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JT^' if- oniis W.6wUi «i’* ^iiiov 'jitj 0*1/ oj '\o^bo{» Jyjj.'Tjrao-now « *’ Ij i.•^.'>•,|' fUR yoH'XJtr sdt ylp.mtisV) ii'M^£.h '.ys'tfit »t !•’ '.h S^-- _ ■ iid) odiniaulli oj miitnotai wo Yl^tifno j ju -li ji I)o« "{ ?biov 'hi onfrsfi - : ''^j 'liTt^b o-i •..•-i' ’ ■ ! ; to ybilMt? ow j( i!u'-v , liiiiigrTCs oifl* .loilJn/t riiuhfBofn irh silt to fdJT' ' •^'>nr''iTty‘-A. j -noo T‘«ifoiiof f'lAtoofkio n^'i oYnd .-.oaiinunjcl y^T'*' *' ' i*' ■ i.ninn lyos;;.iit/h!* 1';^ ^ ■; Jaait -Mlf Tuj 'AbliT'joTnijfi, ll-M/ ,b‘)^?jbiV|jtoi ii4.Sk’^ OWiif 3o iUli; fii;: - j -O -lei? j : >')hf^'brA8^:':'T5^o£fw ofL- /joiTtj ^t'lT’biiitr c f« b.' .■.•~ji ■•>£:» .•»iy)’i,'rjj‘'''i.' HJm'/ .’'fi>.'f.u;.‘f^ -^..AAxi. ‘ ‘tt/o 'fd >b*r( ?b.f>7!ih.' n' -.‘v'lqc-i v,, <1;. / ■k .Ttloqqu •Muiv^^J/I n‘?> .ill'" r'Tv'^v'crj sloVi ;tiTS ' i?! ?£ olrui'^afYU p L* •ife kF'- .: • I V - / r % . 5 ■ Pf»- 'vT' •5V-. THE ANIMAL KINGDOM. INTRODUCTION. SECT. I NATURAL HISTORY IN GENERAL, AND METHODS OF ARRANGEMENT. Nature — Division of the Physical Sciences — Natural History — General Principles — Conditions of Existence, or Final Causes — Observation — Classification Arti- ficial or Natural — Subordination of Characters, We deem it necessary to commence our work by clearly defining the ob- ject of Natural History, and by establishing a precise line of demarcation, so as to separate tliis science from others, to which it is nearly allied. This is tlie more requisite, as confused and indistinct notions on the subject very generally prevail. Various significations have been applied to the term Nature, in our language as well as in most others ; — sometimes it denotes the qualities of a being derived from original constitution, as distinguished from those ac- quired by art ; — sometimes it signifies the vast concourse of beings com- posing the universe; — and sometimes the laws which govern those beings. It is especially in this last sense that we are accustomed to personify Na- ture ; and, from a proper feeling of respect, to use this term for the name of its divine Author. Physics, or Physical Science, may consider nature in any of these three points of view. The name of the Supremo Being, which never ought to be pronounced without emotion, could not he introduced into philosophical discussions upon every occasion, tvithout a violation of decorum. Accordingly, it has become an established practice to use the milder term Nature, a.s an appellation of similar import. This is done with- out any intention of deifying the powers of nature. On the contrary, the best and 'Visest natural philosophers agree with Dr Clarke in considering “ that there is UO such thing as what wo commonly call the course of nature, or the power of na- ture. The course of nature, truly and properly speaking, is nothing else than the Will of God, producing certain effects in a continued, regular, constant, and uniform manner, which course or manner of acting being in every moment perfectly arbitrary, is as easy to bo altered at any time as to be preserved. So that all those things which we commonly say are the effects of the natural powers of matter and laws of motion, of gravitation, attraction, and tho like, are indeed (if we will speak strictly and properly) the effects of God's acting upon matter, continually and every moment, uither immediately by himself, or mediately by some created intelligent being." In •hese and following passages, the term law is used in a metaphorical sense. An ordinary law of civil society is addressed by an intelligent legislator to persons, oapable both of understanding tho meaning of the law, and of regulating their actions ^ordingly. But, when we use the phrases law of vegetable life, law of gravitation, 't is evident that the word is used in a sense widely different from the former. Na- ture, that is, the Supreme Being, not only prescribes the law, but executes it ; a law "f nature being nothing more than that particular regular mode of acting which tho ®eity has prescribed to himself. Physical Science is either general or particular. IDien we deduce effects from causes, and, by explaining the various phenomena of uture, obtain the power of applying the materials she presents to purposes useful to mwkind, it is termed General Physics, or Natural Philosophy; but, when we con- >'der the various objects presented by Nature, simply for tho purpose of obtaining a ^“owledge of their order, their arrangement, and the disposition of their parts, tvithout eferring effects to their causes, it is termed Particular Physics, or Natural History. ^ thus appears, that while Natural Philosophy is the ultimate object of science, Na- mal History is the source whence all science must necassarily arise. The former is “Rivalled for sublimity of ideas and depth of investigation, tho latter for variety of ' aracter and interest in its details. While Natural Philosophy is best fitted to occupy ® mind in its severer moments. Natural History affords an agreeable relief, by the ^pneral beauty of its objects, the elegance of their forms, the richness of their colour- "g. the singularity of their habits and instincts, and the exquisite adaptation of all mr parts. Both alike Ic.ad us to form elevated and enlightened conceptions of tho P»wer and beneficence of tho Creator. General Physics exaininos, in an abstract manner, each of the pro- Pt'rties of tliose moveable and extended bodies, to which we apply the Spheral term matUr. That branch called Mechanics considers the particles of matter as col- lected in masses, and deduces mathematically, from a very small number of experiments, the laws of equilibrium, of motion, and of its communi- cation. Its several divisions take the names of Statics, Dynamics, Hy- drostatics, Hydrodynamics, Aerostatics, &c. according to the nature of the bodies, the motions of which are under examination.* Optics consi- ders solely the peculiar vibrations of light; but in this science various phenomena, ascertained entirely by experiment, are daily becoming more numerous. Chemistry, the other division of General Physics, explains the laws, by which the elementary particles of bodies act on each other, at indefinitely small distances ; the combinations or decompositions resulting from the affinity of their ultimate elements ; and the manner in which the operation of affinity is modified by various circumstances, capable of increasing or diminishing its action. Being chiefly an experimental science, it cannot, on that account, be classed with others more exclusively mathematical. ■ | The theories of heat and electricity may belong almost equally to Me- chanics or to Chemistry, according to the point of view in winch each of them is considered. The mode of proceeding adopted in all the departments of General Phy- sics is, to consider, either mentally or experimentally, only a small number of the properties of bodies at once, in order to reduce them to the greatest attainable simplicity; then, to calculate or discover the effects resulting therefrom ; and finally, to generalize and incorporate the laws of these pro- perties so as to form series of theorems; and, if possible, to resolve them into one universal principle, which will serve as a general expression for them all. 1 ARTICULAR Physics, ot Natural History (for both of these terms are used indiscriminately), may [be extended so as to] include the particular appli- cation of the laws, ascertained by the different branches of General Physics, to the numerous and diversified created beings existing in nature, in order to explain the phenomena which each exhibits. When used in this ex- tensive signification, it also includes Astronomy; but this latter science, being fully elucidated by the light of Mechanics alone, is entirely subser- vient to its laws, and employs methods of investigation, too different from those admitted by Natural History, to be [extensively] cultivated by the same persons. It is usual, also, to include Meteorology among the branches of General Physics, and to confine Natural History to objects which do not admit of rigorous mathematical investigation, or precise measurement in all their parts. Geoloyy ranks next to Astronomy for the sublimity and depth of its investigations, and ought, logically, to be classed with Natural Philosophy. But the science is based upon so vast a mass of historical detail, and is still so much in its infancy, that it will long continue to be arranged with tho branches of Particular Physics. It contrasts with Astronomy in this respect, that while tho last-mentioned science leads us to ex- plore the infinity of space, Geology unfolds the secrets of the infinity of past time. In the one, tho present place of man is considered but as a point in tho vast regions of space, in the other, tho present time but as an instant in tho middle ot two infini- ties— time past and time to come. Natural History properly considers only the inorganic bodies called Minerals, and the various kinds of living beings [called Animals and Plants,] almost all of which are under the influence of laws, more or less uncon- nected with those of motion, of chemical affinity, and of various others, ’ In this, and in similar passages, wo have thought it more agreeable to received usage to transpose the tenns Mechanics and Dynamics from tho position in which they stand in the original, the former being, as we conceive, the more general term -— Translator. ° 2 NATURAL HISTORY analysed in the several departments of General Physics. We ought, in treat- ing of Natural History, to employ precisely the same methods as in the Ge- neral Sciences ; and, therefore, we endeavour to adopt them, whenever the subjects under examination become sufficiently simple to permit that mode of investigation. But as this is seldom practicable, there arises, hence, an essential difference between the General Sciences and Natural History. For, in the former, the phenomena are examined under circumstances completely within the reach of the inquirer, who arrives, by anal3'sis, at general laws ; while, in the latter, they are removed, by unalterable con- ditions, beyond his control. In vain, he attempts to disengage them frohl the influence of general laws, already ascertained. He cannot reduce the problem to its elements, and, like the experimental philosopher, withdi'aw successively each condition ; but he must reason upon all its conditions at once, and only arrive, by conjecture, at the probable result of such an analysis. Let him seek to ascertain, by direct experiment, any one of the numerous phenomena essential to the life of an animal, though but slightly elevated in the scale of being, “ And ere he touch the vital spark — ’tis fled.” Thus, it appears that, while Mechanics has become a science chiefly of CALCULATION, and Chemistry of experiment. Natural History will long re- main, in most of its departments, a science wholly of observation. The latter part of this remark must, however, he restricted to the early stages of Natural History ; because, in its more matured condition, it becomes a science of demonstration. Every branch of physics has one leading object in view, and that is, the discovery of the ultimate laws of Nature. Philosophy regards this as of primary importance ; while utility is held only as of secondary rank. Science, in its most comprehensive sense, is a superstructure founded on facts, or acquired by oxperionco ; and hence, in its early stages, wo consider it as entirely limited to observation : but when we have learned to generalize, and find that truths agree in their several relations, we have arrived at the demonstrative part of the science. It is not, therefore, from a mere knowledge of correct nomenclature, or from a capacity to recognize at sight a natural object, that we arc entitled to apply the name of scientijic knowledge to Na- tural History; but only when we have succeeded, by observation, in deducing the laws which regulate these objects, in their relatioms to surrounding beings. These three terms, Calculation, Observation, and Experiment, express, with sufficient accuracj', the manner of cultivating the several branches of Physical Science ; but, by exhibiting among them very different degrees of certainty, they indicate, at the same time, the ultimate point to which Chemistry and Natural History ought to tend, in order to rise nearer to perfection. Calculation, in a manner, sways Nature; it determines the phenomena more exactly than can be done by observation alone: Expe- riment obliges Nature to unveil: Observation watches when she is refrac- tory, and seeks to surprise her. Natural History employs with advantage, on many occasions, a principle of reasoning peculiar to itself, termed the conditiojis of eiisiencc, or, more commonly, final caiues. zVs nothing can exist except it contains within itself all the conditions which render e.xistence possible, it is evident, that there ought to be such a mutiud adaptation of the various parts of each being among themselves, and such ;in accommodation of their structure to the circumstances of surrounding beings, as to render possible the ex- istence of the whole. The analysis of these conditions often leads to the discovery of general laws, with a clearness of demonstration, surpassed only by the evidence of direct experiment or calculation. It was by the knowledge of this principle, that the celebrated Dr William Harvey was enabled to discover the circulation of the blood in Man. The Honourahlo Robert Boyle relates his conversation with Ijr Harvey on this subject, in the following words : — “ I remember, that when I asked our famous Harvey, in the only discourse I had with him (which was but a little while before he died,) what were the things which induced him to think of a Circulation of the blood? he answered mo, that when he took notice that the valves in the veins of so many parts of tho body were so placeil, that they gave free passage to the blood towards the heart, but opposed tho passage of the venal blood the contrary way, ho was invited to think, that so provident a c.-.use as Nature had not placed so many valves without design : and no design seemed more probable than that, since the blood could not well (because of the intei-posing valves,) bo sent by the veins to the limbs, it should bo sent through the arteries and return through tho veins, whose valves did not oppose its course that way.” It is evident from this, and many other similar instances, that, in ozamining the subjects of Natural History, wo shall best advance the science, by considering attentively the uses and ends designed by Nature in their fommtion, and the functions which their organs arc destined to perform. This manner of investigation has been objected to by some philosophers, among whom is Des Cai tos, as being a presumptuous attempt on the part of human reason, far above its powers, to penetrate into the secret designs of tho Creator. The following passage, extracted from the works of Mr Boyla above quoted, forms a satisfactory answer to this objection : — “ Suppose that a countryman, being in a clear day brought into the garden of some famous niathematici.'m, should see there one of the muious gnomonic instruments, that show at once tho place of the sun in the zodiac, his declination from the equator, the day of tho month, tho length of the day, &o. &c., it would indeed be presumptuous in him, being unacquainted both with tho mathematical disciplines, and the several intentions of the artist, to pretend or think himself able to discover all the ends for which so curious and elaborate a piece was framed : but when he sees it furnished with a style, with horary lines and numbers, and, in short, with all the requisites of a sim-dial, and manifestly perceives tho sha- dow to mark from time to time the hour of the d.ay, it would be no more a presump- tion than an error in him to conclude, that (whatever other uses the instrument was fit or was designed for,) it is a sun-dial, and was meant to show the hour of the day.” The whole science of Natural History teems with instances, showing the successful application of the general principle called the conditions of existence. Thus, when we sec an animal, possessed of a capacious stomach, long intestines, and a massive struc- ture, wo may safely infer th.at it is herbivorous, or feeding on vegetables, slow in its movemohts, and of timid and gentle habits. On the contrary, when wo find .an animal with short intestines, straight stomach, and .armed with weapons of offence, we immediately conclude it to be carnivorous, or feeding upon flesh, and of a fierce and active disposition. It is further observed by the author, in his Lectures on Comparative Anatomy, that the construction of the alimentary canal determines, in a manner perfectly absolute, the kind of food on which the animal is nourished. For, if the animal did not possess, in its senses and organs of motion, the means of distinguishing the- kinds of aliment suited to its nature, it is obvious that it could not exist. An animal, therefore, which can only digest flesh, must, to preserve its species, Imvcthc power of discovering its prey, of pursuing, of seizing, of overcoming, and of tearing it in pieces. It is necessary, then, that tho animal should have a penefratuig eye, a quick smell, a swift mo- tion, adilress ajid strength in tho jaws and talons. Agreeably to this necessity, a sharp tooth, fitted for cutting flesh, is never co-exlstcnt in the same species with a hoof covered with horn, which can only support tho animal, hut cannot grasp any thing : hence the law, according to which all hoofed animals are herbivorous, and also those still more detailed laws, which are hut corollaries to the first, that hoofs indicate molar teeth or grinders with flat crowns, a very long alimentary canal, with a ca- pacious and multiplied stomach. It is only after having exhausted all the laws of general physics, and the conditions of existence, that we are compelled to resort to the simple laws of observation. The most eflectual mode of deducing these is by comparison; by observing the same body successively in the various po- sitions in which it is placed bj' Nature; and by comparing dificrent bodies with each other, until wo obtain a knowledge of some constant relation.s between their structure and tlie phenomena exliibited by them. These various bodies thus form a species of experiments, performed entirely by Nature’s hand, where diflerent parts of cacli are supplied or abstracted, as we would desire to treat tliem in our laboratories; and the results of these additions or abstractions arc presented to us spontaneously. We are thus enabled to deduce the invariable laws influencing these relations, and to apply them in a manner, similar to the laws determined by general physics. Could we but incorporate these laws of observation with the general laws of physics, either directly or by means of the principle called the conffitions of existence, the system of natural science would be com- plete, and the mutual influence of all beings would he perceived through- out the whole. To approach this great end the eflbrts of naturalists should be steadily directed. All researches of this kind presuppose that we have the means of dis- tinguishing witli certainty, and of describing to others with accuracy, the objects under investigation; otherwise, we shall be continually liable to fall into confusion, amidst the innumerable beings which surround us. Natural History ought, therefore, to have for its basis, what has been tech- nically termed a system of nature, or a methodical and extensive catalogue, arranged with divisions and subdivisions, in whicli all beings shall bear suitable names and distinct characters* That we may always be able to discover the cliiiracter of any particular being from knowing its name, or the name from knowing its specific character, wo must found this peculiar description upon some essential or permanent properties of the being. We must not derive the character from habits, or colour alone, as these projter- ties are ever liable to be modified by external circumstances, but froni internal organization or coMrosmoN. MTicn Natural History was in its infancy, the objects were few and easily reineni- bered. Systems of classification were eitiier neglected as unnecessary, or confined only to those general tbvislons and subdivisions, which it was impossible to overlook. But ever since the chiys of Aristotle, A.C. 330, when Alexander the Great iiad in- creased the number of known species of animals by some of the productions of the conquered East, tho necessity of a precise system of classification has been univer- sally admitted; and now, the progress of geographical knowledge has enlarged the bounds of the science to so vast an extent, and disclosed a variety so inconceivable of forms hitiiertu unknown, that the naturalist would, without classification, he over- whelmed with endless details. Yet tho different kinds of animals are daily becoming more numerous by the contributions of enlightened travellers. In 17S0, the number of distinct species of insects was estimated at 20,000, and now it cannot be Ics:* than 100,000. And when it is considered how small a part of tho globe has been • The word character, in Natural History, denotes that iwcullar description of an object which distinguishes it from all others. Tims wo say, tho character of t«“'* is, “ Teeth of throe kinds, posterior extremities furnished with feet anterior with himds, &c. &c.” — Translator. ‘ LIVING BEINGS— ORGANIZATION IN GENERAL. 