in a Supreme Intelligence. It would not surprise us if many of those who have become fasci- nated with the apparent simplicity of that philosophy which insists upon the universality of law, should persuade themselves that we are misrepresenting their favourite system. They have not discovered that the system involves the denial of an intelligent and infinite First Cause. We have already reminded them that the great modern apostle of the doctrines to which they listen with so much satisfaction expressly says, however seldom the impious words may have been allowed to reach their ears, that philosophy finds no place for God in nature. This philosopher is a most dangerous logician. It is not in his reasoning that flaws are discoverable; it is in his first principles, — and these first principles are exactly those which they have been seduced to think favourably of. Let them not forget that a rigid logic brings out falsehood as certainly as truth, if the princi- ples be false. Among these first principles, all the victims of this system of universal law, we have no doubt, are well familiarized with that which enunciates that, between any two events in nature reputed to stand to each other in the relation of cause and effect, there is no link discoverable except invariable sequence ; or that nothing more can be known of their connection, except that the one is uniformly the antecedent of the other — the second the uniform consequent of OUR OPINIONS AND PRINCIPLES. 53 the first. It follows from this proposition, when stated as above, without any qualification, that the term "cause" is superfluous in reference to the changes which take place in the economy of nature. Authors who have adopted such views, still employ the term cause • but when we examine the use they make of that term, we find it to be exactly synonymous with law. For example, if the question be asked what is the cause of the curvilinear path of the planets, and the answer is, that the attraction of the sun draws them from the straight line, the cause here assigned is manifestly nothing more than a reference to the law of gravi- tation. The question would "© have been answered in exactly equivalent terms, if it had been said, by the law of gravi- tation, two bodies moving oth- erwise than in the same straight line deflect each other into a curvilinear orbit; and if the one be much inferior to the other in magnitude, the less will circulate around the greater. If, then, there be no case, in the whole of nature, in which, when a change takes place, anything more can be discovered than that an invariable antecedent has been succeeded by an invariable consequent, there is no case in which the term cause is applicable in any other sense than as expressive of the law under which the change in ques- tion falls, if such a law has been discovered. And if no law including the change has been discovered, then no cause can be assigned beyond the affirmation that such and such a phenomenon has been invariably observed to succeed another phenomenon; that is to say, as a par- ticular instance of an undiscovered law. If, then, man can discover nothing but law in nature, there is no separate sense for the term cause; and if there is no room for the term cause, then there is no known instance of the evercise of power. And if man be incapable of discovering the exercise of power in the universe, then he is inca- pable of discovering the hand of God; for what is God in nature but Infinite, Intelligent Power ? Such is the logical conclu- sion from the unqualified statement that nothing is discoverable by man, in the investigation of the operations of nature, but a mere sequence of phenomena. But to this proposition we maintain that an important addition is indispensable. Man cannot, indeed, discover anything but invariable sequence in the phenomena of nature; but he never sees two phe- nomena thus succeed each other in invariable sequence, without an involuntary acknowledgment than an exercise of power has taken 5* 54 OUR OPINIONS AND PRINCIPLES. place. This is the addition required to the doctrine of law in phy- sical science; and this feeling of the exercise of power, as often as a change is seen to take place in the universe, is easily proved to be the light of nature, at every moment suggesting to men's minds the presence of Omnipotence. This point admits of easy illustration. That our earth was once destitute of every living thing, plant, or animal on its surface, admits of the clearest evidence. At a period, how distant from our time is immaterial, the earth became stocked with plants and animals. Here, then, are two states of our planet to be compared together in reference to the signal change implied in the proposition. We clearly understand that the crust of the earth may at one time have been in a liquid state, owing to the high temperature then pre- vailing at the surface. Hence all the existing water, and all the volatile chemical compounds, such as the carbonic acid, now so abun- dantly known in combination with lime, magnesia, and other earths and metallic oxides, would, at that time, form a part of the atmo- sphere. But by the simple familiar process of cooling, that crust, in the course of ages, would become solidified; the water, along with the less volatile bodies, would descend to the surface, and, dissolving the soluble substances with which it came in contact, would create in them new arrangements, from which the present character of many parts of the crust of the earth would be derived. In such changes nothing is apparent but the activity of laws and properties known to belong at this moment to the Mineral Kingdom. But although it be now known, from the evidence of chemical analysis, that all the members of the Animal and Vegetable King- doms are entirely composed of materials to be met with in the crust of the earth, never has any one property of mineral matter come to light, from which it could be justly conjectured that there is any natural tendency, in the mineral substances composing organic bodies, to pass from the mineral state into any forms of organiza- tion, however simple. Here observation is completely at fault. No fact exists to form the very embryo of an induction. The doctrine of equivocal generation held its ground only while uninvestigated; and the alleged results of the experiments of Mr. Crosse, which, if correct, would have been so easily authenticated, are believed by nobody but the credulous and partially instructed. To say that we are entitled to assume that the germs of the organic bodies exist in the minerals of the earth, is to revert to the philosophy of the an- cients—to throw aside the precepts of Bacon—to forget that induc- tion consists in first discovering facts, and then principles. If it be OUR OPINIONS AND PRINCIPLES. 55 said that this is merely an hypothesis brought forward to stimulate inquiry, we simply reply that an hypothesis which has not the shadow of a fact in its favour is no better than an idle dream. We maintain, then, that the contemplation of the transition of the earth, from a state destitute of living things to one teeming with life, forces upon the human mind, by its very constitution, the con- viction that in that vast change, so irreconcileable with the ordinary properties of the mineral matter out of which the organic world has arisen, there has been an exercise of Power—that is, of a Personal Intelligence—commensurate with the wonders of the work which has been accomplished. The philosophy, then, to which we shall uniformly conform throughout our undertaking is easily understood. We set out with the belief that there are other truths within man's reach besides those determined by observation. There are, in the first place, cer- tain necessary truths, which, independently of all observation and experience, man, by the very constituent of his nature, must believe. Of these some are intuitive, and others established by reasoning back to the intuitive truths. The conviction in each individual of his personal identity, and of the reality of all acts of consciousness, are intuitive necessary truths — also such propositions as that, when equals are taken from equals, equals remain; that things which are equal to the same are equal to one another; that things which are doubles or halves of the same, are equal to one another; that twice four are eight; and that when two are taken from four two remain. All Mathematical demonstrations are necessary truths, not intuitive, but resting upon intuitive necessary truths, being established by reasoning back to such truths; for example, that the angle in a semi- circle is a right angle, and that two tangeuts to a circle drawn in opposite directions from the same point are equal. There are also intuitive truths which are not necessary truths, — that is, intuitive truths, the opposite of which, or a greater or less deviation from which, does not involve a contradiction. The in- tuitive truths which are not necessary truths, are such convictions as the belief in an external world, and in the free agency of self; the feeling that every, event has a cause; and that there is an exercise of power whenever a natural event takes place. There are also truths obtained by reasoning back to those intuitive truths. For example, by reasoning back to the two truths that every event has a cause, and that an exercise of power is felt to have occurred when- ever a natural event takes place, we obtain the conclusion, as soon as we can combine with these the observation of the infinite extent of the universe, that there is an Infinite Omnipotent Cause. 56 OUR OPINIONS AND PRINCIPLES. Such truths we regard as the first principles on which the super- structure of man's knowledge rests. When this acknowledgment is made, we may embark on the wide ocean of physical investigation, without fear of reaching those impious conclusions to which we have above referred. When we add, that every proper occasion will be seized to develope the true grounds on which Teleology rests, without at all infringing upon the precepts of Bacon with regard to the possible abuse of final causes in philosophical investigations, we think we have sufficiently indicated the character which this work will sustain as respects Opinions and Principles. THE PHYSIOLOGY OF ANIMAL AND VEGETABLE LIEE. Order in Physiology. — The Physiology of Animal and Vege- table Life, being a subject of great extent, must be methodically treated; and first, it is necessary to determine what principle of arrangement is to be adopted, in order to exhibit, in a connected form, the complete phenomena of these kinds of existence. There are several modes in which such phenomena have been methodized ; and it will be convenient briefly to consider some of these, as exhibit- ing a general view of the whole subject. The phenomena of animal and vegetable life may be described as Mechanical Phenomena, Chemical Phenomena, Electrical Phenomena, and the peculiar Phenomena of Excitability — the first three orders being common to all departments of nature. A great part of many of the most important actions of the perfect animal body are purely mechanical or purely chemical, or partly chemical or partly mechani- cal ; while such actions are, in their remaining part, the result of a peculiar excitability. In the circulation of the blood, for example, in man, and in the animals resembling man, the blood is propelled onwards by mechanical forces, while these mechanical forces are called into activity in obedience to the laws of excitability. In the function of respiration the air enters the lungs in conformity with the laws of that part of mechanical science termed Pneumatics. The change which the blood undergoes by the contact of this air is a chemical change, or a change closely analogous to a chemical change ; while these laws of pneumatics, and the chemical laws, are brought into operation by the agency of an organic excitability. The fluids contained in the leaves of plants in contact with atmospheric air, by the influence of light, undergo a chemical change, or a change exactly (57) 58 INERT MATTER DISTINGUISHED FROM ORGANIC. analogous to a chemical change; while the leaf presents its upper surface to the light, under the direction of a peculiar excitability. Excitability, however, can hardly be defined; and in the present state of physiology it is more a negative than a positive^ term. All the properties of an organic tissue, whether from the animal or from the vegetable kingdom, which are neither mechanical nor chemical, fall under excitability. Thus, excitability is that which renders animal and vegetable tissues susceptible of certain phenomena, differ- ent from the phenomena produced by the same causes on inert matter. For example, with inert matter, the form and textures of a leaf may be exactly imitated; but such an artificial leaf will be destitute of the susceptibility to turn towards the light in sunshine. Under these several heads all the phenomena of plants and ani- mals might probably be arranged; but the arangement would be far from convenient. It belongs to the arrangement of the phenomena of organic life to point out what distinction exists between au organic body and inert matter; and the extreme divisibility of inert matter supplies the readiest ground of distinction. The divisibility of inert matter is either infinite, or, at least, such that no limit can be assigned to it— the minutest portion still retaining all the properties of the original mass. An organic body, on the contrary, is destroyed by division. Again, it seems a universal law, that living bodies alone can give origin to other living beings, either by a partial division of them- selves, or by the process of generation; whereas the origin of inor- ganic substances is always quite independent of any pre-existing substance of a similar kind. Finally, the actions of organic sub- stances, having attained their acme of intensity, gradually decay, aud at length, from causes which are inherent in each individual, cease altogether, when the substance becomes at once amenable to the operations of merely chemical and mechanical agents. Such is not the case, however, with inorganic substances, which maintain the same state unalterably, and for any length of time, provided no external agents are brought to operate upon them. But, from the very earliest times, it has been perceived that a kind of agreement exists between plants and animals; and that, in certain respects, both possess a common nature. In the fifth cen- tury before the Christian era, Empedocles taught that seeds are the true eggs of plants; and that plants, like animals, exhibit difference of sex, and a degree of sensibility. Setting out with the idea of this common nature of plants and animals, philosophers naturally next sought to discover some prominent mark of distinction between the two kinds of organic existence. Since the time of Aristotle, in the fourth century before the Christian era, the search after such a distinction has been often renewed; yet, strange to say, almost every PLANTS DISTINGUISHED FROM ANIMALS. 59 distinction hitherto fixed upon, though sufficiently obvious whon con- fined to the higher orders of plants and animals, has been found to fail when applied to discriminate those organic beings lying on the confines of the two kingdoms. The distinction pointed out by Aris- totle has been revived in recent times, though hardly with the expected success. This distinction proceeds on the ground that ani- mals receive their nutriment into an internal cavity before it is absorbed into the substance of the body ; that plants, on the contrary, absorb their nourishment by the external surface. Animals, in short, have a mouth and stomach; while plants feed by the spongioles of their radicles, and by their leaves. While this distinction to a very great extent holds good, it cannot be affirmed that it has supplied an adequate test in doubtful cases. The most recent test suggested for distinguishing whether an organic existence of doubtful aspect belongs to the vegetable or to the animal kingdom, is of a chemical character. Starch is a con- stituent of vegetable tissues; and by the blue colour which iodine imparts to starch, even when present in the most minute proportion, it can be detected, wherever it exists, with the greatest facility. This substance, starch, then, being supposed not to exist in the animal kingdom, promised to solve the long-studied problem, or, at least, to be the only test of distinction which, until very lately, could hold its ground ; but the recent researches of some German physiologists have demonstrated the existence of particles of an amylaceous nature in some of the lower animals; and even in the brain and spinal cord of man a substance, termed cellulose, hitherto presumed to be proper to vegetables, has been discovered. It is not to be concluded, however, because so great a difficulty occurs in discriminating from each other those plants and animals which stand on the confines of the two kingdoms, that the laws governing the vegetable economy are identical with those governing the animal economy. On this important point, we will cite the following passage from the recent work of one of the most distinguished of living physiolo- gists (Valentin's Physiology, by Brinton) :— " The constant physical and chemical changes which accompany life depend upon various exchanges, which are produced by the work of the different parts of the body — the extrusion of what is useless.; the assimilation of what is received; and the restoration of the organs, by which all these operations are effected. The whole of the vegetable or general organic functions on which nutrition and gene- ration depend, are repeated in every living body. It has often been supposed that all their particulars correspond in the two organic kingdoms; that there is a digestion, a respiration, a perspiration, and an excretion, in plants as well as animals. But a more accurate 60 VEGETATIVE FUNCTIONS. examination teaches that this is not the case. Vegetables possess no tissues which allow of the same kind of nutritive absorption, of distribution of juices, or of secretion, that we meet with in, at least, the higher animals. They have no large cavities in which consider- able quantities of food can be collected and dissolved by special fluid secretions. They possess no point midway in the movement of their juices, and no mechanism, other than that of a casual and secondary apparatus for the inhaustion or the expulsion of the respiratory gases. They are devoid of the changeable epithelial coverings, which play an important part in many of the animal excretory organs. In one word, the general organic functions are introduced into the two living kingdoms of nature, and probably into their subordinate divi- sions, by two different ways. This difference leads at once to the conclusion, that the structure of the animal is not a simple repetition of that of the plant, with the addition of a series of new apparatus. The nature of roe tissues, the mode of their actions and change — form, division, and destiny of the organs — all these rather teach us that animals of any development are constructed upon an altogether different plan." Whatever in the above quotation may appear obscure to those to whom physiological ideas are new, will be cleared up, we trust, by what we are about to say on the prominent distinctions between those organic existences which are unequivocally animals, and those which are unequivocally plants, with reference to a basis for the arrange- ment of the phenomena of vegetable and animal life. In physiology, the term function is of continual occurrence. What, then, does function signify? Function is the use of a part or organ. The function of the eye is sight; that of the ear, hearing; that of the lungs, the purification of the blood by ventilation; that of the stomach, digestion; that of the liver, to secrete bile. In plants — that of the spongioles of the radicles, to absorb from the soil; that of the leaves, to decompose the carbonic acid of the atmosphere, so as to appropriate the carbon for the uses of the plant; that of the anther, to impregnate the ovule, by means of its secretion, the pollen; that of the ovary, to mature the ovule into a seed. As the functions in all the higher animals and the higher plants are numerous, there is room for method in the arrangement of them. Various methods have been suggested; and, in accordance with some one or other of these arrangements, it has been common to methodize the various topics belonging to physiology. The kinds of function common to plants and animals, are properly termed vegetative functions—the same which are called vegetable or general organic functions in the quotation from Valentin. The kinds of function, not so obviously possessed by plants, so as to seem pecu- liar to animals, are named the animal functions. VEGETATIVE FUNCTIONS. 61 ...../ The vegetative functions are the functions of maintenaice; the animal functions are the relative functions, or the functions of rela- tion. The vegetative func- tions end in the organism Fig. 22. of the individual, or, at n o a b e most, in the organism of the species; the functions of relation establish rela- tions between the animal and the world without. If we follow the food, in one of the higher ani- mals, from the mouth to its incorporation, with the previously existing tissues of the body, the waste of which it is its office to supply, we shall discover what are the more imme- diate vegetative functions — the same which, by other names, are known as the functions of main- tenance; the functions of nutrition; the assimilative functions, or functions of assimilation; and the func- tions of organic life. The food — let it be a piece of meaf, or bread — is reduced to a pulp by the movements of the teeth, and the admixture of the saliva, secreted by-the sali- vary glands; it is then swallowed by a somewhat complex muscular action. It is moved about in the stomach by the contraction of its muscular fibres; and, being mixed with the gastric juice, a peculiar fluid secreted by the lining membrane of the stomach, it passes into chyme : this chyme is then, in successive portions, transmitted, by muscular contraction, into the highest part of the intestinal tube, termed the duodenum, which is a kind of second stomach, where the partially assimilated food is first mixed with the bile, and then with the secretion derived from the sweetbread, or pancreas. The mass is now ready to afford chyle, the immediate nourishment of the blood, to the absorbent 6 / DIGESTIVE apparatus of man. oesophagus; b, pancreas; c, stomach ; d, spleen; e, colon; f, small intestines; g, rectum: h, anus; i, appendix of csecum; /.-, ca»™ra; I, large intestines; m, gall-bladder and ducts; n, liver; o, pylorus and stomach. 62 ASSIMILATIVE ORGANS. vessels, termed lacteals, the extremities of which abut on the lining membrane of the higher parts of the intestinal tube, while the residue is sent downwards by what is termed the peristaltic action of the tube, for evacuation. The chyle, taken up on a very wonderful plan by the lacteal tubes, is transmitted through the singular small organs Fig. 23. Fig. 24. CHVLE VESSELS. a, thoracic duct receiving lacteal tubes from 6, the intestine; c, aorta. termed the mesenterio glands, whence, after important changes, it is again col- lected by what are named the efferent lacteal tubes; these by degrees unite together into a trunk, which joins the lymphathic vessels coming from the pelvis and the lower parts of the body, to form the thoracic duct a, commencing in the abdomen, dividing opposite the middle of the dorsal vertebrae into two the course anb termination op the branches, which soon reunite rjassine thoracic duct—after Wilson. i, i • j 4i u .r xi -i , •■ 8 2, the aorta; 7, the superior cava; b?bind fche arch Of the aorta and Subcla- io, the greater vena azygos, in vian artery, and making its turn at b which, in some mammals, the duct „i •. • ° , , .' terminates. where it receives several lymphatic trunks, terminates at the point of junc- tion of the internal jugular and subclavian veins on the left side of the neck, and into which it pours its contents. The chyle, being thus mixed with the venous blood, is carried with it to the right side A S S I M I L A T I V E ORGANS. 03 of the heart; and, by the motion of the heart, is thoroughly mingled with that blood; from the right side of the heart the blood, rein- forced by the chyle, is transmitted to the lungs, where, by exposure to the air, the venous blood is converted into arterial; the arterial blood, so rendered fit for the nutrition of the body, being sent forth from the left side of the heart, is conveyed by the aorta, the great arterial trunk, and its branches, to the capillary blood-vessels, which pervade all the sensible parts of the body. From these capillary blood-vessels, the several component textures of the living frame attract the new matter, of which they stand in need ; while that which is already reduced to the state of debris, re-enters the blood of the capillary system, and returns with the blood, now become venous, to the right side of the heart. The blood, having become impure by the admixture of the debris of the tissues, and from other causes, is purified partly by the lungs, by which a superfluity of carbon is thrown off, while, by the slow combustion which it sustains, animal heat is developed ; and partly by the kidney, of which last organ the particular office plainly is to keep the blood free from the various chemical products generated during the successive decompo- sitions which the textures and their first debris undergo. Such is a rapid sketch of the functions named vegetative in the higher animals, while it indicates the order in which each conies into operation. This sketch also indicates why the epithets nutritive and assimilative, often applied to this order of functions, are not inappro- priate; assimilative signifying the making a thing to be of like kind, and bearing reference to the object of these functions being to con- vert the aliment into a like substance with the body. Thence it appears, also, that the epithet vegetative is rightly applied to this order of functions; because all the obvious functions of plants have the same object, namely, the conversion of their aliments, such as water, carbonic acid, and ammonia, into the vegetable texture. Even in popular language, a person is said to vegetate when he does nothing to withdraw himself from the category of those " fruges consumere nati,"—born to eat and drink. How inactive soever a person may be, while he vegetates he lives. It is by the exercise of the vegetative functions that life is preserved. As an order of functions they are — some more directly, some less directly—necessary to life. Hence the vegetative functions are sometimes termed the vital functions. But the term vital, as applied to functions, having been used for ages in a restricted sense, should be wholly laid aside. By the older physiologists the term vital was confined to those functions, the uninterrupted exercise of which is indispensable to the life of the higher animals; namely, the circula- tion of the blood, the respiration, and that part of nervous action which is necessary for the continuance of the circulation of the blood G4 FUNCTIONS OF REPRODUCTION. and the respiration. It is undeniable that these three functions are pre-eminently vital. If anyone of these is arrested, even for a very short period of time, the others likewise cease, and immediate death is the consequence. Thus, there are three modes of death readily produced by accident, or disease, corresponding to the three so-called vital functions : death by the heart, death by the lungs, and death by the brain. While, however, the remaining vegetative functions — Digestion, Secretion, and Excretion, according to the terms longest in use among physiologists—may be interrupted for a time without the loss of life •—being not less necessary to life in the main than the three func- tions just referred to — they are fully entitled to the epithet vital, unless convenience altogether forbade the use of that term. The vegetative functions, then, are common to plants and animals, in so far as both plants and animals possess functions concerned in nutrition ; but the particular functions concerned in that process in plants do not exactly correspond to the special nutritive actions in animals. There is another order of functions common to plants and animals — namely, the functions of reproduction. These are commonly regarded as distinct from the vegetative functions; although, by taking a somewhat larger view of the term " vegetative," they may be properly included under that name. Thus, if the vegetative functions — namely, the functions of nutrition or assimilation — be held to terminate in the individual, whether plant or animal, then there must be adopted a separate order of functions, under the name of reproductive. But if the larger, and, perhaps, more correct view, be made choice of, that each species is one whole in physiology, having a determinate duration, from the present individuals down to the last survivors, then the reproductive functions, as necessary to the life or continuance of the species, will fall under the same defi- nition as the functions of maintenance in general. According to this view, then, the vegetative functions in plants and animals are the functions during the activity of which the life of a species continues. The non-vegetative functions are not essential to life; they are present only when the actions of the organic being do not terminate in itself, or in its species. In man, such non-vegetative functions have their highest development. They are the functions by which relations are established between the individual and the world with- out. Such relations fall under the two heads of relations of know- ledge and relations of power, — in general terms, the functions of locomotion and of sense. The same functions in man may be de- scribed as the functions of consciousness, iucluding sensation, thought, and volition. TABLE OF FUNCTIONS. 05 To this statement it need only be added that the vegetative func- tions correspond to the functions of organic life, while the relative functions are identical with those of animal life. TABLE OF THE FUNCTIONS IN MAN. I. — VEGETATIVE functions. Vital, of Old Authors. Natural, of Old Authors. Formerly separate. n.—functions of relation. Locomotion, Thought, Sensation, Voice. Such, then, is the ordinary general arrangement of the functions of animals, founded on presumed differences in their essential condi- tion— the first class, requiring for their display only a general pro- perty common to all living matter—the latter, some specific properties in addition. There is also another foundation for such an arrange- ment, in certain general ends, to which more or fewer of the several functions — independently of the individual end to which each is subservient — conjointly conduce. These general ends are three — the ultimate object of every function being either to preserve the individual in a state of life and health, to perpetuate its species, or to maintain its relation with the external world. Of these, the first extend no further than the individual, and have no ulterior end; the second is exercised for the sake, not of the individual, but of the race; and the third furnishes us with the only means which we possess of maintaining an intercourse with each other, with Nature, and with Nature's God. Their consideration is well calculated con- tinually to inculcate upon the mind the main purposes of our exist- ence as living and rational creatures; and to lead us to observe, while investigating the phenomena of each function, the admirable adap- tation of the means to the object, not only individual, but general, for which this function was appointed, and to which, in common with others, it conduces, as subservient, directly or indirectly, to the great end of our being. We pass over the systematic arrangements usually followed in studying the animal and vegetable existences, and which are com- monly discussed in physiological works. Such subjects, in our Circle of the Sciences, will fall under the general divisions of Zoology and Botany, where they will be more fully explained than could be possible in a general treatise. We therefore at once pro- ceed to the consideration of 6 * Circulation of the mood Respiration............. Digestion, Absorption... Secretion, Kxcretion.... Reproduction........... 06 ELEMENTS OF 0 R G A N I C ' M A T T E P. . THE ULTIMATE AND PROXIMATE ELEMENTS OF ORGANIC BODIES. The chemical constitution of Organic Bodies is most readily under- stood by a reference to what have been named their Ultimate Ele- ments, and their Proximate Elements. The ultimate elements are all those substances found in organic matter which rank as simple bodies in modern chemistry; that is, bodies which have hitherto resisted all further analysis. In the whole of nature, chemists admit the existence of no more than sixty-three or sixty-four such simple bodies. Out of these sixty-three or sixty-four elementary sub- stances, seventeen exist in organic nature. The proximate elements are formed by the union of several of these ultimate elements. Most commonly three or four ultimate elements unite in large proportion, while a few others are present in very minute proportion. The proximate elements, in which there are three principal ultimate constituents, are termed ternary com- pounds; those containing four are called quaternary compounds. The ultimate elements, which enter in large proportion into the ternary and quaternary proximate elements of organic nature, are the simple constituents of air and water — namely, oxygen, nitrogen, carbon, and hydrogen. As examples of the proximate elements formed out of these, united in different proportions, we may enume- rate albumen, well known under the form of white of egg, and caseine, the essential constituent of cheese — what, in short, makes up nearly the whole of well-pressed cheese made from skimmed milk; also the starch extracted from the flour of wheat and sugar; and lignine, which constitutes ninety-five per cent, of wood. As the proximate elements are made up of ultimate elements, so the solid textures and fluids of organic bodies are composed by the union of the proximate elements. By the union of textures, organs are formed; by the union of organs, the body itself is framed. Here, then, we obtain a mixed analysis of the organic frame, in part chemical, and in part mechanical. The modern idea of the organs being made up of textures, so that each might be conceived as being reducible to its ultimate mechanical elements, was a happy improvement on the ruder notion of ancient times, which represented the animal body as consisting of flesh, blood, bone, skin, hair, nail, gristle, sinew, nerve, brain, &c. What, then, is a texture ? This question is more easily answered by examples than by a definition. The muscular flesh — that is, the lean of beef or mutton — is the muscular texture or tissue; the substance of the brain and nerves is the nervous texture or tissue; the connecting medium of the several organs of the body is the cellular tissue, called also the filamentous, or areolar tissue; and these three are the PRO PERTIESO FOXY GEN. 07 best distinguished textures or tissues of the animal body. In the vegetable kingdom, the cellular tissue is almost the only texture. This kind of mechanical analysis does not admit of a rigid exact- ness ; because it is only in idea, for the most part, that the decom- position can be carried out to a complete mechanical simplicity. Hence, in a practical point of view, we do not define a texture as a simple solid, as if the next act of decompounding would bring us to the proximate chemical elements contained, in it, but content our- selves with saying, in the plural number, that the textures are the simpler solids which enter into the structure of complete parts and organs. This general view being premised, we must now look a little more narrowly—1st, into the ultimate elements ; 2ndly, into the proxi- mate elements; aud, 3rdly, into the component textures of organic bodies. The ultimate elements are divisible into two orders : those which are at once in larger proportion and more constantly present; and those which, while they usually exist in small proportion, follow a more variable rule as to their presence or absence in the several textures. In the first order, as before pointed to, stand Oxygen, Hydrogen Carbon, and Nitrogen. In the second order we find Chlorine, Iodine, Bromine, Fluorine, Sulphur, Phosphorus, Potas- sium, Sodium, Calcium, Magnesium, Silicium, Iron, and Manganese. In. a third order, two or three simple bodies might be placed, which are met with accidentally along with the proper elements of organic matter. ULTIMATE ELEMENTS OF THE FIRST ORDER. Oxygen.—This chemical element, when in the isolated state at common temperatures, exists in the form of a gas, with the properties of common atmospheric air, which is indeed oxygen gas diluted, and thereby rendered less energetic in its effects. Oxygen gas is essen- tial to the life of plants and animals; but unless diluted, it destroys both by its excessive stimulus. It supports the combustion of combustible bodies, such as phosphorus, much more vividly than atmospheric air. In combination with other bodies, oxygen exists, diffused extensively throughout the three kingdoms of nature. Besides nearly making a fourth part, by weight, of the atmosphere, it constitutes eight-ninths of the whole weight of the waters of the globe, and not far from one-half of the weight of the common crust of the earth. In the animal kingdom, it forms something less than the fourth part of the weight of dried muscular flesh, and one-half of the weight of lignine, which, as we have seen, is nearly identical with wood. There are, indeed, but few natural bodies at the earth's surface which do not contain oxygen. These are easily 08 FIRST ORDER OF ULTIMATE ELEMENT?. enumerated, — the few bodies which exist in a simple form ; carbon as in the state of diamond ; sulphur in some of its states; such metals as are found in the virgin state; the combinations of metallic bodies with chlorine, iodine, and sulphur,— for example, the beds of rock- salt, and the sulphurets of iron, copper, and zinc. The process of combustion, in which oxygen plays so important a part, is not altogether foreign to the subject of Physiology. Com- bustion is a chemical action, in which the union of one body with another is attended with development of heat, and, under ordinary circumstances, with an evolution of light. When a bit of phospho- rus is introduced into a jar of pure oxygen gas at an elevated temperature, the phosphorus unites so rapidly with the oxygen, that vivid combustion is exhibited. What, then, is the source of the heat? To resort to the common explanation, the compound formed has a much less capacity for heat than the oxygen and phosphorus taken together; hence the excess becomes developed or sensible, having been before latent. Or, the explanation may as usefully be drawn from the rule, that when a body passes from a rarer to a denser state of aggregation, as from the gaseous to the liquid or the solid state, heat is uniformly evolved. In the case under considera- tion, the phosphorus, by uniting with the gaseous oxygen, rapidly condenses it into a solid, in which state the compound exists; and so, in obedience to that rule, much heat is evolved. In most cases of combustion, the temperature of the combustible body must be raised considerably above the common temperature of the atmosphere, by some means independently of the combustion; but as soon as the union between the combustible and the supporter of combustion commences, as between the wick of a lamp charged with oil and the atmosphere, theu new heat is developed. The product of the union of the two bodies in combustion is not always solid, as in the case of phosphorus and pure oxygen gas, more frequently the product is gaseous; thus, when charcoal, a form of carbon, burns, whether in oxygen gas or in atmospheric air, the product is carbonic acid gas—the same gas which is continually dis- charged from the lungs of animals with the expired air. Neverthe- less, heat is evolved in this case,—the oxygen becoming considerably denser by the addition of the carbon. Of late, in the chemistry of the animal kingdom, the term combustion has been extended to include those processes of oxidation which take place slowly within the bodies of animals, accompanied by an evolution of heat; the distinctive name eremacausis, or slow combustion, being employed in this sense. By this eremacausis, not only do the simpler forms of carbon within the animal body become changed by combination with oxygen into carbonic acid, but the salts which contain a vege- table acid, as the acetates, the tartrates, and citrates, pass into carbon- FIRST ORDER OF ULTIMATE ELEMENTS. G9 ates of the same base, just as the tartar of wine (the impure bitar- trate of potassa) is changed by a destructive heat into carbonate of potassa, so long known, as derived from this source, by the name of salt of tartar. Nitrogen.— Nitrogen, like oxygen, exists, at the ordinary tempe- rature of the earth's surface, in the gaseous state, and possesses the common physical properties of atmospheric air. Unlike oxygen, however, it can support neither combustion nor life. It forms nearly four-fifths of the atmosphere by weight, it exists but sparingly in the mineral kingdom, and is not contained, like oxygen, in the common rocks of the crust of the earth. Its chief source in mineral nature, besides the atmosphere, is in two orders of salts, the nitrates and the salts having ammonia for their base. It exists also in the compound mineral inflammables, such as coal, justly regarded as being of vegetable origin. It exists in both the organised kingdoms of nature, yet is much niore extensively diffused in the animal than in the vegetable kingdom. Under the head of the nutrition of plants, nitrogen must come in for a large share of attention. Hydrogen. — Hydrogen is a gaseous body, and the lightest of known ponderable substances. The great source of hydrogen is the waters of the globe, of which it forms one-ninth part by weight. It does not exist in the rocks of the crust of the earth, unless in so far as they contain water. Combined with nitrogen, it is present in ammonia. It makes up about one-sixteenth part of the whole weight in the tissue of wood, and nearly the same in starch and sugar; and of dried muscular flesh it forms about one-thirteenth by weight. In such proportions, then, does the hydrogen of water contribute to the substance of animal and vegetable tissues. Carbon.— At ordinary temperatures carbon is a solid body; and its most familiar form is the charcoal of wood. Uncombined, it exists very sparingly in the mineral kingdom ; but combined with oxygen, in the form of carbonic acid gas, it exists abundantly, as in combination with earthy and metallic bases, — such as the carbonate of lime, the carbonate of magnesia, the carbonate of zinc. The carbonate of lime, as chalk, marble, limestone, marl, is one of the most abundant substances in mineral nature; and of this substance carbon forms one-seventh part by weight. In the atmosphere car- bonic acid is uniformly present, but in variable proportion. It exists also in waters. The respiration of animals and the combustion by conimou fires are continually adding to the carbonic acid of the atmo- sphere ; while the process of vegetation is as constantly decomposing it, appropriating to itself the carbon, and setting free the oxygen. In dried muscular flesh the proportion of carbon by weight is not far from one-half; and in the tissue of wood the weight of carbon is nearly three-sevenths. TO SECOND ORDER OF ULTIMATE ELEMENTS. ULTIMATE ELEMENTS OF THE SECOND ORDER. Chlorine.—Chlorine does not exist free in organic nature, but only in combination with metallic bases, or with hydrogen._ The chloride of sodium, or common salt, is a constituent of the animal fluids, and in certain classes of animals must be regarded as essential to life, because it is the source of muriatic or hydrochloric acid, the presence of which is one of the conditions of their digestion. Iodine. — Iodine exists in sea-water, in some mineral waters, and in a few minerals. Its chief source, however, is the oceanic algae or sea-weeds; it exists also in sponges; and has been detected in the oyster and other marine molluscs. Bromine. — Bromine exists also in sea-water, and in some mine- ral waters. It has been found in marine plants, and in the ashes of at least one animal, the janthina violacea, one of the testaceous molluscs. Fluorine. — Fluorine exists, combined with lime, in the bones and teeth of animals. It has been found also in the vegetable king- dom to a sufficient extent to account for its existence in the animal kingdom. In the mineral kingdom it exists in great abundance. 1 Sulphur. — Sulphur exists as widely diffused in the mineral king- dom as in volcanic products, also combined with metallic bodies, and in mineral waters; and to these sources in the mineral kingdom should be added the sulphates, — such as the sulphates of lime, as selenite, alabaster, and plaster of Paris; the sulphate of magnesia, or Epsom salts; and the sulphate of baryta, or heavy spar. In the vegetable kingdom sulphur does not exist in much profusion; the sulphates are among the salts met with in the analysis of vegetable tissues; and sulphur is particularly found in some orders of plants, as the cruciferous family and the lichens. In the cruciferous plants — such as the coleworts — the presence of sulphur is indicated by the smell of sulphuretted hydrogen, given off during their decom- position. Phosphorus. — Phosphorus hardly exists free in any part of nature. The salts which its acid combinations with oxygen form, are widely spread through the three kingdoms of nature, and appear to have important offices assigned to them in the economy of organic life. Phosphorus exists diffused through all fertile soils. The source from which these important constituents of vegetable and animal substances originally reach the soil, is now proved to be the mineral kingdom. The phosphate of lime exists in the mineral kingdom under two forms—namely, apatite and phosphorite—which, though in some districts they constitute even mountain masses, yet are not widely spread over the earth's surface. But recent chemical analysis has satisfactorily shown that minute portions of phosphates PHOSPHORUS DERIVED FROM MINERALS. 71 are everywhere spread throughout the earth's surface; so that nothing is easier than to understand, that by the disintegration of these rocks — a process at all times in activity — minute portions of phosphates are continually added to the adjacent soil. Even in sea- water phosphates have been detected. As to the existence of phos- phorus in the vegetable kingdom, the ashes of red wheat contain, according to Liebig, 94-44 per cent, of phosphates; the ashes of white wheat, 91-47 per cent.; the ashes of pease, 85-46 per cent.; the ashes of beans, 97-05 per cent, of the same salts; whence it follows that the ashes of these several substances have phosphorus present in them to the extent of 15 to 20 per cent. And as phos- phates are invariable constituents of the seeds, not only of all kinds of grasses and leguminous plants, but also of the seeds of plants in general which are fit for food, it is not too much to say, that phos- phorus, in minute proportions, is spread throughout the vegetable kingdom. In the animal kingdom phosphates make a prominent figure among its saline constituents. It has even been believed of late that uncombined phosphorus exists in the animal body, as in albumen and fibrine. If the phosphates in the human body amount to about one-fifth part of its weight, as indicated by some calculations, then every human body must contain several pounds of phosphorus. The phos- phates, and particularly the phosphate of lime, are the chief hard materials of the bones in vertebrated animals, the carbonate of lime being in very inferior proportion. In the true shells, as in those of the crustaceous molluscs, or testaceous animals, there appear to be no phosphates, the hard substance being almost entirely carbonate of lime; but in the true crustaceous animals, as in the shells of the lobster, crab, and crayfish, there is both phosphate of lime and car- bonate of lime, the latter predominating. In egg-shells there is a portion of phosphate of lime, while the predominating constituent is the carbonate of lime. The bone, as it is termed, of the cuttle-fish, contains no phosphate of lime. In the zoophytes the composition of the indurated part varies in differ: Tit animals. Madrepore con- sists entirely of carbonate of lime, without phosphate; and the red coral yields a little phosphate of lime. In the higher animals phos- phates are found generally throughout the fluids and soft parts, as well as in the skeleton. Silicon, or Silicium. — Silica, or silicic acid, is found in small proportion throughout the organised kingdoms of nature. In the animal kingdom it is met with, in trifling quantity, chiefly in the bones and in the urine. In the vegetable kingdom it performs the important office of imparting strength to the stem, as in grasses, so as to enable them to support the weight of the grain. In the stem 72 POTASSIUM DERIVED FROM MINERALS. of the equisetacea, or horse-tails, the silica is seen to be disposed in a crystalline arrangement. In the bamboos of the East Indies there occurs a deposit of pure silica in considerable masses, to which the name " Tabashen" is given, and to which various mystical properties are ascribed. Potassium. — The ashes of trees and of herbaceous plants grow- ing elsewhere than on the sea-shore, contain the carbonate of potassa; and such is the sufficient proof of the existence of potassium gene- rally throughout the vegetable kingdom. The proportion of potas- sium varies considerably in different plants; and those which contain a large proportion refuse to grow in soils not rich in salts of potassa. The carbonate of potassa was formerly called the vegetable alkali, as if it belonged peculiarly to the vegetable kingdom. But it is now well ascertained, that all the potassa of the vegetable kingdom had its original source in the mineral kingdom, whence, by the dis- integration of the rocks containing it in small proportion, new sup- plies are continually passing into soils. In the animal kingdom potassium is not found so extensively diffused. Salts of potassa exist in some of the fluids of the human body, as in the blood, the milk, the urine. The same salts are abundant in the urine of herbivorous animals; that is, the excess of potassa received with vegetable food is thrown off by the urine. Sodium. — In the ashes of sea-weeds, and of plants growing on the sea-shore within reach of sea-water, the carbonate of soda exists. Kelp and barilla are the names applied respectively to the soda ob- tained from these two sources. Soda was formerly termed the mine- ral alkali, and perhaps it is more easily obtained from the mineral kingdom than potassa, owing to its salts existing in a more isolated form in that kingdom; for example, the chloride of sodium in the shape of rock-salt and sea-water, the nitrate of soda, and natron, found in certain districts of the globe. Soda, like potassa, exists also diffused through mountain rocks in minute proportion; for example, the difference between felspar and albite, or natron felspar, is, that in the latter the potassa of the felspar is replaced by soda. Soda is more particularly the alkali of the animal kingdom. Besides the chloride of sodium, widely diffused, as already men- tioned, in the animal kingdom, the sulphate of soda, the phosphate of soda, and various combinations of soda with the organic acids, are met with, particularly jn the animal fluids. Calcium. — Lime, or the oxide of calcium, exists widely spread in organised nature. In the vegetable kingdom the salts of lime everywhere exist in minute proportion, while in the animal kingdom these salts accumulate so as to obtain a particular prominence, as has been already indicated under the head of phosphorus. Magnesium. — Magnesia, or the oxide of magnesium, exists much FORMS OF PROTEINE. 73 more sparingly than lime in organic nature. Phosphate of magnesia is a salt of continual recurrence in the chemical analysis of the parts of vegetables. Thus, in the ashes of wheat, rye, beans, and pease, the phosphate of magnesia exists to a considerable extent. It also occurs in the human blood, and in the bones. Iron. — Iron appears to possess important offices in organic nature. Its oxide exists, combined with phosphoric acid, in such seeds as wheat, rye, and pease; and the oxide is discoverable in the ashes of various kinds of wood,—for example, in the ashes of fir-wood the oxide has been found to the extent of 22-3 per cent. In the animal kingdom iron is a universal constituent of the blood. Manganese. — Manganese is found in the analysis of various woods, and also in the human hair. THE PROXIMATE ELEMENTS OF ORGANIC NATURE. The proximate elements of organic nature are divisible into the azotised and non-azotised proximate elements; that is, into those which contain nitrogen, and those destitute of nitrogen. Albumen, fibrine, and caseine are proximate elements, common to both kingdoms. According to a view which has excited much atten- tion, these three proximate elements are merely slightly modified forms of the one proximate element, proteine. Mulder, the author of this view, conceived that the compound to which he gave the name of proteine was the basis of these several substances, and that the difference in their properties depended on the circumstance that the proteine in each was united with a different proportion of sulphur, or, in some cases, of sulphur and phosphorus and salts. A degree of doubt still envelopes this view; but certain it is, that the three proximate elements just enumerated, differing as they do very materially in properties, agree very closely in ultimate composition. All the three, whether obtained from the vegetable or from the animal kingdom, consist of oxygen, hydrogen, carbon, and nitrogen, with a proportion of sulphur and phosphates; the proportion of nitrogen being about fifteen or sixteen per cent. Albumen. — This proximate element is most conveniently repre- sented by the white of eggs. It is soluble in water, and exists dissolved in the serum, or watery part, of the blood, and in vegetable juices. It is coagulated by heat; that is to say, after having been exposed to the heat indicated by the 160th degree of Fahrenheit's thermo- meter, it ceases to be soluble in water, and several chemical agents produce the same effect as heat upon it. Albumen exists in the serum of the blood; in the secretions poured into what are termed the shut cavities of the animal body, such as the thorax and abdo- men; in the humours of the eye; in the bile; in the muscular tissue; and, more or less modified, in many of the animal solids. 7 74 FORMS OF PROTEINE. It is met with, also, in many vegetable juices, and in seeds, such as nut*, almouds, &c. Fibrine. — Like albumen, fibrine is known under two forms — the coagulated and the non-coagulated. The latter is found in fresh- drawn blood and in fresh-drawn vegetable juices; but, on standing, each coagulates. In the coagulated state it exists naturally in muscular flesh, in the gluten of wheat flour, and in the seeds of the grasses. Caseine. — In milk caseine is found. It does not coagulate spontaneously, like fibrine, nor by heat, like albumen, but by the action of acids it coagulates. Cheese made from skimmed milk, and well pressed, is nearly pure caseine. The name legumine was formerly applied to a substance quite identical with caseine, found in the seeds of eguminous plants. The ashes of caseine are rich in phosphate of lime and in potass. Coagulated caseine is a compound of caseine with the acid employed in the coagulation. When milk, by long standing, seems to coagulate spontaneously, the effect is pro- duced by the previous generation of lactic acid, a portion of which has combined with the caseine. In the oily seeds, such as almonds, nuts, &c, caseine is present, together with albumen. Gelatine. — Isinglass represents the chemical body termed gelatine, which consists of carbon, hydrogen, nitrogen, oxygen, and sulphur. To speak strictly, it does not exist in the animal tissues, but is formed out of certain of these by the action of boiling water. Gelatine is soluble in hot water, and by cooling forms a jelly. It is precipated by tannic acid, and upon this property depends the for- mation of leather. The gelatinous tissues, as they are termed, are the bones, the tendons and ligaments, the cellular tissue, or filamen- tous tissue, and the membranes in general. Glue and size are formed from such tissues by long boiling. Gelatine is found to be more closely allied to albumen, fibrine, and caseine, than was at first sup- posed. It is believed, however, that it cannot be transformed within the animal body into albumen, fibrine, or caseine; and that is the reason why animals fed exclusively on gelatine die with symp- toms of starvation. Chondrine. — Between gelatine and chondrine, which forms the tissue of cartilage, there is a close resemblance ; with this difference, however, that chondrine is not precipitated by tannic acid. Horny Matter. — Of horny matter there are two varieties, the membranous and the compact. The membranous constitutes the epidermis and the epithelium, or lining membrane of the vessels, the intestines, the pulmonary cells, &c. The compact forms hair, horn, nails, &c. Feathers are allied to horny matter. Hematosine. — The colour of the blood is due to a peculiar albuminous principle, termed hematosine. UREA AND URIC ACID. 75 Globuline. — In the blood-globules, besides hematosine, there is another albuminous principle, on which the name globuline has been bestowed. Kreatine.—There has been obtained of late, from the juice of flesh, a remarkable substance, to which the name kreatine has been given. It is a crystalline compound, consisting of oxygen, hydroo-en, carbon, and nitrogen. It has neither acid nor basic properties. It is very soluble in hot water, and cold water retains a minute portion of it in solution. By the action of strong acids it is resolved into a new body, named kreatinine. Kreatine has been found, in minute quantity, in the muscular flesh of the common domestic quadrupeds, and also in that of birds and fishes. Urea. —The chief peculiar constituent of the urine is urea, which consists of oxygen, hydrogen, carbon, and nitrogen, the last being the predominant element. Although, then, the constituents of urea are the same as those of albumen, fibrine, and caseine, the propor- tions are very different. In those albuminous bodies the proportion of nitrogen is only about 15 per cent., while in urea it is 47 per cent. In those so-called forms of proteine the carbon amounts to 52 or 53 per cent. : while in urea it is no more than 20 per cent. In the former, the hydrogen is very much the same per cent, as in the latter; but the oxygen in urea is 27 per cent., while in the forms of proteine it is about 22 per cent. Uric Acid. — In uric acid th£ proportion of nitrogen is also great, while that of carbon is also considerable. The nitrogen is present to the extent of 32 per cent., while the carbon amounts to 37 per cent. Uric acid is secreted, not only by animals and birds, but also by serpents and many insects. Guano consists chiefly of uric acid combined with ammonia. Hippuric Acid.—In the urine of graminivorous animals another acid has been discovered, to which the name of hippuric has been given. In this acid there is no more than 8 per cent, of nitrogen. THE NON-AZOTISED PROXIMATE ELEMENTS OF OROANIC BODIES. Oil, Or Fat.— For sake of convenience, we still speak of the oily constituents of organic bodies as proximate elements, though, strictly speaking, the oily acids, of which these oils consist, are the true proxi- mate elements. The term fixed oil, or fat, denotes a compound of oxide of glyceryle with certain organic acids, chiefly compounds of that oxide, with stearic, margaric, and oleic acids,— two of these, and often all three, being present. In animals, fat occurs chiefly in the cellular membrane, or in a tissue connected with it. Among plants, oils occur in the seeds, capsules, or pulp surrounding tho seeds, and very seldom in the root. 70 COMPONENT TEXTURES OF ORGANIC BODIES. Starch.—Fecula, or starch, as already stated, has only lately been recorded as existing in the animal kingdom. In vegetable nature it is everywhere met with. It occurs abundantly in the seeds of the cerealia; in the tubers of tuberiferous roots, as in the potato; in the stems of palms; and in lichens. Starch, by its ready convertibility into soluble forms—such as dextrine and sugar—is well fitted to act important parts in the economy of vegetable nature. It appears to be stored up in the seeds, roots, and pith of plants, to supply materials for some of the most essential vegetable products. Gum. — The mucilaginous compound, gum, is widely spread throughout the vegetable kingdom. It is soluble in water, and in- soluble in spirit. Its precise uses in the vegetable economy have hardly yet been made known. Lignine. — The basis of wood, and of the stems and leaves of herbaceous plants, is termed lignine, or woody fibre. It is a fibrous matter, insoluble in all ordinary solvents, and is left after vegetables have been successively exposed to the effects of ether, alcohol, water, diluted acids, and diluted alakalies. Lignine forms about 95 per cent, of baked wood, and is the chief constituent of linen, paper, and cotton. Lignine, together with starch and gum, constitutes the principal mass of the vegetable kingdom. Such are the chief proximate elements of the organised kingdoms of nature; as to the rest, it would be tedious to enter upon any allusion to them at present, while such of them as deserve particular attention, will meet with the necessary mention in the further course of this treatise. THE CHIEF COMPONENT TEXTURES OF ORGANIC BODIES. It will be sufficient to exhibit a few distinct examples of the character and properties of the component textures of organic bodies, without attempting, at this stage of our undertaking, to exhaust the whole of the details which might come under this section. In the animal kingdom, as before hinted at, there are three well- distinguished textures, namely, the muscular, the nervous, and the filamentous. In the vegetable kingdom there is only one distinct texture, namely, the cellular. The muscular tissue — to confine our attention to a single fibre — has the property of shortening and elongating itself by a molecular movement of its minute constituent parts, so as to impart a mechani- cal impulse to the adjacent solids, or fluids. In the meantime the cilia, as they are termed, or the minute bodies observed in motion on membranous surfaces, may be ranked with the muscular texture, though it be still uncertain to what extent the molecular action in each is different. The nervous texture has the property of beino- so SARCOLEMMA — SARCOUS ELEMENTS. 77 influenced from without, as to -execute and regulate the movements of muscular fibres. The muscular and the nervous textures admit of little modification, retaining nearly the same structural character under all kinds of circumstances. The third texture, the filamen- tous, being merely the connecting medium of the several component parts, may be regarded as suffering various modifications, or, at least, as representing various other tissues, particularly membrane, bone, and cartilage. The Muscular Texture.—Two kinds of muscular fibre are known in the animal kingdom, and these, in the higher animals, are well distinguished from each other. One of these occurs in the voluntary muscles, and is named, from conspicuous cross markings, the striped muscular fibre; the other, found in the alimentary canal, the womb, and the bladder, being destitute of such cross markings, is termed the unstriped. In the heart and the gullet both kinds are met with. The elementary striped mus- FIG- 25. cular fibres are arranged in sets parallel to each other; the unstriped muscular fibres, on the contrary, cross each other at various angles, and interlace, being arranged like membranous organs enclos- 0 ing a cavity, which, by their contraction op striped muscle.—Phitos. Trans, constriction, is contracted. 1840 . Fragment of rlernentary fibre of an eel partially The Striped fibres are USU- contracted in water — magnified 300 diameters, allv as Ion!? Or nearlv as a, uncontracted part; 6, the contracted part. i i i • i • long, as the muscle in which they exist. They vary in diameter from one-sixtieth to one-fifteen- hundredth of an inch; they are of the greatest breadth in crusta- ceous animals, fishes, and reptiles, and of least breadth in birds. Their average width in the human body is one-fourteen-hundredth of an inch. They are not cylindrical, but more or less flattened. This primitive fibre consists of a great number of primitive particles, or sarcous elements, enclosed in a tubular organ, termed sarcolemma. The ordinary diameter of the unstriped fibre is from one-two- thousandth to one-three-thousandth part of an inch. It is doubtful if they possess a sarcolemma. The absence of cross stripes seems to arise from a less uniform arrangement of their interior particles, or sarcous elements. In the lower animals, the distinctive characters of these two kinds of primitive muscular fibre begin to be confounded, especially when the fibres become much reduced in size. The transverse stripes 7* 78 EFFECTS OF MUSCU.AR CONTRACTION. become irregular, not parallel, and interrupted; and sometimes a fibre shows the transverse stripes near its centre; in short, as the fibres become extremely minute, these anatomical characters are lost; and this may be the reason why in infusory animalcules, the wonderful movements of which they are capable cannot, even with the best microscopes, be referred to the presence of muscular structure. Each primitive muscular fibre is properly regarded as a distinct organ complete in itself; and there are instances in the animal king- dom of a striped muscle consisting of a single fibre, and this fibre containing only a single file of sarcous elements. Whenever a primitive muscular fibre preserves a rectilineal direc- tion from end to end, the movement it undergoes is simply rectili- near; but the compound organs, termed muscles, in the human body, and in the larger animals, consist of many thousands of these primitive muscular fibres : still, however, the result must be described as a mechanical traction, compounded of the rectilineal motion, in a number of minute fibres, or parts of fibres, as to length, that original rectilineal motion being the effect of molecular movement of the sarcous elements within the primitive fibres. ■ These primitive muscular fibres are plainly extravascular; that is, the minute blood-vessels which nourish them and replace their sub- stance, continually reduced to inert chemical products by the exer- cise of living action, do not enter the fibre, but merely convey the blood to its exterior surface, whence the nutrient matter is attracted into its interior. Of the nervous filaments supplying the primitive muscular fibre, a like remark may be made as respects all those animals in which nervous filaments can be traced to the component fibres of a muscle. The primitive tubules of a nerve " pass among the fibres of a muscle, and touch the sarcolemma as they pass; but, as far as present re- searches have informed us, they are entirely precluded by this structure from all contact with the contractible material, and from all immediate intercourse with it." — Physiological Anatomy, by Todd and Bowman, p. 101. Contractility. — The property of a muscular fibre to shorten itself on the application of a stimulus, and, by a quick alternation, again to return to its former length, is contractility. When, then, the contractility of a muscular fibre is spoken of, the term is to be understood in this special sense, or as indicating the quick alterna- tion of shortening and lengthening. In the works of Haller, the greatest of physiologists, this special property of muscular fibre is termed irritability. But as irritability may be sometimes employed in a larger sense, contractility appears to be the more appropriate EFFECTS OF MUSCULAR CONTRACTION. 