3 carefully examinod, wlien there are vast tracts in the interior of Asia, Africa, America, and the isles of the Southern Ocean, which have never been trod by civilized man, while many portions, oven of Europe, are but superficially explored, and when the depths of the vast ocean present insuperable barriers to investigation, wo may reason- ably expect, that the whole number of species will be found to be very much greater. Improved microscopes have disclosed myriads of animalcules previously unknown, and almost every fluid contains an enormous variety of distinct forms, many of them pecu- liar to each kind of liquid. All this appiircut chaos is by the art of the naturalist reduced to a beautiful system, and immediately one universal principle of order may bo traced throughout the whole. Scarcely any oliject in nature is so peculiar in its formation, as to bo at once defined by any single trait in its character. We are almost always under the necessity of combining many of these peculiarities, in order to distinguish an object from others to which it is nearly allied; especially when these allied objects possess some, though not all, ol its peculia- rities, or when these peculimitios are united to other properties of a dif- ferent character. The more numerous the objects are which h.ave to be distinguished, the more it becomes necessary to multiply the terms of their several characters ; so that, without some contrivance, they would become descriptions of inconvenient length. To remove this objec- tion, divisions and subdivisions are employed. A certain number of al- lied species are collected together into one group, and it then becomes necessary only to express, for their respective characters, the points wherein they differ, which, according to the above supposition, form but a small part of their description. The whole group is termed a genus. The same difficulty would be experienced in distinguishing the genera from each other, if wc did not repeat the operation, by grouping the allied genera to form an order; and then assembling the allied orders to constitute a class. Subdivisions intermediate to these are established when necessary. This aggregation of divisions, in which the superior contain the inferior, is termed a system or method. It may be compared, in some respects, to a dictionary, wherein the properties of things are an index to their names, being the reverse of ordinary dictionaries, in which the names are given, as an index to their meanings or properties. Thus it appears, that a collection of individuals of the same form constitute ^ species. Of species ^ genus. Of genera order. Of orders ^ class. And of classes - a kingdom. To explain this arrangement more clearly, wo shall take an example from the Ani- mal Kingdom; suppose, tho horse. This animal belongs to the class Mammalia, containing all which suckle their young ; to the order Fachydermata, or thick-skinned animals, such a.s the elephant, boar, and rliinocoros; and to the genus Eqmis, com- posed of animals with solid hoofs, as the ass and zebra. From these allied species it h finally distinguished by the term caballus. Thus, the scientific name of tho horse ^ Equus cahallus, terms derived from its genus and species. But, as different natu- falists often give different names to the same animal, it becomes necessary to add to these the name of the nahualist who first introduced tho generic and specific names. In the above example, we therefore write Equas caballus, Lixs. for the celebrated na- turalist Linnajus. In the following pages, we shall give an extensive list of tho various ®ynonymes, or names bolenging to the same animals, for facilitating rcfcronco to other Works on the same subject. Such is the method indispensably required, in framing tho arrangement of tho al- most unbounded objects of Natural History. IVo need «carccly caution our readers against the errors of tho Realists, once tho eause of so much contentioti in the schools. The individustls alone, or more properly hie particles composing each individual, havo a real existence in nature, while species, Sunera, &e. are but general words, invented by man, to express certain points of re- ■lerablanco, which he perceives among their properties. There are two different principles observed in the formation of systems of arrange- ment, according as they are intended to be orii/ieiat. or natural. The design of an artificial system is to enable the student to find the name of an object, whose proper- hes arc known, and to this alone its utility is, in general, confined. Thus, Linnosus ''>T,anged plants, chiefly according to the number and situation of tho stamens and pistils contained in their flowers. But, being fuimded on tho comparison of only one single "''sun, the artificial method conveys no general knowledge of other properties, and *^re(jucntly separates objects whicli ought never to bo disjoined. It is altogether dif- ^urent with a naittrul methoih Its tlivisions are not founded upon the consideration a single organ, but are derived from characters presented by all tho parts of the "''jeet. Accordingly, the objects are dispo.sed in such a manner, that each bears a fireater affinity to that which immediately precedes and follows it, than to any other. this method, therefore, is good, it is not confined to a mere list names. If the subdivisions have not been selected arbitrarily, hut rest "Pon real and permanent relations, and upon the essential points of re- ^®'nl>lanco in objects, the natural method is the means ol reducing the bmpenies of beings to general laws, of expressing them with brevity, of fixing them permanently on the memory. To produce these re- ^nlts, objects must be assiduously compared under the guidance of another Seneral principle, necessarily proceeding from that of the conditions of ^'^'stenco formerly explained, called the subordination of characters, •which we shall here briefly elucidate. The several parts of a being having a mutual adaptation, there are certain constitutional arrangements which are incompatible with others ; again, there are some with which they are inseparably connected. When, therefore, certain peculiarities belong to an object, we may calculate with facility what can, and what cannot, co- exist with them. Wc, accordinglj', distinguish by the terms important or leading characters, those parts, properties, or constitutional arrangements, having the greatest number of these relations of inconsistenc}', or of ne- cessary co-existence ; or, in otiicr words, which exercise upon the whole being the most marked influence. Others of minor importance are termed subordinate characters. The superiority of characters is sometimes deter- mined in a satisfactory manner, by considering the nature of the organ.s described in the character. When this is impracticable, we must resort to simple observation; and, from the nature of a character, must infer such to he the most decided as are found the least liable to vary, w'hen traced through a long series of beings, differing in degrees of resemblance. For this reason, we sliould select for the grand divisions, those characters which are at once important and permanent; and may reserve, ■with pro- priety, the subordinate and variable characters for the minor subdivisions of our system. There can he but one complete system, and that is, the natural method. Here species of the same genus, order, or class, resemble each other more than they do the species of any other corresponding division ; the place of each object is decided by its relation to surrounding beings; [and the whole arrangement forms a type of that beauteous system of nature which, “ changed tlmo’ all, thro’ aU remains the same." Even Linnaeus, who framed the iiest artificial system ever presented to the world, ob- serves, in his Philosoph. Bot. § 77, that natural historians should regard the natural method of arrangement as the ultimate aim of their labours. In a -word, the natural method is the very soul of Natural History. “ Unerring nature, still divinely bright. One clear, unchanged and universal light.”] SECT. II or LIVING BEINGS, AND OF OBGANIZATION IN GENERAL. Life — Itsdefinition — Death — Oryanhation — Generation — Spontaneous Generation — Reproduction — Species — Varieties — Permanence of Species — Pre-existence of Germs. Life, being the most important of all the properties of created e.xistence, stands first in tlio scale of characters. It has always been considered the most general principle of division ; and, by universal consent, natural ob- jects have been arranged into two immense divisions, organic beings [comprising animals and plants], and inorganic beings [comprising mine- rals.] The word Life ia used under two significations which arc often confounded. It may he applied merely as a general term to express, with brevity, tho various pheno- mena peculiar to living beings ; or it may signify the cause of these phenomena. It is in tho latter sense that the terras vital principle, or principle of life, are employed ; being, in this rospeet, perfectly analogous to the terms gravity, heat, attraction, and electricity, which are used hi the general sciences under a twofold signification, the one physical, — the other metaphysical. But, it is with the phenomena alone, or the physical sense of these terms, that Natural Philosophy has any concern. Tho know- ledge of causes is removed far beyond the reach of human reason; and, by neglecting to discriminate between these two senses, ancient philosophers before Lord Bacon, and too many modern ones shiee his time, havo fallen into endless discussions, and ob- scured the light of real science, "yet, it is difficult, upon a subject so interesting as life, in which we all feel deeply concerned, to restrain curiosity wdthin the bounds of reason and philosophy. A recent anonymous writer asks, “ Who has not put to him- self the question ‘ What is life?’ Wlio would not receive a clear and just solution of tho inquiry, with a feeling of interest, far beyond that afforded by the successful result of any ordinary scientific investigation ? We can comprehend part of the mechanism by which life acts ; wo feet its result. We see that mechanism to be so delicate, so com- plicated, so fragile, so easily set wrong, while our interest is so deep that it should act well, and permanently well, that the exquisiteness of adjustment, the skill of contrivance, and tho completeness with which the intended result is secured all subjects of distinct and interesting investigation — only increase tho earnestness of our wish, that wo could see beyond the mechanisni, and understand that, wliich it is permitted us to know only by examining its phenomena. “Wo do not commonly oonsiiler how much is given us in life, — the daily enjoyment of the boon renders us insensible to the variety and plenitude of its richnes.s. We shall become more sensible of it upon contemplating the various tissues of organic particles that have been formed; tho number of properties that are attached to oach; tho number of organs that arc constituted by their aggregation and arrangement ; the number of functions that are exercised by those organs; and the number of adjust- ments by which all arc combined, harmonized, mid made effectual to the production of one grand result. It is then wo perceive, how many things must exist, how many relations must he established, how many actions must bo p’erformed, how many 4 LIVING BEINGS— ORGANIZATION IN GENERAL. combinations of actions must be secured, before there can be sensation and motion, thought and happiness.” JMany attempts have been made to account for the vital principle, but hitherto all these have proved abortive. It is possible, that various functions of the aninial frame may hereafter be discovered to proceed from mechanical or from chemical laws; but, we believe, that the ultimate springs of the phenomena of life will ever remain con- cealed from human knowledge. In order to form a just idea of the essential conditions of life, we must first examine those beings, which are the most simple in the scale of crea- tion ; and we shall readily perceive that these vital conditions consist, in a power possessed by certain bodies, for a period of time only, of exist- ing in a determinate form; of continually drawing into their composition a part of the surrounding substances ; and of returning back, to the in- fluence of the general laws of matter, certain portions of their own mate- rials. These phenomena are exhibited by the conferva rivularis, a small bundle of green filaments, finer tban hair, found in rivulets and stagnant pools. Being without root or leaves, it is simply attached by a broad surface to the margin of the water. While life exists, it increases in size and weight, throws out filaments like branches, assimi- lates the particles of water, and of other inorganic substances around it, into vegetable matter, and lays them down in an oblong cellular form. In animals and plants, nutri- tion is the effect of an internal power ; their growth is a development from within. In minerals, on the contrary, growth goes on by the external deposition of successive strata or layers; whibt organized bodies, by means of their vital power, grow and in- crease by the assimilation of different substances. The stalactite., once supposed to be an exception, is now proved to be subject to the ordinary laws of inorganic mat- ter. Thus life may be compared to a whirlpool of variable rapidity and in- tricacy, drawing in particles of the same kind, and always in the same direction ; but where the same individual particles are alternately entering and departing. The form of living bodies seems, therefore, to be more essentially their own, than the matter of which they are composed. Tho matter forming the bones of animals has been ascertained to undergo a very considerable change in a few days; and from this fact the probability of a corres- ponding change in the other parts of the frame is inferred. The very singular rapi- dity with which this change is effected was accidentally discovered. Certain animals were fed with madder (rubia tinctoruni), a plant cultivated for its red dye; and in twenty-four hours all their hones were found to he deeply tinged with its colour. On continuing tho same food, the colour became very deep; but upon leaving it off, the colour was completely removed in a very few days. By alternately changing the food, the bones were found to he marked with concentric rings of the red dye, accord- ing to the number of times that the change was made. These phenomena, so far sur- passing any thing that cduld have been anticipated, are well calculated to convey an idea of the extraordinary rapidity with which the particles of the animal frame are removed, while the form remains without any apparent alteration. While this movement continues, the body wherein it takes place lives ; when it entirely ceases, the body dies. After death, the elements which compose the living frame, being surrendered to the influence of the ordinary chemical affinities, begin to separate ; and the dissolution of the once living body speedily follows. It was, therefore, by the vital movement, that dis- solution had been previously arrested, and that the elements of organized bodies were preserved in a state of temporary union. All bodies cease to live after a certain period of time, the duration of which is fixed for each species. Death appears to be a necessary effect of life; and the very exercise of the vital power gradually alters the structure of the body, so as to render its longer existence impossible. The frame undergoes a re- gular and continual change, as long as life remains. Its bulk first increases in certain proportions, and to certain limits, fixed for each species, and for the several organs of each individual; and then, in tho course of time, many of its parts become more dense or solid. This last change api)ears to be the immediate cause of natural death. If different living bodies be examined with attention, we shall find tliein to be composed of an organic structure, which is obviously essential to such a whirlpool, as that to which we have already compared the vital action. There must not only he solid particles to maintain the forms of their bodies, but fluids to communicate the motion. They are, therefore, composed of a tissue of network, or of solid fibres and thin plates (or laminse,) which contain the fluids in their interstices. It is among the fluid particles that the motion i.s most continuous and exten- sive. Foreign substances penetrate into the innermost parts of the body, and incorporate with it. They nourish the solids by interposing their particles ; and, in detacliing from the body its former parts, which have now become superfluous, traverse the pores of the living frame, and finally exhale under a liquid or gaseous form. During their course, the foreign substance,s enter into the composition of the solid framework, containing the fluids ; and, by contracting, communicate a part of their motion to the liquid particles within them. This mutual action of solids and liquids — this transition of particles from the one form to the other, presupposes a great chemical affinity in their elementary constituents ; and we accordingly find, that the solid parts of or- ganized bodies are composed chiefly of such elements as are capable of being readily converted into liquids or gases. The solids would also require to be endowed with considerable powers of bending and expanding, in order to facilitate the mutual action and reaction between the solids and the fluids ; and hence, this is found to be a very general characteristic of the solid parts of organized bodies. Tliis structure, common to all living bodies — this po- rous or spongy texture, whose fibres or laminm, ever varying in flexibility, intercept liquids, ever varying in quantity — consitutes what has been termed organization; and, from the definition we have already given of the term life, it necessarily follows that none but organized bodies are capable of enjojnng life. Thus we see, that organization results from a great number of arrangements, all of which are essential conditions of life; and hence it follows, that if living bodies he endowed with the power of altering even one of these conditions, to such an extent as to obstruct or arrest any of the partial movements, composing the general action, they must possess within themselves the seeds of their own destruction. Every organized body, besides the ordinary properties of its texture, possesses a form peculiar to its species ; and this applies, not merely to its external arrangement in general, but even to the details of its internal structure. From this form is derived the particular direction of each of its pai'tial movements; upon it depends the degree of intricacy in the general motion; and, in fact, it is this which constitutes the body a species, and makes it what it is. Life is always attended by organization, just as the motion of a clock ever accompanies the clock itself ; and this is true, whether we use the terms in a general signification, or in their application to each par- ticular being. We never find life, except in beings completely organized and formed to enjoy it; and natural philosophers have never yet dis- covered matter, either in the act of organizing itself, or of being orga- nized, by any external cause whatever. The alements forming, in succes- sion, part of the body, and the particles attracted into its substance, are acted upon by life, in direct oiiposition to the ordinary chemical affinities. It is impossible, therefore, to ascribe to the clieraical affinities tliose plieno- mena, wiiich are the result of tlie vital principle ; and there are no other powers, except those of life, capable of re-uniting particles formerly se- parated. Tile birth of organized beings is, therefore, the greatest mystery of organic arrangements, and indeed of all nature. We see organized bodies develop themselves, but they never jfbm themselves; on the contrary, in all those cases where we have been able to trace them to their source, they are found to derive their origin from a being of similar form, but previously developed; that is, from a parent. The offspring is termed a germ, as long as it participates in tlie life of its parent, and before it has an independent existence of its own. In various species differences arc found to exist in the place where the germ is attached to its parent ; and also, in the occasional cause which detaches it, and gives it a separate ex- istence; but, it is a rule which holds universally, without one single ex- ception, 'that the progeny must have originally formed part of a being like itself. The separation of the germ is termed generation. Many ancient, and some more recent philosophers, believed that certain organized beings could be produced without parents ; and this opinion, though now completely e.xploded among the learned by the most convincing experiments, still maintains its ground with the ignorant. It originated, as most errors do, from hasty and inaccu- rate observation. Virgil gravely attempts, in a very elegant passage of the Georgies, t“ Explain The great discovery of the Arcadian swain ; How art creates, and can at will restore Swarms from tlie slaughter'd bull’s corrupted gore. And Kircher, who lived in the seventeenth century, gives a recipe to make snakes, which, however, ho doe.s not appear to have tried. In Scotland, the country people still believe that the hair-worm ( Gordius aquaticus, Linn.) can bo formed artificially by placing a horse's hair in water; and this unfounded opinion is, wo understand, generally diffused throughout the kingdom. The mites in cheese, the blight on plants, and the maggots in meat, seem at sight to favour the belief in spontaneous generation; but in all these cases the insects have been demonstrated to proceed from eggs, deposited instinctively by the parent, upon a substance capable of affording nutriment to her young. Tho popw lar mistakes on this subject are generally, however, concerning the lower tribes of ani' mals. But the ancients taught that even man could be produced without a parent- The newly-formed earth wa.s supposed to have been originally covered with a green down, like that on young birds ; and, soon afterwards, men, like mushrooms, rose front the ground. Lucretius (A. C. 60) relates, that even in his time, when the eartii t'SS supposed to be too old for generation, “ many animals were concreted out of mud by showers and sunshine.” ORGANIZED BEINGS— ANIMALS AND PLANTS. Every organized being produces others resembling it. Without this provision, all species would become extinct, since death is the necessary consequence of the continued action of life. Certain animals possess the power of reproducing some of their parts, after these have been removed. This power is termed iiepboduction, and it is found in various degrees of perfection, according to the species. In general, this power of renovating mutilated parts is found to exist most per- foetly in the lower species of organized Ireings. 