79 term. At the same time, it cannot be denied that irritability in- cludes contractility; that is to say, that contractility of muscular fibre is a species of irritability, and the same thing may be said of excitability. The contractility of a muscular fibre, in the sense hero indicated, is a species, or form, of its excitability. The stimulants which call the contractility of a muscular fibre into activity, are either mechanical, as irritation with a sharp instru- ment; chemical, like some acid chemical fluid; electrical, like a shock of galvanism; or psychical, like the human volition. When a muscular fibre, the opposite extremities of which are attached, for example, to adjacent points of two bones, is made to fig 26. BONES OF AEM, HOLDING WEIGHT. shorten itself forcibly by the application of a stimulus, the more moveable point is drawn nearer to the more fixed point; and this is the great law on which locomotion by muscular fibres depends. Thus the fore-arm is bent upon the arm by a muscle, D, which arises from the top of the latter, and which is inserted at E, at a short distance from the elbow-joint. A very slight contraction will raise the hand, but a considerable increase of power is required to overcome a re- sisting force. Tonicity. — There is another form of muscular contraction, which may or may not be the result of the same property, modified by a difference of circumstances. In past times, however, it has been re- garded as a different property, and is known by the name of toni- city. The character of this so-called property of the muscular fibre is better taught by examples than by description. If a muscle in the living body be cut right through, each portion, after a few quivers, begins slowly to shorten itself in a permanent manner, so that an empty space is left between the two cut extremities. There being no tendency in these two shortened portions to return to their 80 SHELL OF THE LOBSTER A SKELETON. former length during an indefinite term, this effect has usually been ascribed to a property different from contractility, under the name of tonicity. Whenever, by any change of the relative natural position of the parts of the skeleton, as by fracture or dislocation, the points to which the opposite ends of a muscle are attached are brought nearer to each other, the muscle becomes permanently shortened by the same so-called tonicity. Again, if the muscles which extend or straighten a joint become paralysed, without a cor- responding loss of power in the antagonistic muscles which bend that joint, then the flexor muscles, as they are termed, become shortened by their tonicity, and the joint remains permanently bent. This explains the permanent bent state of the elbow-joints in the paralysis of the upper extremities attendant on the painter's colic, to which all artisans are exposed whose occupations bring them into daily contact with preparations of lead. Some forms of permanent lock-jaw seem to be of the same character; the muscles closing the jaw, which correspond to flexors, remaining in full vigour, while their antagonists have lost their power. Muscular Texture. — The muscular flesh constitutes a large pro- portion of the soft parts of the animal frame. In the higher animals nearly the whole of the muscles are attached to the skeleton, or are skeleton-muscles. In common quadrupeds there is a peculiar subcutaneous muscle — the panniculus carnosus — by which these animals are enabled to move the integuments, so as to shake off from their skin insects and other annoyances. In the human body there is a muscular expansion occupying the neck, corresponding to the subcutaneous muscles in quadrupeds, which anatomists term pla- tysma myoides. The platysma myoides and panniculus carnosus, in higher animals, are conceived to represent an entire system of muscles, which, in its full development, belongs to a different part of the animal kingdom. For example, in the crab and lobster, the muscles which move the limbs are inserted into the shell, which is plainly the integument of these animals, though in them it takes the place of a skeleton. Thus the muscles of locomotion in the crab and lobster are a highly developed system of subcutaneous muscles, corresponding to the platysma and panniculus, or the hypo- dermal system in mammals, and which, as opposed to the skeleton system of muscles, belongs in general, under its developed state, to all animals, with the exception of the vertebrata. As organs of motion, the ciliary processes, or cilia, might be spoken of with the muscular tissue; but will be referred to elsewhere. Nervous Texture. — The nervous matter exhibits two forms, the vesicular and the fibrous. The vesicular nervous matter is gray, or STRUCTURE OF NERVES. 81 Fig. 27. cineritious, in colour, and granular in texture; it contains nucleated nerve-vesicles. The fibrous nervous matter is white and tubular; in some parts, however, it is gray, and its fibres are solid. When both these kinds of nervous matter are united into a variable-shaped body, that body is termed a nervous centre; and the threads of fibrous matter which pass to and from it, are termed nerves. The office of the latter is called " internuncial;" that is, they establish a communication between the several parts of the body and the ner- vous centre, and between the nervous centre and the several parts of the body. Of all the solids, the nervous matter comes nearest to the fluid condition. It contains from three-fourths to seven-eighths of its weight of water. In general terms, its chemical analysis may be thus given: albumen, seven parts; fatty matter, five parts; water, eighty parts; while the remainder consists of inorganic matter, the chief of which is phosphorus, if not free, in the state of phosphoric acid. The fibrous nervous matter is most extensively diffused throughout the animal body. It enters largely into the nervous centres, and is the chief con- stituent of the nerves, which extend in every direction. Besides the tubular fibre, or nerve-tube, there is also what is termed the gelatinous fibre; the latter is much less abundant, being found chiefly in the great sympathetic nerve. In the tubular fibre, there is externally the tubu- lar membrane, analogous to the sarco- lemma of the striped muscular fibre. A white substance, called the white sub- stance of Schwann, forms an interior tube, and within that the material is transparent. The nerve-tubes lie par- allel to each other, and never branch. In the cut, a represents a nerve tube in water. The delicate line on its exterior indicates the tubular membrane. The dark, double-edged inner one, is the white substance of Schwann, slightly wrinkled, b is the same in ether. Several oil-globules have coalesced in the interior, and others have accumulated 'round the exterior of the tube. The white sub- stance has in part disappeared. The vesicular matter exists in the nervous centres; but is never found in nerves. It essentially consists of vesicles or cells, contain- O.'i wM'P '0 NERVE TUBES OF THE F.F.L, in Water anfl ether—after Todd and Btrur- mann. Magnified 300 diameters. 82 DISTRIBUTION OF AREOLAR TISSUE. ing nuclei and nucleoli. The wall of each vesicle is formed of an extremely delicate membrane, containing a soft but tenacious finely granular mass. The prevailing form is globular; but that figure is liable to be changed by packing. There is also a kind of nerve- vesicle, termed caudate, from exhibiting one or two tail-like processes. A nerve is a leash of nerve-fibres, surrounded and connected by areolar tissue. The areolar tissue surrounding the nerve-fibres is called the neurilemma : from the internal surface of which, processes are sent inwards, to form partitions between the smaller leashes and the individual fibres. The blood-vessels are distributed upon the investing neurilemma and its partition-like processes — and thus the individual nerve-fibre is, like the ultimate fibres of the muscles, extravascular. The nerve-fibres within the sheath lie in simple jux- taposition, the several fibres being parallel to each other. These fibres, which in the cerebro-spinal nerves are chiefly of the tubular kind, while varying considerably, do not exceed the one-fifteen-hun- dredth of an inch in man and the mammalia. Areolar Tissue, Membranes, &c. — The areolar tissue of recent authorities has a very perplexing number of names. Among the newer names applied to this tissue, is that of filamentous tissue. It is the tela cellulosa, the cellular tissue of the older authorities, called also cellular substance; but, in its ultimate structure, it appears to be of a fibrous character, and hence the term cellular is inappro- priate. The areolar tissue is most extensively diffused over the ani- mal body, connecting the other component parts of the frame in such a manner as to allow of a greater or less freedom of motion between them. Owing to this manifest use of the areolar tissue, the additional name " connexive tissue " has been proposed for it. It is placed in the interstices of other textures in greater or less abundance, and in a more or less lax state, according to the exigen- cies of the case. It everywhere surrounds the blood-vessels, and is hardly absent in parts supplied with blood. In the more solid parts of bone, in teeth, and cartilage, it does not exist, nor scarcely in the substance of the brain, except around the larger blood-vessels. In the muscles it connects the elementary fibres together, yet does not penetrate the sarcolemma, or touch the contractile elements within. It is remarkable, that abundant as it is in the muscles at large, it is in very sparing proportion within the substance of the heart. It exists largely immediately beneath the skin; and hence it is this lax layer of areolar texture which is the seat of the dropsy termed anasarca, and of the occasional accumulation of air termed emphy- sema. The areolar texture, moreover, surrounds all the organs, particu- larly those, like the pharynx, gullet, lumbar colon, bladder, &c, DISTRIBUTION OF AREOLAR TISSUE. 83 which have no free surface. It dips also into the interior of organs, and connects their proper anatomical elements together. It appears, however, that the importance of the areolar tissue in the parenchy- matous organs, as they are named — the lungs, the liver, &c. — has been overrated. It always attends the distribution of the blood- vessels in such organs; ''but wherever, either from the intricacy of the interlacement of the capillaries with the other essential elements of the particular organ, or the greater strength of these elements themselves, the firm contexture of the whole is provided for, while little or no motion is required between its parts, this interstitial fila- mentary tissue will be found to be confined to the larger blood- vessels, and to the surface of the natural subdivisions of the organ." — Todd and Bowman, p. 87. Under the microscope, the areolar tissue presents an inextricable interlacement of tortuous and wavy threads, intersecting one another in every direction. Of these threads, there are two kinds, the white fibrous element, and the yellow fibrous element. The threads a ' of the former are inelastic, of un- equal thickness, forming bands with the marks of longitudinal creasing, the largest of the bands being often one-three-hundredth part of an inch in width. The threads of the latter are long, single, elastic, branched fila- ments, disposed to curl when not put upon the stretch, and for the most part about the one- eight-thousandth part of an inch in thickness. They interlace with those of the white fibrous element, but there appears to be f'the ^g10"^- cavities are called the ventricles of the larynx. The mucous mem- brane, descending from the mouth and nostrils, covers and forms a lining to these parts in its passage downwards into the windpipe and lungs; so that the so-called superior ligaments of the larynx are often described as mere folds of the mucous membrane, extending between the posterior pyramidal cartilages and the protecting carti- lage. It appears, however, from more minute investigation, that these folds of the mucous membrane do actually contain an elastic substance, not less capable, under certain circumstances, of vibratory action than the true vocal cords, or true vocal ligaments. To recapitulate, then, the prominent points in the conformation of the larynx—the windpipe, called by anatomists the trachea, is surmounted by a complete cartilaginous ring, about an inch in diame- ter. This ring is the only outlet of the lungs by which air can issue from their numerous cavities, and is the only inlet by which air can penetrate from the atmosphere into the same cavities. This ring, being of a firm cartilaginous structure, is plainly incapable, under any ordinary circumstances, of dilatation and contraction. But the air is permitted neither to pass inwards, nor to come forth through the whole area of this cartilaginous ring, whether in respiration or in the exercise of voice. Its area is closed up on each side by im- pervious texture, so as to permit a passage to the air only by a chink, variable in its size, extending in the direction of its antero- posterior diameter. This chink is bounded, according to the com- mon descriptions, by the vocal ligaments. It is more accurate to say 178 CHINK OF THE LARYNX. that this chink is bounded in its anterior part by the vocal liga- ments, one on each side, and at its posterior part by the cartilaginous processes of the base of the movable pyramidal cartilages to which these cords are connected. This chink, when most expanded lengthways, is about eleven lines in length, and of this space seven lines lie between the vocal ligaments, and four between the opposite cartilaginous bases of the pyramidal cartilages, above spoken of, to which anatomists give the name of arytenoid. This chirtk, as above stated, is usually described as triangular, with its base between the two arytenoid cartilages, and its apex attached to the anterior angle of the protecting cartilage, above spoken of, to which anatomists give the name of thyroid. More correctly, at its greatest dilatation, it has a lozenge shape, with the posterior angle truncated. Thus the chink commences narrow immediately behind the thyroid carti- lage, expands between the vocal ligaments to their attachment at the base of the arytenoid cartilages, and then contracts in the space between the cartilaginous bases of these two bodies, not to a point, but to a truncated angle. The widest part of the chink, in its greatest state of dilatation, is about five lines and a half—nearly half an inch. This greatest degree of dilatation takes place during inspi- ration; during expiration, the chink undergoes a slight contraction. But during the exercise of voice, the posterior part, bounded by cartilaginous margins, as being between the base of the arytenoid cartilages, is entirely obliterated. Thus it is correctly stated, that the chink, concerned in the exercise of voice between the true vocal ligaments, at its greatest dilatation, is of a triangular shape, being entirely bounded on the sides by the vocal ligaments, and its base corresponding to the points between their attachment to the aryte- noid cartilages. As before stated, the arytenoid cartilages are attached to the upper surface of the posterior part of the basement cartilage of the larynx, or cricoid cartilage; and the vocal ligaments being attached to the bases of these arytenoid cartilages, it is mani- fest, that when these cartilages are drawn together, the vocal cords must approximate; that when they are drawn asunder, the vocal cords must recede from each other at their posterior part; that when the arytenoid cartilages are drawn backwards, the vocal cords must be put on the stretch; that when the thyroid cartilage, to the interior of which the apex of the triangle, formed with the cords, is attached, is drawn forwards, they must also be put on the stretch. All these changes are known to occur by the action of particular sets of muscles. The thyroid cartilage, which forms " Adam's apple," is connected to the basement, or cricoid cartilage, by an elastic membrane, which of itself tends to keep the thyroid cartilage nearly in the same perpendicular line with the cricoid, so as, in some degree, to stretch the vocal ligament. But there are two MUSCLES OF THE LARYNX. 179 muscles extending between the cricoid cartilage and the thyroid, by which the thyroid cartilage is drawn forwards, so as distinctly to stretch the vocal ligaments. There are also two muscles extending between the posterior part of the cricoid cartilage and the posterior surface of the arytenoid, by which the arytenoid cartilages are drawn back. These two pairs of muscles, when they act concurrently, must very much stretch the vocal ligaments. A set of muscular fibres, before spoken of, passing between the arytenoid cartilages on their posterior aspect, by their contraction causes the cartilages to approximate. Two other mjjscles, extending from the sides of the cricoid cartilage to the arytenoid, draw them asunder. Some other muscular fibres are found connecting the cartilages of the larynx; but the account of these, owing to their less importance, may be omitted. The small muscles of the larynx are represented in the an- nexed figures. The crico-thyroidei (b, fig. 88, a, fig. 89), and the crico-arytenoidei postici (6, fig. 89), extend the vocal cords in the direction of their length, and, at the same time, narrow the glottis. The crico-arytenoidei laterales (c, fig. 89), and the thyro- arytenoidei (d, fig. 89), rather relax the vocal cords. The oblique and transverse fibres of the arytenoideus (eand/<7, fig. 89) close the posterior half of the glottis. The epiglottis (K, fig. 89) forms a valve, which can be brought over the glottis by fine muscular fibres attached at b and i (fig. 89). Fig. 88. Fig. 89. 180 MOTIONS OF THE LARYNX. Such, then, are the parts of the larynx which must be explained to render the phenomena of voice intelligible. The larynx, like other organs of the body, is largely supplied with blood by the common blood-vessels. Two nerves on each side are devoted to the actions of the larynx. These nerves are from the eighth cerebral pair: the superior laryngeal nerve is expended chiefly on the mucous lining of the larynx; the inferior laryngeal nerve, derived from the recurrent of the eighth pair, sends minute filaments to the several muscles concerned in the movements of the larynx. Besides the movements of the component cartilages of the larynx on each other, attention must be paid to the motion of the whole larynx upwards and downwards. This motion takes place constantly in the act of deglutition, but also on many occasions when the voice is exercised, particularly in singing. When the whole larynx is raised, the windpipe is drawn proportionately upwards from the chest, and so put on the stretch. This movement has unquestion- ably some effect in extending the compass of the voice. It was before stated that the hyoid bone is connected to the protecting car- tilage of the larynx, and that when this bone is drawn upwards, the larynx is drawn upwards along with it. The hyoid bone is drawn upwards by muscles attached in particular to the lower jaw, and also to the temporal bone of the skull. The hyoid bone is drawn down- wards by muscles attached to the superior part of the breast-bone and to the shoulder-blade. From the upper part of the breast-bone a pair of muscles ascends, to be attached to the thyroid cartilage of the larynx, and a pair of muscles also extends between the thyroid cartilage and the hyoid bone. Thus ample provision is made for the movement of the whole larynx in concert with the movements of the hyoid bone. A few words must next be devoted to the cavities through which the air passes outwards after issuing from the larynx. Behind the larynx is the cavity of the pharynx, situated in front of the cervical vertebrae, and ascending to the inferior aspect of the base of the skull. This cavity, not improperly termed the posterior cavity of the mouth, communicates with the nostril above, and on either side, by a narrow canal, called the " Eustachian tube," with the cavity of the drum of the ear. This posterior cavity of the mouth is divided from the anterior cavity by the veil of the palate, a musculo-mem- branous movable curtain, which by its motions more or less com- pletely divides the anterior from the posterior cavity of the mouth. The movable, tongue-like valve, before spoken of, termed by anato- mists the epiglottis, overhangs the orifice of the larynx; the arches of the palate descend on either side, possessed of a muscular cha- racter. From the union of these above the uvula hangs down.. The THE HUMAN VOICE. 181 tongue, free and movable in its anterior part, forms the floor of the whole passage between the root of the epiglottis and the incisor teeth of the lower jaw. The muscular mass forming the cheeks contracts the cavity of the mouth on the sides, and the lips by their mobility variously modify the aperture, by which the air issues. Thus the air issuing from the larynx may pass out either by the nostrils or the mouth. It passes out by the nostrils when the mouth is closed, or even when the veil of the palate descends. When the veil of the palate is raised, and the mouth is opened, a free passage is afforded, through what has been called the oral canal, outwards. The oral canal is manifestly capable of much greater modification as to size, than the passage of the nostrils. "The tongue, the lips, articulate; the throat, With soft vibration, modulates the note."—Darwin. On the Human Voice.—In the investigation of the human voice, two points in particular deserve attention—first, the inquiry into the precise seat of the sounds; and secondly, into the mode in which these sounds are produced. As to the first question, it is now determined, beyond all doubt, that the sound of the voice is generated in the glottis, and neither above nor below that point. Before going further, it should be remarked that this word glottis has not always been used in exactly the same sense. "By turns," says the eminent French physiolo- gist, Adelon, " the superior aperture of the larynx, its inferior aper- ture, and the intermediate space between these two apertures, has borne the name of glottis ; but, according to the etymology of the word, derived from yx^csa., the tongue, the speech, no other part of the larynx should be called by that name but that where the vocal sound is formed—and we shall see that that part is the inferior aper- ture or chink."—Physiologic de L'Homme, ii. 256. In this sense alone, then, the word glottis is here employed, namely, to signify the aperture between the two vocal ligaments, that is, between the two inferior vocal cords, as they are sometimes called. Among the proofs that this chink, or glottis, is the seat of voice, it may be mentioned, that if an aperture exist in the windpipe, the sound of the voice ceases. Such an aperture is frequently formed in man as a surgical operation, and an opening has often been made in the same situation in animals for the purpose of experiment. Also, when an opening exists above the glottis, that the voice is not lost. Again, that though the epiglottis, the superior vocal ligaments of the larynx, and the upper part of the arytenoid cartilages, be injured, the voice is not lost: moreover, that in living animals, when the glottis is laid bare, it is seen that the inferior ligaments of the larynx which form the boundaries of the fissure termed glottis, are 10 182 SEVERAL THEORIES OF VOICE. thrown into vibration : it is known, too, that the division of the laryngeal nerves supplying the muscles, which regulate the states of the aperture, and make the vocal cords tense, destroys the power of producing vocal sounds. It is also found that sounds can be pro- duced in the dead human body by forcing a current of air from the windpipe through the larynx, provided the vocal cords be in some degree tense and, the glottis be narrow. The larynx has been cut from the body, and freed from all the parts in front of the glottis; thus, the epiglottis, the upper vocal ligaments, and the ventricles of the larynx between the superior and inferior, or vocal ligaments, the greater part of the arytenoid cartilages, namely, their upper part, may be removed — in short, if nothing remain but the inferior liga- ments or vocal cords, and these be so approximated that the glottis shall be narrow, clear tones will be produced by forcing air through it from the windpipe. Such facts as these entitle us to regard the glottis and the vocal cords, which form its immediate boundaries, as the essential source of voice, while the windpipe simply conveys air, and the cavities above the glottis, comprehending the upper part of the larynx and the air passages through the mouth and nostrils, correspond to the tube of a musical instrument, by which the sound is modified, but not generated. It has been already remarked that the vocal ligaments are com- posed of elastic tissue, and that it is owing to this elasticity that they are adapted to the office which they perform. While, then, it is quite certain that no proper vocal sounds can be produced, except in the glottis, it seems manifest that the adjacent somewhat abun- dant tissue of the same kind is susceptible of a vibration and reso- nance in unison, so as at least to modify the sounds of the voice. In reference to the second question — what is the nature of the change produced in the glottis during the formation of voice — no inconsiderable difficulty is met with. The points of debate which have arisen on this subject are, whether the vocal ligaments be a set of membranous cords obeying the laws of musical strings; if the aperture of the glottis be a reeded instrument, in which the vocal ligaments play the part of vibrating tongues; or even whether the real source of the sounds of the voice be not a molecular vibration of the air, produced by its passage through the narrow aperture of the glottis; and, lastly, whether the organ of the voice does not in part combine all these three sources of sound, so as to be at once, in some respects, a stringed instrument, a tongued instrument, and a simple wind instrument. The ancients regarded the sounds of the voice as analogous to those of a flute. According to this view, the vibrations of the larynx are of little account, the actual sounds being produced by a RECEIVED THEORY OF VOICE. 183 molecular undulation of the air. That the organ of voice is not, in some degree, analogous to this kind of musical instrument, is not to be absolutely denied, but it is certain that this is not the prin- cipal mode in which the sounds are produced. One of the earliest ideas of modern times on the subject of the voice is, that the larynx is analogous to a horn; that is to say, to a wind instrument, in which the vocal cords act the same part as the lips of the performer on a horn. Not much more than a hundred years ago arose the idea that the larynx is a set of musical cords — namely, that the vibrations of these cords, on the same principle as a stringed instrument, produce the sound, which is then conveyed outwards by the air. The prevailing opinion of the present day is, that the larynx is a wind instrument, but a reeded wind instrument. This common view may be expressed as follows :—the expired air is thrown into the lar}Tnx through the windpipe by the muscular action of the chest; the proper muscles of the larynx being con- tracted, create a sufficient tension of the vocal cords to permit them to be thrown into vibration by the impulse of the air. The sound so produced is conveyed through the mouth and nasal passages, un- dergoing various modifications in its passage outwards. Let us consider then, in the first place, what evidence there is that the organ of the voice is a reeded instrument, with a double membranous tongue. In short, the action of the organ of voice may be best ex- plained in general terms, by comparing it with the pipe of an organ. Let us suppose Fig. 90 to be the wind-tube, into which the air is driven from below; b, the stopper, in which is placed the tongue; a and if the body-tube ; and let there be a pipe, o (Fig. 91), to the wind-box, c c, and the air be driven from the bellows, ffp, through t. The air throws the tongue, a (Fig. 90), into a state of vibration, and passes out in undulating movements from the body-tube. Such is a general view of the nature of voice. An experiment has been before referred to, which illustrates tho 184 RECEIVED THEORY OF VOICE. effect of an clastic organic tissue, like that of the vocal ligaments, in producing sound on the principle of a double tongue. The ex- tremity of a tube is closed by two bands of moist elastic tissue, for example, arterial tissue, so applied as to cover the whole end of the tube, with the exception of a slight fissure between the bands. In the experiments before referred to, India-rubber, or leather, was mentioned as being employed for this purpose. Both these sub- stances produce a similar effect, but it appears that the middle arte- rial coat, being composed of the same tissue as the vocal ligaments, and having the same physical properties, forms the best kind of ar- tificial larynx. When this tube is blown through at the .free ex- tremity, the tongues not only vibrate readily, but produce a range of musical tones. To obtain a pure quality of tone, it is neces- sary that the two membranous bands should be of equal weight and breadth, and subject to equal tension, otherwise they cannot vibrate equally in equal parts of time. If the human larynx be dissected out, and the vocal cords be stretched, they will vibrate like a piece of artificial tissue, such as India-rubber or leather, in a current of air. In conducting these experiments, the same conditions must be secured as are required in the experiment with the tube, and the two membranous laminas, before referred to. For example, the inner edges of the glottis, that is to say, of the vocal ligaments, must be turned outwards to- wards each other, so that they shall be in the same plane and parallel to each other, otherwise they will not produce any sound. Hence it may be inferred, that when the tension of the vocal ligaments takes place in the living animal, they turn upon their axis, till their planes which, in the state of relaxation, are inclined to the axis of the vocal tube, become perpendicular to it, and as the edges of the glottis approximate, its chink is nearly or entirely closed, and they acquire the true vibrating position. The production of the most simple tones of the voice requires the associated action of a most extensive range of organs; for it is calculated that in the ordinary modulation of the voice, more than one hundred muscles are brought into action at the same time. As the air rushes up from the windpipe, a portion of each edge of the glottis yields to its pressure, and is curved upwards, so as to form an angle with the axis of the vocal tube, and leave between the two edges a narrow aperture, through which the air escapes. 1 he tension and elasticity of the vocal ligaments tend to restore them to the plane of their former position. The air having been rarefied below the glottis during their elevation, becomes dense from their depression, and the necessary force beiujj; again accumulated, they are re-elevated, and thus an oscillating movement, consisting of an opening and closing of the glottis, takes place, which being com- EXPERIMENTS ON DEAD LARYNX. 185 municated to the contiguous air, the sounds of the voice are produced. The vibrating edge of the glottis varies in length according to the pressure of the column of air in the windpipe, and the resistance of the vocal ligaments. When other ciicumstances are alike, the in- tensity of the voice is determined by the pressure of the column of air in the windpipe, and the range of movement described by the vibrating edges of the glottis. The pitch of the voice does not depend solely on the teusion of the vocal ligaments, but jointly on the variations which they undergo in length and tension. Magendie observed, in the larynx of a dog, that a longer portion of the vocal ligaments vibrated while grave tones were produced, and that a di- minution of length accompanied the succession of acute tones. Mayo has described the movements of the glottis in a man who had at- tempted to destroy himself by cut- ting his throat. The larynx in this case was cut through just above the vocal cords, and, owing to the ob- lique direction of the wound, an in- jury of the arytenoid cartilage and of the vocal cord on one side had occurred. When respiration was going on, the glottis was seen to be of a triangular form, but when the voice was exerted, the vocal cords passed into a parallel direction, and the glottis itself had a linear form. The posterior part of the aperture appeared to remain unclosed. The cut represents the prepared head of a corpse, after Muller. A thread e, which passes over a roller to a scale, is so applied to the larynx that the tension of the vocal cords can be increased by placing a greater weight on the scale. The action of the muscles is thereby imitated. The compressing appa- ratus seen on the wood-cut brings the vocal cords nearer to each other, aud thus produces the requisite diminution in the width of the vocal fissure. The tube f serves to convey the wind, which throws the tongue-apparatus into action. And thus, if we use the human bead, or the head of the dog, or of the pig, or of any other animal, we can imitate the voice of man, the bark of the dog, the grunt of the pig, &c. 16* 186 OBJECTIONS'TO THE TRUE THEORY OF VOICE. Membranous tongues, like those in the larynx, differ widely from a metal tongue, shutting up the aperture, and necessarily opening and closing as the air issues. Objections have been taken to the view which represents the voice as the result of sounds produced by membranous tongues set in motion by air, 1st, That the vibration of tongues consists in the periodical opening and shutting of the orifice through which the stream of air passes, this not being the case in the glottis; 2nd, That had it the structure of a reed, the edges of the vocal ligaments which open the chink would be alternately separated by the column of air in the larynx, and drawn together by their tension, while it has been found by experiment that air transmitted through the glottis gives rise to sound, notwithstanding that its edges are from one-sixth to one-fourth of an inch asunder. In these objections, however, there is a mistake as to the essential principle of reeds — for those of the clarionet, bassoon, hautboy, &c, fail to close entirely the passages through which the breath escapes; and the case is not otherwise with the natural reed, which the lips of players on the flute and horn represent. In short, a sound can be produced by a tongue apart from the surrounding framework, indicating, beyond doubt, that so much importance should net be ascribed to the usual mode of forming reeded and tongued instruments, and to the cir- cumstance of the air passing between the tongue and its frame. It has been shown that the law by which the variation in the notes yielded by the tongue of a mouthpiece or reed is regulated, is the same when the tongue is made to vibrate by a current of air, as when it is thrown into vibrations by being struck or inflected. By the same law are regulated the vibrations of vibrating rods; the fre- quency of the vibrations of two rods of the same texture and thick- ness being in the inverse ratio of the squares of their length. The note afforded by a reed without a tube is of the same pitch, whether it be the result of a current of air, or be produced by striking the tongue. The strength of the blast does not, for the most part, de- termine the pitch or sharpness of the note; but when the force of the blowing is increased, the strength of the tones is augmented. The size of the fissure between the tongue and the frame within which it vibrates, is of little consequence; when the opening is large there is a greater difficulty in obtaining the tone, but its pitch is not altered. Some slight difficulties may still exist, in the explanation of the theory of the voice as considered to be chiefly the result of a double vibrating tongue; but, altogether, as close a resemblance has been proved to exist between that kind of artificial musical arrangement and the structure of the living larynx, as can reasonably be expected in such a case. VOCAL CORDS ANALOGOUS TO MUSICAL STRINGS. 187 It was already hinted that the vocal lig-unents may possibly act not only as vibrating tongues in the pr< ducnon of voice, but also on the principle of musical strings. On this point a few words must be added. It may seem at first sight that the remark of so distin- guished a philosopher as Biot, when he says, " What is there in the larynx that resembles a vibrating string ? Where is the space for such a string of sufficient length to yield the lower notes of the voice? How could sounds, of the compass which the human voice represents, be produced by a string which the larynx would con- tain ?" weuld suffice altogether to set aside the idea of the vocal cords acting as musical strings. But Biot here seems to have fallen into error. Deep notes are still produced by a string greatly short- ened, if it retain, after a sufficient amount of relaxation, the elas- ticity required for vibration. His attention does not seem to have been drawn sufficiently to the nature of organic membranes, strips of India rubber and elastic animal membranes still retaining enough of elasticity for this purpose, after being much relaxed. There is, then fore, a peifect agreement between the vocal cords and vibrating strings,'though their vibrations, whether as strings or as tongues, are produced not by the direct impulse of a solid body, but by the mo- mentum of air. When the ordinary principles to which musical strings are subject are applied to the vocal ligaments, there is found to be a very close agreement, if allowance is made for the peculiari- ties of elastic animal substances as respects elasticity and the like. In their ordinary state, the vocal cords must be regarded as sub- ject to a considerable tension, which, however, admits of being di- minished, so as to add to the range of the lower notes. At the ordinary pitch of the voice, the glottis may be regarded as partially closed, and becoming more open as graver tones are produced; this opening of the glottis coinciding with the relaxation of the vocal cords, a double cause is afforded of the lowering of tone. When higher notes are uttered the glottis closes, assuming more of a linear form, while, at the same time, the vocal ligaments, though elongated, are thrown into a much higher state of tension. In the words, then, of Mr. Bishop, " since the vocal ligaments have been proved to extend and contract for acute and grave sounds respectively, and after death vibrate in a great measure like musical strings, we think it may be fairly inferred that they likewise obey, to a certain extent, during life, the laws of the vibrations of such strings." * * * * "It is moreover observable, that the extension and relaxation of the vocal cord, which, as we have seen, are analogous to those of a musi- cal string, produce a corresponding s-hortening and elongation of its axis, regarded as a tongue; and, lastly, since one tone only is pro- duced at a time, the vibrations resulting from the double action which appears to exist in the vocal apparatus must be synchronous." 188 THE VOCAL ORGANS THE PERFECT TYPE. * * * * "It might possibly be objected to the idea of this two-fold action, that the production of sound by the vocal cords is sufficiently accounted for by supposing them to vibrate merely as elastic tongues; but then it is found by experiment, that by artifi- cially dividing their length into two ventral segments, there results the octave of the fundamental note, which proves that at all events they vibrate as cords. In conclusion, we must bear in mind the vast difference between natural and artificial mechanism, and how- ever complicated a problem it may be to determine that constitution of the vocal apparatus, by which the thyro-arytenoid ligaments may simultaneously obey the laws of cords and tongues, yet to a physio- logist who is accustomed to meet with the most admirable contri- vances and combinations in the animal frame, the difficulty of find- ing a strictly mathematical solution is, in such a case, no objection to its truth, when the facts, as far as they have been observed, are decidedly favourable to its reality."—Cyclopsedia of Physiology, article Voice, p. 1481. It was before hinted at, that the vibrations of the walls of the tubes through which the voice is conducted may, in some degree, in- fluence its sound. In rigid tubes, the vibrations depend on the nature of the impulse propagated in the air within, jointly with the length of the pipe. So long, then, as the length of the pipe re- mains the same, and no change takes place on the material of its walls, the pitch of the sound produced by the undulations of the air within, remains unaffected. The dimensions of the windpipe, such as its length and diameter, are invariable; and, were the height of the larynx, and the dimensions of the bifid tube (the nose and mouth) through which the air issues after the formation of voice, equally invariable, the vibrations of these parts would produce no change on the pitch of the voice, the quantities being constant for each tone produced in the glottis. It has been found that, by taking tubes composed of layers of paper, of constant length, but varied in thickness, graver sounds were produced as the parieties became thinner, and that the gravity of the sound was increased by moisten- ing and relaxing the sides of the tubes. It was before noticed, that the windpipe is capable of being drawn upwards from the chest to a small extent, while the larynx is elevated, and that this tube admits of being diminished in its diameter by about one-third part. More- over, the pharynx, the mouth, and the nasal cavities are also suscep- tible of various modifications of diameter, so that the pipe, so to speak, near the middle of which the vocal sound is produced, is in a very different condition from a rigid tube. Hence, it has been con- cluded that provision is made for an invariable adaptation between the amount of tension, the vibrating length of the vocal ligaments, and the walls of the vocal tube, for the production of the ordinary OF VARIOUS MUSICAL INSTRUMENTS. 189 tones of the voice. It appears, indeed, to have been proved that the vocal tube is so short, that were it rigid, it could not influence the pitch of the note which the glottis originates. But its want of length is compensated for by the relaxation of its walls, so that it comes to vibrate synchronously, and so to give forth sounds equally grave with those of the glottis. Its effect, therefore, is to add to the force of the tone, which, without its aid, would have been found to possess less intensity. After considering this subject in every possible light, the conclu- sion appears to be that to which Mr. Bishop has come, namely, that the evidence shows " the vocal apparatus to be influenced by the air expelled from the chest, in precisely the same way as if it were a stretched cord, a reed, or a vibrating tube. Why, then," he con- tinues, " should we he.-itate to adopt the obvious conclusion that the vocal organs do, in fact, combine the properties of these various instruments, and are thus the perfect types of which these instru- ments are only imperfect imitations?" Singing. — The notes of the human voice are capable of being produced in three separate kinds of sequence. In ordinary speak- ing, the successive notes have nearly all the same pitch. This kind of succession, then, is properly termed the monotonous. Some de- viation from this monotony occasionally arises, as when certain syl- lables receive a higher intonation for the sake of accent, and when, in reading or reciting poetry, rhythm is added to the accent. In these cases, however, the deviation from monotony of pitch is too slight to require a separate head. In the expression of passion, ac- companied by vehement exercise of the voice, there is heard a sudden transition from high to low notes, or the reverse. This, then, con- stitutes the second kind of sequence in the notes of the human voice. Musical notes constitute the third mode of sequence. In music the sound has the requisite number of vibrations, and as the sounds succeed each other they exhibit that relative proportion in the number of vibrations which jointly characterize the notes of the musical scale. Of the adaptation of one sound to succeed another, so as to preserve the musical character of the succession, the human ear is the only original standard. Compass of the Voice.—In singers the compass of the voice ex- tends through two or three octaves. When the male and female voices are taken together, the entire scale of the human voice in- cludes four octaves. The lowest note of the female voice is about an cc!ave higher than the lowest of the male voice; the highest of the female voice is about an octave higher than the highest of the male. The first four notes of all voices are most commonly weak. There are two kinds of male voice, the bass and'tenor; and two kinds of female voice, the contralto, and soprano. The essential 190 DIFFERENCE BETWEEN distinction between these voices does not consist in their difference of pitch. The bass voice commonly reaches lower than the tenor, and its strength lies in the low notes; while the tenor voice extends higher than the bass. The contralto voice has most commonly lower notes than the soprano, and is strongest in the lower notes of the female voice; while the soprano voice reaches higher in the scale. It is found, however, that bass singers can sometimes go very high, and the contralto not unfrequently sings the high notes like soprano singers. The difference between the ba'ss and tenor voice, and between the contralto and soprano, is plainly, then, not one of pitch, but consists in the peculiar timbre or quality of the notes — for these several voices are distinguished from each other even when sounding the same note. The qualities of the baritone and mezzo- soprano voices are less marked; the baritone being intermediate be- tween the bass and tenor, the mezzo-soprano between the alto and soprano. MEZZO-SOPRANO. SOPRANO. The difference of pitch between the male and female voice is con- nected with the different length of the vocal ligaments in the two THE MALE AND FEMALE VOICE. 191 sexes. _ It appears that the lengths of the male and female vocal cords in repose are nearly as 7 to 5, and in tension as 3 to 2; in boys at the age of fourteen the length is to that of females, after puberty^ as 625 to 7, —so that the pitch of the voice is nearly the same. The difference in the quality of the female voice, as com- pared with that of the male, is owing to the considerable difference presentedby the two sexes in the walls of the larynx; the male larynx being much more expanded, and forming a much more acute angle in front. It is not yet clearly understood what is the cause of the different qualities of voice, as exhibited in the tenor and bass, and the contralto and soprano. As Muller remarks : " We may form an idea of the cause of these differences of timbre, from re- collecting that musical instruments made of different materials, as metallic and gut-strings, metallic, wooden, and membranous tongues, metallic, wooden, and paper pipes, or flutes, may be tuned to the same note, but that each will give it with a peculiar quality or timbre." In short, when the variations of the larynx in different indivi- duals of both sexes, and at different ages, under the various cir- cumstances more or less favourable to the development of the respi- ratory organs, are considered, as well as the remarkable fact that every human being is characterized by a speaking voice peculiar to himself, we shall be at no loss to understand why the singing voice should vary in different persons, not only in pitch, but also in quality. The voice termed falsetto has much engaged the attention of phy- siologists. Most singers, particularly males, besides their natural voice falling under one or other of the before-mentioned characters, have the power of producing a double series of notes, of a different description. To the second series of notes the name of falsetto is applied. The notes of the natural voice — called also chest-notes— are fuller, and distinctly indicate a stronger vibration and resonance, while the falsetto voice has more of a humming character. It is only with the natural voice that the deep notes can be produced, while the highest notes of a male voice are falsetto. The notes be- longing to a middle pitch may belong either to the natural or the falsetto voice. Thus the two registers, as they are termed, of the voice are not bounded in such a manner that the one ends where the other begins, as, through a certain compass, they run side by side. It is remarked that the bass voice becomes falsetto lower in the scale than the tenor. In the female voice there is less seldom presented very marked distinction between the natural and falsetto registers. In a human larynx detached from the body two distinct series of tones can be produced, when the tention of the vocal cords is very slight. One of these scries corresponds to the tones of the ordi- 192 N A S A L I N T 0 N A T 10 N nary voice, the other to the tones of the falsetto voice. With a certain degree of tension of the vocal cords both these kinds of tones may be produced; sometimes the one kind, sometimes the other, being heard. With a different kind of tension of the cords, notes of the falsetto character are constantly produced, whether the cur- rent of air passing through the glottis be forcible or feeble. If the vocal ligaments be much relaxed, the sounds of the ordinary voice always result, whether the current be feeble or forcible. When a slight tension of the ligaments is kept up, the falsetto is most easily produced by blowing very gently; while if the blowing be more energetic, the sound belongs to the ordinary voice. Thus, two dif- ferent notes may be produced, under the same degree of tension of the ligaments, by a different force in the blowing; and the distance of these two notes from each other may be as much as an octave. "The real cause," says Miiller, "of the difference between the fal- setto and the notes of the natural voice is, that for the former the thin aperture only of the lips of the glottis vibrates, while for the latter the whole breadth of the cords are thrown into strong vibra- tions, which traverse a larger sphere." The peculiarities of the voice in different individuals must be chiefly dependent on the parti- cular form of their air-passages and of the lining membranes, and the consequent differences in their mode of resonance. That such causes are adequate to produce all the varieties of the voice in indi- viduals, appears from the circumstance that niaDy persons, by alter- ing the form of their vocal organs, can imitate the various tones of the voices of other individuals. The usual quality of the voice is determined by like causes. This nasal tone appears to be given to the voice in two ways; thus a nasal sound is produced, though the external openings of the nostrils be closed when the arches of the palate approach each other, and the larynx ascends higher than in the natural voice. When the nostrils are obstructed by mucus a nasal sound is produced ; this obstruction having the same effect as the voluntary closure of the anterior open- ing of the nostrils. In the second mode by which the nasal sound is produced, the nostrils are open, the larynx ascends considerably, the arches of the palate contract, the upper surface of the tongue ascends towards the palate, so that the air passes between the nar- rowed arches of the palate, and receives the resonance of the nasal cavities without that of the cavity of the mouth. The deficiency of tone in the voice of old people arises from the ossification of the cartilages of the larynx, and the altered state of the vocal cords. It is unsteady, owing to the loss of nervous command over the muscles. The strength of the voice depends partly on the extent to which the vocal cords are capable of vibration, and partly on the great capa- WHISTLING. 193 city of the chest, and the fitness of the various parts over which the air passes for communicating resonance. The intensity or loudness of a given note cannot be rendered greater by the mere augmentation of the force of the current through the glottis. Such an increase of force in the current will raise the pitch both of the natural and falsetto notes. It is therefore concluded that the variation in the intensity of a note, without the alteration of its pitch, must depend on some other cause than the mere change in the force of the cur- rent. Such a provision plainly lies in the power of modifying the tension of the vocal cords. To render a note more intense, without increasing its pitch, the vocal cords must be relaxed in proportion as the force of the current of the breath through the glottis has increased. When it is desired to render a note fainter, an opposite mode of action must be adopted. The failure of perfectness in the notes of the human voice may arise from many causes. Variations in the temperature of the atmosphere, and in its states of humidity, have a powerful influence on the pitch of the voice. While a cold, moist state of the atmos- phere prevails in England, the voices of singers become lower by two or three notes, while they regain their usual pitch when the air becomes dry. Mr. Bishop mentions that when Grassini came to England, owing to the change of the air from that of Italy, her voice became one octave lower. After singing for two or three sea- sons her natural voice returned, but it had lost its attractions with the loss of the low tones which had gained her so great applause. After long singing dissonance of the voice is apt to arise; this is easily accounted for by the slight changes produced on the vocal cords in consequence of repeated tension, together with the fatigue of the muscles concerned, which, as in other cases of muscular contraction, at length cease accurately to obey the will, and hence arise unsteady movements. Whistling.—Before leaving the subject of the human voice, whistling deserves a few words. The sound in whistling does not arise from the vibrations of the lips. Several experiments prove that the lips are not thrown into vibrations. They may be touched, covered, or may have a disc of cork with a central hole placed between them, and yet the same sounds will be produced. It has been supposed, then, that the air is thrown into sonorous vibration by friction against the borders of the opening. According to Miiller, the cause of the vibration is the same friction of the air; but the vibration produced upon the borders of the opening throws the whole column of air in the mouth into vibrations, and these by a reciprocal influence, determine the rapidity of the vibrations of the air at the orifice. The only difference, according to him, between whistling and the sounds of a pipe is, that in whistling the whole 17 194 SPEECH. column of air is in constant progressive motion through the tube and orifice, while in a pipe the air in the tube merely vibrates, and does not move as a current. Speech.—Speech is peculiar to man. Because speech is not pos- sessed by individuals deprived of the organs of voice or of hearing, it is not, therefore, to be concluded that it originates in the mere possession of these organs. Inferior animals are fully provided with the organs both of hearing and of voice, and yet, in all essential respects, they are destitute of speech. Speech, therefore, must be considered under the light of a potentiality of man's intelligence, the condition of the exercise of which is the presence of the organs of hearing and of voice. That is to say, man is born susceptible, by the development of his nervous system, of the acquisition of speech, provided his organs of hearing and voice are perfect. But if man be born susceptible of speech, it may be asked, why does not the deaf-mute invent a language ? He does invent a language, but it is a language of expression independently of speech; he fails to express his inward feelings by the use of speech, because the defect of hearing prevents him from discovering the sounds which his voice is capable of producing. His language, therefore, is con- fined to the other modes of expression by which an intercommuni- cation, however, imperfect, can be carried on between men. The deaf-mute might undoubtedly carry the use of the natural signs of expression much farther, were he not overwhelmed and overpowered by the multitude of ideas which his fellow-men around bim possess, and are continually striving to make him understand. It may also be asked if, owing to this natural susceptibility of speech, every infant should not invent a language. In so far every infant does invent a language, but as, long before any progress is made in its language, the sounds which it continually hears are caught up, it is impossible to judge to what extent each individual is capable of car- rying such an invention. There is no more interesting speculation than to consider the se- veral steps by which language must have arisen among men. It is easy to understand how, in the rudest community of mankind, con- ventional signs must have arisen of every description; nor is it dif- ficult to perceive that those sounds of speech which are most easily produced would quickly form a large share of those conventional signs. But it forms no part of our present design to investigate the origin of languages; it is more to the purpose to consider, in a few words, how men came to understand the several acts concerned in speech. At a certain period, then, in the progress of mankind, it appears that languages of no inconsiderable extent had already been formed, and yet that no attention could have been paid to the indi- vidual sounds composing those languages. Men spoke, and in that REPRESENTATION OF SOUNDS BY SYMBOLS. 195 speech employed words without the least reference to letters, and perhaps with none even to syllables. The curious inquiry, then, which arises is, in the first place, how men were led to reduce speech to letters; that is, to analyse words into their elementary sounds. We may suppose that the difficulty of pronouncing certain sounds, such as the words of a foreign language, must have been the first circumstance which would lead men to reflect on the modes by which speech is produced. Man's natural curiosity would not fail to en- gage him more largely in this inquiry as soon as the subject was suggested. Little progress, however, could be made in this pursuit till some method of fixing the sounds by name, and of representing them to one's self, or to others, at periods more or less distant from their first recognition, was invented. It may be supposed that men had already acquired the art of depicting objects of sight, were it no more than rude representations made with a rod on the sands left by a receding sea. The idea, however, of representing a sound by such a symbol is plainly not of the same kind. To think of repre- senting a sound by a symbol is manifestly a fresh step in discovery. It required, in short, an effort of invention to produce such a stretch of thought. But the moment the idea arose all difficulty must have vanished. Nothing was easier than to observe the similar simple sounds occurring in the compound sounds which constitute speech. The mere observation of the form of the mouth, as certain simple sounds are uttered, would be sufficient to afford a foundation for this kind of knowledge. What the original symbols corresponding to our modern alphabets were, is of little moment. The first alpha- bets, doubtless, consisted of the representatives of but a small num- ber of sounds. It is easy, however, to perceive that as soon as this kind of investigation was fairly commenced, it would make rapid progress, there being no great difficulty in discovering the collocation of the several parts of the mouth concerned in the production of most of the simple sounds. Thus, by an easy analysis, syllable- sounds would be reduced to letter-sounds, and each letter would quickly come to be marked by a particular symbol. The most re- markable effect of this great discovery, simple as it seems to us, would unquestionably be the rapid multiplication of sound-symbols — that is to say, the vast extension of language. The greatness of the discovery hardly strikes us at the first sight. Some idea of the character of it is obtained from the fable of words spoken becoming frozen at, the moment in their fixed forms, and not reaching the ear until the return of a more genial temperature. Letters, in short, are the pictures of sounds, by which any sound now pronounced is perpetuated, while the picture itself, or a copy of it, shall endure. Speech, then, consists of combinations of sounds produced in the larynx, and variously modified in their transition through the oral 196 CONVERSION OF VOICE INTO VOWEL SOUNDS. or nasal passages outwards. No language exhausts all the sounds which can be produced in the passage of the voice outwards in this manner. Languages may be described as composed of those sounds which are most easily produced in the passage of the voice from the larynx outwards into the atmosphere. And languages differ from each other chiefly by presenting various predominant groups of such sounds. The chief distinction of the sounds of speech is according as they are transmitted through the oral canal before spoken of, or the nasal passage. Another important distinction between articulate sounds is, that some are only of momentary duration, taking place during a sudden change in the conformation of the mouth, and are not capable of prolongation by a continued effusion of the breath, while others can be prolonged all the while that a particular dispo- sition of the mouth and a constant expiration are maintained. The same sound produced in the larynx is converted into any one of the vowel-sounds merely by a modification of the parts of the mouth through which it passes. The parts of the mouth concerned have been termed the oral canal and the oral opening. The oral canal, it is to be remembered, is the space between the tongue and the palate; the oral opening is the aperture formed by the lips. Some physiologists have described five degrees of size in each of these two parts — that is, five degrees of size in the oral canal, and five degrees of size in the oral opening. One sound, then, produced in the larynx is converted into a, e, i, o, u, according to the modifi- cations in the size of these two parts. Thus when the size of the oral canal is in the third degree, and the size of the oral opening is in the fifth or highest degree, the act of voice is converted into the sound of the English a in far. When the size of the oral canal is in the second degree, and that of the oral opening in the fourth de- . gree, the sound of the English a in name is produced. When the size of the oral canal is in the first or lowest degree, and that of the oral opening in the third degree, the sound of the English e in theme is produced. When the size of the oral canal is in the fourth de- gree, and that of the oral opening in the second degree, the sound of the English o is produced. When the size of the oral canal is in the fifth or highest degree, and that of the oral opening in the first or lowest degree, the sound of u like oo in cool is produced. Of the general truth of this statement any person may satisfy him- self by remarking, when he utters the broad a, how much he opens his mouth, simply breathing forth the voice with open mouth. When, on the contrary, he with the same breath attempts to pro- nounce e, he finds the mouth close considerably, and the tongue rise towards the roof of the mouth, so as to contract the oral canal. In pronouncing o he will observe how the lips are thrown into the form of the letter, the tongue at the same time raised from the bottom SOUNDS OF CONSONANTS. 