'I'he head of the snail (^Limax, Linn.') may be cut oft', and the whole organ, including its elegant telescopic eyes, will be re- produced. The claws, feet, and feelers (or antennee) of crabs and lobsters, as well as (he limbs of sjhders, when amputated, arc completely restored by the fresh growth of new organs. AVhen accident deprives a shark of its teeth, they are replaced wil.h facility. If the ftiw of fishes he cut, they will reunite, and the raya thcrasolves will ho reproduced, provided only the small parts at their bases are left. The eyes of lizards, though possessed of an intricate apparatus of coats and humours, if removed, will be replaced by new eyes equal to the former. Even nun and the higher animals possess the same power, only restricted within narrower limits. Injuries to various parts of our frame are speedily repaired, and the wounds heal. The effect of injury to a living hone is curious. A new bone is produced round the old one; which finally dies, and is absorbed or discharged. The new bone, which at first was spongy in its texture, and irregularly formed, assumes, in a few years, its natural dimensions, and all ap- pearance of chaiigo is completely removed. Thus we see the bountiful provision of Nature, and the effect of that principle of reproduction, which restores most of the organs of the body to their natural form and action, when deranged by injury or by disease. Organized beings are developed with greater or less rapidity and perfec- tion, according as they arc placed in favorable or unfavorable circum- stances. Heat, the quantity or quality of their nutriment, and other causes, exercise considerable influence over them ; and this infltience may extend over the whole frame, or he confined only to certain organs. Hence, it follows, that the resemblance between the progeny and its parents can never be perfectly exact. These minor differences among organized beings are called varieties. The different kinds of dog (^Canis familiaris, Linn.), of horse (Equus cahallus, Linn.), of sheep (Oris arics, Desjn.), are all varieties of the same species, and are pro- duced by merely accidentul causes, such as domestication, climate, &e. By cultivation, the sloe has been transformed into the plum, and the crab-tree into the apple-tree. The '■'auliflower and red cabbage, though apparently very different plants, are descended from the same parents, — the wild Brassica oleracoa, — a weed growing near the sea. Air Herbert relates, in the Horticultural Transactions, that ho succeeded in raising, from the natural seed of a highly-manured red cowslip, a primrose, a cowslip, oxlips "f the usual and other colours, a black polyanthus, a hose-in-hoso cowslip, and a natural primrose, bearing its flower on a polyanthus stalk ; — all these are instances of varieties, depending upon soil and situation. There is, liowevor, tin real ground for supposing that all the diff'erences observable in organized beings are the result of accidental circumstances. Every thing hitherto advanced in favour of this opinion is purely conjec- tural. Oil the contrary, experience clearly shows, that, in the actual state of the globe, species vary only within very narrow limits ; and, as far as past researches liave extended, these limits arc found to have been in ancient times the same as at present. The French naturalists, who visited Egypt vs-ith Bonaparte, found the bodies of tho crocodile, tho ibis, the dog, the cat, the bull, and the ape, which had been embalmed three thousand years ago by the Egyptians its objects of veneration, to he perfectly identical w ith the living species now seen in that country, even to tho minutest bones end the smallest portions of their skins. Tho common wheat, the fruits, seeds, and “ther parts of twenty dift'eront species of plants, were also discovered, some of them from closed vessels in the sepulchres of the kings ; and they resembled in every respect the plants now growing in the East. The human mummies, also, exactly corresponded "uh the men of the present day. Wo arc, therefore, compelled to admit that certain forms have been ''t'gularly transmitted to us from the first origin of things, without having tran.sgressed the limits assigned to them, [except in a slight degree, when ihodified by certain accidental circumstances.] All beings, derived from ’-I'e same original form, are said to constitute a species -, and the varieties “fe, as has been stated, the accidental subdivisions of species. Generation appears to be the only means of ascertaining the limits by which varieties are circumscribed ; and we may therefore define a speciks be — a group or assemblage of individuals, descended, one from another, 'W from common parents, or from others resembling them, as much as resemble each other. However rigorous this definition may appear, 'ts application in practice to particular iudividuids is involved in many difficulties, especially when we are unable to make the necessary experi- tiients. In conclusion, we shall repeat, that all living bodies are endowed with functions of absorption [by which they draw in foreign substances] ; assimilation [by wliich they convert them into organized matter] ; of ^^^halation [by whicli they surrender their superfluous materials] ; of de- velopment [by which their jiaris increase in size and density] ; and of generation [by which they continue the form of their species.] Birth and death are universal limits to their existence: the essential character of their structure consists in a cellular tissue or network, capable of con- tracting; containing in its meshes fluids or gases, ever in motion: and the bases of their chemical composition are substances, easily convertible into liquids or gases ; or, into proximate principles, having great affinity for each other. Fixed forms, transmitted by generation, distinguish their species, determine the arrangement of the secondary functions assigned to each, and point out the part they arc destined to perform on tile great stage of the universe. The.se organized forms can neither produce themselves, nor change their characters. Life is never found sepvarated from organization ; and, whenever the vital spark bursts into a flame, its progress is attended l)y a boaufil'ully-organized body. The impenetrable mystery of the pre- existence of germs alike defies observations the most delicate, and medi- tations the most profound. Wo trace an individual to its parents, .and these again to their parents. After a few generations the clue is lost, and in vain we inquire, Whence arose the first animal of the species? and what produced the first germs from which have descended the innumerable trihos of animals and plants, that we see in constant succession rising around us? WTience did the species jian arise? Philosophical inquiry fails to lead us through the labyrinth ; and we fed the force of the same principle which inspired Adam, when he says, with Milton, “ Thou sun, fair light. And thou enlightened earth, so fresh and gay, Ye hills .md ikies, ye rivers, woods, and plains, And ye that live and move, fair creatures, tell, T 111! if you saw, how came I thus, how hero, Not of myself?" SECT, III DIVISION or OIIG.A.NIZED BEINGS INTO .*NI.MALS AND PLANTS. Animuh and Planti — IrritahUity — Animals possess Intestinal Canals Circulating Sgstem — their Chemical Composition — Respiration. Living or organized beings have been subdivided by universal consent, from the earliest ages, into animals endowed with sensation and motion, and into plants destitute of both, and reduced to the simple powers of vegetation. Some plants retract their leaves when touched ; and all direct tlieir roots towards moisture, and their flowers or leaves towards air and light. Cer- tain parts of plants even exliibit vibrations, unassignable to any external cause. Yet, these difl'erent movements, when attentively examined, are found to possess too little resemblance to tho motions of animals, to au- thorize us in considering them as proofs of perception and of volition. They seem to proceed from a power, possessed in general by all living substances, of contracting and expanding when stimulated, — a power to which tho name of irritahiUiy has been assigned- The fibres composing the heart of animals alter- nately expand and contract, altogether independent of the will of the animal; and thick hair will grow on the skins of some animals, when removed into a cold climate. As wc neither ascribe volition nor sensation to the heart or to the hair, so we cannot attribute these qualities to the heliotrope, to the sun-flower, or to the sensitive plant. The nice distinction of character must be cautiously olisorved, between sensation and mere irritability ; like the higher powcr.s of reason and instinct, they arc “ For ever separate, yet for ever near.” The power of voluntary motion in animals necessarily requires cor- responding adaptations, even in tliose organs simply vegetative. Animals cannot, like plants, derive nourishment from the earth by roots ; and hence they must contain within tliemselves a supply of aliment, and carry the reservoir witli tliem. From this circumstance is derived tlie first trait in the character of animals. They must possess an intestinal canal, from wliich the nutritive fluid may penetrate, by a species of internal roots, tlirougli pores and vessels into all parts of the body. The organization of this cavity, and of the parts connected with it, ought to vary accord- ing to the nature of tiie aliments, and the transformations necessary to supply the juices proper to bo absorbed; whilst the atmosphere and the earth liave only to present to vegetables tlie juices .already prepared, wiien they are immediately absorbed. Animal bodies, having tlius to perform more numerous and varied func- tions than plants, ought to possess a much more complicated organization ; and, in consequence of their several parts having the power of changing their position relatively to each otlier, it becomes necessary that tlie motion of the fluids should be produced by internal causes, and not be altogether dependent on the external influences of heat and of the atmosphere. This is the reason tliat animals are endowed with a circulating system, or 6 OllGANIC FORMS OF THE ANIMAL BODY. organs for circulating their fluids, being the second characteristic peculiar to animals. It is not so essential, however, as the digestive system, for it is not found in the more simple species. The complicated functions of animals require organized systems, which would be superfluous in vegetables ; such as, the muscular system for vo- luntary motion, and the nerves for sensation. It was also necessarj' that the fluids should be more numerous and varied in animals, and possessed of a more complicated chemical composition than in plants, in order to facilitate the action of these two systematic arrangements. Therefore, anotiier essential element was introduced into the composition of animals, of which plants, excepting some few tribes, are generally deprived ; and while plants usually contain only three elements, oxygen, hydrogen, and carbon, animals add to these a fourth, namely, azote or nitrogen. This difference in chemical composition forms the third trait in the character of animals. Plants derive their nourishment from the soil and atmosphere, and thence obtain water, composed of oxygen and hydrogen ; also, carbonic acid, which is a compound of carbon and ox5 gcn ; while the atmosphere yields an unlimited supply of air, composed of oxygen and nitrogen [with a slight mixture of carbonic acid.] From these materials, the supplies necessary to preserve their own composition unaltered, are obtained; and, while hydrogen and carbon [with a certain portion of oxygen] are retained, they exhale the superfluous oxygen [untainted.] The nitrogen, on the contrary, is [either absorbed in very small quantities, or] altogether re- jected. Such is the theory of vegetable composition ; in which one of the most essential parts of the process, namely, the exhalation of o.xygen, can only be performed by the assistance of light. When plants are deprived of light, an opposite effect ensues. Instead of giving off- oxygen-gas, and absorbing carbonic acid, the reverse takes place ; and carbonic acid is disengaged, while oxygen is absorbed. The effect of plants upon the air is, there- fore, to increase its purity during day-light, but to deteriorate its quality during the darkness of night. Animals require for their nutriment, directly or Indirectly, the same substances which enter into the composition of vegetables, namely, hy- drogen, carbon, [and a certain portion of oxygen.] But, in addition to these, it is essential, for the preservation of their peculiar constitution, that they accumulate a much larger portion of nitrogen, and disengage any excess of hydrogen, and especially any superfluity of carbon. This is performed by respiration, or breathing, in wliich process the oxygen contained in the atmosphere combines with the [excess of] hydrogen and carbon in the blood ; with the former of these, it forms watery va- pour, and with the latter carbonic acid. The nitrogen, to whatever part of the system it may penetrate, seems chiefly (though not altogether) to remain there. The quantity of nitrogen retained in the system varies with the seasons, being greater in siunmer, and less in winter. The degree of variation is different for ani- mals of different species: in some it is very small in qua:itity, while in others it is equal to their entire bulk. The effects produced upon the atmosphere by plants and animals, are of an opposite kind; the former decompose water and carbonic acid, while the latter reproduce them. Respiration forms the fourth character- istic of animals, and is the most distinguishing function of the animal frame ; namely, that which forms its essential difference from all other beings, and in a manner constitutes it an animal. So important is its influence over the whole body, that We shall presently be able to show, that ani- mals perform the functions of their nature with greater or less perfection, according as their respiration is more or less perfect. Thus we perceive that animals arc distinguished from plants by the following cha- racteristics: — 1st, They are possessed of an intestinal canal; 2dly, Of a circulating system; 3dly, Nitrogen enters l.wgely into their composition; and finally. They are endowed with organs adapted for respiration. SECT. IV. THE ORGANIC FORMS OF THE ANIMAL EODY, AND THE PRINCIPAL CHEMICAL ELEMENTS OP ITS COMPOSITION. Cellular Tissue 'feinbranes — Gelatine — Medullary Substance — Muscular Fibre — Pihrin Blood. Albumen — Secretion — Nutrition. A POROUS tissue of network, and at least three chemical elements (car- bon, hydrogen, and o.xygen), arc essential to all living bodies, while a fourth element (nitrogen) may be almost considered peculiar to animals. We shall now proceed to describe the various kinds of meshes, of which the network is composed, and the different combinations into which these four elements arc found to enter. There arc three kinds of organized principles, or forms of network; the cellular tissue, the medullary substance, or marrow, and the muscular fibre. To eacli of these forms is attached a peculiar combination of che- mical elements, as well as a particular function. The cellular substance is composed of an indefinite number of small lamina;, without any apparent arrangement, crossing so as to form very small cells, communicating with each other. It may be compared to a species of sponge, similar in form to the entire body ; while all other ani- mal particles either occupy its cells, or traverse its substance. It pos- sesses the property of contracting indefinitely when the causes, which preserved it in a state of extension, are removed. Tliis power retains the body witliin the limits, and in the form, assigned to it by Nature. The cellular substance, or tissue, enters into the composition of every part, forming regular series of cells. We find it equally in the brain, the eye, and the nerves, only somewhat finer in its texture than in the bones and muscles. Its cells move with fa- eiUty, and accommodate themselves to the motions of the body, being moistened, at the points of contact with the ailjacent cells, by a liquid, which lubricates them like the synovia, or oily fluid of joints, so as to facilitate their motion. When the cellular substance is compressed into compact plates, it forms laminm of various extent, called mambrancs. These membranes, when united into cylindrical tubes, more or less ramified, receive the name of vessels. The filaments, called fibres, are entirely composed of cellular substance ; and the bones are nothing more than cellular substance, rendered bard by the deposition of earthy particles. The general matter of which the cellular substance is composed, con- sists in the proximate principle or combination, called gelatine; the dis- tinguishing character of which is, that it can be dissolved by boiling water, and, upon cooling, takes the form of a tremulous jelly. Gelatine, when analyzed by Gay-Lussac and Thenard, was found to contain in 100 parts, by weight — carbon, 48; hydrogen, 8; oxygen, 27; and nitrogen, 17; very nearly. The medullary substance cannot bo resolved into any simpler organic structure. It appears to the eye as a soft wliitish pulpy matter, com- posed of an infinite number of very minute globules. No peculiar mo- tions can he observed in it ; but it possesses that most wonderful of all properties, the power of transmitting to the mind the impressions made on the external organs of sense, and of rendering the muscles subser- vient to the determinations of the will. The brain and spinal marrow arc almost entirely composed of medullary substance; and the nerves, which are distributed through all the organs capable of sensation, arc, in respect to their composition, nothing but bundles (or fasciculi) of this substance. The muscular, or fleshy fibre, is composed of a particular kind of fila- ments, having the peculiar property, during life, of contracting or folding themselves up, when touched or injured by any external body; or when acted upon, through the medium of the nerves, by the will. The muscles are the immediate organs of voluntary motion, and are composed entirely of bundles of fleshy fibres. All the membranes and vessels, which are required to exercise any compressive force, are armed with these fibres. They are alwa)-s united intimately with the nervous filaments, or threads ; but certain muscles are observed to execute mo- tions, altogether independent of the will, especially in the exercise of func- tions possessed in common with plants. Thus, although the wdll is fre- quently the cause of muscular motion, yet its power is neither general nor uniform in its action. Fleshy fibre lias, for the basis of its composition, a particular principle. ■atm&di fibrin, which is [nearly] insoluble in boiling water, and seems na- turally to assume a filamentous arrangement. It consists of white solid fibres, inodorous and insipid. Wlien analysed by Gay- Lussac and Thenard, 100 parts were found to contain about 53 parts of carbon, 7 of hydrogen, 20 of oxygen, and 20 of nitrogen. The nutritive fluid, or blood, when recently extracted from the circulat- ing vessels, may not only be ultimately resolved, for the most part, into the general elements of the animal body, carbon, hydrogen, oxygen, and nitro- gen; but it already contains fibrin and gelatine, prepared to contract the:'' substance, and to as.sumc respectively the forms of filaments or of mca'" branes, according to circumstances, whenever a slight repose enables them to exhibit this tendency. In addition to these, the blood contains an- other proximate principle, called albumen, [composed very nearly of parts of carbon, 7 of hydrogen, 24 of oxygon, and 16 of nitrogen.] character is to coagulate in boiling water, [like the white of eggs, com- posed almost entirely of albumen.] We also find in the blood nearly a the other elements, which enter into the composition of each animal hot y in small quantities ; such iw, the lime and phosphorus deposited in t bones of the liiglier animals ; the iron, whicli seems essential to the colouf ACTIVE FORCES OF THE ANIMAL BODY. of the blood and other parts ; and the fat, or animal oil, placed in the cellular tissue to render it flexible. In fact, all the solids and fluids of the animal body are composed of chemical elements contained in the blood. It is only by possessing some elements, of which the otltcrs are deprived, or by a diflcrcnco in the proportions in which they combine, that [in general] they can be distinguished. From this it appears that it only requires, for their formation in the body, to abstract the entire, or a part, of one or more elements of the blood ; or, in a few cases, to add a foreign clement, procured from another source. Some substani'oji, differing very much in ehar.ictcr, seem, however, to possess nearly tile same chemical compo-sition ; we must therefore consider the peculiar arrangement of tho particles as an essential distinction among animal fluids and solids, as well as tlieir composition, and the proportions of their elements. We might, without impropriety, assign the term secretion to denote the various operations by which the blood nourishes and renovates the solid and fluid parts of the body. But, we shall restrict the term to tho pro- duction of Jluiils only; while, we shall apply the term nutrition, to signify the production and deposition of the materials, necessary for the growth and maintenance of the solids. To each solid organ, and to every fluid, is assigned that peculiar composition which is suited to its place in the system ; and, by the renovating power of the blood, their composition is preserved during hcaltli, and the continual waste repaired. Tims, by affording continual supplies of nutriment, the blood would undergo a perpetual deterioration, were it not restored by the new matter obtained from the digestion of the food; by respiration, vvhich relieves it of the superfluous carbon and hydrogen; by perspiration, and various other means, which deprive it of any excess of other principles. These continual changes in the chemical composition of the several parts, are as essential to the vital action, as the visible motions of the old particles, and the constant influx of new ones: indeed, they seem to be tho final object for which tho latter motions wore designed. SECT. V. — ACTIVE FORCES OF THE ANLUAL BODY. Muscular Fibre — Nerves — lltjpoihesis of a Nervous Fluid. The muscular fibre is not confined, in its functions, to be merely the organ of voluntary motion. We have shown, that it is one of the most powerful agents employed by Nature, in efTecting such necessary motions and transference of particles in the bodies of animals, as arc possessed by them in common with vegetables. Thus, the muscular fibres of tho in- testines produce tlie peristaltic motion, which renders those canals per- vious to the aliment; and the muscular fibres of tho heart, with the arteries, ai-e the agents in the circulation of the blood ; and thus, ultimate- ly, of all the secretions. The Will contracts certain portions of the muscular fibre through the medium of the nerves. Certain other fibres, such as those to which we have just alluded, are independent of the Will, and yet are animated by nerves extending through them. We may therefore conclude, from ana- *°Sy> that those nerves arc the causes of their involuntary contraction. The nerves are composed of several distinct filaments, resembling each other in every respect; and they appear to ho formed of tho same soft pulpy material, commonly ealled marrow, or medullary substance, surrounded hy a cellular membrane. The fila- ments are again enveloped in a tube of this membrane, forming a continued nerve, extending from tho br.ain to various parts of the muscles and sUn. Yet the functions of the several filaments