197 of the mouth. The form of the vowel o in most languages points to one source of origin of those representations of sounds which we call alphabets. Some consonants, like vowels, can be pronounced with an unin- terrupted sound, which continues as long as the expiration can be prolonged, the disposition of the parts within the mouth remaining throughout as at the commencement of the sound. Of these, the aspirate h is pronounced with the whole oral canal open; no inter- ruption is offered to the passage of the breath; its sound is the simple result of the resonance of the walls of the cavity during ex- piration. Others of the same class, such as m, n, and ng, are pro- duced by continuous expiration through the nasal canal, the aperture of the mouth being closed either by the lips, or by the tongue being pressed against the palate. The mouth is closed by the lips while m is pronounced, the sound being produced by the simple passage of the air through the nasal cavity. When n is pronounced, the mouth is closed by the extremity of the tongue being pressed against the fore part of the palate. Ng is regarded as a simple sound in the words sing and bang. It is produced also by the passage of sound through the nostril, while the posterior part of the tongue is pressed against the palate. Other consonants, again, of the same class, are continuous sounds developed by the valve-like application of different parts of the mouth to each other, such as/, s, r, I. F is pronounced by the application of the lower lip to the teeth. In pronouncing s, the teeth are brought into contact with each other, while the point of the tongue touches the lower teeth; in the sound of r, the tongue vibrates against the palate; in the sound of /, the point of the tongue is applied close to the palate, and the air escapes between the tongue and the cheeks. The English th is a modifica- tion of s. The mute consonants with explosive sounds are next to be spoken of. The organs of speech by which these sounds are formed un- dergo a sudden change of position during their production. The sound commences with the closing of the mouth and terminates when it opens—that is to say, these consonants cannot be prolonged at pleasure; b, g, d, of which p, k, t are modifications, coming under this head. In sounding b, the lips are brought together and elose the mouth, while they separate agaiu at the moment the air is expired. In sounding d, the tongue is applied to the anterior part of the palate, or to the upper teeth, so as to close the mouth, which opens with the escape of the breath. In soundings — that is, the hard g, as in gold—the momentary closure of the passage through the mouth takes place, more posteriorly, by the application of the back part of the tongue to the palate. In sounding^, I, and k, the requisite modifications of b, d, and g are produced by a stronger as- 17* 198 VENTRILOQUISM. piration during the opening of the mouth, which was previously closed. All the sounds hitherto mentioned are capable of being pronounced in a whispered speech. The English y and z cannot be uttered without an accompanying vocal sound. Thus, when an at- tempt is made to sound the English y in a whisper, the German ch is produced in its stead. All the vowels are capable of being pro- duced equally in whispered speech, and with a vocal tone. Many consonants also, as/, s, r, I, m, n,ng, can be pronounced either with mute sounds or with vocal intonations. The continuous consonant h can only be pronounced in whispered voice; and it is quite impos- sible to combine the sounds of the explosive consonants, b, d, g, and their modifications, p, t, k, with an intonation of the voice. Besides the ordinary sounds of consonants which enter into the formation of languages, other sounds are capable of being produced in the mouth and throat. The smacking sounds produced by the separation of the teeth from the tongue or palate, are reported by travellers to occur in the language of the Hottentots and in those of other African tribes. The several sounds and tones of language can even be imitated by artificial contrivances. When the sound of the voice is made to pass into a cylindrical tube, before which the hand is held, and then withdrawn, the sound of b is produced; and if the tube be a pipe with a membranous tongue, the sound of v is produced. Various speaking machines, by attention to such principles, have been con- structed ; the most perfect of these is that contrived by Faber. The automaton invented by him has a singing voice extending over twelve notes. The difference in the height of the notes is made by varying the width of the glottis without tension of the cords. In this respect it is hardly an exact model of the human organal voice. The singular faculty possessed by ventriloquists has engaged much of the attention of physiologists. Many different views as to the nature of this kind of speech have been at various times brought forward. One of the oldest and most common ideas on this subject is, that ventriloquism consists in speech produced during inspiration. It is unquestionably possible, though not without difficulty, to articulate during inspiration, and the sounds so produced have some resem- blance to the tones uttered by a ventriloquist. A more recent view of the nature of ventriloquism is, that it is a mere imitation, produced in the larynx, of the various modifications which the voice ordinarily suffers from distance, by the interposition of a partition, as if the individual were enclosed in a narrow space, — in a trunk, a cask, or the like. This view has been supported with much ingenuity by Magendic. The distinguished German physiologist, Midler, has adopted an STAMMERING. 199 idea on this subject which coincides better with the original name of this artifice. He says that the notes of ventriloquism are pro- duced by inspiring very deeply, so as to protrude the abdominal con- tents by the deep descent of the diaphragm, and the diaphragm being retained in this position, by speaking through a very narrow glottis, expiration is performed very slowly by the lateral walls of the chest alone. He affirms that the quality which the voice has in speaking through an expiration thus performed, is that peculiar to ventriloquism, aud that sounds may be thus uttered which resemble the voice of a person calling from a distance. A very large share of the artifice practised by the ventriloquist, particularly in the imitation of voices coming from particular direc- tions, lies in the deception of other senses besides the hearing. The directions in which sounds reach the ear are never very easily distin- guished^ and when the attention is drawn to a different point, the imagination is very apt to regard the sounds produced as coming from that quarter. Of the imperfections of speech, stammering is that which has been chiefly investigated; and it lies in a momentary inability to pro- nounce a consonant or vowel, or to connect it with the preceding sounds. This impediment may occur either in the commencement or in the middle of a word. When the impediment arises in the middle of a word, the commencement of the word is often several times repeated. Hence stammering is apt to be defined as the suc- cessive repetition of one sound. The repetition of the commence- ment of the word, however, is not the essential defect which consti- tutes stammering; it merely marks repeated attempts to overcome the difficulty. Neither is it correct to say that the difficulty in stam- mering lies chiefly in pronouncing the consonants, for the impedi- ment most frequently occurs in the case of vowels. The best account which has been given of the nature of stammering is, that it depends on the momentary closure of the glottis, so that the passage of the air necessary to the pronunciation of the particular sound is arrested. In persons severely affected with this impediment, there are manifest indications of the struggle at the glottis, occasioned by the impedi- ment to expiration, in congestion of blood in the head and in the veins of the neck. The real cause of stammering, therefore, must be described as an unusual movement in the larynx, associated with the articulate movements. In short, stammering is a temporary spasmodic affection of the glottis. For the prevention of stammer- ing, the proper plan is to endeavour to bring the associated move- ments of the larynx with the organs of speech more under the com- mand of the will. To sing words is one method of obtaining this effect; since in singing more attention is directed to the action of the larynx than in ordinary speaking. Moreover, it is observed that 200 DUMB SHOULD BE TAUGHT TO ARTICULATE. persons who stammer pronounce better in singing than in mere speaking. The raising of the point of the tongue towards the palate has some effect in counteracting this habit, and this elevation of the tongue seems to have been the object of the plan practised by the ancTents, of placing bodies, such as pebbles, under the tongue. Miiller recommends for the cure of stammering that the patient should prac- tice himself in reading sentences in which all the letters which can- not be pronounced without a vowel sound — namely, the explosive consonants, b, d, g, p, t, and k—are omitted, and only those conso- nants included which are susceptible of an accompanying intonation of the voice. He also directs that all those letters should be very much prolonged. He says that by this means a mode of pronun- ciation will be attained in which the articulation is constantly com- bined with vocalization, and the. glottis, consequently, never closed. As already mentioned, dumbness is dependent, not on the defect of the organs of speech, but on the absence of hearing. By assidu- ous efforts deaf-mutes learn the movements of articulation by means of their sight. The speech which they acquire is most commonly harsh, owing to the want of the sense of hearing to regulate their articulation. There was no discovery hailed with greater interest than that of teaching the dumb to speak; and undoubtedly, harsh though the sounds be—and yet they are not always disagreeably harsh—there can hardly be a greater triumph of human art. It will hardly be believed that some innovators on the education of the deaf and dumb seek to abolish the practice of teaching them to articulate, on the ground that their harsh speech is unfitted for the uses of societ}', and that they can communicate with their fellows sufficiently by other means, as by speaking on the fingers and by writing. This is a most unwarrantable view of the case of these unhappy persons, particularly when they belong, as by far the major part of them must do, to the labouring classes of society. We have only to consider how many persons one in the condition of a laborour must meet with daily who cannot write, or read writing, to be satis- fied that this innovation on the education of the deaf and dumb should be at once put down in every institution in which it has gained a footing. There is every reason to believe, that in propor- tion as a knowledge of the mode in which the sounds of the human voice in speech are produced becomes better understood, the artifi- cial articulation of the deaf and dumb will become less and less harsh and disagreeable. Comparative Physiology of Voice.—Organs of voice occur among inferior animals, in the mammalian tribes, birds, and reptiles. In mammals the organs of voice bear a close resemblance to those of man. In birds considerable modifications occur on these organs. In reptiles the apparatus of voice is of greater simplicity. MUTE MAMMALS. 201 Fia. 93. Voice of Mammals.—Among mammals some are mute, and yet these are not always deficient in those parts of the larynx which are most essential to voice. Among the orders which compose the class mammalia, the ceta- ceans, consisting chiefly of the whale tribe, are often described as mute. These animals, however, are not mute altogether, but pos- sess only a single lowing note, or at the utmost they have the power of simply bellowing. There are two distinct sections of cetaceans. The first includes what have been termed the herbivorous cetaceans, such as the sea-cow, the representative of the popular mermaid, and the dugong. The second order includes the common cetaceans, popu- larly known as blowers. The act of blowing, from which they derive their name, consists in the expulsion of water by the nostrils; that is, along with their prey they receive a large quantity of water into the mouth, and while the mouth remains closed they blow out this superfluous water by a hole in the upper part of the head. This expulsion of water is pro- duced by means of a peculiar arrange- ment of the veil of the palate. The water accumulates in a sac situated at the external orifice of the cavity of the nose, whence, by the com- pression of powerful muscles, it is violently expelled through a narrow aperture pierced on the summit of the head. By this contrivance these animals throw forth those jets of water which are seen by mariners at a great distance. The larynx has a pyramidal form, and penetrates into the posterior portion of the nostrils to receive air, and conduct it to the lungs, without the animal being obliged to raise its head and mouth above water for the purpose. As there are no projecting laminae in the glottis, they can hardly be said to have the proper organs of voice, section op tongue, pharynx, and larynx , , .1 ■ i i of porpoise—Museum of College of Sur- and thus the noise they make may geons of London. be described as a simple vehemence ''^^^^^^ of expiration. The larynx, however, in these animals is highly developed in other respects. pha- open. 202 VOICE OF RUMINANTS AND PACHYDERM ATA. Among the animals commonly described as mute is the giraffe or camelopard, termed by naturalists Cameleo-pardalis giraffa. In the giraffe the vocal ligaments appear to be absent. The armadillo (Dasypus) is another of the mammalians described as mute. The only peculiarity of the larynx which has been ob- served is, that the epiglottis, or valve-like cartilage of the larynx, is bilobed. The armadillo, it will be remembered, is remarkable among mammals for the scaly, hard, bony shell, composed of pave- ment-like compartments, which cover the head, the body, and even the tail. These animals belong to the order termed Edentata. They live in burrows, which they excavate. To the edentata also belong the ant-eaters (Myrmecophagee), which are regarded as mute. In the same order is found the sloth (Bradypus tridactylus). In this animal, however, vocal ligaments are found, and the windpipe is convoluted. The voice is a plaintive melody, consisting of an ascend- ing and descending scale of the hexachord. Among the Bodentia, or gnawers, the common porcupine of Eu- rope is mute. In this animal it has been ascertained that there are no vocal ligaments. Such, then, are a few examples of the animals in the class Mam- malia, which are mute, or nearly mute. In the order lluminants we find animals possessed of a sonorous voice, exemplified particularly in the ox. In the ox the larynx is well developed; there are no superior vocal ligaments, but the infe- rior or true vocal ligaments are strong, and nearly an inch in length; the windpipe consists of fifty-two cartilaginous rings, that is, nearly three times as many as they number in man. The voice is sonorous, intense — pitched in C = 256 vibrations in a second. The sheep belongs to the same order of quadrupeds. The larynx differs from that of the ox only in dimensions. The voice is gut- tural, pitched in F = 341 vibrations in a second. To the same order belongs the camel (Camejus Bactrianus). In the camel the larynx is well developed; the superior vocal ligaments are present, and the inferior vocal ligaments are strong. The voice is grave, but seldom exercised. Jn the Pachydermata, or thick-skinned animals, there are many species possessed of a sonorous voice. Among these are the horse, the ass, the hog, the rhinoceros, and the elephant. In the horse the larynx is highly developed, and the windpipe has as many carti- laginous-rings as that of the ox. The superior vocal ligaments are not prominent. Above the junction of the proper vocal ligaments, between that and the epiglottis, there is an oval cavity, and on the posterior surface of the epiglottis there is a groove, furnished at its base with a semi-lunar membrane. To this membrane much effect has been ascribed in the production of the peculiar neighiug of the LARYNX OF THE ASS, MULE, ETC. 203 horse. It is doubtful, however, if this peculiar sound be so much dependent on this membrane as has been believed. Fig. 94. Fig. 95. LARYNX OF CAM3L LAID LARYNX OF HORSE—Bishop. open — Bishop. a, epiglottis; 6, semi-lunar membrane; a, epiglottis; 6, superior c, aperture at base of the epiglottis; vocal cords; c, inferior; d, groove; e, ventricles; /, arytenoids; d, arytenoid cartilages; g, inferior vocal cords; h, trachea. e, vertical ridge; h, tu- bercle ; /, trachea. In the ass the larynx is also well developed. In the windpipe the rings are spiral. The bray of the ass — which seems greatly to depend upon the presence of two large sacs placed between the vocal ligaments and the internal surface of the thyroid—is well known; it has a range of about five tones. In the mule the larynx resembles that of the ass. The voice is a species of bray, more resembling that of the ass than the neighing of the horse. The tapir (Tapir Americanus) has some peculiari- ties in its larynx. It has, however, superior vocal ligaments, which are short and distinct, and inferior vocal ligaments, which are strong. The voice is a species of whistle. The hog (Sus scrofa) has also some peculiarities in its larynx; its voice, as is well known, is a grunting, discordant sound. The rhinoceros is remarkable for having the superior vocal cords very prominent. 204 ROAR OF THE LION. Fig. 97. In elephants the larynx is largely developed. The superior vocal ligaments are indistinct; the inferior or proper vocal ligaments are strong. The windpipe exhibits thirty rings, which are often par- tially subdivided, as in the case of the bronchial ramifications. The voice, aided by the trunk, is intense, and of a grave pitch. Under the head of Marsupial animals, we find the kangaroo and the opossum. Fig. 96. In the kangaroo (Macro- pus major) several peculiari- ties occur in the larynx. In particular, the vocal cords are membranous, and fold upon themselves, so that they can- not be stretched by the ary- tenoids. The voice when in pain consists of a piteous A. lateral view of larynx moan. In the opossum (Di- of didelphis opossum. delphis opossum) the vocal a, thyroid cartilage; fc, cri- ligaments are very short, coid; c, cricothyroid hga- . ° . . . J m. ' ment; d, trachea. hence the voice is acute. -J he B. posterior view of the opossum purrs JiKe a cat. SAME- In the order Carnivora we c, cricoid; e. laryngo-tra- find examples of animals with cheal ligament; d, trachea. • .„„______;__ intense voice. In the lion (Felis leo) the larynx is well deve- loped; the vocal ligaments, both superior and inferior, are present; the superior being promi- nent. The ventricles of the larynx are deep, forming a sac between the upper and under vocal ligaments. The windpipe is possessed of fifty car- tilaginous rings. The voice is grave, highly in- ( tense, the roar terrific. The tiger (Felis tigris) has a larynx resem- bling that of the lion, the superior vocal ligaments being very pro- minent. The voice of the tiger is more acute than that of the lion. It purrs like the cat. The leopard and the cat belong to the same genus. Felis leopardus and Felis catus. These two animals, like the rest of the feline tribe, have the superior vocal ligaments well developed. It is supposed that by these superior vocal ligaments the purring sound is produced. The voice of both animals is a mewing—they have by night a melancholy cry. In the order Quadrumana, to which the apes and monkeys belong, tho essential form of the organ of voice does not vary much, but larynx of cat. tongue; 6, epiglottis; c, superior vocal cords; d, inferior vocal cords. VOICE OF THE APES, MONKEYS, AND BIRDS. 205 Fig. 98 peculiarities occur in the resounding walls. Thus in the ourang- outang a sac exists between the thyroid cartilage and hyoid bone, and in the mandrill, pavian, and macacos, membranous sacs are ob- served below the hyoid bone. In the Myceti, or howling apes of the lNew World, the apparatus for the resonance of the voice is greatest. In these the hyoid bone and the thyroid cartilage are ex- panded in such a manner as to contain large cavities, which open into the ventricles of the larynx, and besides this there appear to be sacs common to the larynx and pharynx. Further, the epiglottis in these apes has a very large and peculiar form. In the Sapajous (Ateles and Cebus) a curved tube is formed by the increased size and altered forms of the epiglottis, and some adjacent structures. The voice of these animals has a whistling character. In the chimpanzee the true vocal ligaments are prominent. The wind- pipe has sixteen rings. The voice is more acute than in women ; its quali- ty inferior, owing probably to the sacculated larynx. In the ourang- oiitang the inferior vocal ligaments are prominent, but not so long as in the families of the human race. The ventricles are valvular, so that the inflation of the peculiar sacs is under the control of the animal. In the Gibbons the ventricles are deep, and communicate with a sac. The voice is acute; the cry " bow wow." In the monkeys of the old conti- nent there are also laryngeal sacs. These sacs modify the quality of the voice, giving to it, even when acute, a peculiar hoarseness. In the Simia appella and Simia capu- cina, there are some peculiarities in the structure of the channel for the passage of air. The voice in quality is like that of a flute; hence these are called whistling apes, and, from the peculiar ex- pression of this whistle, which is a plaintive melcdy, they are termed weeping apes. Voice of Birds.—The great peculiarity in the organs of voice among birds is the inferior larynx; that is, birds, in addition to the larynx corresponding to that possessed by mammals, have one pecu- liar to themselves at the inferior extremity of the windpipe. Even the superior larynx of birds differs considerably from the larynx in 18 LATERAL VIEW OF LARYNX OF CHIMPANZEE. aa. ant- connected with the lateral ven- tricle: 6, hyoid bone, with c, sac pro- truding at its base; d, thyroid; e, tra- chea ; f, cricoid. 206 LARYNX IN BIRDS. mammals The superior larynx, like that of mammals, is placed just below the hyoid bone. It is partly cartilaginous and partly osseous. In the superior larynx of birds there are cartilages corresponding to the thyroid and the cricoid, the two arytenoid, and the epiglottis. The cricoid is much less developed than in mammals; it forms but a small portion of a ring, occupying the posterior part of the larynx, and supporting, as in mammals, the two arytenoid cartilages. The thyroid cartilage, consequently, rests on the first ring of the windpipe. To the posterior margins of the thyroid cartilage are connected two quadrilateral bones, by which the extent of the protection afforded by the wings of the thyriod cartilage is much increased. The arytenoid cartilages are long, and taper upwards and downwards; they form by their inner margins the chink of the glottis. They are generally ossified; their external margins section of inferior are bounded by the thyroid cartilage. The epiglottis larynx of birds. m mos^ Dirds is rudimentary, and generally is osseous. The chink of the glottis in birds is triangular, the apex being directed upwards. It is bounded in front by the thyroid cartilage, on each side by the arytenoid cartilages, and behind by the cricoid cartilages; but it has no salient membranous laminae, such as the vocal ligaments in man and mammals are. It is capable of expan- sion and contraction under the action of several muscles. The inferior larynx is, as we have seen, peculiar to birds. It varies very much in form and structure. This larynx, the vocal instrument of birds, is a tube, at the opening of which is a membranous tongue. This tongue is a doubling of the interior lining of the bronchus, its free margin being directed upwards; and birds have for the most part a smaller or greater number of muscles, capable of shortening this tongue or of lengthening it in the direction of its height, and of rendering it tense or lax in a transverse direction. In general the inferior larynx of birds is produced by a membrane which makes a projection on each side of the inferior orifice of the windpipe; this orifice is divided into two apertures, sometimes by an osseous bar passing from before backwards, sometimes merely by the angle of union between the two bronchial divisions of the windpipe The bronchi are not composed, like the windpipe, of complete rings, but merely of osseous or cartilaginous segments of rings of a greater or smaller number of degrees in extent, each having a proper curvature in the state of rest, which curvature may vary to a certain amount by the action of voluntary muscles. It hence follows, that the portions of the walls of the two bron- chial divisions of the windpipe, adjacent to (that is, looking towards) LARYNX IN BIRDS. 207 each other, are for a greater or smaller extent membranous, being there destitute of any osseous or cartilaginous structure; and it is to this usually large portion of the wall of each bronchus to which Cuvier gives the name tympaniform membrane. Thus two tympani- form membranes descend, looking towards each other from the angle at which the windpipe divides, forming the interior wall of each of its subdivisions, and being extended transversely between the ante- rior and posterior extremities of the upper osseous segments of these same subdivisions; these osseous segments extending only along the posterior, the external and anterior part of their wall, so as to leave the inner part of each bronchus simply of a membranous structure. The first osseous segment of each bronchus has much the same curvature as the windpipe itself; but the second and third are por- tions of larger circles, and are less convex exteriorly than the first, so that these last project on the iuner side of the tube. On this interior projecting part the lining membrane forms a fold, and it is this fold, half shutting one of the inferior apertures of the windpipe, which offers to the air issuing forth a tongue capa- ble of vibrating and of producing sound. The inferior larynx of singing birds, and some other birds whose voice is far from musical, is very complicated. The last rings of the windpipe unite into a structure two or three lines in length, nearly cylindrical above, and expanded below, where it has two obtuse points, one anterior, another posterior, joined by the bony bar pass- ing from before backwards, already spoken of more than once. This bar is so placed that the windpipe opens below by two oval holes, making with each other an obtuse angle, and each of these holes communicates with one of the bronchi. The three first osseous segments of each bronchus are more near to each other and flatter than those which succeed them. From the first to the third there is a gradual elongation behind, so that the posterior extremity of the last makes a sort of projection, owing to the sudden diminution of the fourth segment. The arc which these segments form hardly exceeds 60°, and in each bronchus the chord of this arc, so to speak, is the tympaniform membrane. The first segment of each bronchus curves its anterior extremity towards the innersurfaceof the tube, where it articulates with a small oval carti- lage which is fixed to the tympaniform membrane, while it forms within a prominence which is the vibrating lamina of the larynx on that side. Thus the transverse section of each bronchus is below nearly circular, the section higher up becomes the segment of a circle which diminishes in one direction while it enlarges in another; and the passage of the air upwards into the windpipe takes place by two oval holes, each furnished at its anterior border with a salient 208 MODIFICATIONS OF THE WTNDPIPE IN BIRDS. lamina. This npparatus is supplied with ten muscles, five on each side. Of these, one descends from the interior of the windpipe to the anterior extremity of the third segment of the bronchus, and, by its contraction, draws that point upwards, thereby making the vi- brating lamina project farther inwards, and, at the same time, ren- dering tense lengthwise all that part of the tympaniform membrane lying below the segment to which the muscle is attached. Another muscle parallel to this has nearly the same attachments, and a like office. A third muscle, much smaller, extends from the inferior and posterior part of the windpipe, and is inserted into the posterior extremity of the second bronchial segment. Its action is similar to that of the former. A fourth muscle passes obliquely from the windpipe to the posterior extremity of the second bronchial segment. It draws that segment upwards and outwards, so as to aid the action of the muscles already referred to, and of that which follows. The fifth muscle is no longer than the preceding, but is much thicker. Taking its origin from the last ring of the windpipe, it passes down- wards and forwards, and is inserted into the anterior extremity of the first bronchial segment, and particularly into the minute cartilage already mentioned as being articulated with that point. Its chief action is to draw forward the small cartilage, and consequently forcibly to put on the stretch, in a transverse direction, the upper part of the tym- paniform membrane. Such a complex structure of the inferior larynx belongs, as was hinted at, not only to singing birds—such as the nightingale, the wren, the blackbird, the goldfinch, the lark, the linnet, the canary, and chaffinch—and to those with a monotonous cry, like the swallow, the sparrow, the starling; but also to some with a decidedly disa- greeable cry, such as the jny, the magpie, the crow, the raven. Thus not only is a complex organ necessary to the musical singing of birds, but also a fine general organization and a singing instinct. The windpipe in birds presents some very singular modifications. As the voice is produced in the inferior larynx of birds, situated at the lower part of the windpipe, this tube comes to form, together with the mouth, the tube or pipe placed in front of the organ of voice. In short, the windpipe of birds comes to occupy a place corresponding to the situation of the organs of speech in the human body. It is capable of being shortened, not only by the diminution of the spaces between the rings themselves, but also by the rings being received one within the other. In many birds the windpipe is much longer than the neck, being thrown into convolutions. This structure is observed in the cock-of-the-wood, the stork, and crane. In the wild swan the convolutions of the windpipe are lodged in a cavity of the breast bone. Nor is the windpipe always cylindrical; EFFECT OF THE SUPERIOR LARYNX IN BIRDS. 209 for in herons and cormorants it has a conical figure, becoming gradually wider and wider towards the mouth. In some species of ducks it presents a sudden dilatation, while in the goosander, and some members of the duck family, it undergoes gradual dilatations. That the inferior larynx of birds is the true organ of voice has been proved by many experiments. For example, anatomists have divided the windpipe in singing birds, such as the blackbird, about the middle of its length, so that the air could no longer pass through the superior larynx, and yet the bird would continue to sing, though with feebler tones than before. Similar experiments have been made on magpies and on ducks. After such an experiment, the magpie is found to cry with as great intensity of tone and with the same acuteness as before the operation. Again, if air is blown into the bronchial divisions of a duck after their separation together with the inferior larynx from the body, a sound exactly similar to the natural cry of the bird is obtained. Even after the bronchi have been cut away, by blowing into the trachea the same sound is produced. It is not, however, to be concluded that the superior larynx exerts no modifying influence on the voice in most birds. It is manifestly opened and closed rapidly in singing birds, so that it is impossible to doubt that it takes an active part in the production of melody. In the song of the canary and the linnet its simultaneous movements with those of the mouth are readily observed. Its effect, however, on the pitch of the voice is not supposed to exceed a semi-tone. Physiologists still doubt whether the sounds of the voice in birds are the result, as in man, of the vibrations of a reed or tongue, or, as in mere flute-pipes, of the vibrations of a column of air excited by friction against the lips of an opening. There is unquestionably a great difference in the mode in which voice is produced in different birds. It seems certain that the simple organ of voice in the duck, the goose, and the like, is a reed instrument. In these the vocal cords, or bands, which form the exterior margin of the opening of the larynx, can be seen to vibrate strongly, while the sound pro- duced closely resembles that arising from the vibrations of mem- branes. But it is by no means so clear that the piping, whistling sounds of singing birds are produced in the same manner; and it is not impossible that these may be effected in the same mode as whistling by the mouth in man. Several reasons, however, may be urged in favor of the opinion that the sounds uttered by singing birds are the effect of the vibra- tions of tongues, as well as the voice of the duck and the goose. For example, the vocal cords under muscular action can hardly escape being thrown into vibrations; and even though the friction of the air may be in part concerned in the production of the sounds, 18* 210 THE VOICE OF BIRDS. a compensation must arise between the vibrations of the air and those of the vocal ligaments. If this be correct, the organ of voice in birds would not be entirely analogous to a whistle or pipe, but would in part possess the constitution of a reed instrument. It is found that; the length of the windpipe has but a very slight influence on the note produced by the larynx; and that fact corresponds with the slight effect on the pitch of the notes produced by placing a tube in front of the human larynx. It is also found that sounds produced by blowing, by means of a tube inserted in a bronchus through the lower larynx of some birds after its separation from the windpipe, are not perceptibly altered in pitch by holding a tube in front of the larynx : thus is confirmed the resemblance of the lower larynx in birds to the character of the larynx in man. It may be added, that the greater number of the notes of birds may be obtained from the inferior larynx by varying the force of the blast, which at first sight seems to point to a resemblance with the effect of blowing by varying force upon the notes of flute-pipes of the same size as the windpipe of small singing birds. But it is to be remembered that the same variations of notes, by varying the strength of the blast, may be produced in reed instruments with membranous tongues, and even in reeds with very delicate metallic tongues. The influence of the windpipe on the notes may be either the same as that of the notes of flute-pipes, or it may merely influence the notes in the manner of the tube of reed instruments. Contrac- tion of the upper opening of the windpipe at the superior larynx may lower the note, as in pipes and reed instruments. An influence may be exerted on the sounds produced in the lower larynx by the tympaniform membrane, which vibrates strongly at the time. Between the internal vocal cord, the semi-lunar mem- brane, and the tympaniform membrane, there is a relation of com- pensation, the latter being analogous to the membrane formed of a reed stalk. The muscles which vary the tension of the walls of the vocal pipe are in continued action during the modulation of the voice, in order to adjust the tube of the windpipe to the pitch of the glottis; but the number of vibrations may be determined by the glottis, rein- forced by the walls of the pipe, as in mammals. The voice of birds, as of other animals, is also in a minor key. The range of notes is commonly within an octave, though some birds can greatly exceed it. In the parrots, which have a voice of great power, the inferior larynx is single. The two membranes of the larynx leave a narrow chink between them, through which the air is forced from the lungs. These membranes, vibrating in all their dimensions, produce that harsh and disagreeable quality of sound peculiar to them. They can also whistle, during which the THE SKYLARK, THE WOODLARK, THE THRUSH. 211 glottis is probably silent, and the column of air vibrates as in a flute, when a vibratory movement is communicated by the air traversing the clastic walls of the tube. Besides the power of speech possessed by some birds, many can imitate almost every s.nind they hear; the blackbird has been known to imitate the sound of the nightingale, the crowing of the common cock, and the cackle of the hen. The jay is said to mock the notes of the greenfinch and the neighing of the horse so closely that it was scarcely believed to be a bird by those who heard it; also the calling of fowls to their food, and the barking of the house-dog. The variety in the s«ng of singing birds is a subject of the great- est interest. The songsters, properly so called, include the skylark, the woodlark, the thrush, the blackbird, and the nightingale. A slight, notice of the notes of each of these follows: The skylark is one of our most agreeable songsters. Its song is composed of several strains, each consisting of trilling and warbling notes variously modulated, occasionally interrupted by a powerful whistling. Sometimes the lark sings on the ground, perched on a clod, or crouched among the grass; but generally in commencing its song it starts off, rises perpendicularly or obliquely in the air, with a fluttering motion, and continues it till it has attaiued its high- est elevation, which not unfrequently is such as to render the bird scarcely perceptible. Even then, as remarked by a distinguished naturalist, if the weather be calm, you hear its warble coming faintly on the air at intervals. The lark is also a bird of singular capacity; the young learn the notes of any other bird which hangs near them in confinement, and some full-grown birds are observed to possess a like facility. There is, however, a considerable difference among larks in the strength and melodiousness of the note. In confine- ment some larks begin to sing as early as November, and go on sing- ino- until moulting time; others begin in March, and cease as early as° August. In the wild state their period of singing is much shortened. The woodlark is considerably less than the skylark, but of all the larks it is the sweetest songster. Its voice has all the melody of the flute, marked at times by a tender and even somewhat melancholy strain. It sings sometimes in the air, sometimes on the top of a tree. When singing in the air it is frequently seen flying in large, irregular circles. The woodlark sings late in the evening, so as sometimes to be mistaken for the nightingale. The female wood- lark, like the female of larks in general, is not destitute of song; but all that it can reach is a few strophes much interrupted. The thrush has a clear and beautiful song. On the tops of the highest trees it welcomes the approach of spring, and sings through- out the whole summer, especially in the morning dawn aud the eve- 212 THE BLACKBIRD, THE NIGHTINGALE, ETC. ning twilight. It is kept in a cage by bird-fanciers, whence often on a morning, even as early as February, it will delight a whole street by its pleasing song, outside the window, or even inside, pro- vided the window be a little open. The thrush in its wild state is fond of bathing. In September and October they are often caught at the places where they water, before sunrise and after sunset, and even so late that they cannot be seen, but only heard. At the time of bathing they have a peculiar call-note. When a thrush finds water, or when it is flying towards a known watering place, it pipes loudly sik, sik, sik, sik, siki, isak, tsak! and immediately all the thrushes in the neighbourhood reply, and come on. The blackbird has a song rich in melody, containing some deep notes, like those of the nightingale, yet varied with some which are unpleasantly harsh. When at liberty it sings from March to July, particularly at night. In the cage it sings throughout the whole year, except at moulting time. Its note is pure, distinct, and clear. It has a good memory, and will learn several airs or melodies with- out confusing them. It is even able to imitate words. The nightingale by the fineness of its voice surpasses every other bird. The variety and peculiarity of its tones express its varying emotions. When the male is alone, its most significant note is the pipe-note witt. But if the harsh syllable, krr, be added, it forms the call of the male to the female. To express anger or fear the note witt is repeated with great loudness and rapidity before the ter- mination krr is added. When happy and contented the nightingale utters a deep tack. Under the excitement of anger, jealousy, or alarm, the nightingale utters an unpleasant shrieking tone, which re- sembles the cry of the jay. When they sport and chase each other, which they frequently do in pairing time, they utter a very short chirping sound. Such notes belong to both sexes; but the power and the brilliancy of his song distinguishes the male. His vocal organ is of striking power; the muscles of his throat are more robust than those of any other singing bird. Besides the strength of his voice, the nightingale is remarkable for the force, the agree- able transitions, and the beautiful harmony of his song. Commen- cing softly, he warbles for a moment a succession of low melancholy notes, which gradually increase in strength, and at last die away upon the ear. A variety of sharp notes follows, and then are uttered numerous hurried sharp notes, intermingled with some detached as- cending notes, with which he generally closes his strain. In the song of a fine nightingale, without reference to slighter variations, there are at least four-and-twenty different strains. Among the sparrow and finch tribes there are many much prized singing birds. The bullfinch has naturally a harsh, creaking tone, but young THE LINNET, THE GOLDFINCH, THE CANARY. 213 birds learn all kinds of songs, airs, and melodies. If it be desired that a bullfinch should sing perfectly, it ought never to be taught more than one melody, in addition to the fanfare, which is always added by way of surplus. The chaffinch has a variety of notes expressive of its wants and desires. There is one delicate note, expressed trecf treef, by which it appears to remark a change of temperature. The call-note, which it uses chiefly on its migration, is a repeated yack, yack. A spon- taneous sound appears to be Jink, fink, which it reiterates, and from which perhaps the root of its name is derived. More remarkable than these notes is its clear and trilling song; as approaching more to distinct articulation, it is termed a quaver. Each bird has one two, three, and often as many as four different songs, each of which lasts a couple of seconds, and consists of several strophes. Those who desire a particular account of the different songs of the chaffinch, may consult "Chamber Birds," by Bechstein, translated from the German by Mr. Shuckard, London, 1848. _ The linnet has a very remarkable, loud, and flute-like song, con- sisting of many connected strophes, which is the more beautiful the oftener it utters some high-sounding notes, which are termed its crowing, from the resemblance to the crowing of a cock. From its natural flute-like voice, this bird surpasses all others in its capacity for imitating melodies in a beautiful and pure style. A young linnet taught by a nightingale has an exceedingly pleasing song. The goldfinch has a shrill, agreeable song, heard during all sea- sons, except at the period of moulting. It contains many warbling and twittering notes, on which it dwells more or less, and the oftener the syllable Jink is repeated the more it is admired. Some birds utter these notes only once or twice in their song, while others give them forth four or five times in succession. The goldfinch does not acquire the song of other birds with so much ease as the linnet and the canary. The cauary is distinguished by correctness of ear, by the remark- able skill it possesses of imitating all tones, and by an excellent memory. While canaries imitate the notes of other birds, they mix them with their own, so as greatly to improve the song. In dif- ferent countries canaries exhibit a different character of melody. Those birds which intermix in their melodies several strophes of the song of the nightingale, are called Tyrolcse canaries. The English canaries, on the contrary, imitate the song of the lark. Even birds of prey often exhibit no small extent of voice. The kestrel has a bell-like ringing voice, kli, kli, kli, which he often repeats in rapid succession. The white owl utters a plaintive cry, which by the superstitious has been regarded as a sign of death. The.raven has a hoarse croak resembling the syllable crock or crude, 214 THE ROOK, THE JACKDAW, THE PARROT. but it also utters a note not unlike the sound of a sudden gulp, or the syllable cluck, which it seems to utter when in a sportive mood. The rooks have a considerable variety of sounds. Their chief cry resembles the syllable khraa, more or less harsh or soft according to occasion. There is great diversity in the voice of individuals, the notes of some being much louder and clearer than those of others. Their cries, separately, are monotonous and disagreeable; yet when at some distance, and uttered by a large flock, they become by no means unpleasant. Mr. M'Gillivray describes the sounds proceeding from a rookery at night as consisting of a variety of soft, clear, mo- dulated notes, very unlike their usual cry. He regarded these sounds as expressive of affection, and was persuaded that the mo- thers were fondling and coaxing the newly-hatched young. The jackdaw is extremely clamorous, with a loud and clear note, resembling the syllable kae or caw, variously modulated. The noise produced by a large flock, though in no degree musical, is far from being disagreeable. The jay can even learn to speak, uttering, however, nothing but solitary words. They may be taught also the fanfare of a trumpet, and other melodies of single bars, as well as little airs and the notes of many birds. The magpie imitates all striking sounds, and can be taught to speak more easily than any other of the crow tribe. The cry of the cuckoo is universally wel- come as the harbinger of spring. His principal sound is nothing but hu-hu or coo-coo, repeated at short intervals; when attention is given, however, it is found that these two loud and mellow notes are preceded by a kind of churring or chuckling sound, which consists of a low and guttural inflexion of the voice, during which the throat seems distended. The parrot tribe are most remarkable for their power of imitating human speech. The cockatoo shrieks its own name, cockatoo, and calls loudly, in a trumpet-like tone, derdeny. The cries of all ani- mals it acquires, particularly those of the domestic cock and hen. It rarely, however, acquires the power of articulating words. There are numerous species of cockatoo parrots having much the same character of voice. Among the commonest of the parrot tribe in Europe is the ash-coloured parrot. This parrot readily learns to speak, and to pipe. It has not the unpleasant wild shriek of some of the parrot tribe. It takes no small delight in imitating the voice of children; hence children are its best instructors. If its education be begun early, it will sometimes acquire entire verses, and even axioms. The gray woodpecker has a note which resembles a loud shout of laughter, whence some of its popular names are derived; this note is never varied, except by its more clamorous repetition during the spring and early summer months, and by the peculiar cry, plui.plui, THE CROAKING OF FROGS. 215 plui, which has been supposed to indicate the approach of rain. The wryneck in spring frequently and loudly utters'gigigigi, which is the call whereby he attracts his mate. The nuthatch utters a loud call, which may be heard at a considerable distance, resembling grew, deck, deck. The ring-dove, or cushat, has a loud and par- ticularly pleasing cooing, during which he makes very grotesque motions, which may be backwards and forwards, or from side to side, moving the head in every direction. The turtle-dove has a peculiar cry, and bows his head while it is uttered. Voice of Reptiles. — The sounds uttered by reptiles and amphi- bious animals have their source in the larynx, like the voice of mammals. In frogs, as well as in the crocodile, there are vocal cords. In the crocodile the larynx, though more simple than in mammals, still retains something of the same character. There is one large, long-shaped cartilage, to which are attached two movable cartilages. ^ The mucous membrane descending from these movable cartilages into a deep pouch beneath, leaves a free fold on each side, which, when the movable cartilages approximate, becomes a vocal cord. In the gecko and the chameleon the vocal cords are more developed than in the crocodile; nevertheless they are formed on the same plan. The lizard has an acute, chirping voice, which has been supposed to depend on a peculiar membranous fold attached to the larynx, but it really seems to depend on a vibration of the margins of the glottis. In the turtle tribe there are no vocal cords, nor is their larynx adapted to a perfect intonation of the breath In the true serpents there are no vocal cords; the hissing sound which constitutes their imper- fect voice is a mere forcible breathing. In the male frog membranous sacs at the side of the neck become distended in the utterance of the voice, and serve to increase its intensity. In the Rana pipa, in which the larynx, as in all other frogs, receives the bronchi directly, without the intervention of a windpipe, there is a large carti- laginous box, within which are two solid reed- like bodies, nearly as long as the larynx itself. The anterior extremities of these bodies are fixed; their posterior extremity is free, and pro- jects on each side towards the opening of the bronchus. The vocal sound is produced by the vibrations of reed-sbaped tongues, which act like ,.,r. ip ' . /> i RANA TEMPORARIA (C0M- a tuning-fork; while in other animals of the mon frog)—Bishop. same class the parts which produce the sound are ""J^e^K^rfSI membranous. If a small piece of cartilage, a d, inferior vocal cords; few lines in length, be fixed by one end, and a broPnchus!X' ' Fig. 100. 216 THE BUZZING OF INSECTS. current of air be thrown from a small tube upon its edge at the other extremity, a humming sound is heard. In the Rana pipa, also, the movable cartilages are convex externally, and concave in- ternally; so that when the entrance to the larynx is closed, they form a dome over the windpipe, which has been compared to a kettle-drum. In the Rana temporaria, R. esculenta and R. hyla, the larynx opens into two sacs on either side of the lower jaw, and these, during the cry of the animal, are filled with air. Sounds produced by Fishes. — A very few fishes are known to utter sounds, such as the trigla, cottus, pogonias. The trigla utters a grunting sound when it is taken out of the water. It has been supposed that the peculiar muscle of the air- bladder in these animals has a share in causing the sound. The cottus, however, from which a sound is heard to proceed when pres- sure is made upon its body, has no air-bladder. The pogonias, on account of the sounds which it produces, has been named the tam- bour. These fishes produce continued sounds under the water. The air-bladder is very large, and is covered by strong muscles; fur- ther, it has appendages, which, according to Cuvier, pass between the ribs, and become embedded in the muscles. Sounds produced by Insects. — Most insects are mute; others produce sounds merely by friction; others, again, by the passage of air through their spiracles. The sounds produced by friction come under the head of stridulation ; those produced by air from the spira- cles, purring or humming. In the orthoptera, and some of the co- leoptera, there are parts adapted to produce stridulation. In the cricket the muscular apparatus may be described as con- sisting of a serrated string like a file, which in the movement of the wings is drawn rapidly over a firm, transparent, and nearly triangu- lar disc, or sounding-plate, surrounded by a string, and by this act the sound is produced. The pitch of the sound of the house-cricket is very acute, being equivalent to about 4096 vibrations in a second. The cicadae, termed sometimes the " chanteuscs," or singers, are so called because the males produce, in the hottest part of the day, a kind of monotonous and noisy music :— " Et cantu querulae rumpent arbusta cicada}."—Viegil. The music of the grasshopper has from early times attracted at- tention. Archias sung of it, and his verse has been thus translated from the Greek :— " Erst on the fir's green blooming branch, 0 grasshopper! 'twas thine To sit—or on the shady spray of the dusky, tufted pine; And from thy hollow, well-winged sides to sound the blythesome strain, Sweeter than music of the lyre to the simple shepherd's swain." THE BLUE-BOTTLE — THE HUMBLE BEE. 217 Those, too, who loved these " living lyres in the olive groves sound- ing all the summer long," have celebrated the locust:— "Soother of loves, encourager of sleep, 0 locust! mystic muse, shrill wing'd;"— And the cicada, "Cicada! thou, who, tipsy with the dews Of weeping skies, on the tall poplar tree Perch'd swayingly, thyself dost still amuse, And the hush'd grove, with thy sweet minstrelsy." Melanger, alluding to the buzzing of insects, says, " Excute fa- cundas pedibus titubantibus alas :"— " Striking thine own speaking wings with thy feet;" but their real organs of sound are placed on the side of the base of the abdomen, internal, and p 1f)1 covered by a cartilaginous plate, like a shutter, which is an appendage of the under side of the meta- thorax or posterior thorax. The cavity which incloses these instruments is divi- ded into two partitions by a scaly and triangular edge. Seen from the under side of the body, each cell exhibits anteriorly a white and folded membrane, and in the hollow part an ex- tended, slender membrane, called the mirror. If this part of the body be opened from above on each side, there is seen another Fig. 102. folded membrane, which is moved by a very powerful muscle, composed of a great number of straight and parallel fibres, extend- ing from the scaly ridge; this membrane is called the timbale. The muscles, by con- tracting and relaxing with quickness, act upon the timbales, stretching them out 19 thoracic spiracle of blue-bottle flt (Musca vomitoria). THORACIC SPIRACLE OF nUMBLE BEE (Bombus terrestris). or bring- 218 APPLICATION OF PHYSIOLOGY. ing them into their natural state, whereby the sounds are produced, and which, even after the death of the animal, may be repeated by moving the parts over each other in the manner they act whilst alive. The cicada? occur chiefly in warmer countries of the world. One species, the Cicada Anglica, the only English species, is found in the New Forest. It is a common belief that the buzzing of insects is produced by the oscillations of their wings during flight. This idea has been often called in question. Johii Hunter found that insects emitted sounds after their wings were cut off. More recently it has been stated that the sounds produced by many insects are the effect of a rapid transmission of air through the thoracic air-holes as they dash through space. Mr. Bishop has observed a peculiar mechanism for this purpose in the blue-bottle fly and humble bee. The preceding figures show one of the large thoracic spiracles in each of these insects, the Musca vomitoria and the Bombus terrestris. The Application of Physiology.—After the foregoing details of the chief points in the economy of living nature, it will not, in con- clusion, be inappropriate to exhibit some of the great truths of Physiology; to trace their connection with other subjects of human inquiry; and to point out some of the uses to which a knowledge of this department of science is practically applicable. Physiology, taken in its largest acceptation, holds a most promi- nent place in the circle of human knowledge. We have seen it trace the development of the perfect man through the grass of the fields back to the common mineral elements of the crust of the earth. It also enlists in its service Anatomy, Chemistry, and not a few departments of general Physics; and it connects itself with Agriculture, Political Economy, and the science of Legislation and Government, hardly less than with Medicine, Surgery, and the pre- servation of health. The most striking truth in physiology is, that organic existences, including alike the highest races of mankind and the meanest vege- table organisms, are, in their material composition, derived from the mineral matter of the earth. The properties of the simple elemen- tary substances entering into the vegetable and the animal kingdom have been ascertained with exactness; in their mineral condition, they have been fully investigated; and their chemical properties and combinations in inorganic nature are well understood. And such knowledge leads to a second great principle in physiology—namely, that there is nothing in the properties of these several elements of the organic world by which any tendency is given to them, beyond the rest of mineral matter, to combine together to produce auy form of organic life, however simple, and however transitory. When, then, in connection with this undeniable truth, it is considered that, IS THE CONTINUANCE OF SPECIES INDEFINITE? 219 for long periods of time, our planet, the earth, must have been, from physical circumstances, totally incapable of supporting any form of organic existence, the conclusion follows, that the appearance of organic existences on the earth implies an exercise of Infinite Power, by which mineral matter was endowed with the new property of passing into the first species of animal and vegetable life. It is vain to say that such statements as these lie without the pale of inductive science. Man's natural curiosity loudly asks whence came organic species, whenever he considers the undeniable truth that the surface of the earth must have lain for ages destitute of such existences; and the answer which, by the original constitution of his mind, he is compelled to give, is, that such a change on the mere matter of the crust of the earth, as its transition into living forms, could not have occurred without the interposition of Omnipotent Power This great truth, then, is not the less a natural inference of the human faculties, because it does not strictly fall within the limits of physiology; it owes its origin to the operation of the great princi- ples of human belief, implanted in the mind by its primitive consti- tution, and on the knowledge supplied by the cultivation of physi- ology. The next great step in the progress of man's knowledge of organic nature lies strikingly within the limits of physiological science. It is the conclusion that each organic species had its origin in a separate creative power. It is vain for any one pretendino- to the character of a philosopher to maintain that the idea of a trans- mutation of species is far more simple and far more in accordance with Infinite Wisdom. Every one endowed with a philosophic spirit must at once reject this idea, simply because there is not a shadow of foundation in its behalf to be met with in the whole of nature. It is impossible to pronounce with certainty, from physiological evi- dence, whether the several races of plants and animals at present living, or discovered by geological evidence to have formerly existed, had their origin from one pair, or from many pairs; but the strongest evidence does exist against the supposition that one species of a lower grade can pass successively into other species of a higher grade. On the contrary, nature has guarded each species from change with the most sedulous care. By artificial means, and within certain limits, man can make various changes in the species, both of plants and animals; and accidental circumstances, without man's interference, produce like variations. But it is fully ascer- tained that, as soon as those circumstances, whether designed or accidental, which have caused a variation, have ceased to operate, then the species returns to its original state. As soon as physiology, by drawing upon the philosophy of mind, has overcome the difficulty attendant on the first appearance of organic nature on the surface of the earth, it traces out by observa- tion all that belongs to the economy of organic existence. By such 220 IS THE CONTINUANCE OF SPECIES INDEFINITE? observations physiology has made known the conditions necessary for the development and maintenance of organic existences as well as for their reproduction; and as far as physiology has yet dis- covered, so long as these conditions can be maintained in respect to each species, no tendency is shown to its becoming extinct. At the same time, a question may arise whether organic species have the power of unlimited existence, as species, so long as the ordinary known conditions necessary for the maintenance of the individuals continue unimpaired, or whether a species be, like the individual, capable only of a limited existence; so that, as in the case of the individuals of which it is composed, its prolific life at last begins to fail. The experience of mankind on the earth is probably not yet sufficiently extended to afford any sufficient data for debating this question. But the striking analogies between individual life and the life of a species in other respects, must prevent us from positively affirming that species can only die by a failure in the ordinary con- ditions under which the individuals of that species are seen at present to live and thrive. In the case of the individuals of every species, no matter how abundantly the conditions of their life are supplied, there comes at last a period when their susceptibility of availing themselves of those conditions declines, so that decay and death are the inevitable consequences. In the species of plants and animals best known to physiologists, no tendency has ever yet been remarked to degenerate, except that which owed its origin to a failure in the conditions necessary for the existence of the individuals of that species. The dodo is an example of a species which has become extinct within the records of history; but a single case hardly affords a sufficient ground even for conjecture; and it is, perhaps, right at present for physiologists to content themselves with the belief that the dodo perished from fortuitous causes interfering with the external conditions necessary to enable the individuals of that species to live and thrive on the earth's surface. Here, however, in stating the great truths of physiology, the im- portance of the law of death in the organic world, as taking that part of nature entirely out of the category in which mineral nature exists, must not be omitted. In physiological nature, then, the law of death may be thus stated—no perfection of organism, no com- pleteness in the supply of the' conditions of existence, can prevent any living individual whatever from at last failing to derive the means of maintenance from those conditions, and from falling into a state of decay and dissolution. Such a law is exclusively known in physiological nature, there being nothing the least analo- gous to it in the case of inert matter. A more practical truth of physiology is, that each species multi- plies in proportion as the circumstances under which it is placed are favourable to the maintenance of the individuals of that species. TRANSITION OF INERT INTO ORGANIC SUBSTANCES. 221 This law appears to admit of no exception. In short, physiological principles are quite sufficient to settle the questions which have arisen as respects the law of population. No country can support more inhabitants than it can supply with the means of maintenance. It is not necessary that the soil of that country should produce enough of corn and cattle to feed all its inhabitants; but then it must produce something else by means of which food can be obtained from other countries. If the inhabitants are skilful workmen, they may convert raw material, derived from other countries, into manufac- tured goods; and for the value of their workmanship they may receive enough of corn and cattle to satisfy their wants. There may be mines of mineral wealth in demand among agricultural nations; and in exchange for this wealth they may obtain a sufficiency of corn and cattle. Still the great law remains unaffected that the number of people which a country can maintain cannot exceed that for which it possesses the means of providing food. Physiology enters upon another practical question of vast import- ance — namely, whether the soil of a country can be renewed inde- pendently of the application of existing organic matter. Every crop which is taken off a field carries with it a certain amount of soil; not, indeed, equal to its actual weight, because a great part of the substance of each crop is derived from the air, and from the rains. Hence a soil necessarily becomes exhausted by repeated crops. It is renewed by the application of manure; but as manure, in common circumstances, is obtained from organic matter, it is plain that the organic matter of a country must be continually declining by being again reduced to mineral matter; unless it be proved that under some circumstances, at least, soil can be renewed from the mineral kingdom. The annual waste of organic matter in every country is enormous—that is to say, a large quantity of organic matter is con- tinually passing back into the mineral state, under such processes as putrefaction, combustion, and the respiration of animals. Plants, no doubt, are continually converting inorganic matter, such as the carbon of carbonic acid and the hydrogen of water, into their own substance. But the organic substances required for food contain not only hydrogen and carbon, but also nitrogen; and therefore, unless it be proved that ammonia, which is the chief source of the nitrogen of plants, be constantly produced in the mineral kingdom, it must be confessed that there is a continued irreparable destruction of or- ganic matter upon the earth's surface. Here there is a controversy among chemical authorities—some contending that ammonia is con- tinually formed in the mineral kingdom; others that the ammonia which appears in a soil is derived solely from the decomposition of organic matter. On the determination of this question our specu- lations rest as to the future history of the organic kingdoms on the surface of our planet. If there be a continual destruction of organic 19* 222 IS SOIL CONTINUALLY RENEWED! matter without any corresponding renewal from the mineral king- dom, then a time will come when plants and animals must perish for want of the means of subsistence at present supplied to them by the soil. It is no part of our purpose to enter upon this controversy ; but the evidence at present seems to be in favour of the unlimited power of mineral nature to produce ammonia, and therefore to supply that important constituent of the food of plants which otherwise must be derived from the destruction of organic matter. Another speculative question bearing on the fortunes of the animal kingdom is sometimes debated in works of physiology. We have already remarked, that the carbonic acid, which is continually thrown into the atmosphere by the respiration of animals, is as con- stantly decomposed and removed by plants for their own support. It is a common view that our atmosphere must, at a very early pe- riod, have contained all the carbon, in the form of carbonic acid, which now exists in the organic kingdoms, and in the soil of the earth. If such were the case, the atmosphere, however fit to sup- port* the life of vegetable organisms, must, it is said, have been totally unfit to maintain the life of animals. The supposition then is, that through the vast preponderance of the vegetable kingdom, for many ages, on the surface of the earth, the carbonic acid was gradually reduced in proportion down to its present small measure; and that the carbon so abstracted from the carbonic acid is that which now forms so large a proportion of the bodies both of plants and animals, and so large a proportion of the soil of the earth. And now that the animal kingdom has begun to preponderate, and a greater proportion of carbonic acid is produced by the respiration of animals than is decomposed by the food of plants, this change will go on increasing, until at last the atmosphere will become again unfit for the support of animals, owing to the great accumulation of cor- bonic acid. The determination of this question involves several considerations. It is true that the forests which covered the earth in ancient times are fast disappearing; but it is also true that these forests are replaced by cultivated crops. Shall we then say that if all the arable parts of the earth become covered with crops, those crops will not destroy as much carbonic acid as the ancient forests? And if this be the case, then the carbonic acid will not undergo any material increase. One thing is certain, that the animal kingdom as respects its constituent carbon, can only increase at the expense of the vegetable kingdom ; so that, while there must remain the same quantity of carbon at the earth's surface, a larger proportion will certainly be contained in the animal kingdom than in the ve- getable, owing to the destruction of the ancient forests. But if the whole quantity of carbon contained jointly in the crops, and in the animal kingdom, and in the soil, remains equivalent to the quantity now in those three conditions, no change can take place in, the quau- NECESSITY FOR SANITARY LEGISLATION. 