of the same nerve are very different. One filament is designed for voluntary muscular motion, another for sensation, and a third for involuntary rao- tmn. gif (Jiiarles Bell, to wliora we owe this remarkable discovery, divides all the nervous filaments of tho body into four general systems; namely, of voluntary mo- bon, of sensation, of respiration, and of involuntary motion. Tho last of these per- forms tho functions of nutrition, growth, and ultimately, of decay. Besides these, fliero arc nerves de.stinod to particular functions of sensation; such as sight, smell, xiid hearing. ^Vhen the sensitive filament of a nerve is injured in any port of its course, pain and bot motion is the result; and the p.ain is referred by the animal to that part of tho skin where the remote extremity of tho filament is distributed into minute fibres. A patient, whose leg has been amputated, will fool a pain, whieli long-continued habit has jaught him to refer to the extremity of the toes; when, in reality, tlie injury has been biflicted upon that portion of the nervous filament which terminates at the stump. hi the remainder of this section, our author proposes to explain tho pheno- biena of the nerves upon tho hyjiothcsis of a nervous fluid, acted upon by certain vheraical affinities. We are aware that several, almost insurmountable, objections ’bay bo urged against this theory, and indeed against every other which attempts to explain the complicated functions of life. Yet, if an hypothesis correspond pretty ■’ccurately with observed facts, it may have its nsrs, by fixing the phenomena in the memory, provided we always recollect, that it is hut an hypothesis, to he modified .as knowledge extends. Thus the phenomena of heat are referred to the imponderable fluid caloric ; of light, to the vibrations of a highly elastic medium ; of electricity, to the electric fluid ; — none of which can be demonstrated to have a real existence in nature. But, in adopting an hypothesis, we must never forget that it is a temporary, not a final, theory ; — a motive fur seeking further analogies, or, as Dr Thomas Brown rightly observes, “ a reason for making one experiment rather than another.” iiyroTiiEsis OF a kervous fluid. Every contraction, and, in general, every change in the dimensions of inorganic matter, is occasioned by a change of chemical composition; either, hy the absolute addition or abstraction of some solid matter, or by the flux or reflux of an imponderable fluid, such as caloric. In this way the most violent convulsions of nature arise, such as explosions, con- flagrations, &c. It is therefore probable that the nerve acts similarly upon tlio muscular fibre, by means of an imponderable fluid, especially as it has been proved th.Tt the impulse is not mechanical. The medullary matter of the entire nervous system is formed through- out of the same material; and, blood-vessels accompanying all its ramifi- cations, it is thus enabled to exercise, in every part, the functions be- longing to its nature. All the animal fluids being secreted from the blood, there is every rea- son to infer that the nervous fluid is derived from a similar source, and that the medullary substance is tlie agent in the secretion. On the other hand, it is certain that the medullary substance is the sole conductor of tho nervous fluid; all the other organic elements are non-conductors, and arrest it, as glass opposes the progress of the electric fluid. AH the external causes, capable of producing sensation, or of occasion- ing contractions in the muscular fibre, are chemical agents, possessing a power of decomposing, such as light, caloric, salts, odorous vapours, &c. It is tlicrefore extremely probable, that these causes act in a chemical manner upon the nervous fluid, hy altering its composition ; and this view appears to he confirmed by the fact, tliat the action of the nerves is enfeebled by long continuance, as if the nervous fluid required a supply of new materials to restore its composition, and enable it to undergo a further alteration. An external organ of sense may be compared to a kind of sieve, which only permits those agents to pass through it, and act upon the nerve, that it is fitted to receive at that place; but it often accumulates the nervous fluid so as greatly to increase its effect. Thus, the tongue has spongy papilla?, which imbibe saline solutions ; the car is furnished with a gelatinous pulp, violently agitated hy the sonorous vibrations of tlie air; and the eye is supplied with transparent lenses, which concen- trate tlie rays of liglit. Tliose substances which liave obtained the name of irritants, from tlieir power of occasioning contractions in the muscular fibre, probably exer- cise this action through the medium of the nerves ; and they influence thorn in the same manner as the Will docs, that is, by affecting the nervous fluid, in the manner necessary to alter the dimensions of the muscular fibre under its influence. Yet the Will is not concerned in producing these effects; often the mind is totally unconscious of their action. Even when tlie muscles are separated from the body, they are susceptible of being irritated, so long as that portion of the nerve, which accompanies them, retains its power of acting. In this case, tho phenomena are to- tally removed from the influence of the Will. The state of the nervous fluid is altered by muscular irritation, as well as by sensation and volun- tary motion : there e:dsts, tliereforc, the same necessity for restoring its original composition. Irritants occasion those movements and transfer- ences of particles necessary to the functions possessed in common by ani- mals and plants; thus, the aliment stimulates the intestine; the blood irritates the heart. These motions are all performed independent of the influence of the Will, and, in general, while health continues, witliout the consciousness of the animal. To effect these objects, the nerves which produce the motion luive, in most cases, an arrangement entirely differ- ent from those affected by sensation or controlled by the 'Will. The nervous functions, by wdiich we moan sensation and muscular ir- ritability, are exorcised with more or less vigour upon every point, in pro- portion as the nervous fluid is more or less abundant there ; and as this fluid is produced by secretion, its quantity ought to depend jointly upon the quantity of the medullary matter secreting it, and upon the supplies of blood received by this medtillary substance. In animals possessing a circulating system, the blood is distributed to all parts of the body, tlirough the arteries, by means of their irritability and the action of the heart. 8 THE ORGANS OF ANIMAL BODIES— THEIR FUNCTIONS. If these arteries be irritated in an unusual degree, they act more forcibly and propel a greater quantity of blood; the nervous fluid becoming more abundant, increases the local sensibility; and, reacting upon the irritabi- lity of the arteries, carries their mutual action to a high degree. This is called nervous excitement, or orgasm; when it becomes painful and per- manent, it is termed injiammaiwu. 'riiis mutual influence of the nerves and muscular fibres, whether in the intestinal or arterial systems, is the true source of those involuntary actions, common both to plants and animals. Each internal organ is susceptible of irritation only from its peculiar ir- ritant, to which it is in a manner especially adapted, just as an exter- na! sense can be affected only by its particular objects. Thus mercury irritates the salivaiy' glands, and cantharides, the vesica. These agents have been called specifics. As the nervous system is continuous and of uniform structure, local irritations, and frequently repeated sensations, fatigue it throughout the whole extent; so that any function, when excessively exercised, may en- feeble all the others. Thus, too much food impedes the action of the intellectual powers, and long protracted study impairs the powers of di- gestion. An excessive local irritation may affect the w’holo body, just as if all the vital cuo gies were concentrated upon one single point. But a se- cond irritation, in another place, will diminish the first, or, as it has been called, determine the first into another part; such is the effect of blisters, laxatives, and other counter-irritants. Wc have thus shown, in the above brief sketch, tliat it is possible to account for all the phenomena of physical life; if we merely assume hy- pothetical! v the existence of a nervous fluid, possessed of certain proper- ties, which are deduced from generalizing the phenomena of the vital s}'.stem. SKCT. VI THE ORGANS OF ANI.M.VL BODIES, THEIR APPROPRIATE FUNCTIONS, WITH THEIR VARIOUS DEGREES OF CO.MPUCATION. Siuxation Touch — Tarte — Smell — Sight ^ TTearing — Muscular Sciuc — Head — Praia Voluittarg Motion — Muscles — Boyies — Tendons — Ligamcntr — Nutrition Stomach Gastric Juice — Chyme — Chyle — Lacteuls — Arteries — eins — Lymphatics — Respiration — Lungs — GUIs — Trachea: — Capillary Vessels — Se- cretory Glands — Generation. After having considered the organic elements of the animal body, the chemical elements of its composition, and the active forces which prevail in it, nothing now remains to complete a general view of the animal sys- tem, excepting a summary account of the several functions of which life is composed, with a description of their appropriate organs. Tile functions of the animal body may be divided into two classes — the animal functions, which are peculiar to animals — and the vital or vegeta- tive functions ; common to animals and plants. The former comprise sen- sation and voluntary motion, the latter nutrition and generation. We shall commence with sensation, which resides in the nervous sy.'tcm. The sense of touch is the most extensively diffused of all the external senses. It is seated in the skin, a membrane enveloping the entire body, and traversed in every part by nerves. Their extreme fibres are ex- panded at the surface of the^ skin into minute papilla:^ or small project- ing filaments, where they are protected by the outer skin, and by other insensible coverings, such as hair or scales. The degree of perfection in which different animals possess this sense varies consi- derably; but its exercise, in a high degree, is always accompanied by certiun conditions. The organ must be supplied with numerous nerves and papill®, under a very fine cu- ticle; with a soft cellular substance, like a cushion; .and with a hard Resisting base. It must also be endowed with, a con.sitlerable degree of flexibility, as a close contact witli the surfaces of bodies is indispensable. Most animals arc possessed of some par- ticular organ, in which the sense of touch is developed in a high degree. In tho hand of man, and particularly at the extremities of the fingers, we find all the necessary reqiujiites of this sense, combined in their most perfect form. The proboscis, or trunk, of the elephant seems to rank next to the human hand; and, among the higher orders of animals, either tho snout or tho Up is endowed with much semibility. This quriity is particularly observable in the nose of the tapir, and of the hog, in the lips of the mole, and in the upper Up of the rhinoceros. Tho seal, and animals of the cat kind, such as the lion and tiger, have whiskers, possessed, near their roots, of consi- derable deUcacy, which renders them of important use to these animals as feelers. Cer- tain species of monkeys have delicate prehensile tails, which they use with surprising agility. In birds, the nerves of touch seem chiefly developed in the feet and toes, and most of the aquatic species are endowed with bills of considerable feeling. Ser- ponrs use their slender tongues as instruments of touch ; and the great flexibility of their bodies renders them well adapted for the exercise of this scue. The snouts of fishes have some nicety ; but, with this exception, these animals seem nearly desti- lule of delicate sensation. Insects feel chiefly by means of their antennse; and the several tribes of annelida, actinicC, and polypi, by their tentacula. Several animals are covered with a dense integument, in many of their parts, which arc thus wholly unfitted for this sense. The thick hides of the elephant and rhinoceros, the feathers of birds, the scales, horny coverings, and shells of the lower animals, arc evidently inconsistent with the necessary conditions of touch. Bats are enabled to fly in the darkest places, by the extreme acuteness of their tactual nerves. Taste and smell are merely more delicate modifications of this sense, for the exercise of which tlie membranes of the tongue and nostrils are snecially organized. In most of the lower animals the sens© of taste is very imperfect, or it is altogether wanting. The tongue of man is supplied with numerous papillx, of a conical form and spongy texture, projecting in a manner visible even to the naked eye. Taste seems in liiin to attain its mo.Ht perfect state; and ho not only enjoys the natural va- ricties of an omnivorous animal, but also a number of acquired tastes, which other species are wholly denied. The tongues of birds, of reptiles, and of fishes, are often covered with a hard and horny cuticle, which renders them altogether unfit for the delicate exercise of this sense. Many animals swallow their food without mastication ; an I they must be thereby effectually deprived of the enjoyments of taste, as a certain degree of contact between the food and the organ is essentially necessary for its exer- cise. The sense of smell resides in an organ, rendered susceptible by tho ex- treme delicacy and extent of its ever humid surface. Very minute particles of an odoriferous .substance arc darted forth in cverv diroo- tion, and are received upon the extensive and complex membrane, wliicli lines the in- ternal parts of the nasal cavity. Matter is thus perceived, when in a stale of great subdivision, with a degree of acuteness far surpassing any of the other senses. The extreme minuteness of these particles may be inferred from tlie fact, that musk, and many other substances, will exhale odour for several year.®, and yet no loss in their weight can be detected, even by the most delicate balances. Carnivorous animals, in general, possess a more acute sense of smell than those living upon vegetable food ; and the struc- ture of their nasal cavities is consequently much more intricate. This power was ob- viously given to facilitate the discovery of their food. In man the sense of smell seems best adapted for vegetable effluvia. A dog, though surpassing him in detecting tho most minute effluvium of another animal, will derive no pleasure from the finest vegetable odours. M. Audubon is of opinion that birds of prey are not endowed with an acute sense of smell. The degree in which this sense is enjoyed by the lower tribes of animals has not yet been completely determined, but it is observed to exist in bees and snsuls. The beauty of the eye, and the unbounded sphere which it exposes to observation, give to tho sense of sight a decided pre-eminence. Light, when emitted from the sun or any luminous body, strikes upon the external covering of the eyeball. By means of the crystalline lens, it is then refracted or bent from its original direction to a focal ]romt, from which the rays of light are again distributed on the expanded extremity of the optic nerve, prepared to receive them. The size of the eyes in quadrupeds, and the iniensity of their vision, hear a constant relation to the nafire of tlieir food. Her- bivorous animals, such as the elephant and the rhinoceros, have very small eyes in comparison with their entire hulk. The eyes of the whale, when viewed singl}*, arc very large; biit they seem disproportionately small, if we contrast them with the enormous mass of the entire body. But quadrupeds and birds feeding on flesh, require powers of vision of very great intensity. In these animals wc accordingly find the organ large, and highly developed, so as commonly to impart a pccnliar expression of ferocity to their countenances. The animals which are the objects of pursuit arc fre- quently supplied with acute vision, thereby enabling them to escape or avoid danger; and this is particularly exoraplifiod in the squirrel, the rat, the deer, and the hare. Animals which burrow under ground, as the mole and the shrew-mouse', have, in general, exceedingly small eyes; while in some they have been found nearly want- ing, as in the blind rat (^Mus typhlusy Linn.) Tlic cat, the lemur, and other animals which pursue their prey during the night, are peculiarly ailaptod, by the construction of their eyes, for acutely perceiving objects, w’hen illuminated by a very small quantity of light. Tiie eyes of reptiles and fish are accommodated to the medium in which they reside. The chameleon can move one eye with rapidity, and in various direc- tions, while tho other remains fixed. Reptiles residing generally in the water, also fish, and the cetacea, such as the dolphin and seal, have their eyes covered with a dense skin, and the lens is more convex than in other animals. The arachnides, or spiders, possess generally eight eyes, arranged upon the upper part of the head in a symmetrical form ; and there are not less than twenty-eight in the common millopcdc (Jnlxis terrestns.) The insect tribes enjoy great variety and intensity in their visual organs ; but the precise limits of this sense among the lowest animals in the scale of creation is not yet clearly ascertained. The organ of hearing is excited by vibrations or undulations of air, of water, or of some solid medium, recurring at intervals, with different degrees of frequency* These impulses are received upon the tympanum or ear-drum ; thence they are com- municated to the acoustic nerve, and arc finally transmitted to the brain. 'When the vibrations are not performed in equal times, or do not occur more frequently than seven or eight in a second, there is heard merely a noise. But when they rise much above this velocity, a very low or grave musical note is first heard. By an incre850 of velocity, the note becomes higher or more acute, and the oar is finally capable uf perceiving sounds resulting from 31,000 impulses in a second. There is a regular gradation among animals in the perfection of the organ of hearing, but none of them can-rival the delicacy with which the practised car in man perceives minute changed of tone, alterations in the quality or expression of sound, and varieties in its intensity loudness. Feeble and timid quadrupeds generally have their ears directed backwards, to warn them of approaching danger; while, in the predaceous tribes, the cars aro THE ORGAN'S OF ANIMAL BODIES— THEIR FUNCTIONS. 9 placed forwards, to aid in discovering their prey. Animals, though seldom susceptible of musical notes, sometimes exhibit an aversion for the low or grave sounds. This is rcmai’kably the case with the lion. In bats, the sense of hearing is surprisingly acute. L’organe de la generation est douS d’un sixieme sens, qui est dans sa peau intcrieure. Perhaps a greater claim to the right of being termed the sixth semse, may be estab- lished in favor of that feeling of resi.stance, or muscxtlar sense, by which we perceive the degree of force exorcised by particular muscles. The mouth and lips of a new- born animal are directed by this sense to their proper function ; and the adult would be in danger of a fall while engaged in wNalking, leaping, or other active exercises, if he were for a moment unconscious of the present state of the muscles appropriated to those actions. Shooting, bounding, and taking aim, presuppose a conaciou.sncss of the degree of mu.seular exertion sulhcient to produce a certain effect; and instances are not wanting of its sur})ri-ctable matter is abstracted and conveyed into the system. In carnivorous animals, the stomach 10 THE ORGANS OF ANIMAL BODIES— THEIR FUNCTIONS. is comparatively simple ; and a supply of abundant nourishment is readily procured from animal food. After passing through the stomach, the food is received into the remain- ing part of tlie canal, where it is acted upon by other juices destined to complete its preparation. The chyme formed in the stomach having passed into the intestine, comes in contact with the bile and the pancreatic juice. An immediate change takes place. The chyme acquires the yellow colour and bitter taste of bile, and at length divides into two por- tions; the one, a white tenacious liquid called chyle, and the other, a yellow pulp. The coats of the intestinal canal are supplied with pores, which imbibe that portion of the alimentary mass adapted for the nutrition of the body [being the chyle], while the useless residue is finally conveyed away and ejected. The canal in which this first function of nutrition is performed, appears to be a continuation of the skin, and it is composed, in a similar manner, of lamince. Even the surrounding fibres are analogous to those adhering to the internal surface of the skin, and called the fleshy pannicle. A mucous secretion takes place throughout this canal, which seems to have some connexion with the perspiration from the surface of the skin ; for, when the latter is suppressed, the former becomes more abundant. The skin exercises a power of absorption very much resembling that possessed by the intestines. The whole length of the intestinal canal is much greater in herbivorous, than in carnivorous animals. It is only in the very lowest tribes of animals that the same orifice is applied to the double purpose of receiving fresh supplies of aliment, and of ejecting the substances unfitted for nutrition. Their intestines assume the appearance of a sack with only one entrance. But in a far greater num- ber of animals, having the intestinal canal supplied with two orifices, the nutritive juice [or chyle] is absorbed through the coats of the intestines, and immediately diffused [by the lacteals] through all the pores of the body. This arrangement appears to belong to the entire class of insects. If we commence from the arachnides [or spiders] and the worms, and then examine all animals higher in the scale of cre.ation, it will be found that the nutritive fluid circulates through a system of cylindrical vessels; and that it only' supplies the several parts requiring nourishment by means of their ramified extremities [or lacteals], through which the nutriment is deposited in the places requiring sustenance. These vessels, which distribute the nutritive fluid or blood to all parts of the body, receive the name of arteries. Those, on the contrary, are called veins, which restore the blood to the centre of the circulating system. This motion of the nutritive fluid is sometimes performed simply in one circle ; often there are two circular motions, and even three, if we include that of the vena-portm [which collects the blood of