223 tity of the carbonic acid in the atmosphere. Again, it is perhaps impossible that the animal kingdom can increase so fast as to dete- riorate the air much, when it is considered, that the only part of the animal kingdom that can be regarded as on the increase, is man himself, and the animals subservient to him. An easy answer to the difficulty which has been here raised is, that by computation, from very probable data (u Edinburgh New Philosophical Journal," July, 1845), the conversion of the whole carbon of the soil, and of living plants and animals, into carbonic acid, would not more than double the small proportion of that gas existing at present in the atmosphere. The connection of pestilential diseases with deficiency of the means of subsistence has too little engaged the attention of legislators. It is true there are certain diseases of an epidemic character, -such as small-pox, measles, scarlet fever, which prevail even among the best fed orders of society. It is undeniable, however, that even these epidemics are far more fatal when joined with an insufficiency of food. In modern times, it is hardly possible to conceive the ravages which, in the earlier ages, epidemics inflicted upon the hu- man race. At those periods, agriculture had made but very slender progress; and what surprises us is not so much that the nations of Europe suffered from such diseases as that they did not suffer even more. Were the same circumstances which so often prevailed in those countries again renewed in the present crowded state of many of the countries of Europe, the devastation would be far greater than even we find to be recorded of those times. Great sanitary improvements have taken place in all the countries of Europe, de- fective as that kind of legislation still is. But when the rapid in- crease of our great towns, without any previous means being secured for their proper drainage and ventilation is considered, physiology cannot too loudly proclaim, not only that virulent epidemic diseases may arise under such circumstances, but extend their ravages even beyond the limits of those localities in which imperfect regulations prevail. As respects the general maintenance of health, physiology sup- plies many important precepts; although nature in this respect has hardly left man to be governed by physiology. Hunger forces man to the highest activity for the preservation of his life; and under this appetite, aided by common sense, a body of popular dietetic rules has arisen, the habitual observation of which, more from imi- tation than from reflection, serves to preserve individuals in health. It is only by seeking a variety of food that man is sure to obtain all the chemical constituents required for the maintenance of his bodily frame. We have already shown that each of the simple elements, of which the human body is composed, is continually passing out by various excretory channels; and that, unless replaced, nutrition 224 RELATION BETWEEN PHYSIOLOGY AND PATHOLOGY. becomes deficient, and the function of that part which fails to re- ceive its just supply is necessarily impaired. It doubtless often happens that the digestive powers are too feeble to extract the sub- stances required from one kind of food, while they may be sufficient to obtain them from another. The desire of a variety of food, then, is plainly a species of instinct implanted in man for the purpose of securing the perfect nutrition of the animal frame. Physiology is the handmaid of medicine; and in its largest sense, it even includes pathology. The relation between physiology proper and pathology has no parallel in other departments of knowledge. In physical science, as there is no death, so there is no disease. The mere derangement of machinery invented by man is very different from the state of disease in physiological nature. But not to waste time on a subject scarcely relevant to our present purpose, it is at least manifest that in the derangement of machines there is not, as in the case of disease, a power inherent in them to rectify and to restore themselves to their former state of efficiency. Such a power, however, is what characterizes pathology in particular. It is some- times said that in meteorology, storms and tempests, as contrasted with calm weather, are the diseases of the atmosphere. But even in this department there is no close analogy between the two cases. A mere disturbance of the equilibrium of the atmosphere, on which every sudden change of the weather depends, bears but a very remote analogy to the pathological states to which living nature, and in particular the human nature, is subject. But when we eome to chemical science — to that science which treats of the combina- tions of bodies, and of their actions and reactions upon each other, then we perceive at once how totally different physical nature (and under chemistry the whole of physical nature falls) is from organic nature, in respect to that class of phenomena which constitute the special department of physiology termed pathology. In chemical nature there is no individuality, unless, rejecting the idea of the in- finite divisibility of matter, we pronounce each atom of a chemical substance to possess an individuality. And this view at present supplies us with the best and most correct notion of the grand dis- tinctions existing between physical and physiological nature. The individuals, then, of which chemistry treats are mere atoms of simple bodies — every massive simple body is merely a group of individual atoms —each of these atoms is, in a very definite sense, an inde- pendent individual; it possesses all the properties which belong to the mass or aggregate in which it is seen to exist; by being sepa- rated from that mass it loses nothing; in the present system of things it is imperishable; it knows no decay, it knows no fatigue, it knows no exhaustion of its properties, it knows no dissolution or death. From its first creation to the time when the Eternal shall pronounce the fiat of its extinction, it knows no change of character. PHYSIOLOGY THE TRUEST GUIDE. 225 How different are the terms in which the individual falling under physiological nature must be spoken of! Here the individuality lies in the peculiar aggregation of a great mass of different particles; no two individuals are exactly alike; no individual is exactly like itself even for a moment; there is a perpetual change; even the very atoms which compose the individual are continually disappear- ing—the form remains, while the substance is continually changing; there is an unceasing rise, progress, decay, and dissolution; the dis- solution, however, does not lie in the loss of the constituent sub- stance, but in the failure of the indispensable form. Here, then, lies the great distinction between the individuals of physiological nature and the individuals of physical nature. In physical nature each individual retains throughout all time its proper identity; is always the same under the same circumstances; associates itself in innumerable ways with other individuals like itself, but never loses its own peculiar properties and character. The individual of phy- siological nature retains its identity through the best part of a cen- tury, while the substance which renders it a sensitive body is con- tinually undergoing a change. It retains no identity of mere matter, but only an identity of form and spirit. An atom of carbon now exists in the crayon of the artist; now floats about the atmo- sphere from pole to pole in a new combination; now enters into the constitution of some vegetable nature; now is a component part of some animal fraWe; now is cast forth again into the atmosphere, and thus enjoys an immortality of existence altogether free from the laws of accident, disease, or death. Physiology is the truest guide in medicine; and man is by nature a physician — is an observer of diseases, and of the meaus under which, whether by design or accident, diseases have disappeared. Medicine in its ruder states exhibits a few individuals who have not only been themselves diligent observers of diseases and remedies, but also inquirers into the experience of others. There are certain parts of medicine and surgery open to common observation without much risk of deception or error. But as long as a man is ignorant of physiology he is groping in the dark; he is deceived at every step; he mistakes mere successive occurrences for events standing in the relation of cause and effect; and, if he be of a rash character, or even only of an ardent mind, he is very apt by his interference to aggravate rather than promote the cure of disease. When phy- siology has made some progress -<- that is to say, when the spirit in which the Creator willed the actions of living nature to take place has been apprehended—then men begin to discriminate the shades of disease with more accuracy, and to observe with less risk of error what remedies have contributed to a cure. Till physiology made such progress, medicine was overburdened with precepts rashly in- ferred by unskilful observers. 226 PHYSIOLOGY EVIDENCES DESIGN. The last great use of the science of physiology to which we shall advert, is its intimate connection with that science which points out the evidence of design in nature; and it is in the organic world chiefly that we find such evidences. It is a great error to suppose that human knowledge is confined to determining the laws according to which phenomena occur. Those who study the evidence of design in the universe, are some- times reproached with deviating from the proper purpose of philo- sophy. They are told that philosophy has nothing to do with the origin of things; but only with the laws which regulate the pheno- mena which man is capable of observing. But this is an assump- tion purely gratuitous. It is quite true that man in early ages made small progress, attempting to find out the purpose for which every- thing that exists was made. It is also true that Bacon described final causes as barren of effect. But if we find that the knowledge of nature, and particularly of organic nature, has now advanced so far that the study of the purposes for which organic parts were made, leads to the elucidation of the science; and that the study of final causes is no longer that barren pursuit which it was in Bacon's time; then we are entitled to repel this reproach, and to consider on what grounds it is affirmed that man's knowledge must be confined within the investigation of the mere laws of phenomena, and not extend to the study of the purposes to which the various forms of organic structure are subservient. There is mdftfestly no other ground for affirming that human inquiry should be confined to the study of the laws according to which phenomena take place, than the argument that this is the only way in which human knowledge can be extended. Those who so argue altogether ignore physiology. The most ancient expression for physiology is the usus pardum, that is to say, the use of the parts of the body. What does this mean? Surely it signifies that the study of the parts of the animal frame and of the vegetable structure, leads to a knowledge of the design with which the animal or the plant was made after that fashion. The discovery of the use of a part is not only a new step in physiology, but the observation of the relation between the struc- ture of a part and its function is a fact in evidencing design. Till that discovery is made the human mind remains altogether unsatis- fied with the most minute knowledge of the mere structure. The extent to which this is true will at once appear from the species of shame with which anatomists and physiologists point out those organs in the animal frame, the distinct use of which has not yet been discovered. There are such organs in the body, for example the spleen, the thyroid gland over the upper part of the windpipe, the supra-renal capsules, and some parts in the anatomy of the em- bryo. The most persevering efforts are continually made to connect the structure of such parts with some definite use iu the living body INQUIRY NATURAL TO MAN. 227 What, are these efforts but the most conclusive confession that the human mind cannot rest satisfied with the mere knowledge of the size, the form, the minute internal structure of a part, unless it be able to conceive with what purpose that part was placed in the situa- tion which it occupies? The character of human knowledge is not to be sought in the speculations of philosophers. A far truer standard of the character of human knowledge will be obtained from the common principles which pervade the minds of mankind at large. It is vain to attempt to extinguish man's curiosity to know why a part was so constructed, or why it was placed in the situation which it occupies. Such in- quiries are as natural to him as the desire to discover the laws which regulate the succession of phenomena. It is not to be supposed, however, that man has been gifted with powers sufficient to discover the whole plan on which organic nature is constructed. He need not expect to become able to explain the particular purpose of every variety of structure which he discovers in the animal and vegetable kingdom. It is long since physiology reached the truth that, in some species, there are parts of structure which do not seem to have any special office; or any special bearing on peculiar habits. It is long since physiology became acquainted with what are termed rudi- mentary structures, both in the imperfect and in the mature state of individuals. The simplest example of a rudimentary organ is the mamma in the male of the human race. It performs no office. The disciple of a positive philosophy points to those organs, and sneeringly asks how this is to be reconciled with our doctrines. But, suppose all the rudimentary organs which are known, and all the peculiarities of structure in animals, which seem to serve no useful purpose in relation to the habits of the animal, were deducted, what an infinitesimal proportion would the total amount of these make as compared with the vast array of organs with distinct uses, left to constitute the evidence of design ! The disciple of a positive philosophy sarcastically asks, of what use it is to the whale to have the bones corresponding to each of the bones in the human arm, or upper extremity? Here we answer by referring him to his fa- vourite term, law : it is a law that the great orders of animals are developed upon one grand type. This law we discover by observa- tion; it is a part of inductive science; it has nothing to do with desigu. But, having ascertained this law of development according to the type, we then discover that the type is made to bend into a conformity with the particular habits and usages of each species. Here, then, is a great fact; and notwithstanding the law, in obe- dience to which the unwieldiy whale, with its short fin-like arms, has in those arms a bone corresponding to every one of those in the human upper extremity, yet are these analogies of the human bones so modified as in the most perfect manner to become subservient to 228 physiology a hymn in praise of god. the different uses to which this animal applies its anterior extremity. The disciple of the positive philosophy no doubt says—surely the fore-paw of a whale might have been constructed on a more simple plan, to answer all the uses to which it is subservient. But does this answer shake the foundations of the evidences of design ? Be- fore his arguments become of any avail, he must show that the fore- paw of the whale is unfit for the purposes required by the habits of that animal, because it is framed on the type of the human upper extremity. We do not pretend to say why it has pleased the Author of Nature to establish that law according to which the skeleton of mammals conforms to a certain type; but we do affirm that the Author of Nature, having restricted His creative power within the limits of that type, has displayed incontrovertible evi- dence of design in adapting the type of the human arm to the form of the fore-paw of the whale, in conformity with the uses which that part has to perform. Such, then, is the kind of difficulty which presents itself in our reasonings upon design. The physiologist should never forget that his subject falls under the laws of inductive science, in as far as these are applicable to it; and he should never permit the disciple of a positive philosophy to refuse him the alternative of so regarding it, or considering the discovery of the fitness of means to an end as a new step in its progress. A very remarkable feature in physiological nature is, that, after all, each individual, though composed of materials derived from mineral nature, is not dependent for his individuality and identity on the continued presence of that same aggregate of mineral sub- stances. At every moment the materials of which a human being is composed are passing away, and giving place to new materials derived from without. In a short period of time, the substance of his body is entirely changed, yet his individuality, his identity, his personality remain. He is the same, and yet different. He is no longer the same matter; but he is the same man. The man is therefore something different from matter. Let the disciple of the positive philosophy expound this to us; If everything be material— if all the phenomena of the organic world be the result of internal laws belonging to material substances, what is it that represents man throughout his long life, notwithstanding the perpetual change of the matter which at any one moment composed his bodily frame? Man surely is something different from matter; he is a thinking spirit and one of the earliest of his thoughts is to refer the changes which he sees taking place around him to Infinite Power and to recognise in the accommodation of means to ends, the inherent design of Infinite Intelligence. Truly did Galen say--The study of physiology is a hymn honour of the Deity." J in INDEX, GLOSSARIAL, EXPLANATORY, AND REFERENTIAL. A. Acoustic capsule (Or. akouo. to hear, andLat. cnpsula, a little cover), 152, 153. Adam's apple, the laryngeal prominence, called the thyroid cartilage. 176, 17!). Air, sound not merely a vibration of, 169. Air-tubes in man. 114: in birds, 116. Albumen (Lat. albus, white), properties of, 73. Algebra (Arab, at, the. and gabron, reduction of fraclions), operations of, 21. Alimentary functions, 107-110 Alkalies (Arabic at. the, and kali, the glass- wort plant), properties of the, 15. Animal economy, importance of the blood in the, 95, 96. Animal kingdom, composed of materials found on tho earth's crust. 54. Animal life, on the physiology of, 57, el seq. Animals distinguished from plants, 59: lo- comotion of. 130 el seq.; senses of, 143 et seq. ; smell of, 143; sight of. 145; hearing of, 151; their taste, 154; their touch, 155; their instinctive powers, 103. Animals and plants, an agreement existing between, 58. Annelida (Lat. annvlus, a little ring), respi- ration in the, 119. Antennae of insects. 157. Ape, larynx and voice of the, 204, 205. Arachnidians (Gr. arachne, a spider), respira- ration in, 118. Arachnoid membrane(Gr. aracAne, and tidos. cobweb-form), the serous membrane of the biain, 8G. Areolar tissue (Lat. areola, a little bed), po sition and functions of the, 82 ; distribu- tion of the, 83. Arithmetic (Gr. arit.hmos, number), truths of, self-evident, 21. Arm, bones of the, 79. Armadillo, laryngeal organs of the, 202. Ass, larynx and voice of the. 202. Attraction of matter, laws of, 29, 30. B. Balance, principles of the, 27. Batrachia (Gr. batrachos.a frog), circulation of the blood in the, 99. Bats, flight of. 140. Bears, acute smell in, 145. Bee, respiration in the, 118; eyes of the, 147; humming of the, 217; thoracic spiracle of the, 218. 20 Bile (Lat. bilis, choler), analysis of the, 110 ; its uses," 110. Birds, respiration in, 115, 116 ; progress and development of incubation in the eggs of, 125. 126; locomotion of, 138; smell in, 144; eyes of, 150; ears of, 153; their sense of touch, 158; larynx and voice of. 205 etsea., 206. Blackbird, song of the, 212. Blood, formation and circulation of the, 63, 95 ; red corpuscles of the, in man and dif- ferent animals, 86, 88, 90. 91; effects of drawing, 87; inflammatory crust of the, 87; small proportion of fibrine in, 88; al- bumen in the, 88; its corpuscles colourless, 91 , salts of the, 93; its waste and repair, 93; its importance in the animal economy, 95; renovation of the, 104; its sources of renovation, 105; daily addition to the, 109; its purification, 111. Blue-bottle fly, suckers of the, 134 ; thoracic spiracle of the, 217. Body, waste and repair of the, 93. Botany (Gr. botane, a plant), utility of, 40. Bromine (Gr. bromos, fetid), elements of, 70. Bulfinch, song of the, 212. Calcium (Lat. calx, chalk), general preva- lence of, 72. Camel, its laryngeal organs, 202. Canary, song of, 213. Carbon (Lat. carbo, coal), elements and pro perties of, 69. Carbonic acid, its transmutations, 130. Carnivora (Lat. caro, flesh, and voro, to de- vour), the larynx and voices of the, 204. Caseine (Lat. caseus, cheese), properties of, 74. Cat, larynx and voice of the, 204. Cephalopods (Gr. kephale, a head, and podss, feet,) respiration in, 117. Cetiicea, or Cetiicians (Gr. kele, a whale), voice of the, 201. Chaffinch, song of the, 213. Chemical nature possesses no individuality, 224. Chemistry (Arab, kimia, the occult art, or (ir. chymos, fermented juice or pulp), an inductive science, 15, 32; relation of art to, 33. Chest and lungs, constitute a musical bel- lows. 173. Chimpanzee, larvnx and voice of the, 205. (229) 230 INDEX. Chlorine (Gr. chloros, green), elements and properties of, 70. Cholic acid, 110. Chondrine (Gr. chondros, a cartilage), pro- perties of, 74. Chyle (Gr. chylos, juice), different from blood or lymph, 94; renovation of the blood by, 104; comparative quantities of chyle and faeces, 105; vessels of, 62. Chyme (Gr. chymos, juicy pulp), 61. Cicada; (Lat. cicada, a grasshopper), musical sounds of the, 216. Circle, area of the, defined, 19; its geometri- cal properties, 20. Circulation of the blood, 96 et seq. Coal-field, stratified view of a, 42. Conchiferou's molluscs (Lat. concha., a shell; and/ero, to bear), respiration in, 117. Consciousness (Lat. cum and scirntia, with self-knowledge), wide signification of, 159. Consonants, sounds of, 197. Contractility, the property of a muscular fibre, 78. Crab, its shell a skeleton, 80; red corpuscles of its blood, 90; its locomotion, 133. Crayfish, eye of the, 152. Crickets, sounds produced by, 216. Crico-arytenoidei postici (Gr. krikos. a rine. arylnina and eidos, ladle shaped, and Lat. posticus, behind), a muscle of the larynx, 179. Crico-arytenoidei laterales (see ante), a mus- cle of the larynx, 179. Crico-thyioidei (Gr. krikos, a ring, lhyros,a folding-door, and eidos, resemblance), a muscle of the larynx, 179. Crocodile, larynx and voice of the, 215. CrucifErae (Lat. crux, a cross, and fero, to hear), one of the great families of plants, 40; its edible properties, 40. Crustaceans (Lat. crusta, a shell), circulation of the blood in, 101 ; smell of, 143. Crustaceous animals, respiration in, 118. Cuckoo, voice of the, 214. Curvilinear magnitudes, measure of by rec- tilinear, 20. Cuttle-fish, circulation of blood in the, 101 ; its wonderful powers of leaping, 142; eyes of the, 146; its sense of hearing, 152. D. Death, caused by the cessation of any one of the vital functions, 64. Deity, omnipotence and benevolence of the. 55, 143, 163. Diamond, known by its angular form, 38. Digestion, process of, 104. Digestive apparatus of man, 61. Diseases, pestilential, 223. Dog, mucous membrane of the, 107. Dogs, "intellectual noses" of, 145. Doves, voices of the, 215. Duck, wild, bill and tongue of the, 158. Dumbness, origin of. 168; caused by the ab- sence of hearing. 200. Duodenum (Lat. dvodeni, twelve), a species of second stomach, 61, 110 E. Ear, use of its external appendages, 154. Education, object and effects of, 43; delusion destroyed thereby, 45; what kind should be provided, 47; on the proper direction of, 50; the controller of thought, 166. Eel, nerve-tubes of the, 81. E"", progress and development of incubation in the, 124-126. Electric science (Gr. eleclrum, amber), purely inductive, 32. Elements of organic nature, 66 et. seq. Elephant (Gr. elcphas, ivory), its larynx and voice, 204. Emotion, physiology of, 161. Epiglottis (Gr. epi and glctta, on the tongue), function of the, 179, 180. Error, observation often a source of, when not directed by knowledge, 48, 49. Errors, popular, 45. "Exhaustions," method of, 18. Eyes of different animals, 146 et seq. F. Faeces (Lat. fax, the dregs of anything), pro- portion of discharged, 105. Fat, a constituent of organic bodies, 75; dif- ferent from adipose tissue, 84; extensively diffused through the animal kingdom, 84. Fibre, muscular, on the contraction of, 77- 79. Fibrine (Lat. fibre, hair-like sprouts'), pro- perties of, 73; properties of, in blood, 88. Fibrous nervous matter, 81. Filamentous texture of the animal system, 77. Fins of fishes, their locomotive power, 134, 135. First Cause, on the, 52 ; natural evidence of a, 55. Fishes, circulation of the blood in, 99 ; res- piration in, 116; locomotion of, 134; leap- ing of, 142; acute smell in, 144; eyes of, 147-149; no tears in, 150; their sense of hearing, 152; of taste, 154, of touch, 157; extreme degree of heat they can bear, 157; sounds uttered by, 216. Fleas, their wonderful power of leaping, 142. Flies, locomotion of, 134. Fluorine (Lat. fluo, to flow), elements of, 70. Fcetus (Lai. fato, to bring forth young), cir- culation of the blood in the, 97. Food, the various functions employed in its distribution through the animal system, 61,62; transmutation of into chyle and faeces, 104; changes which it undergoes, 110. Forces, doctrine of, 25, 26. Frog, red corpuscles of its blood, 91; croak- ing of the, 215. Function, general use of the term in physi- ology, 60. Functions, vegetative and animal, 60, 61; of reproduction, 64; table of in man, 65. G. Gasteropods (Gr. gaster. the belly, and podts, feet), respiration in, 117. Gastric juice (Gr. gaster, the stomach), 61 ; changes which it effects in the stomach, 110. Gelatine (Lat. gelo, to congeal), elements I and properties of, 74. INDEX. . 231 Geology (Gr. ge and logos, a discourse on the earth), lessons taught by. 42 Geometry (Qr.ge and metron, the measuring of laud), demonstrative principles of, 15- Germination of seeds (Lat. germino, to bud), process of, 128. Gibbons, larynx and voice of the, 205. Glaucus (Lat. glaucus, sea-green), locomo- lion of the, 132. Globuline (Lat. globus, a ball), principles of, Glottis (Gr. glotta, the tongue), 179; on the use of the term, 181 ; the seat of the hu- man voice, 181-183. God, an infinite, intelligent power, 53. Goldfinch, song nf the, 213. Grasses, the great family of, 41. Grasshoppers, their wonderful power of leaping, 142; musical sounds of the, 216. Gravity, law of, discovered by observation, Gum, general prevalence and use of, 76. H. Harpyia Pallasii (Gr. harpazo. to seize, and Pallas, the goddess Minerva), win»s of the, NO. ' Health, important precepts supplied hv phy- siology for the maintenance of, 223." Hearing, sense of. in various animals, 151, 152; absence of, the cause of dumbness^ Heart, anatomy of the, 99 ; its mechanism 96. ' Heights, inaccessible, first rude measurement of. 22-24 ; application of trigonometry to. 24. ' ' Hematosine (Gr. haima, blood), principle of. 74. Hippuric acid (Gr. hippus, a horse, and Lat. urina. urine), properties of, 75. Hog, its larynx and voice, 203. Horny matter, varieties of, 74. Florse, its laryngeal organs, 202, 203. Hydra virolis (Gr. hydor, water, and Lat. viridis, green), locomotion of the, 131. Hydrogen gas (Gr. hydor, water, and Lat. gennao, to generate), experiment of burn- ing with oxygen gas, 33; properties of, 69. Hypotenuse (Gr hypo, under, and teino, to subtend an angle), mathematical prooer- ties of the, 16. I. Icosandroiis plants (Gr. eikosi, twenty, and aver, a man), their edible properties, 41. Incubation (Lat. incubo, to sit upon), pro- gress of, in the egg, 124-126. Induction, abuse of the term, 47. Industrial education, importance of, 48. Inert matter distinguished from organic, 58. Infero-branchiata (Lat. inferus, beneath, and bronchia, the gills), respiration in the, 117. Infusoria (Lat. ivfusus, infused), microsco- pic anim.ilcula, 131. Inquiry, natural to man, 227. Insects, circulation of the blood in, 103; res piration in, 117; locomotion of, 133; their action in leaping, 142; smell of, 144; eyes of, 147; their sense of hearing, 152; their / sense of touch, 156; antenna) of, 156; on the buzzing produced by, 216-218 Instinct, powers of, 163, 164. Iodine (Gr. iodes, resembling a violet), ele- ments of, 70. ; Iron, its important offices in organic nature, Jackdaw, voice of the, 214. Jay, voice of the, 214. K. Kangaroo, its action in leaping, 141 • its larynx and voice, 204. Kestrel, voice of the, 213. Kidneys, structure and functions of the, 119 Knowledge, on the nature and uses of the great departments of, 13; first rudiments ol, 14; prominent groups of, 15; arrange- ment of, 43; uses of, 43; not to be sought in speculation. 227. Kreatine (Gr. kreas, flesh), elements and properties of, 75. L. Lacteal vessels (Lat. milk), functions of the 02. 106. ' Languages, origin and progress of, 194, 195. Lark, song of the, 211. Larynx (Gr. larynx, a whistle), anatomical structure of the, 173, 174; basement ring of the, 175, 176; chink of the, 178 ; muscles of the. 179; different theories respecting the, 182, 183; experiments on the, 183, 184, 185; of the ruminants and pachydex- mata, 202; of birds, 205 etseq. Leaping of different animals, 141, 142. Leech, locomotion of the, 133. Life, the physical and chemical changes which accompany, 59. Lignine (Lat. lignum, wood), properties of, 76. Linnet, song of the, 213. Lion, larynx and voice of the, 204. Liquor sanguinis (Lat. the sanguiferous fluid), 86. Liver, on the structure and functions of the, 111, 112. Lizards, locomotion of, 137; larynx and voice of, 215. Lobster, its shell a skeleton, 80; circulation of blood in the, 102; locomotion of the, 134, its sense of smell, 144. Locomotion of different animals, 130 et seq. Logarithms (Gr. logos and aritlrmos, a dis- course on numbers), great utility of, 21. Lunes (Lat. luva, the crescent moon), of Hippocrates, 19. Lungs, mechanism of the, 96; structure and functions of the, 113. Lymph (Lat. hjmpha, pure water), its pro- perty and uses, 94 ; probable origin of the, 104. M. Magnetism (Gr. magnet, a magnet), science of, 32; properties of. 72. Magnitude, mathematical illustrations of, 18. 232 INDEX. Magnitudes, curvilinear, measurement of by rectilinear, 19. Magpie, voice of the, 214. Malpiphian bodies of the kidney. 119. Mammalia, Mammals, or Mammiferous ani- mals (Lat. mamma, a teat), locomotion of, 138: the kidneys in. 119: smell in, 144; auditory apparatus of the, 154; sense ol touch in, 158; their voices, 201. Man, digestive apparatus of, 61 ; principal organs of circulation in. 96; air tubes and lungs of, 114; the kidneys in, 120; his ac- tion in leaping, 140; his organs of voice and speech, 173, his organs of smell, 145; inquiry natural to, 227. Manganese, where found, 73; its existence in the crust of the earth. 129. Mathematics (Gr. maihema, learning), de- monstrative principles of, 15; objects of, 18; truths of, self-evident, 21; laws of, different from physical laws, 26 ; its truths intuitive, 18, 50; demonstrations of. ne- cessary truths, 55. Measurement of inaccessible heights, 24. Medicine (Lat. medico, to heal), physiology the handmaid of, 224; and the truest guide in. 225. Medusae, their locomotive organs, 131. Membranes, animal, produce sounds even when relaxed, 187. Membranous tongues, vibrating, 172, 173. Mind and matter, sensation the link be tween, 100. Mineral nature, relation of organic nature to, 129, 130. Minerals, phosphorus derived from, 70; po- tassium derived from, 72. Mineralogy, vast importance of a correct knowledge of. 37. Molluscs (Lat. mollis, soft), circulation of the blood,in, 101; respiration in, 117, Momentum ami velocity. 30. Monkeys, larynx and voice of the, 204, 205. Motion, on the laws of, 25, 26. Mucous membrane (Lat. mucosKS, slimy), 85; of a dog. magnified, 107 Mule, its larynx and voice. 203. Muscle (Gr. myon, a muscle), on the contrac- tion of the fibres of, 77; effects of contrac- tion, 79 ; two kinds of muscular tissue, 77; tonicity of the muscular fibre. 79; muscu- lar texture constitutes a large portion of the animal frame, 80. Music, instruments of, and their vibrations, 186; musical notes, or sounds, distinct from noise, 170-172; adaptation of the voice to, 191, 192. Mycutes (Gr. mukao, to howl), larynx and voice of the, 205. Myriopgda (Gr. myrios, a myriad), and podes, feet), respiration in the, 119. N. Nasal intonation of the voice, 192. Natural History, allied with the descriptive sciences. 37; importance of the study of, 37. Natural laws, on the ignorance of, 45 Nautilus (Lat. nauta, a sailor), fable of the, 132. ' Nemestrina longirostris (Gr. nema, a thread, and Lat. longis roslris, with long beaks), sucking tnb.; of the. 155. Nerves, structure of the, 82. Nervous texture of the animal system, 76; two forms of. vesicular and fibrous, 77. Neurilemma (Gr. neuron, a nerve, and lem- ma, a coat). 