the intestines, and conveys it to the liver.] ,The velocity of its motion is frequently assisted by certain fleshy organs called hearts, which are placed at some one centre of circulation, often at both. In the vertebrated and red-blooded animals, the nutritive fluid, or chyle, leaves the intestines either white or transparent; and is conveyed into the venous system, by means of particular vessels called lacteids, where it mixes with the blood. Other vessels similar to the lacteals, and com- posing with them one arrangement, called the lymphatic system, convey into the venous system those nutritive particles which have either escaped the lacteals, or have been absorbed tlnough the cuticle or outer skin. Before the blood is fitted to renovate the substance of the several parts of the body, it must receive, from the surrounding element, through the medium of respiration, that modification which we have already noticed. One part of the vessels belonging to those animals, which possess a cir- culating sy stem, is destined to convey the blood to certain organs, where it is distributed over a large extent of surface, in order that the action of the surrounding element may be the more energetic. When the animal is adapted for breathing the air, this organ is hollow, and called lungs. But when the animal only breathes [the air dissolved] in water, the organ projects, and is called branchim, or gills. Certain organs of motion are always arranged so as to draw the surrounding element cither within or upon the organ of respiration. In animals which do not possess a circulating system, the air penetrates into every part of the body, through elastic vessels called trachece; or else water acts upon them, either by penetrating, in a similar manner, through vessels, or simply by being absorbed through the surface of the skin. In Man, respiration is porfonned by means of the pressure and clastic force of the air, which rushes into the lungs, where a vacuum would otherwise have been formed by the elevation of the ribs, and the depression of the diaphragm. Muscular force then expels the air, after the necessary puritication of the blood existing in the lungs has been performed; and the same actions arc again repeated. The blood, which was of a dark purple colour, while slowly travelling from all parts of the body to the heait, has no sooner been purified by yielding its excess of carbonic acid to the surrounding air, and by absorbing oxygen, than its colour changes into a bright vermilion. In Birds, it was necessary to combine lungs of small bulk with an extensive aera- tion of the blood ; and, accordingly, the blood ni.t only passes into the lungs, but through them into capacious air ceUs; from which, by the action of the chest, it is again expelled. The lungs thus act twice upon the same portion of air. The change of the tadpole into the frog is accompanied by extraordinary alterations in its respiratory organs, which will be more fully explained hereafter. In the first, or tadpole state, the organs are branchial, in the frog they are puhuonary. The ar- rangements are striking and singular. All respiration must bo either aquatic or atmospheric. In the former case, the respiration is said to bo cutaneous or branchial, according as it is performed through the skin or through gills. On the other hand, atmospheric respiration may be cither tracheal or pulmonary, according as it is performed through the air-tubes called trachea:, or by means of lungs. After the blood has been purified by respiration, it is fitted to restore the composition of all parts of the body, and to execute the function of nutrition properly so called. The wonderful property, possessed by the blood, of decomposing itself so as to leave precisely, at each point, those particular kinds of particles which are there most wanted, constitutes the mysterious essence of vegetative life. We lose all traces of the secret process by which the restoration of the solids is performed, after having arrived at the ramified extremities of the arterial canals. But in the pre- paration of fluids we are able to trace appropriate organs, at once varied and complicated. Sometimes the minute extremities of the vessels are simply distributed over extended surfaces, from which the liquid exudes; and sometimes the liquid runs from the bottom of minute cavities. But the more general arrangement is, that the extremities of the arteries, be- fore changing into veins, form particular vessels called capillary, which produce the requisite fluid at the exact point of union between these two kinds of vessels. The blood-vessels, by interlacing with the capillary vessels which we have just described, form certain bodies called conglo- merate or secretory glands. With all animals destitute of a circulation, and especially with Insects, the nutritive fluid bathes the solid parts of the body; and each of them imbibes those particles necessary for its sustenance. If it become requi- site that any particular fluid should be secreted, capillary vessels, adapted for this purpose, and floating in the nutritive fluid, imbibe, through their pores, the elements necessary for the composition of the fluid to be se- creted. It is thus that the blood continually renovates all the component parts of the body, and repairs the incessant loss of its particles, resulting ne- cessarily from the continued exercise of the vital functions. The gene- ral idea which we are able to form of this process is sufficiently distinct, although the details of the operations performed at each particular point are involved in obscurity, from our ignorance of the precise chemical composition of each part, and our consequent inability to determine the exact conditions necessary for their reproduction. In addition to the secretory glands necessary for performing a part in the internal economy of the system [such as the liv'er and the pancreas], there are others which secrete fluids destined to be rejected, either as being superfluous, or for some purpose useful to the animal. Of the lat- ter we may mention the black fluid secreted by the Cuttle fish [with which, when pursued, he obscures the water to cover his retreat], and the purple m:itter of several Mollusca. The function of gkner.vtion is involved in much greater obscurity and difiiculty than that of simple secretion; and this difficulty attaches chiefly to the production of the germ. We have already explained the insuper- able difficulties attending the pre-existence of germs ; yet, if once we as- sume their existence, no particular difficulty remains attached to genera- tion [which is not equally applicable to ordinary secretion.] While the germ adheres to the mother, it is nourished as if it formed a part of her own body; but when the germ detaches itself, it possesses a distinct life of its own, essentially similar to that of an adult animal. The form of the germ, in its passage through the several progressive states of development, successively termed the embryo, the foetus, and, finally, the new-born animal, never exactly resembles that of the parent; and the difference is often so very great that the change has received the name of metamorphosis. Thus, no person could ever anticipate that the caterpillar would finally be transformed into the butterfly, until ho had either observed or been informed of the fact. INTELLECTUAL FUNCTIONS OF ANIMALS. 11 These remarkable changes are not peculiar to Insects, for all living beings are more or less metamorphosed during the period of their growth j that is to say, they lose certain parts altogether, and develop others which were formerly less considerable. Thus, the antennas, the wings, and all the parts of the butterfly, were concealed under the skin of the caterpillar; and, when the insect cast off' its skin, the jaws, the feet, and other organs, which belong not to the butterfly, ceased to form a part of its body. Again, the feet of the frog are inclosed within the skin of the tadpole ; and the tadpole, in order to become a frog, loses its tail, mouth, and gills or branchia-. Even the infant, t)eforc its birth, at that period, and during its progress to maturity, undergoes several metamorphoses. In the earlier periods of development, the em- bryo corresponds, in some of its parts, with certain of the lower animals. At first, it seems destitute of a neck, and the heart is situate in the place wdiero a neck after- wards appears, an arrangement, whicli is found to exist permanently in fish. There is also a striking resemblance between the lower extremity of the vertebral column in the embryo, and the tail of the fish. About tho end of the fifth month, it is covered ■all over with a yellowish white silk, like the down of a young duck, ndiich entirely disappears in six or seven weeks. The limbs arc fonnod under the skin, and reaching it, gradually shoot out into their fiermancnt position; yet, even wlien fully developed in other respects, tho shoulders tuid thighs are still concealed under the skin. In this respect, the embryo resomhles the horse and other animals, which have the shoulders and thighs permanently enveloped under a thick covering of muscle. Tho fingers, when first formed, are .surrounded by a skin, which entirely covers them, like the mitten-gloves used for an infant. This covering i.s gradually absorbed, when it takes the form of a duck’s web, and finally disappcai-s. M. Tieddeman and M. .Serres, have shown that tho brain of the foitus, in the highest class of animals, assumes in succession the various forms which belong to Fishes, Ueptiles, and Birds, before it ac- quires those additions and modifications which are peculiar to the hfammalia. “ If you exainiue the brain of tho Wiraimalia,” says M. Serres, “ at an early stage of ute- rine life, you perceive the cerebr.al hemispheres consolidated, as in Fish, in two vesicles isolated one from the other ; at a later period, yon see them atfoct the configuration of tho cerebral hemispheres of Beptilcs ; still later again, they present you with the forms of those of Bird,s; finally, they acquire, at the era of birth, and sometimes later, the permanent forms which the adult Mammalia present." As the infant grows tow.ards manliood it loses, at a certain age, the thymus gland; by degrees it acquires hair, teeth, and beard; the relative size of its organs changes ; the body' increases at a much greater rate than the head, and tho head more rapidly than the interna! part of the ear. Le lien oh los germes se montrent, rassemblage de cos gerrnos se nomme I’ot’nu'c; le canal, par oh les gerincs une fois detaches se rendont an dc- liors, Voviductius : la cavite oh ils sont obliges, dans plusicurs especcs, de sejourner un temps plus on moins long avant de naitro, la matricc on I’affru.!; rorificc exterieur par lequel ils sortent, la vidoc. Quand il y a ties sexes, le sexc mfile est, cehii qni fcconde; le sexe femcllo celni dans lequel les germes paraissent. La liqueur fccondante se iiommo sperme; les glandes qni la sSparent du sang, tcslicules; ct, quand il faut qu’elle sou introduite dans le corps do la femelle, I’organe qni I’y portc s'ap}>cl!e verge. SECT. VII A BRIEF NOTICE OF THE INTEI.I.ECTOAL EITNCTIONS OF ANIMAI.S. ^Hnd — Matter — Setisftiiou — Tllusious — Perception — Memory — Amoe.iatloti of Ideas — Abst ractian — Jvdymeni — Faculties of Man and other animals compared — In- stinct— Connexion heticecn the Brain and Intellectual Faculties. have already cxplaimul, when treating of the nervous system, that before the ttend can perceive an object, an impression must bo made upon an organ of sense, Bither immediately, or through some material medium ; and that this impression must ke transmitted through the nerves to the brain. Hut the manner in which sensation, .and its consequent perception, are produced, is a mystery impenetrable to the human understanding; and, Since philosophy is unable to prove* the existence of matter, it is only ha- zarding u gratuitous hypotho.sis to attempt to explain mind by materialism, [or by analogies borrowed from tlie qualities of matter. The considera- tion of the Physiology of the Human Mind, or Metaphysics, forms the subject of another science.] But it is the province of the naturalist to ^certmn the conditions of the liody attendant on sensation, — to trace the Oktreme gradations of intellect in all living beings, — to investigate the precise point of perfection attainable by each animal, — and, finally, to ■tscortain whether there be not certain modifications of tlie intelleetual powers, occasioned by' tlie peculiar organization of each species, or by momentary state of each individual body. It has been already explained, that, to enable the mind to perceive, ' First truths do not admit of proof; they are assumed. IVe cannot prove the cx- stenee of mind, but we are conscious of its existence; and we cannot prove the ex- *stcncc of matter, for wo perceive it. there must be an uninterrupted communication of nerves between the external organ of sense, and the central masses of the nervous system. The mind is, tbcroforc, conscious only of some impression made upon these central masses. It follows, then, that the mind may be conscious of real sensations, without any corresponding affection of the external organ ; and these may be produced either in the nervous chain of com- munication, or in the central masses themselves. Tins is the origin of dreams, and visions, and of several casual sensations. The various kinds of spectral illusions proceed from impressions, which, being made on the retina, are thence communicated to the brain, and arc referred by the rahid to an object in actual existence. “ When the eye or the head receives a sudden blow, a bright flash of light shoots from the eyeball. In the art of sneezing, gleams of light are emitted from each eye, both during the inhalation of the air, and during its sub- sequent protrusion ; and in blowing air violently through the nostrils, two patches of light appear above the axis of tho eye and in front of it, while other two luminous spots unite into one, and appear as it were about tho point of tho nose, when the eyeballs are directed to it. In a state of indisposition, the phosphorescence of the retina appears in new and more alarming forms. W'hen tho stomach is under a temporary derangement, accompanied by headache, the pressure of tho blood-vessels upon the retina shows itself, in total darkness, by a faint blue liglit floating before the eye, varying in its shape, .and passing away at one side. The blue light increases in intensity — ^becomes green and then yellow, and sometimes rises to red ; all these colours being frequently seen at once ; or the mass of light shades off into darkness. When we consider the variety of distinct forms which, in a state of perfect health, the imagination can conjure up when looking into a biu-ning fire, or upon an irregu- larly shaded surface, it is easy to conceive huw the masses of coloured light which float before the eye may be moulded, by the .same power, into those fantastic and un- natural shapes which so often haunt the conch of the invalid, even when the mind retains its energy, .and is conscious of the illusion under which it labours. In other cases, temporary blindness is produced by pressure upon the optic nerve, or upon the retina; and under the excitation of fever or delirium, when the physical cause which produces spectral forms is at its height, there is superadded a powerful influence of the mind, whicii imparts a new character to the phantasms of the senses.”* Many cireum.staneos render it extremely probable, that the pictures drawn in tlie mind by memory, or created Ijy imagination, do not merely exist “ in tho mind’s eye,” hut are actually figured on the retina. During health, and in ordinary ca.sps, these images are faint, and are easily didingnished from the sensations resulting from real perception. It is only wlnm the body is affected by certain diseases, or during sleep, that tho impressions on tho retina appear to proceed from objects in actual existence. Several instances might be brought forward to illustrate the illusiuns of the senses. By the well -known experiment of raiddng a galvanic circuit through the tongue, a piece of zinc and one of silver, there is produced a pungent metallic taste, in the same manner as would have followed the real application of a sapid substance. Thus it may be seen that, if we communicate an impression to tho nerve on ils passage to the central mas.s, the mind will bo affected in the same maimer as if the impression had been made on the external organ. By the terms central massc.t, we understand a certain portion of tlie nervous system, which is always more circumscribed as tlie animal is more perfectly constructed. In Man it is exclusively a limited portion of the brain. On tlie contrary, in lleptilos the central mass may include either tiie brain, tlio entire marrow, or any portion of them taken sepa- rately; so that the absence of the entire brain does not deprive them of sensation. The extension of the term, when applied to lower classes of animals, is much greater, as their sensitive power is still more widely diflitscd. We arc hitherto completely ignorant of the nature of the changes which take place in the nerves and brain during perception, and of the manner in which the process is carried on. Analogies derived from matter, sensible species, images, and vibrations, obscure rather than explain this mysterious subject. A certain state of mind follows a certain impression upon an external organ. We refer tlie cause of the sensation to some external object. This constitutes perception ; and the mind is said to form an idea of the oliject. By a necessary law involved in the constitution of tho mind, all the ideas of material objects are in time and in space. When an impression has once been made tlirongh the medullary masses upon the mind, it jiossesses the pow'or of recalling the impression after the exciting cause has been removed. This is memory, a faculty which varies much with the age and health of tho individual. During childhood, and in youth, tho memory is very vivid. Accordingly, this period of life Ls most favorable to the acquisition of knowledge, especially of those subjects involving a great extent of detail, such as languages, geography, civil his- tory, and natural history. The memory fails with increasing years. Vivid perceptions and sensations are easily conceived; but the memory of a former mental impression is in general more faint. Certain diseases, such as apoplexy, destroy tho memory, either entirely or partially. A disordered state of the stomach will deprive the mind of the power of following a continued train of deep thought. This is also the case in the first st.ages of fevers. * Letters on Natural Magic, by Sir David Brewster. 12 INTELLECTUAL FUNCTIONS OF ANIMALS. Blows and other injuries of tho head will often affect the memory in a manner alto- gether incredible and surprising: and similar effects are sometimes produced by a high degree of nervous excitement. Ideas which resemble [which contrast], or which were produced at the same time [or in the same place], have the power of recalling each other. This is termed the atsociation of ideas. The order, the extent, and the quickness in which this power is exercised, constitutes the perfection of the memory. Evorj- object presents itself to the memory with all its qualities, and all the ideas associated therewith. The understanding possesses the power of separating these associated ideas from the objects, and of combining all the properties resembling each other in different objects under one general idea. This power of generalization, by which an object is imagined to be divested of certain properties, which in reality are never found separate, is termed Abstraction. The power of abstraction appears to belong exclusively to Man; who, by the in- vention of general tenns, is enabled to reason concerning entire classes of objects and events, and to aj-rive at general conclusions, comprehending a multitude of parti- cular truths. Every sensation being more or less agreeable, or disagreeable, experi- ence and repeated trials readily point out the movements necessary to procure the one, or to avoid the other. The understanding thence de- duces general rules for the direction of the Will relatively to pleasure and pain. An agreeable sensation may produce unpleasant consequences ; and tho foresight of these consequences m.ay react upon the first sensation, and thus produce certain modifications of the abstract rules framed by the understanding. This is prudence or self-love. The lower animals seem influenced only by their present or very recent sensations, and they invuiriably yield to the impulse of the moment. Man alone appears able to form the general idea of happiness, .and, by taking a comprehensive view of things, to lay down a plan for tho regtdation of his future conduct, and the attainment of his favourite objects. But an inseparable barrier is placed between man and inferior intelligences, by the power of perceiving those qualities of actions which are termed right and wrong, and the emotions which attend their perception. The supremacy of conscience, and its claim to be considered an original faculty of the mind, are clearly pointed out by Bishop Butler. “ Virtue,'* he elsewhere observe.s, “is that which all ages and all countries h.ave made profession of in public — it is that which every man you meet puts on the show of — it is that which the primary and fundamental laws of all civil constitutions over tho face of the earth make it their business and endeavour to enforce the prac- tice of. upon mankind, such as justice, veracity, or a regard for the common good." By applying terras to express our general ideas, we obttiin certain for- mulas or rules, which are easily adapted to particular cases. This is judg- ment or reasoning [which may be either intuitive or deductive.'] When origin;U sensations and associations forcibly recur to the memory [the mind possesses the power of combining and arranging them, to form a new creation of its own], this is called imagination, and it may bo ac- companied by agreeable or painful associations. Wan being endowed with superior privileges, possesses the faculty of connecting his general ideas with particular signs. These are more or less arbitrary, easily fixed in the memory, and serve to suggest the gene- ral ideas, which they were intended to represent. We apply the term symbols to designate these signs when associated with our general ideas, and they form a language when collectively arranged. Language may be addressed cither to the ear or to the eye; in the former case it is termed .speech, in the latter, hieroglyphics. Writing is a series of images, by which the elementary sounds are represented to the eye [under the form of letters.] By combining them [into words], the compound sounds of which speech is composed are readily suggested. Writing is therefore an indirect representation of our thoughts. This power of representing general ideas by particular signs or symbols, which are arbitrarily associated with them, enables us to retain an im- mense number of distinct ideas in the memory, and to recal them with facilitj’. Innumerable materials are thus readily supplied to the reason- ing faculty and to tho imagination. The experience of individuals is also communicated by written signs to the whole human species, and by this means the foundation is laid for their indefinite improvement in knowledge through the course of ages. Tho art of printing, by multiplying copies, bas ensured the permanence of knowledge, and has afforded a powerful aid to the intellectual progress of the species. This capacity for indefinite improvement forms one of the distinguish- ing characters of human intelligence. The most perfect animuls are infinitely below Man, in respect to the degrees of their intellectual faculties ; but it is nevertheless certain that their understandings perform operations of the same kind. They move in consequence of sensations received; they are susceptible of lasting affections ; and they acquire by experience a certain knowledge of exter- nal things, sufficient to regulate their motions, by actually foreseeing their consequences, and independently of immediate pain and pleasure. When domestic.ated, theyfeel their subordination. They know that the. being who punislies tliem may refrain from doing so if he will, and they assume be- fore him a supplicating air, when conscious of guilt, or fearful of his anger. The society of man either corrupts or improves them. They are suscep- tible of emulation and of jealousy; and, though possessed among tlicm- sclves of a natural language, capable of e.xpres'sing the sensations of the moment, they acquire from man a knowledge of the much more compli- cated language through which he makes known his pleasure, and urges them to execute it. We perceive, in fact, a certain degree of reason in the higher animals, and consequences resulting from its use and abuse, similar to those ob- served in Man. The degree of their intelligence is not far different from that possessed by the infant mind, before it lias learned to speak. But, in proportion as we descend in the scale of creation to animals far below man in organization, these faculties become more languid ; and, in the lowest classes, they are reduced to certain motions obscurely indicating .same kind of sensation, and the desire of avoiding pain. The degrees of intellect between these extremes are infinite. Dogs, cats, horses, liirtls, and other animals, may have their original faculties modi- fied hy personal experience ; and they are accordingly trainetl to tiio performance of those extraordinary feats, which in all countries form a favourite amusement of tlie people. “ By e.xperience,” says Jlr Hume, “ animals become acquainted willi the more obvious properties of external objects ; and gradually, from their birth, treasure up a knowledge of the nature of fire, water, stones, earth, heights, depths, fee. The ignorance and inexperience of tho young are here plahily distiuguisiiable from tho cunning and sagacity of tho old, who have learned by long observation to avoid what hurt them, and pursue what gave ease and pleasure. horse that has been accus- tomed to the field, becomes acquainted with tho proper height he can leap, and will never attempt what exceeds his force and ability. An old greyhound will trust the more fatiguing part of the chase to the younger, and will place himself so as to meet tliB hare in her doubles; nor are tbe conjectures which he forms on this occasion founded on any thing but his observation and experience. This is still more evident from the effects of discipline and education on animals, who, by tho proper applica- tion of rewards and punishments, may be taught any course of action the most con- trary to their natural in.stinct3 and propensities. Is it not experience wliich renders a dog apprehensive of pain, when you menace him, or lift up the whip to beat him? Is it not even experience which makes him answer to his name, and infer, from such an arbitrary sound, that you mean him rather than any of his fellows, and intend to call him when you pronounce it in a certain manner and with a certain accent?” There exist.*:, however, in a great number of animals, a faculty dif- ferent from intelligence, called instinct. This power causes them to per- form certain actions necessary to tlie preserv.ition of the species, but often altogether removed from tho apparent wants of the individual- These arc often so very complicated and refined, that it is impossible to suppose them the result of foresight, without admitting a degree of intel- ligence in the species performing tiiem, infinitely superior to what they exhibit in other respects. The actions proceeding from instinct are still less the effect of imitation, for the individuals executing them have some- times never seen them performed by others. The degree of instinct i.-* by no moans proportioned to tlie general intelligence of the species; but it is in those animals which, in tlieir other actions, manifest the utmost stupidity, that instinct appears most singular, most scientific, and most disinterested. It is so much the property of each entire species, that idl individuals exercise it in precisely the same manner, without ever attain- ing to higher degrees of cultivation. “ Every other animal, hut Man, from the first ouUet of the species and of the >»' dividual, is equal to ids task ; proceeds in the shortest way to the attaimuent of hi* purpose, and neitlier mistakes tho end nor the means bv which it is to be obtained' In wliat ho performs, svo ufteu justly admire the ingenuity of the contrivance and the completeness of the work. But it is the ingenuity of the species, not of the individual , or rather it Ls tho wisdom of God, not tlie deliberate effect of invention or choirH’ which the created being is fitted to employ for himself. His task is prescribed, and his manner of performing it secured. Observe tho animal? most remarkabl,' h"' “ happy choice of materials, and for the curious execution of their works. The turd, how unvaried in tlie choice of the matter she employs in the structure, or in the sUU' ation, she has chosen for her eyrie or nest! Insects, most exquisitely artful in execution of tlicir little works, for the accommodation of their swarms, and the lodgi'j ment of their stores; how accomplislicd in their first and least-experienced attenipi** liow uniform and unchanged in tiie la,?tl Nature .appears to have given to the othav animals a specific direction to the means they are to employ, without any rational con- ception of tlie rad for which they are to employ tlicm.” CLASSIFICATION OF THE ANIMAL KINGDOM. 13 Thus, the working bees, from the crcntion of the world, have always constructed edifices of great ingenuity, upon principles deduced from the highest branches of geometry, for the purpose of lodging and nourishing a posterity which is not even their own. “ It is a curious mntlicmatical problem,” observes Dr Reid, “ at wbat precise angle three planes which compose the bottom of a cell in a honey-comb ought to meet, in order to make the greatest saving, or the least expense, of material and labour; and this i.s the very angle in which the three planes in the bottom of a cpll do actually meet. Shall we a.sk here, w'ho taught the bee the properties of solids, and to resolve the problems of maxima and minima i tVe need not say that bees know none of these things. They work most geometrically, somewhat like a child, who, by turning the handle of an organ, makes good music, without any knowledge of music. The art is not in the child, but in Hiai who made the organ. In like manner, when a bee makes its comb so geometrically, the geometry is not in the bee, but iu that Great Geometri- cian who made the bee, and made all things in number, weight, and measure.” The solitary bees and wasps construct very complicated nests for the reception of their eggs. From each egg there proceeds a worm which has never seen its mother, which knows not the structure of the prison en- closing it; and yet, after it has undergone its metamorphosis, will con- struct another nest, precisely similar, to contain its own egg. No satisfactory explanation can be given of the phenomena of instinct, except we admit that these animals pos.scss some innate and constant internal power, which determines them to act, in the same manner as when they arc influenced by ordinary and accidental sensations. Instinct haunts them like a perpetual reverie or vision ; and all the actions pro- ceeding therefrom may be compared to those of a man walking in his sleep. Instinct has been wisely bestowed upon animals by the Creator, to supply the defects of their understandings, the want of bodily force or fecundity; and thus the continuation of each species is secured to the proper extent. There is no visible mark, in the conformation of an animal, by which we can ascertain the degree of instinct which it possesses. But so far as observation has hitherto extended, the degree of intelligence seems pro- portioned to the relative size of the brain, and especially of its hemis- pheres. Without venturing to decide upon this point, we must remark that the latter asser- tion has been controverted by many recent observers, especially by Dr Herbert hlayo, in his valuable Outlines of Human Physiology. “ It does not appear," he remarks, that an iucrea.ee in the absolute weight of the brain confers a superiority in mental endowments. Were this the case, the intellects of the whale and of the elophant should excel the rational nature of man. Neither does the relative weight of the brain to the whole body appear the measime of mental superiority. The weight of fbe human brain is but one thirty-fifth part, while that of a canary bird is one-four- teenth part. Nor in conjunction with parity of form, and strueture even, does this relation appear of .any value. The eagle is probably as sagacious as the canary bird; but the weight of the brain is but one two-hundred-and-sixticth part of its entire Weight. “ We may next inquire,” he proceeds, ‘‘ whether au increasing number and eompli- cation in the parts of the brain is essentially connected with improved mental func- tions. The first instances which occur to the mind are in favour of the alHrmative of this supposition. It may bo inferred, from their docility and surprising capability of receiving instruction, that birds have higher mental endowments than fish ; and ae- vordingly, in place of tlio nodules of the fishes’ brain, whioh arc scarcely more than tubercles to originate nerves, birds possess an ample cerebrum and cerebellum (or lobes ®f their bruin). But iu pursuing this argument, if we compare, on the other hand, the brain of birds with those of alligators and tortoises, we find no striking ditforonco tw physical superiority in the former over the latter ; yet in mental development, the tortoise and alligator are probably much nearer to fish than to birds. The instunlia ^’ucis (or decisive experiment), however, upon this question, is found in the compimi- ®on of the brain of the cotaceous mammalia (such as whales or dolphins), with the luman brain on tho one hand, and with that of fish on the opposite. The cetaceous mammalia,” he observes, “ have brains which, besides being of go size, ore nearly as complicated as those of human beings ; they might therefore lari be expected, if tho opinion which I am combating were true, to manifest a remarkable ^iid distingijishing degree of sagacity. Endowed with a brain approaching nearly in rtimploxity and relative size to that of man, the dolphin should resemble in his habits “be of the transformed personages in eastern fable, who continued to betray, under b brute disgtdse, his human endowments. Somclliing there should be, very marked ‘b bis deportment, which should stamp his essential diversity from the fishes, in whose general mould ho is cast. His habits too, not shunning human society, render him especially open to observation ; and the class of moo vvho have the constant opportunity Watching his gambols in the deep, are famed for their credulity, and delight to boli ‘eve in the mermaid, tho, sea-snake, and tho kraken. Yet the m.oriner sees no- ','bg in the porjioiso or the dolphin but a fish, nor di.stinguishcs him, except by his un- wieldy hulk, from the shoal of herrings he pursues. Tho dolphin shows, in truth, no bgacity or instinct above the carp, or the trout, or tho salmon. It is probable even b the latter, which have but the poore.st rudiment of a brain, greatly exceed him bbnning and sagacity. 1 am afraid that the instance which I have laSt adduced sufficient to ovortlirow most of the rceeivod opinions respecting the relation of the ^ “b, shape, and organization of the brain to mental development ; nor is it easy to find besting-place for conjecture upon this subject.” SECT, vm ON THE CLASSIFICATION OF THE ANIMAL KINGDOM. General Distrihulion of the Animal Kingdom into Four Great Divisions. 1. Vertebrata — 2. Moltusca — 3. Articuiata — 4. liadiata. After the observations which have already been made concerning sys- tems of cla.ssification in general, we have now' to ascertain those leading characters of animals, upon which we must found tlie primary divisions of the Animal Kingdom. It is evident tliat these must he derived from the animal functions, tliat is, from sensation and motion ; for not only do tliese functions constitute tliem animals, but they point out tlie rank whicli they hold in the aiiinud world. Observation confirms the correctness of this ro.asoning, hj' showing tliat their development and intricacy of .structure correspond in degree with tliose of tho organ.5 performing tlie vegetative functions. Tile heart and tlie organs of circulation form a kind of centre for the vege- tative functions, in tlie same manner as tlie brain and the trunk of tlie ner- vous system are the centres of the animal functions; for we see these two systems become gradually more imperfect, and finally disappear together. In the very lowest classes of animals, where nerves can no longer be dis- covered, all traces of muscular fibres are obliterated, and the organs of digestion are simply excavated in tlie uniform mass of their bodies. The vascular system [or systematic arrangement of vessels] in insects, disap- jiears even before the nervous ; but, in general, the medullary masses arc dispersed in a degree corresponding to the agents of muscular motion. A spin.al marrow, on which are various knots or ganglions, representing so many brains, corresponds exactly to a body divided into numerous annu- lar [or riiig-like] segments, supported upon pairs of limbs, distributed along its entire length. Tin's general agreement in tlie construction of animal bodies, resulting from the arrangement of their organs of motion, the distribution of the nervous masses, and the energy of tho circulating system, ought, then, to form the Itasis of the primary divisions of the Animal Kingdom. We shall now proceed to examine what the characters are, which ought to succeed immediately to the above, and give rise to tlie first subdivisions. If we divest ourselves of the popular prejudices in favor of long estab- lished divisions, and consider the Animal Kingdom upon the principles already laid down, without reference to the size of the animals, their uti- lity, the greater or less knowledge we may have of them, or to any of these accidental circumstances, but solely in reference to their organiza- tion and general nature, we sliall find that there are four principal forms, or (if wo may use the c.xpression) four general plans, upon which all animals appear to have been modelled. The minor subdivisions, by whatever titles they maybe ornamented by Naturalists, are merely slight modifications of those great divisions, founded upon the greater develop- ment or addition of some parts, while the general plan remains essentially the same. 1. Vertebrata — Vertebrated Animals. In the first of these forms, which is that of Man, and of the animals most resembling him, the brain and the principal trunk of the nervous system are enveloped in a bony covering, composed of the cranium [or skull], and the vertebra; [or bone.s of the neck, hack, and loins.] To the sides of this medial column are attached tlie ribs, and tlie bones of the limbs, forming collectively tlie framework of tlie body. Tlie muscles, in general, enclose the bones which they set in motion, and the viscera are contained within the head and trunk. Animals possessed of this form are called Vertebrated Animals (Ani- malia vertebrata), [from their possessing a vertebral column, or spine.] They are all supplied with rod blood, a muscular heart, a mouth with two jaws, one being placed either above or before the other, distinct or- gans of sight, hearing, smell, and taste, iu the cavities of the face, and never more than four limbs. The sexes are always separate, and tho general distribution of the medullary masses, M'ith the principal branches of the nervous system, are nearly tlie same iu all. Upon examining attentively eacli of tlie parts of tliis extensive division of animals, we shall always discover some analogy among them, even in species apparently the most removed from each otlior; and the leading features of one uniform plan may be traced from man to tlie lowest of the fishes. The following are examples of Vertebrateil Animals: Man, quadrupeds, whales, birds, serpents, frogs, tortoises, herrings, carps, &c. 2. Mollusca — Alolhiscous Animals. In the second form of animals wo find no skeleton. Tho muscles are at- tached solely to the skin, which forms a soft envelope, capable of con- 4 14 GENERAL REVIEW OF LIVING BEINGS. tracting in various ways. In many species earthy lamina; or plates, called shells, are secreted from the skin, and their position and manner of production are analogous to those of the mucous bodies. The nervous system is placed within this covering along with the viscera; and the for- mer is composed of numerous scattered masses, connected by nervous filaments. The largest of these masses are placed upon the oBsoj>hagus, or gullet, and are distinguished by the term brain. Of the four senses which are confined to particular organs, we can discover traces only of taste and of sight, but the latter is very often found wanting. In only one family, however, there are exhibited the organs of hearing. We al- ways find a complete circulating system, and particular organs for respip ration. The functions of digestion and of secretion are performed in a manner very nearly as complicated as in the vertebrated animals. Animals possessed of this second form are called Molluscous Animals (Animalia mollusca), [from the Latin, mollis, soft.] Although the general plan adopted in the organization of their e.xternal parts is not so uniform as in the vertebrated animals, yet, in so far as re- gards the internal structure and functions, there is at least an equal de- gree of mutual resemblance. The cuttle-fish, oyster, slug, and garden-snail, are familiar instances of this class of animals. 3. Akticulata — Articulated Animals. The third form is that which maybe observed in Insects and Worms. Their nervous system consists of two long cords, extending the entire length of the intestinal canal, and dilated at intervals by various knots, or ganglions. The first of these knots, placed upon the oesophagus or gullet, and called the brain, is scarcely larger than any of the others, which may be found arranged along the intestinal canal. It communicates with the other ganglions by means of small filaments, or threads, which en- circle the oesophagus like a necklace. The covering of their body is di- jdded into a certain number of ring-like segments, b}’ transverse folds, having their integuments sometimes hard, sometimes soft, but always with the muscles attached to the interior of the envelope. Their bodies have frequently articulated limbs attached to the sides, but they are also very frequently without any. We shall assign the term Articulated Animals (Animalia articulata) to denote this numerous division, in which we first observe the transition i'rom the circulating system in cylindrical vessels of the higher animals, to a mere nutrition, by imbibing or sucking in the alimentary substances ; and the corresponding transition, from respiration through particular organs, to one performed by means of trachem, or air cells, dispersed throughout the body. The senses most strongly marked among them are those of taste and sight. One single family exhibits the organ of hearing. The jaws of the Articulated Animals are always lateral, but sometimes they are altogether wanting. As instances of this form, we may mention the earth-worm, leech, crabs, lobsters, spiders, beetles, grasshoppers, and flies. From the circumstance of their coverings, or limbs, being divided, or jointed, they derive the name of “ articulated,” from the Latin articulus, a little joint- 4. Radiata — Hadiated Animals. To the fourth and last form, which includes all the animals commonly called Zoophytes, may be assigned the name of Radiated Animals {Ani- vialia radiaia^ In all the other classes the organs of motion and of sensation are arranged symmetrically on both sides of a medial line or axis; while the front and back are quite dissimilar. In this class, on the contrary, the organs of motion and of sensation arc arranged like rays around a centre; and this is the case even when there are but two scries, for then both faces are similar. They approach nearly to the uniform structure of plants; and we do not alway.s perceive very distinct traces of a nervous system, nor of distinct organs for sensation. In some we can scarcely find any signs of a circulation. Their organs for respiration are almost always arranged on the external surface of their bodies. The greater number possess, for intestines, a simple bag or sac, with but one entrance; and the lowest families exhibit nothing but a kind of uni- form pulp, endowed only with motion and sensation. The fullowing are instatmes of this singular class of animals : — The soa-nettle, polypus, hydra, coral, and sponge. The name zoophyte is derived from two Cireek words, Caou (zorm), an animal; (pvroi/ (phyton), a plant; while that of radiata, derived from the Latin, evidently points out the radiated or ray-like arrangement of their parts. “ lieforc my time,” says the Baron Cuvier in a note to his first edition, “modern naturalists divided all Invertebrated Animals into two classes — Insects and Worms. I was the first who attacked this view of the subject, and proposed another tUvision, in a paper read before the Society of Natural History at