82. Nightingale, song of the, 212. Nitrogen (Gr. nitron, nitre, and Lat. gennao, to generate), properties of, 69. Non-vegetative functions, not essential to life. 64. Nudibranchia'a (Lat. nudus, naked, and branchim. gills), respiration in, 117. Number, properties of, intuitive, 21. Nuthatch, voice of the, 215. 0. Observation, fallacious without knowledge, 49. Oil, a constituent of organic bodies, 75. Opinions, profession of. 51 et seq. Opossum, its larynx and voice, 204. Oral canal (Lat. oris, of the mouth), situa- tion of the, 181. Organic bodies (Gr. organon. an instrument by which some process is carried on), gene- ral functions of, 65 ; elements of, 66 el seq., ultimate elements of the first order, 67; of the second order, 70; proximate elements of, 73; the non-azotized proximate ele- ments of. 75; the chief component tex- tures of. 76. Organic life, leading objects connected with, 128; its relation to mineral nature, 129. Organic matter distinguished from inert, 58; transition of inert matter into organic, 218. Organic nature, disquisition on, 57 et seq. Organs, assimilative, 63. Ourang-outang. larynx and voice of the,205. Owl, its eye-balls, 150; its ears, 153; voice of the, 213. Ox. voice of the, 202; red corpuscles of its blood, 90. Oxygen (Gr. oius, acid, and gennao, to gener- ate), properties of, 67; physical history ol an atom of, 129, 130. Oxygen gas. its transmutations. 130. Oyster, its locomotive powers, 142. Pachydermia (Gr. pachus, thick, and der- mala, skins), voices of the, 202. Pancreatic liquor (Gr. pan and chreas, all flesh), properties of the, 111. Parr, the, identical with the fry of salmon, 39. Parrot tribe, voice of the, 214. Pathology (Gr. pathos and logos, a discourse on disease), physiology the hand-maid of, 224. Pectinihranchiata (Lat. pecten, a comb, and branchial, gills), respiration in. 117. Penguin, locomotion of the, 138. Pericardium (Gr. peri, around, and cardia, the heart), the serous membrane of the heart. 86. Peritoneum (Gr. peri, around, and teino, to stretch), the serous membrane of the abdo- men, 86. INDEX. 233 rhosphates (Gr. phos, light), constituents and properties of, 71. Phosphorus (Gr. phos. light, and fero, to bear), properties of, 70 ; derived from mi- nerals, 70. Physics (Gr. physis, nature), various depart- ments of, 31. Physiology (Gr. physis. nature, and logos, a discourse), general laws of, 34; important objects of, 35; on the order in, 57 ; of ani- mal and vegeteble life, 57 et seq. (see pas- sim); its general application to the chief purposes of life, 218 et seq.; the hand-maid of medicine, 224; and its truest guide, 224 ; design manifested in, 224, 228; a hymn in praise to God, -J2"8. Pigeon, red corpuscles of its blood, 90. Planets, attraction between them and the sun, 29; cause of the curvilinear path of the, 53. Plants, an agreement existing between them and animals, 58; distinguished from ani- mals, 58, 59 ; sap of, 121 ; food of, 122. Pleura (Gr. pleuron, a rib), the serous mem- brane of the chest, 86. Podura (Gr. podes, feet, and oura, a tail), its action in leaping, 142. Polygon (Gr. polu, many, and gonia, an an- gle), illustrations of the, 19. Popular errors, 45. Porpoise, laryngeal organs of the, 201. Potassium (from pot and ashrj), elements and properties of, 72. Poulp, eyes of the, 146. Principles, profession of, 51 ctseq. Proportion, the great instrument of abstract science. 22. Proteine (Gr. protos, first), different forms of, 73. Psychology (Gr. psyche and logos, a discourse on mentality, or the soul), essential to precision of language, 36. Pulmonary arachnideans (Lat. pulmo, the lungs, and Gr. arachne, a spider), respira- tion in, 118. Pyramids of Egypt, first measured by Thales, 22. Q- Quadrumana (Lat. quatuor, four, and mana, hands), larynx and voices of the, 204. Quadrupeds (Lat. quatuor, four, and pedes. feet), locomotion ef, 140; acute smell in, 145. R. Raven, voice of the, 213. Reason, a collective power, 161. Red corpuscles of the blood in man and dif- ferent animals, 86, 88, 89-91. Reproduction, functions of, 64; process of, " analogous in animals and vegetables, 123; in the animal kingdom, 127. Reptila, or Reptiles (Lat. reptilis, creeping along), circulation of the blood in. 98; res- piration in, 116; locomotion of, 136. 137; smell in, 144; eyes of, 149; their sense of hearing. 153: their sense of touch, 157; larynx and voice of the, 215. Respiration (Lat. respiratio, continuous breathing), organs of, 113; mechanism of, 114; in birds and different animals, 115, 116. Rhinoceros, its larynx and voice, 202, 203. Rook, voice of the, 214. Ruminants (Lat. rumino, to chew the cud), voices of, 202. S. Salmon, the fry of, and the Parr, identical, 39. Salts of the blood, 93. Sanitary legislation (Lat. sanitas, health), necessity for, 223. Sap of vegetables, 121. Sarcolemma (Gr. sarx, flesh, and lemma, a coat), 77. Schwann, white substance of, 81. Science (Lat. scientia, the knowledge of things), on the general principles of, 13; systems of knowledge founded on, 14; va- lue of the term, 15. Science, abstract, proportion the great in- strument of, 22. Seeds, germination of, 128. Sensation, physiology of, 159 ; the link be tween mind and matter, 160. Senses, fallacy of the, 49, 50. Senses of animals, 143 et seq.; smell, 143; sight, 145; hearing, 151 ; their taste, 154; their touch, 155. Serous membranes (Lat. scrum, whey), the inner membranes of the body, 85. Serpents (Lat. serpens, creeping), distinction between the venomous and the harmless, 39,40; respiration in, 119; locomotion of, 136, 137; vertebrce of, 136; ribs of, 137; their sense of hearing, 153; larynx and voice of. 215. Sheep, voice of the, 202. Shrew, ear of the, 154. Sight, sense of, in various animals, 145. Silicon (Lat. silez, flint), properties of, 71. Singing, produced by successive notes of the voice. 189; compass of the voice in, 189, ]P0: causes of failure in, 193, of birds, 209 et seq. Skylark, song of the. 211. Smell, sense of. in various animals, 143-145. Sodium (Ger. soda, glass-wort), elements and properties of. 72. Soil, on the continual renewal of. 221. Sound, sources of, 108 ; not merely a vibra- tion of air, 108: velocity of, 169; a musi- cal one distinct from a noise, 170-172. Sounds, representation of, by symbols, 195; conversion of voice into, 195, 196; of con- sonants. 197. Speech, one of the principal foundations of man's progress, 167; organs of, 173, 197; the potentiality of man's intelligence, 194; historical progress of, 194, 195. Species, on the indefinite continuance of, 220. Spiders, circulation of the blood in, 102; lo- cornotion of, 133. Stammering, causes of, 199; remedy, 199, 200. Starch, its general prevalence and use, 76. Statistics, an important branch of know- ledge, 36; fallacies of the age connected with. 46. Stomach (Gr. stomachos, the belly), digestive 234 INDEX. apparatus of the, 01 ; changes effected by the gastric juices in the, 110. Sulphur, elements and properties of, 70. Supreme Intelligence, on the belief of a, 52. Surinam sprat, singularity of its eye- ball, 149. Symbols, sounds represented by, 195. Synovial membrane and joint (Gr. sun, with, and oon, an egg), 86. T. Taste, sense of, in various animals, 154; the immediate instruments of, 155. Tectibranchiata (Lat. tectus, covered, and branchial, gills), respiration in the, 117. Teleology (Gr. telos and logos, a discourse on final causes), true grounds of, 56. Textures in the animal kingdom—the mus- cular, nervous, and filamentous, 76. Thales first measures the great pyramid of Egypt, 22. Thoracic duct (Gr. thorax, the breast), 62; course and termination of the, 62. Thought, a vague term, 165; controlled by education, 166, Thrush, song of the, 211. Tiger, larynx and voice of the, 204. Todd, Dr., his opinion on the alimentary functions, 107, 108. Tonicity (Gr. tonos, tone), a property of the muscular fibre, 79. Touch, sense of, in various animals, 155. Trachea (Gr. trachus, rough), the wind-pipe, 177. Trachearean arachnideans (Gr. trachea, the wind-pipe, and arachne, a spider), respira- tion in, 118. Triangle, right-angled (Lat. tria angula, three angles), properties of the 16. Triangles, equivalence of, 18. Trigonometry (Gr. tria, three, gonia, an an- gle, and metron, a measure), rules of ap- plied to the measurement of heights, 24. Truths, which are self-evident, 55. Tunica vaginalis (Lat. tunica, a tunic, and vagina, a sheath), the serous membrane of the testicle 86. IT. Urea (Lat. urina, urine), elements and pro- perties of, 75, 120. Uric acid, elements and properties of, 75,120. Urinary secretion, 120. Urine (Lat. urina), constituents and proper- perties of, 120, 121. % V. Vegetable kingdom, on reproduction in the, 127; germination in the, 128; chemical changes in the, 130. Vegetable life, on the physiology of, 57 et seq. Vegetables, sap of, 121; food of, 122. Vegetative functions, 61 ; digestion, secre- tion, and excretion, 64; table of, 65. Venous blood, renovation of the, 108, 109. Ventriloquism (Lat. venter, the belly, and loquor, to speak), faculty of, 198, 199. Vesicles, fat, assuming the polyhedral form, 84. Vesicular nervous matter (Lat. vesica, the bladder), 80-82. Vili (Lat. villus, a hair), the processes so called, 107. Vital functions, three so called, 64. Voice, physiology of the, 167 ; sharper in the open air, 169; organs of the, in man, 173; dissertation on the, 181 et seq.; different theories on the, 182; compared with the pipe of an organ. 183; received theory of the, 183; objections to the true theory of the, 186; the organs of, combine the pro- perties of various instruments, 189: com- pass of the, 189; difference between the male and female, 190: nasal intonation of the, 192; its strength depends on the vo- cal cords. 192, 193; causes of failure in the perfectness of the notes of the, 193; con- verted into vowel sounds, 196; compara- tive physiology of, 200; of mammals, 201; of various animals, 202 et seq; of rumi- nants and pachydermia, 202; of birds, 206 et seq. Vowel sounds conversion of voice into, 196. W. Whale, tail of the, 139; its eye, 151. Whistling, causes of, 193. Wind-pipe, anatomical structure of the, 173 etseq.; of the ruminants and pachyder- mata, 202; of birds, 206 et seq. Woodlark. song of the,-211; Woodpecker, voice of the, 214. Wryneck, voice of the, 215. Z. Zoology (Gr. zoos and logos, a discourse on animals), utility of the knowledge of, 38- THE END, CATALOGUE OF BLANCHABD & LEA'S PUBLICATIONS. CAMPBELL'S LORD CHANCELLORS. New Edition- (Just Issued.) LIVES OF THE LORD CHANCELLORS AND KEEPERS OF THE GREAT SEAL OP ENGLAND. FROM THE EARLIEST TIMES TO THE REIGN OF KING GEORGE IV. BY LORD CHIEF-JUSTICE CAMPBELL, A. M., F. R. S. E. Second American, from the Third London Edition. Complete in seven handsome crown 8vo. volumes, extra cloth, or half morocco. This has been reprinted from the author's most recent edition, and embraces his extensive modifications and additions. It will therefore be found eminently worthy a continuance of the great favor with which it has hitherto been received. Of the solid merit of the work our judgment may be gathered from what has already been said. 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Dr. Lardner's extensive acquirements in all departments of human knowledge, and his well-known skill in popularizing his subject, have thus enabled him to present a text- book which, though strictly scientific in its groundwork, is yet easily mastered by the student, while calculated to interest the mind, and awaken the attention by showing the importance of the principles discussed, and the manner in which they may be made subservient to the practical purposes of life. To accomplish this still further, the editor has added to each section a series of examples, to be worked out by the learner, thus impressing upon htm the practical importance and variety of the results to be obtained from the general laws of nature. 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It is just the sort of book I think needed in most colleges, being far above the rank of a mere popular work, and yet not beyond the comprehension of all but the most accom- plished mathematicians. ELEMENTARY CHEMISTRY; THEORETICAL AND PRACTICAL. BY GEORGE FOWNES, Ph. D., Chemical Lecturer in the Middlesex Hospital Medical School, &c. &c. WITH NUMEROUS ILLUSTRATIONS. Third American, from a late London edition. Edited, with Additions, BY ROBERT BRIDGES, M. D., Professor of General and Pharmaceutical Chemistry in the Philadelphia College of Pharmacy, &c. &c. In one large royal 12mo. volume, of over five hundred pages, with about 180 wood-cuts, sheep or extra cloth. The work of Dr. Fownes has long been before the public, and its merits have been fully appreciated as the best text-book on Chemistry now in existence. We do not of course, place it in a rank superior to the works of Brande, Graham, Turner Gre°o'rv or Gmelin, but we say that, as a work for students, it is preferable to any of them —Lon- don Journal of Medicine. We know of no treatise so well calculated to aid the student in becoming familiar with the numerous facts in the science on which it treats, or one better calculated as a text-book for those attending Chemical Lectures. * * * * The best text-book on Che- mistry that has issued from our press.—American Med. Journal. We know of none within the same limits, which has higher claims to our confidence as a college class-book, both for accuracy of detail and scientific arrangement —Au- gusta Med. Journal. . ELEMENTS OF PHYSICS. OR, NATURAL PHILOSOPHY, GENERAL AND MEDICAL. Written for uni- versal use, in plain, or non-technical language. By Neill Arnott M D In one octavo volume, with about two hundred illustrations. BLANCHARD & LEA'S PUBLlCATIONS.-(Educational Works.) 7 NEW AND IMPROVED EDITION.—(Now Ready.) PHYSICAL GEOGRAPHY. BY MARY SOMERVILLE. A NEW AMERICAN FROM THE LAST AND REVISED LONDON EDITION. WITH AMERICAN NOTES, GLOSSARY, ETC. BY W. S. W. RUSCHENBERGER, M. D., U. S. N. In one neat royal 12mo. volume, extra cloth, of over five hundred and fifty pages. The great success of this work, and its introduction into many of our higher schools and academies have induced the publishers to prepare a new and mulh improved edition In addition to the corrections and improvements of the author bestowed on the work in its passage through the press a second time in London, notes have been introduced to adapt it .more fully to the physical geography of this country; and a comprehensive glossary has been added, rendering the volume more particularly suited to educational purposes. 3 Our praise comes lagging in the rear, and is wellnigh superfluous. But we are anxious to recommend to our youth the enlarged method of studying geography which her present work demonstrates to be as captivating as it is instructive We hold such presents as Mrs. Somerville has bestowed upon the public, to be of incalculable value, disseminating more sound information than all the literary and scientific insti- tutions will accomplish in a whole cycle of their existence.—Blackwood's Magazine. From Lieutenant Maury, U. S. N. r ,, , , , ,, „. . , National Observatory, Washington, June 26,1853. I thank you for the « Physical Geography;" it is capital. I have been reading it, and like it so much that I have made it a school-book for my children, whom I am teaching I here is, in my opinion, no work upon that interesting subject on which it treats-Physical Geography—that would make a better text-book in our schools and colleges. I hope it will be adopted as such generally, for youhave Americanized it and improved it in other respects. Yours, iruly, Dr. W. S. W. Rcschenberger, U. S. N., M' F" MAURY- Philadelphia. . From Thomas Sherwin, High School, Boston. I hold it in the highest estimation, and am confident that it will prove a very efficient aid in the education of the young, and a source of much interest and instruction to the adult reader. From Eraslus Everett, High School, New Orleans. I have examined it with a good deal of care, and am glad to find that it supplies an im- portant desideratum. The whole work is a masterpiece. Whether we examine the importance of the subjects treated, or the elegant and attractive style in which they are presented, this work leaves nothing to desire. I have introduced it into my school for the use of an advanced class in geography, and they are greatly interested in it. I have no doubt that it will be used in most of our higher seminaries. JOHNSTON'S PHYSICAL ATLAS. THE PHYSICAL ATLAS OF NATURAL PHENOMENA. FOR THE USE OF COLLEGES, ACADEMIES, AND FAMILIES. BY ALEXANDER KEITH JOHNSTON, F. R. G. S., F. G. 8. In one large volume, imperial quarto, handsomely and strongly bound. With twenty-six plates, engraved and colored in the best style. Together with one hundred and twelvepagesof Descriptive Letter-press, and a very copious Index. A work which should be in every family and every school-room, for consultation and reference. By the ingenious arrangement adopted by the author, it makes clear to the eye every fact and observation relative to the present condition of the earth, arranged under the departments of Geology, Hydrography, Meteorology, and Natural History. The letter-press illustrates this with a body of important information, nowhere else to be found condensed into the same space, while a very full Index renders the whole easy of reference. 8 BLANCHARD & LEA'S PUBLICATIONS.—(Educational Works.) SCH|VnTZ AND ZUMPT'S CLASSICAL SERIES. Under this title Blanchard & Lea are publishing a series of Latin School- Books, edited by those distinguished scholars and critics, Leonhard Schmitz and C. G. Zumpt. The object of the series is to present a course of accurate texts, revised in accordance with the latest investigations and MSS., and the most approved principles of modern criticism, as well as the necessary element- ary books, arranged on the best system of modern instruction. The former are accompanied with notes and illustrations introduced sparingly, avoiding on the one hand the error of overburdening the work with commentary, and on the other that of leaving the student entirely to his own resources. The main object has been to awaken the scholar's mind to a sense of the beauties and peculiarities of his author, to assist him where assistance is necessary, and to lead him to think and to investigate for himself. For this purpose maps and other en- gravings are given wherever useful, and each author is accompanied with a biographical and critical sketch. The form in which the volumes are printed is neat and convenient, while it admits of their being sold at prices unpre- cedentedly low, thus placing them within the reach of many to whom the cost of classical works has hitherto proved a bar to this department of education; while the whole series being arranged on one definite and uniform plan, enables the teacher to carry forward his student from the rudiments of the language without the annoyance and interruption caused by the necessity of using text- books founded on varying and conflicting systems of study. CLASSIC At TEXTS PUBLISHED IN THIS SERIES. I. C^ESARIS DE BELLO GALLICO LIBRI IV., 1 vol. royal 18mo., extra cloth, 232 pages, with a Map, price 50 cents. II. C.C. SALLUSTII CATILINA ET JUGURTHA, 1 vol. royal 18mo., extra cloth, 168 pages, with a Map, price 50 cents. III. P. OVIDII NASONIS CARMINA SELECTA, 1 vol. royal 18mo., extra cloth, 246 pages, price 60 cents. IV. P. VIRGILII MARONIS CARMINA, 1 vol. royal 18mo., extra cloth, 438 pages, price 75 cents. V. Q. HORATII FLACCI CARMINA EXCERPTA, 1 vol. royal 18mo., extra cloth, 312 pages, price 60 cents. VI. Q. CURTII RUFI DE ALEXANDRI MAGNI QVM SUPERSUNT, 1 vol. royal 18mo., extra cloth, 326 pages, with a Map, price 70 cents. VII. T. LIVII PATAVINI HISTORIARUM LIBRI I., II., XXL, XXII., 1 vol. royal 18mo., ex. cloth, 350 pages, with two colored Maps, price 70 cents. VIII. M. T. CICERONIS ORATIONES SELECTS XII., 1 vol. royal 18mo., extra cloth, 300 pages, price 60 cents. IX. CORNELIUS NEPOS, 1 vol. royal 18mo., price 50 cents. ELEMENTARY WORKS PUBLISHED IN THIS SERIES. I. A SCHOOL DICTIONARY OF THE LATIN LANGUAGE. By Dr. J. H. Kaltschmidt. In two parts, Latin-English and English-Latin. Part I., Latin-English, of nearly 500 pages, strongly bound, price 90 cents. Part II., English-Latin, of about 400 pages, price 75 cents. Or the whole complete in one very thick royal 18mo. volume, of nearly 900 closely printed double-columned pages, strongly bound in leather, price only $1 25. II. GRAMMAR OF THE LATIN LANGUAGE. By Leonhard Schmitz, Ph. D., F. R. S. E., Rector of the High School, Edinburgh, &c. In one hand- * some volume, royal 18mo., of 318 pages, neatly half bound, price 60 cents. BLANCHARD & LEA'S PUBLICATIONS.—(Educational Works.) 9 SCHMITZ AND ZUMPT'S CLASSICAL SERIES—Continued. III. ELEMENTARY GRAMMAR AND EXERCISES. By Dr. Leonhard Schmitz, F. R. S. E., Rector of the High School, Edinburgh, &c. In one handsome royal 18mo. volume of 246 pages, extra cloth, price 50 cents. (Just Issued.) PREPARING FOR SPEEDY PUBLICATION. LATIN READING AND EXERCISE BOOK, 1 vol., royal 18mo. A SCHOOL CLASSICAL DICTIONARY, 1 vol., royal l8mo. It will thus be seen that this series is now very nearly complete, embracing eight prominent Latin authors, and requiring but two more elementary works to render it sufficient in itself for a thorough course of study, and these latter are now preparing for early publication. During the successive appearance of the volumes, the plan and execution of the whole have been received with marked approbation, and the fact that it supplies a want not hitherto provided for, is evinced by the adoption of these works in a very large number of the best academies and seminaries throughout the country. But we cannot forbear commending especially both to instructors and pupils the whole of the series, edited by those accomplished scholars, Drs. Schmitz and Zumpt. Here will be found a set of text-books that combine the excellencies so long desired in this class of works. They will not cost ihe student, by one half at least, that which he must expend for some other editions. And who will not say that this is a consider- ation worthy of attention ? For the cheaper our school-books can be made, the more widely will they be circulated and used. Here you will find, too, no useless display of notes and of learning, but in foot-notes on each page you have everything necessary to the understanding of the text. The difficult points are sometimes elucidated, and often is the student referred to the places where he can find light, but not without some effort of his own. We think that the punctuation in these books might be improved; but taken as a whole, they come nearer to the wants of the times than any within our know- ledge.—Southern College Review. Uniform with SCIMTZ AND ZDIPT'S CLASSICAL SERIES—(Now Ready.) THE CLASSICAL MANUAL; AN EPITOME OF ANCIENT GEOGRAPHY, GREEK AND ROMAN MYTHOLOGY, ANTIQUITIES, AND CHRONOLOGY. CHIEFLY INTENDED FOR THE USE OF SCHOOLS. BY JAMES S. S. BAIRD, T. C. D., Assistant Classical Master, King's School, Gloucester. In one neat volume, royal 18mo., extra cloth, price Fifty cents. This little volume has been prepared to meet the recognized want of an Epi- tome which, within the compass of a single small volume, should contain the information requisite to elucidate the Greek and Roman authors most com- monly read in our schools. The aim of the author has been to embody in it such details as are important or necessary for the junior student, in a form and space capable of rendering them easily mastered and retained, and he has con- sequently not incumbered it with a mass of learning which, though highly valuable to the advanced student, is merely perplexing to the beginner. In the amount of information presented, and the manner in which it is conveyed, as well as its convenient size and exceedingly low price, it is therefore admirably adapted for the younger classes of our numerous classical schools. 10 BLANCHARD & LEA'S PUBLICATIONS.—(Educational Works.) SCRIPTURE GEOGRAPHY AND HISTORY.—(Now Ready.) SCRIPTURE GEOGRAPHY AND HISTORY. Illustrating the Historical Portions of the Old and New Testaments. DESIGNED FOR THE USE OF SCHOOLS AND PRIVATE READING, BY EDWARD HUGHES, F. R. A. S., F. a. S., &c. &c. In one neat volume, royal 12mo., extra cloth, of about four hundred pages, with twelve colored Maps. The intimate connection of Sacred History with the geography and physical features of the various lands occupied by the Israelites renders a work like the present an almost necessary companion to all who desire to read the Scriptures understandingly. To the young especially, a clear and connected narrative of the events recorded in the Bible, is exceedingly desirable, particularly when il- lustrated, as in the present volume, with succinct but copious accounts of the neighboring nations and of the topography and political divisions of the countries mentioned, coupled with the results of the latest investigations, by which Messrs. Layard, Lynch, Olin, Durbin, Wilson, Stephens, and others have suc- ceeded in throwing light on so many obscure portions of the Scriptures, verify- ing their accuracy in minute particulars. Few more interesting class-books could therefore be found for schools where the Bible forms a part of education, and none, perhaps, more likely to prove of permanent benefit to the scholar. The influence which the physical geography, climate, and productions of Palestine had upon the Jewish people will be found fully set forth, while the numerous maps present the various regions connected with the subject at their most pro- minent periods. HISTORY OF CLASSICAL LITERATURE.—(Now Ready.) HISTORY OF ROMAN CLASSICAL LITERATURE. BY R. W. BROWNE, M. A., Professor of Classical Literature in King's College, London. In one handsome crown octavo volume, extra cloth. ALSO, Lately Issued, by the same author, to match. A HISTORY OF GREEK CLASSICAL LITERATURE, In one very neat volume, crown 8vo., extra cloth. From Prof. J. A. Spencer, New York, March 19, 1852. It is an admirable volume, sufficiently full and copious in detail, clear and precise in style, very scholar-like in its execution, genial in its criticism, and altogether display- ing a mind well stored with the learning, genius, wisdom, and exquisite taste of the ancient Greeks. It is in advance of everything we have, and it may be considered indispensable to the classical scholar and student. From Prof. N. H. Griffin, Williams College, Mass., March 22. 1852. A valuable compend, embracing in a small compass matter which the student would have to go over much ground to gather for himself. GEOGRAPHIA CLASSICA: OR, THE APPLICATION OF ANCIENT GEOGRAPHY TO THE CLASSICS. By Samuel Butler, D. D., late Lord Bishop of Litchfield. Revised by his Son. Sixth American, from the last London Edition, with Questions on the Maps, by John Frost. LL. D. In one neat volume, royal 12mo., half bound. AN ATLAS OF ANCIENT GEOGRAPHY. By Samuel Butler, D. D., late Lord Bishop of Litchfield. In one octavo volume, half bound, containing twenty-one quarto colored Maps, and an accentuated Index. BLANCHARD & LEA'S PUBLICATIONS.—(Educational Works.) 11 ELEMENTS OF THE NATURAL SCIENCES-(Now Ready.) THE BOOK OF NATURE; AN ELEMENTARY INTRODUCTION TO THE SCIENCES OF PHYSICS, ASTRONOMY, CHEMISTRY, MINERALOGY, GEOLOGY, BOTANY, PHYSIOLOGY, AND ZOOLOGY. BY FREDERICK SCHOEDLER, Ph.D. Professor of the Natural Sciences at Worms. First American Edition, with a Glossary and other Additions and Improvements. FROM THE SECOND ENGLISH EDITION, TRANSLATED FROM THE SIXTH GERMAN EDITION, BY HENRY MEDLOCK, F. C. S., &c. Illustrated by six hundred and seventy-nine Engravings on Wood. In one handsome volume, crown octavo, of about seven hundred large pages. To accommodate those who desire to use the separate portions of this work, the publishers have prepared an edition, in parts, as follows, which may be had singly, neatly done up in flexible cloth, at very reasonable prices. NATURAL PHILOSOPHY, . . 114 pages, with 149 Illustrations. ASTRONOMY, .... 64 « 51 CHEMISTRY, . . . 110 « 48 MINERALOGY AND GEOLOGY, 104 " 167 BOTANY,.....98 " 176 ZOOLOGY AND PHYSIOLOGY, . 106 « 84 INTRODUCTION, GLOSSARY, INDEX, &c, 96 pages. Copies may also be had beautifully done up in fancy cloth, with gill stamps, suitable for holiday presents and school prizes. The necessity of some acquaintance with the Natural Sciences is new so uni- versally admitted in all thorough education, while the circle of facts and princi- ples embraced in the study has enlarged so rapidly, that a compendious Manual like the Book of Nature cannot fail to supply a want frequently felt and ex- pressed by a large and growing class. The reputation of the present volume in England and Germany, where re- peated editions have been rapidly called for, is sufficient proof of the author's success in condensing and popularizing the principles of his numerous subjects. The publishers therefore would merely state that, in reproducing the work, they have spared no pains to render it even better adapted to the American student. It has been passed through the press under the care of a competent editor, who has corrected such errors as had escaped the attention of the English translator, and has made whatever additions appeared necessary to bring it com- pletely on a level with the existing state of science. These will be found prin- cipally in the sections on Botany and Geology; especially the latter, in which references have been made to the numerous and systematic Government surveys of the several States, and the whole adapted to the nomenclature and systems generally used in this country. A copious Glossary has been appended, and numerous additional illustrations have been'introduced wherever the elucidation of the text appeared to render them desirable. It is therefore confidently presented as an excellent Manual for the private stu- dent, or as a complete and thorough Class-book for collegiate and academical use. Written with remarkable clearness, and scrupulously correct in its details.—Mining Journal. His expositions are most lucid. There are faw who will not follow him with pleasure as well as with profit through his masterly exposition of the principles and primary laws of science. It should certainly be made a class-book in schools.— Critic. 12 BLANCHARD & LEA'S PUBLICATIONS.—(Educational Works.) NEW AND IMPROVED EDITION—(Now Ready.) OUTLINES OF ENGLISH LITERATURE. BY THOMAS B. SHAW, Professor of English Literature in the Imperial Alexander Lyceum, St. Petersburg SECOND AMERICAN EDITION. WITH A SKETCH OF AMERICAN LITERATURE. BY HENRY T. TUCKERMAN, Author of "Characteristics of Literature," "The Optimist," &c. In one large and handsome volume, royal 12mo., extra cloth, of about 500 pages. The object of this work is to present to the student a history of the progress of English Literature. To accomplish this, the author has followed its course from the earliest times to the present age, seizing upon the more prominent " Schools of Writing," tracing their causes and effects, and selecting the more celebrated authors as subjects for brief biographical and critical sketches, ana- lyzing their best works, and thus presenting to the student a definite view of the development of the language and literature, with succinct descriptions of those books and men of which no educated person should be ignorant. He has thus not only supplied the acknowledged want of a manual on this subject, but by the liveliness and power of his style, the thorough knowledge he displays of his topic, and the variety of his subjects, he has succeeded in producing a most agreeable reading-book, which will captivate the mind of the scholar, and re- lieve the monotony of drier studies. This work having attracted much attention, and been introduced into a large number of our best academies and colleges, the publishers, in answering the call for a new edition, have endeavored to render it still more appropriate for the student of this country, by adding to it a sketch of American literature. This has been prepared by Mr. Tuckerman, on the plan adopted by Mr. Shaw, and the volume is again presented with full confidence that it will be found of great utility as a text-book, wherever this subject forms part of the educational course; or as an introduction to a systematic plan of reading. From Prof. R. P. Dunn, Brown University, April 22,1852. I had already determined to adopt it as the principal book of reference in my depart- ment. This is the first term in which it has been used here ; but from the trial which I have now made of it, I have every reason to congratulate myself on my selection of it as a text-book. From the Rev. W. G. T. Shedd, Professor of English Literature in the University of Vl. I take great pleasure in saying that it supplies a want that has long existed of a brief history of English literature, written in the right method and spirit, to serve as an intro- duction to the critical study of it. I shall recommend the book to my classes. From James Shannon, President of Bacon College, Ky. I have read about one-half of " Shaw's Outlines," and so far I am more than pleased with the work. I concur with you fully in the opinion that it supplies a want long felt in our higher educational institutes of a critical history of English literature, occupying a reasonable space, and written in a manner to interest and attract the attention of the student. I sincerely desire that it may obtain, as it deserves, an extensive circulation. HANDBOOK OF MODERN EUROPEAN LITERATURE. British, Danish, Dutch, French, German, Hungarian, Italian, Polish and Rus- sian, Portuguese, Spanish, and Swedish. With a full Biographical and Chronological Index. By Mrs. Foster. In one large royal 12mo. volume, extra cloth. Uniform with " Shaw's Outlines o (English Literature." »"* ' ft". 'VV '■rJ-}I;'i:*Y:'M