Paris, the 21st Morcal, year iii. (or 10th ISIay 1795), and which was afterwards printed in the Decade FhilosO'^ phiqae." In this paper, I pointed out the characters and limits of the Mollusca, the Crustacea, the Insects, the Worms, the Echinodermata, and the Zoophytes. The red-blooded worms, or Annelides, were not distinguished until a later period, in a paper read before the Institute, on the 11th Nivose, year x. (or 31st December 1801.) I afterwards distributed these several classes into three grand divisions, analogous to that of the Animalia Vertebrata, in a paper read before the Institute in July 1812, and afterwards published in the Annales du mus. d'llistoirt Nat. tome xix,*' SECT. IX. — GENERAL REVIEW OF LIVING BEINGS. Life — Animals and Hants — Definition of an Animal. When we contemplate the face of the earth, we perceive it to be covered with living beings. Animals and plants are to be found in every corner of the globe, with the exception of the poles, where perpetual frosts and the long darkness of winter ren- der the land incapable of supporting them; and where, to use the words of the poet, “ Life itself goes out.” We even find the remains of living bodies at enor- mous depths below the surface, in spots which once formed the beds of running streams, or the bottom of a mighty ocean, from which situations they have been ele- vated by the ordinary laws of volcanic agency. The mould forming iho surface of the earth is composed of the remains of generations which are now no more : it serves to maintain the growth of living plants, and, through them, of all living animals. In the atmosphere surrounding the globe, every thing is fitted for life: light and heat bring organized bodies into existence; the air, covering the earth in every direction to the depth of many leagues, contmoally exchanges its particles with those of living bodies. Finally, water, which ]mscs incessantly from the sea to the clouds, and from the clouds to the sea, is another clement essential to Life. Life is one of those my.stcrious and unknown secondary causes, to which we assign a certain series of observed phenomena, possessing mutual relations, and succeeding each other in a constant order. It is true that we arc completely ignorant of the link which unites these phenomena, but we are sensible that a connexion must exist; and this conriction is sufficient to induce us to assign to tliem one general name, which is used in two senses: first, as the sign of a particular principle; and, secondly, as indi- cating the totality of the phenomena which have given rise to its adoption. As the human body, the bodies of the other animal”, and of plants, appear to resist, during a certain time, the laws which govern inanimate bodies, and even to act on all around them in a manner opposed altogether to those laws, we innpioy the terms Life and Vital Principle to designate these apparent exceptions to general laws. It is, therefore, by determining exactly in what these exceptions consist, that we shall be able to understand clearly the meaning of tho.se terms. For this purpose, let us con- sider living bodies in their active and passive relations to the rest of nature. For example, let us contemplate a female in the prime of youth and health. The elegant form, the graceful flexibility of motion, the geutle warmth, the checks crim- soned with the blushes of beauty, the brilliant eyes sparkling wth the fire of genius, or animated with the sallies of wit, seem united to form a most fascinating being. A moment is sufficient to destroy the illusion. Motion and sense often cease without any apparent cause. The body loses its heat, the mviscles become flat, and the angular prominences of the bones appear 5 the cornea of the eye loses its brightness, and the eyes sink. The^c are, however, but the preludes of changes still more horrible. The neck and abdomen become discoloured, the cuticle separates from the skin, which becomes successively blue, green, and black. The coqise slowly dissolves, a part combining with the atmosphere, a part reduced to the liquid state, and a part moulder- ing in the earth. In a word, after a few short days there remain only a small number of earthy and saline principles. The other elements are dispersed in air end water, prepared again to enter into new combinations^ and to become the constituent parti- cles, perhaps, of another human body. It is evident that this separation is the natural effect of the action of the air, heat, and moisture; in a word, of external matter upon the dead animal body; and tliat its cause is to be found in the elctrtivc attraction of these different agents for the elements of which the body is composed. That body, however, was equally surrounded by those agents while living, their affinities for its molecules were the same, and the latter would have yielded in the same manner dining life, had not their cohesion been pre- served by a power superior to those affinities, and which never ceased to act until tli® moment of death. All living beings aro found to possess one common character, whatever differences may prevail among them. They are all born from bodies siraikir to themselves, and grow by attracting the surrounding particles which they assimilate with their sub- stance. All are formed with different parts, which we call organs, and from w'liicb they derive the appellation of organized beings. These organs united together fom^ a whole, which is a perfect unity in respect to form, duration, and the phenomena exhibits; and, as one of these projicrtics cannot bo abstracted from the rt‘st without annihilating the whole, a living being receives the name of individual. Each bein^ possesses a degree of heat, differing in different beings, and, to a certain point, ind^'" pendent of surrounding bodies. They all resist the laws of affinity which sway th^ mineral kingdom, and the compositions which they form arc submitted to laws diff‘'^' ent from those influencing the mixtures of the chemist. They all absorb something from witliout, and transform it within ; and all exhale certain principles, the produf of the vital action. All reproduce other and similar beings, by the same actions by which they wore themselves produced. All exist for a time, variable for each indi- vidual, but nearly the same for the same species, when in the wild state of nature- After this active individual existence, they all cease to live; and, finally, their bodies are dissipated into their more simple eleiuenta, according to the universal laws o Inorganic Chemistry. . . Thus every living being forms, by its unity, a little world within itself; yet this Idt world cannot remain isolated from the universe without. In Life, there is always bond of mutual dependence among the organs — a universal concourse and agreeme GENERAL REVIEW OF LIVING BEINGS. 15 of actions. Every part corresponds witli the whole, and the whole with the uni- verse. If, then, we wish to distinguish a living hody from another organized body, but without life, we have only to ascertain whether it continue to interchange particles with the soil, or gaseous fluids, which surround it; or, on the contrary, whether it maintain no active or cfHcacious relations with the universe. Again, if we wish to distinguish an organized body, which has ceased to live, from a mineral, we have only to ascertain whether the particles are othc^^s ise united than by the ordinary molecu- lar attractions, and whether the free action of the elements is about to annihilate it either by destruction or putrefaction. The division of Living Beings into Animals and Plants has been already explained. The former, being of a complex nature, Jire provided with an internal cavity which re- ceives their aliment, and are endowed witli sense and spontaneous motion. Directed by instinct, they are alike capable of iivoitUng injury, and of pursuing their natural good. The latter, fixed to the earth by their roots, and deprived of the faculties of sensation and inoiiou, are placed by Nature in situations fitted to supply their wants. The materials necessary for their sustenance are absorbed directly, witiiout instinct or motion, and arc abundantly supplied without either preparation or complicated labour. Animals, endowed with the distinctions of sex, both of which sometimes co-oxist in tho same individual, but more frequently in separate individuals of tlic same species, pre- serve these distinctions during tho whole period of their lives. Almost all plants, on the contrary, httvt! the two sexes united in tho same beii»g; and the distinctive cha- racters of sex are lost and renewed every year. Again, tho inUfrnal structure of ani- mals is more complicated than that of plants: it is internally that the great functions of Ufa are pcirformcd. With plants, on the contrary, the principal organs are placed on the surface; and their functions are mostly performed externally. As soon as an animal is born, its organs aro exhibited: they require nothing but development and grow’th to form a perfect animal ; and, if we except certain metamorphoses, the exter- nal form of tlie adult is already sketched. The vegetable, horn from a seed, develops • ts organs successively; first the root, then the stalk, leaves, and flowers; — and when the flowers have bloomed, they die; the rest of the organs perish, the whole ceases to live, or sometimes only the stalk, or perliaps only the leaves- Not a year elapses but flower is destroyed or renewed, partially or entirely. Thus, tho two classes of hoings possess in eonimon the powers of nutrition and of reproduction. The animal has, Ixowever, something more than the vegetable, and enjoys tho liigher powers of sensation and voluntary motion. The animal alone possesses nerves, muscles, blood, and some kind of stomach. One at least of these organs is always visible ; and, as the nerves and muscles are intermittent in their action, and incapable of maintaining a long- continued exercise without repose, animals possess a notv distinctive mark in that pe- riodical sleep to which they aj*e at intervals subjected. To a person w'bo has considered Life only in hlan, or in those liigher animals which most resemble him, it appears almost superfluous to explain the essential difference between an animal and a plant. If there existed upon tho face of tho earth only such •■nimals as Birds, Fishes, or Qu.adrupcds, there would then be no occasion to enlarge so fully upon the ilistinctions in their functions: the line drawm by tho hand of Nature ^’ould suffice. should readily be preserved from error on this point by their senses, their voluntary motion, the symmetry and complexity of their structure, but, 5ibove all, by tho instinct which directs their actions. Tlien tve might say with Lin- najus, “ Vegetabiliacrcscunt et vivunt; Animalla crescunt, vivunt ct sentiunt,” (Ve- getables grow aiuUivc; Animals grow, live, and feel); and tbisdefmition would boas ac- t:urate as it is brief. We should not be obliged to separate Corals, Polyiii, Insects, tlrustacea, and Sj-mmctrical Shells, from the Vegetable Kingdom. fiut such is not the case. All animals tlo not exhibit the distinctive marks of complicated structure mul voluntary motion. This may be easily inferred from the fact, that Tounuffort, a man of great talents, mid an able naturalist, actually formed uiiu! genera in the seventeenth family of his Botanical system with those Ibilypi which Were known to him and to his learned contemporarius. At a later period, Trembley besitated for a long time before lie could determine whether the Hydra wjw an animal or a plant; and the experiments which he performed to determine the question have been admired by all tho philosophers of his time. Tho dexterous manipulations of "ftembley are the more remarkable, as Pc-yssonel had previously observed that mi- *mte animals inhabit tho different compai‘tmcnts of the corals. This discovery was extended by Ellis and i^lolander to all kinds of Polypi; while Donati, Reaumur, and • de Jussieu, brought the subject prominently forward in their public lectures and Writings. Tho question, however, still remained in an unsatisfactory state, and at- Ji’JLctod the attention of tho distinguished naturalists of tlic eighteenth century. Buf- proposed to establish an intermediate class between anira.als and plants. I.innmus opted tliis suggestion, although it proceeded from ButFon ; and rendered the distinc- tion permanent by the title of Zoophytes, or Animated I'lants. The celebrated Pallas ."flowed Linna?us; Cuvier adopted the word and the distinction ; while Lamarck re- Jiicted them both. Tliose doubts and differnnecs of opinion among onliglitcnnd mon could only have proceeded from the obscurity of tho subj^t. One cause of the obscurity arose from ^ c false direction which their studios had unfortunately talten. Confining themselves ^0 their cabinets, Naturalists remained too far from Nature, 'fhev h»,l cii.i i,o- >os Corals, Spoiigos, Alcyonia, Polypi, of inuumerahle sliapcs, s sometimes covered with -an. r . 1 • '■ awiiicunw.s voveruu witli ^ and moveable bodies, and sometimes without them. Instead of considering the soft “ y as the artificer of tlio solid mass, they believed that the latter produced tho for- ' - — --a;*' produced tlio for- ^ > and as the solid masses wore observed to grow and vegetate, they were hastily '•“nadered to ho plants, while the sn.'t bodies were regarded as the fiowers of these t aordinary vegetables, at the 1 The error was further confirmed by tho e.ircumstauee, that 0 particular period when those Polypi reprnikce other beings of the same species, ^'^Ir bodies .ire covered with little buds and shoot.s, which lii'ar a great resemblaneo certain fiowers, the structure of which cannot be very distinctly perceived, liut and supposed fiowers were observed to bo endowed with spontaneous motion, ^ lat they were possessed of sensation, a great difficulty arose; and tho name ot ant es, or a?iimatedJIowcrSf was assigned to them. I as now, however, been completely ascertained that the Polypi thoinsulvos fa- bricate these solid apparent vegetables, which serve for their abodes. They se- crete them in very nearly tho same manner as the Mollusca form their shells ; the Teredo its testaceous tube; the Lobster its crustaceous envelope; the Tortoise its shield; the Fishes their scales; Insects their elytra or wing-cases; Birds their plu- mage; the Armadillo his scaly covering; the Whales their horny laminie; Quadrupeds their skins and organs of defence; and ^lan, his hair, nails, and cuticle. In all these beings there are to he found some parts which vegetate ; and if it were necessary to class with plants all beings which arc found to vegetate in any of their parts, wo ought, consistently, to include all the animals just named with the Zoophytes or ani, mated plants of Linnjnus and Pallas. The following are the eharaefers by which we may always ascertain whether a liv- ing being, organized, growing, drawing in nutriment, possessing an internal tempera- ture peculiar to itself, and reproducing its kind, be an Animal or a Plant, If it he irritable to the touch, and move spontaneously to satisfy its wants, — if it be not deeply rooted in tho soil, hut only adhere to the sm'face, — if its body he provided with a eentral cavity, — if it putrify after death, — if it give out the ammoniacal odour of burnt horn, — and finally, if in its chemical composition there be found .an eitcess of azote over carlion, — then wo may be certain that it is an Animal. But if, on tho contrary, tho doubtful being under examination enjoy no lasting or spontaneous power of motion, — if it he destitute of an internal cavity, — if it bo deeply inserted in tlie soi!, — if, when dolachcd, it speedily fade and die, — if, when dead, it merely ferment, bui do not putrify, — if it burn without the odour of a burnt quill or horn, and if its re- sidue ho very considerable and chiefly carbon, — then we may venture to declare it to be a Plant. These characters are sufficient, and can, in general, be easily ascertained. In this enumeration, no allusion has been made to sensation as a distinctive mark of the two classes of living beings ; because, in the lowest classes of animals, where alone any difficulty can .arise, it is only from the property of irritability that we can infer sensa- tion. The phenomena of reproduction have likewise not been alluded to, because it is in the lowest animals, which we arc llic most likely to confound with plants, that this power is still involved in great obscurity, or altogether unktiown. It is not, as we might at first sight suppose, the most perfect, or, to speak mure correctly, the most complicated plants that are likely to be mistaken for animals. A moment’s re- flection will readily show how utterly impossible it is to confomid a plant, bearing leaves and fiowers, with any animal whatever. But it is otherwise with tho less cha- racterized beings ; and the Animal and Vegetable Kingdoms may ho compared to two mighty pyramids, which touch each other by tbelr b.ascs, while their opposite vertices diverge to two infinitely remote points in either direction. IVo have thus shown how extremely difficult it is to characterize the essential dif- ferences of animals and plants in one short definition. Even Cuvier himself, who spent twenty years of his life in examining the organization of animiOs, from the simple Polypus up to Man, has carefully abstiiincd from proposhig any such defini- tion. This difficulty increases in proportion to the number of animals under ex.amination. It doe.s not consist in ascertaining the characters appropriated to partical,ir animals, but in selecting suc'h a trait as shall bo common to them all. Wo know that, none but animals are possessed of a brain, nerves, muscles, he.art, lungs, stomach, or ske- leton. Wo know that they alone move, digest, respire; that they alone have blood, and seem to feel;— but tho point is to ascorlaiu which of these characters remains throughout the vast cliain of beings, and which of them can ho traced in the last link as well as in the first, We see tho lungs disappear, then successively the ghmds, the brain, the skeleton, the heart, the gills, the blood, the nerves, the muscles, and toal- ly, even the vessels ; while in tho lowest animals of all, we can seareoly ascertain whether they possess a digestive cavity or a stomach. However, as wo find this last- mentioned organ in almost all animals, and as it can be clearly observed oven in those which have no other externally visible organ, we may reasonably conclude that it is to be found in all ; and, if we fail to discover a stomach in many, we should rather suppose our failure to proceed from want of Bkill, or from want of suffiment delicacy in our senses, arising probably from the excessive minuteness of the beings under ex- amination. Wo shall, therefore, assume that all animals possess a stomach, and tliat th{ty digest ; we may inter that they are all possesswl of sensation ; but it is absolute- ly certain that they all, and they alone, permanently posse.ss the power of voluntary motion. ^ If, therefore, we may venture to propose a definition which shall be generaliy appli- cable to all animals, w e should define thorn to ho Livin;/ Bangs having slomachs. The stomach is, in fact, tho groat essonti.al spring of every animated being. Nerves and muscles, organs of sensation and motion, appear indeed to bo of a higher and more elevated character than the organ of digestion. Yet w'^ard to the roots of plants, and the branches of large trees, \rc observe that a great irregularity generally prevails. But this is owing rather to inequalities of the soil, and to varieties in the intensity of light, than to any natural disposition to irregularity in the plants themselves. The soil is not composed of uniform materials, and the roots alwavs direct their fibres toward those ports w'hich are most easily moved and yield the most abundant nutriment. Tho loaves and buds, again, arc delicately sensible to nice degrees of light. Wo accordingly observe that the Conifera?, such as tho Pino and Fir, being resinous, and cver-green trees, upon which these powers have least influence, present the most regular and symmetrical forms. The regular arrangement among plants ia no where found in greater perfection than among the Labiata*. Wc do not here allude to their flowers, which are not so very remarkable in this respect, but to their square stems, their opposite leaves, their branches, and their peduncles. In most of tbetus plants, each loaf, taken separately, is arranged with regularity. But none even of tliosc can compare with the beautiful symmetry observable in llie leaves of the Sensitive Plant, the Acacias, and tlie Firs. In by far the greater number of plants, we find the utmost exactness in the distances between tho several divisions of the calyx and corolla,— the flowcr-cup, and tlic flower itself; in the dimensions of each stamen, of uadi pistil; in every compartment of tho ovarium, and of the fruit. With the e.xception of certain flowers analogous to thoso of the Acacia.!, of the Labiatai, of the Orchidea*, and some others, tho irregularities which many occasionally [tre.^ent are due lo the abortion of certain ports, to their ad- herence, or to their transmutation into other forms. Ascending to the Animal Kingdom, and arriving at the Polypi, thoso lowest of ani' mated beings, wc already find the same symmetrical arrangements. Their cilia, their tentacula, or little arms, these appendages of more animated sacs, are dis])osed with regularity, around that single orifice, which we dignify by the name of mouth. B only in those calcareous and arborescent masses which they form and inhabit, and which compose by their aggregation, rocks, islands, and rudimentary continents, that we fail to observe tins regular arrangement. We may rccogiii.se the same order if* the starry rays of the Euryalia, and in the spinous compartments of the Echini, or Sea- urchins. In rcRpi'Ct to Insects, tho sjTmnolryis exquisite. M'e find the same quality in many Mollusca, but most particularly in their shells, and in the crustaceous lopes of Crabs and Lobsters. It is, however, in the higher or Vertebrated Animals that symmetry is brought to its greatest degree. Their bones, their nerves, tlieir organs of sense, their brara» their muscles, their glands, their gills or lungs, are all arranged in lateral pairs^ when their number is even ; or they are placed in the exact central axis of tho body» when their number is odd. Wo must admit, however, that it is externally wo can best trace this correspondence, for the internal organs are not thus arranged. this respect the contrast is altogether surprising: in vain we seek for symmetry ^ the disposition of the intestines, the liver, or the heart. GENERAL REVIEW OF LIVING BEINGS. 17 This physiological arrangement is ably illustrated by the cxcelbrnt Dr Palcy. The regularity of the animal structure,” ho observes, “ is rendered remarkable by the three following considerations : — First, the limbs, separately Lakeu, have nitt this co-rclation ef parts, but the contrary of it. A knife taken down the chine, cuts the human body into two parts, externally equal and alike ; you cannot draw a straight line which will not divide a hand, a foot, tho log, the thigh, the check, tho eye, the ear, into two parts equal and alike. Those parts which are placed upon tlie middle or partition lino of tho body, or which traverse that line, as the nose, the tongue, the lips, may be so divuled, or, more properly speaking, arc double organs ; but other parts cannot. This shows that the correspondency which wo have been dcsmbbig does not arise by any neces- sity in tho iiaturo of the subject; for, if ncces.sary, it would be universal; whereas, it is observed only in the system or assemblage : it is not Iruc of the separate parts ; tliat is to say, it is found where it conduces to beauty or utility ; it is not found wliero it w’ould subsist at the expense nf both. The two wings of a bird always corres- pond ; tho two .sides of a feather frequently do not. Iii centipedes, millepedes, and tlic whole tribe of InsecU, no two legs on the same side ar(? alike ; yet tlicro is the most exact parity between the legs opposite to one another. The next circumstance to be remarked is, that, whilst the cavities of the body are so configurated as exter^ nally to exhibit the most exact correspondency of the opposite sides, the contents of these cavities have no such correspondency. A line drawn down tho middle of the breast, divides the thorax into two sides exactly similar; yet these two sides enclose very different contents. The liciirt lies on tho left side, a lobe of tho lungs on the right, biilanoing each other neillier in size nor shape. The same thing holds of the abdomen. The liver lies on tho right side, without any similar riscus opposed to it on the left. Tlie spleen indeed is situate over against the liver, but agreeing with the liver neilher in bulk nor form. There is no equi-pollcncy between these. Tho stomach is a vessel both irregular in its shape and oblique in its position. Tho fold- ings and doublings of the intestines do not present a parity of sides. Yet that sym- metry which depends upon the co-relalion of the sides, is externally preserved through- out the whole trunk ; and is the more rcmai’kablc in the lower part of it, as the in- teguments are soft ; and the shape, consequently, is not, as tho thorax is by its ribs, reduced by natural stays. It is evident, therefore, that the external proportion docs not arise from any equality in the shape or pressure of tho internal contents. What is it indeed but a correction of inequalities? — an adjustment, by mutual compensation, of anoinaloiM forms into a regular congeries ? — the effect, in a word, of artful, and, if we might be permitted so to speak, of studied collocation ? Similar also to this, is a third observation ; that an internal inequality in the feeding vessels is so managed, as to produce no inequality of parts which were intended to correspond. The right arm answers accurately to tho left, both in size and shape ; but the arterial branches, which supply the two arms, do not go off* from their trunk, in a pair, in the same man- ner, at the same place, or at the same angle, under which want of sirailiUide it is very difficult to conceive how the same quantity of Wood should be pushed through each artery : yet the result is right ; — in tho two limbs which are nourished by them, we perceive no diiferenee of supply, no effects of excess or deficiency. Con- cerning the difference of manner, in which tho subclavian and carotid arteries, upon the different sides of tho Iwdy, separate themselves from the aorta, Chcseldcn seems to have thought, that the adv'antago which the left gains by going off* at an angle much more acute than tho r'lght, is made up to the right, by their going off* together in one branch. It is very possible that this may be tho compensating contrivance ; *iid if it be so, bow curious — how hydrostatlcal I” Many animals form .singular ami remarkable exceptions to tins general law of sym- metry. The Mollusca have generally their digestive orifices, as well as the distinc- tive characters of sex, placed on one side of the body, and that is usually the right side. Flat fishes swim on one side; both Iheir oyes arc placed on that which is turn- od was transported to the lungs through the pulmonary ai-leries, and again brought back, through the pulmonary veins, after having been purified. This partitd aeration of tho blood imj'arts to tho Batrachia or frogs a cold and sluggish character. The Fishes Imvc a double circulation, but their respiratory organ is formed for breathing through the medium of water; and their blood receives the action only of that portion of oxygen wbicli is dissolved or niixed in the water. From this circumstance it follows that the degree of their respiration is still less tlian that of the Reptiles. The gills of Fishes arc situate at each side of the throat, and immediately adjoining the heart. Dr Monro is of opinion, that they present an extent of surface to the action of the water equal to that of the entire human body. The fibres resemble the teeth of an exceedingly fine comb, and they are covered with minute protu- berances, rcscrabling the ])ile of velvet, while innumerable blood-vessels distribute their delicate fibres over the entire surface. The distribution of these vessels on the folds and divisions of the gills forms one of the most minute and delicate arrangements lu tho animal economy. By means of these organs, the Fish is enabled to absorb the oxygen dissolved in the water; and after yielding tins substance, the water is dis- charged through the branchial openings. 'I'he Fishes form a contrast with animals of the other divisions, in this respect, that they do not inspire by the same opening through w^hich tliey expire. lu the Mammalui, the circulation is double, and the aerial rcspii-iition 'S simple, that is to say, it is performed only in the lungs. The quantity of their respiration is therefore greatly superior to that of Reptiles, in consequence of the form of the heart, or circulating organ, and also to that of the Fishes, from the nature of the surrounding element. The quantity of respiration possessed by Birds is yet greater than that ^f the Mammalia, because they not only have a douljle circulation, with ^ direct aerial respiration, but they also breathe through many other cavities besides the lungs. The air penetrating into the cells distributed over the body, acts upon the branches of the aorta, or arteries of the ^edy, as well as upon the ramifications of tho pulmonary artery. From these circumstances arc derived the four kinds of motion for ■^hich each of the four classes of AT'rtebratod animals seems particularly designed. The QuADEurEDs, in which the quantity of respiration is modc- ^■ate, are generally formed for walking, for hunning, and for developing l^hese motions with vigour and precision. The Birds, wherein respiration is much more perfect, possess muscular vigour and that liglUncss of construction necessary for ^Ugut. Tu'e Rei'tiles, endowed with a more feeble respiration, arc con- demned to CRAWL upon the earth, and many of them pass a part of their ^fe in a continued state of torpor. The Fishes, in order to execute their less vigorous motions, require 7 to be supported in a fluid of nearly the same specific gravity W’ith their own bodies. All the other organic arrangements proper to each of these four classes, and especially those which are connected with motion and with external sensation, bear a necessary relation to these essential characters. MOTIONS OF THE VERTF.BRATED ANIMALS. Jralltinff — Leaping — lit/nninif — Trotting — Gallopmg — Climbing — Flying — Darting — Faddling — JDh'ing — iiwimmhxg. To perform all the different kinds of progressive motion which are enjoyed by Man and the lower animals, it is necessary that a certain velocity should be communicated, in one particular direction, to the ventre of gravity of the animal body, or that point in the body around w'hich all the parts balance and remain at rest. A certain number of joints mu5t exist, capable of a greater or less degree of flexure. Their relative position must be so adapted that it may he comparatively easy to extend tlicm on tho side to which the centre of gravity is made to incline, and difficult on tho opposite side, so that the general movement may tend in the former direction. The mech.mical part of Animal motion may be understood from the followinf»- illustration : — If we imagine a spring divided into two branches, one of which rests ujion a firm resisting base, and then suppose that the branches are compressed by some e.Kternal force, their elasticity will cause them to recede as soon as the compres- sing force has been removed, and the two branches will bo inclined at the same angle to each other as they were before the compression. But as that branch which rests upon the basis is unable to overcome its resistance, the movement takes place wholly in the opposite direction, and the centre of gravity of the spring is forced from the resisting body with more or loss velocity. Accordingly, in any animal, while tho muscles (Jlexors)^ which bend the part employed in effecting the movement, represent the external compressing force of the spring, and those muscles (cxteyinors)^ which slretcb it out, correspond to the elasticity that makes the branches of the spring fly asunder, tbs ground supporting the animal, or fluid in which it moves, forms the resisting basis. In IValhing., the centre of gravity is alternately moved by one part of the extremi- ties and supported by the other, the body never being completely separated from the ground. It differs essentially from Leaping^ where the entire body is projected into the air; and from Hunning, which consists of a number of short leaps. In general, it is less painful to walk than to stand, because the same muscles arc not continued in action for so long a period; and it is much easier to counteract those unsteady motions Avliich occur in walking by contrary and alternate actions than it is to prevent them entirely. Thus it follows, that though all animals which stand erect on two legs, such as l\I-iu and Birds, can also walk on two legs, yot many moving in an UjUight position with sufficient case, cannot stand on two foot for any time without very great fatigue and exertion. When I\Ian intends to walk on level ground, he first extends one foot. Ills body then rests equally npon both leg.s, tho advanced log making an obtuse angle witli the tarsus or instep, and tho other an acute angle. As tlio ground does not yield to the point of the foot, the heel and the remainder of the leg must necessarily be raised, otherwise the heel could not be oxiouJed. The pelvis and trunk are consequently thrown upwards, forwards, and somewhat in a lateral direction. In this manner they move round llie fixed foot as a centre, with a radius consisting of the leg belonging to that foot, which, during the movement, continually diminishos the angle formed with the tarsus. Tho log communicating this impulse is then thrown forw.ard and rests its foot upon tho ground; while tho other, which now forms an acute angle with its foot, h.is the heel extended in Us turn, and in like manner makes the pelvis and trunk tiwii round upon the former log. Tbe ceutro of gravity is thus carried forward by these movements at each progressive stop, inclining, however, at the same time to tlie right and loft alternately, so as to bo supported by each leg in its turn. It will also be seen tliat each leg, immediately on extending ita heel, bends and rises, in order to its being moved forward, — extends in order to rest its foot upon the ground, turns upon this foot as on a fixed centre, so as to support the weight of tlic body, and then extends its heel again in order to transfer this wnight to the other leg. In this manner, each leg supports the body in its turn; but it is also necessary that the extcnsois of the thigh and Unco should be brought into action, to prevent their articulations from giving way; and this motion is followed by a corresponding action of the flexors of the same articulations. It will be observed, tliat the three principal articulations of each leg are situate in opposite directions to each other, tliat tho foot should bo raised by their flexion iimiiediatcdy over the placa which it occupied during their extension. It would otherwise be impossible to bond them without throwing the foot backwards or forwards. In consequence of the impossibility of regulating the undulatory motion, in a man- ner perfectly equal on both sides, a man cannot walk in a straight line wdth his eyes shut; nor could he even preserve a uniform direction, did he not correct these devia- tions by the sense of sight. In descending a stair-case, or in walking down an inclined plane, the alvanced leg is placed lower than that remaining behind; and tho body would fail upon it with a fatiguing ami dangerous jerk, were it not carcrull}^checked by the extensors of the hip. By this racaiw, the body is compelled to descend gradually; but the muscles of tho loins soon become fatigued by tho exertion. On the contrary, in ascending a st-iir-case, or an inclined plane, it is requisite at each step, not only to transport the body horizontally, os on a level surface, but also to bear it up against its own weight, by means of the extensors belongingto the knee of the advanced leg, and to the heel of the leg reraahiing behind. I'ho kuoc and calf of the leg are therefore fatigued in ascending. A mechanical a.tvanlage is gained by lean- ing the body forward in ascending, because the lever, by which its weight retards the 26 THE FIRST GREAT DIVISION. motion of the knee, is thereby shortened in equal proportion. A fatigue^ similar to that produced by the action of ascending, is occasioned by walking with a very wide step. As the legs are thereby placed considerably apart, the body sinks lower at the moment of their separation ; and as it is necessary to raise the body proportionally, when turning alternately on each leg, the fatigue is consequently greater. Man is not compelled to swing his arms greatly to assist his walking, except when confined to a very narrow path from which he cannot depart, and then he employs every means to correct the unsteady motion of the body. Apes always require the assistance of their arms in walking; and such as have these extremities longest, like the Orang Outang {Pithecus Satyriis)^ and the Long-armed Monkey or Gibbon {Vithveus ftrr), use them with the greatest advantage. Among Quadrupeds, the action of walking is performed in the following manner; The articulations of the hind-legs arc first bent slightly, and extended in order to carry the body forward ; in which movement the extensors of the knee and heel par- ticularly contribute. The breast is thrown forward by this movement, the fore-legs incline backwards, and the animal would certainly fall, did it not instantly throw its fore-legs forward in order to support itself. The trunk is dratvn upon the fore-legs, which are now fixed in this position, and the action of the hind-legs is again repeated. But it must be observed that, In the action of walking, these movements are not per- formed at the same instant, by the legs of each pair ; for, in that case, the animal would necessarily be completely suspended for a moment over the ground. Its motion would then no longer be a walk, but a succession of leaps, particularly denominated a full-gallop. On the contrary, each step is executed by t^YO legs only, one belong- ing to the fore pair, and the other to the hind pair. WTicn tlie motion is performed by the legs on the same side, it is called an amble — when by legs on opposite sides, a pace. During the amble, the body being alternately supported by two legs of the same side, is obliged to balance itself to the right and left, in order to avoid falling, and the right fore-foot moves to sustain the body, urged onwards by the right hind-foot. Tt is this balancing movement which renders the arable of the Horse and Ass so agree- able to invalids. In the pace, the body is supported alternately by two legs placed in a diagonal manner. The right fore-leg is advanced to sustain the body, thrown forward by the extension of the loft hind-foot ; and at the same instant the latter bends in order to its being moved forward. MTiile these are raised, the right hind-foot begins to extend itself, and the moment they touch the ground, the left; fore-foot moves forward to sup- port the impulse of the right foot, whicli again moves fonvard. Quadinipeds having the fore-feet longer than the hinder, as may be observed in tha Giraffe, or Ciunelupard, possess tlic chief strength of their body in the fore-legs, and accordingly the principal impulse is given by extending tho fore-foot. The Sloths, and all animals which like them have the fore-legs greatly disproportioned to tho others, drag themselves onwards with a laborious and tedious movement, by first extending the anterior legs, and then bending them so as to draw the body onward.® ; and witii the Slcths, tliis diiEcult motion is further increased by the imperfect articu- lations and general feeblcnc.ss of the hinder-legs. The legs of the Mammiferous Quadrupeds move forwards and backwards in planes nearly parallel to the spine, and not far from the middle plane of the body upon whicli the weight operates. On the contrary, iu the Oviparous Quadrupeds, the thighs are directed outwards, while the bendings of the limbs take place in planes perpendicular to the spine. In the latter case, the weight of the body acts with a much longer lever in opposing the extension of the knee. These animals, therefore, have the knees always bent, and the belly drags upon the ground between the legs. For this reason they have received the name of Reptiles. The short leaps of the Hares, and particularly of the Jerboas, arc occasioned by the great length of their hinder as compared to the fore-legs. Indeed, their fore- legs arc so short, that had they not the precaution to make this prancing movement, these animals would be thrown down by each impulse of the hind-feet. It is only in ascending a hill, that they can be said to walk at all. Their movement on level ground is performed by a succession of short leaps ; and when they attempt to walk slowly upon level ground, they arc compelled to move themselves by the fore-feet, and merely to drag the hinder pair after them. We may obaervo tho latter movement in the Rabbit, aiul still more distinctly in the Frog. The Otters, Beavers, Water Tortoises or Turtles, and other quadrupeds designed for swimming, have the hinder-legs placed very far apart to facilitate the motion. They arc, therefore, impelled laterally, the line of motion becomes crooked, and tho trunk is urged onwards from side to sidc- In Leaping, the body rises entirely from tho earth, darts into the air, and remains suspended for a momentary period, depending for its duration on the force of projec- tion. Ihis movement is performed by the sudden extension of all tho inferior arti- culations, after they have undergone an unusual degree of flexion. Their rapid ex- tension gives a violent shock to the bones composing the articulations. The impulse IS then communicated to the centre of gravity of the animal’s body, and it is pro- jected with a determined velocity depending on its weight. Aleaping body is, therc- tore, a projectile which gradually loses the acquired velocity by which it ascended, its motion being continually retarded, and finally destroyed by the force of gravity exer- cised by the earth. We are therefore enabled to ascertain the curve described by a leaping body in the air, with the time and place of its descent, when the projectile force and the force of gravity are given, and allowance made for the resistance of tho air. All the animals which leap best have the hinder-legs and thighs much longer and ■ thicker than the antoi ior — the projectile force, and consequently the extent of the leap, being regulated by tlic proportional length of the muscles. Tho surprising leaps of the Kangaroo, Jeiboa, and Frog, arc plainly owing to this cause. The smaller animals leap much farther than the larger, in proportion to their size. This must follow obviously, if it be considered that when tho projectile force impressed on two bodies is in propordon to their different magnitudes, their velocity will be equal, and that the extent of the space through which they pass depends entirely upon their respective velocities. The leaps of small and large animals arc therefore nearly equal. Man and Birds are the only animals capable of leaping vertically or hopping, be- cause they alone have the trunk placed directly over tho legs, and tho direction of a leap depends upon the situation of the centre of gravity, in respect to the member by which the impulse is given. They are also capable of leaping forward, by impressing a greater degree of force on the rotatory motion of tho thigh than on that of the leg; or they may even leap backwards, by making an opposite exertion. On the contrary, Qu.*idrupcd3 can only leap forwards. Hunning differs from walking, only in tho body being projected forward at each step, and in the hinder-foot being raised before the anterior foot touches the ground. It consists, in fact, of a series of low leaps performed by each leg. As tho acquired velocity is preserved, and augmented at each bound by the new velocity thereby added to it, running is more rapid than the quickest walking step. An animal cannot, there- fore, stop itself instantaneously when running, though a stop may be made at each step in walking. In leaping forward, a previous run is advantageous, because it acids the momentum acquired during the run to that obtained from tho leap itself; but a vertical leap or hop would be entirely prevented by a run, or at least consider- ably diminished. For this reason, a horse in full gallop, preparing to leap, retards his velocity before making the spring. In running, an animal inclines its body forwards, that the centre of gravity may be in a proper situation for re- ceiving an impulse in that direction from tho Iiind«r-leg. It is also requisite to move the fore-leg rapidly forward to guard against falling. Were any obstacle to inten’cne, so as to prevent this leg from reaching the ground in time to support the body, a fall would be the consequence. It also follows, lliat interruptions of this kind are more dangerous in running than in walking, on account of the greater momen- tum of the body, and for the same reason they occur more frequently. lilan never varies his manner of running, except in taking longer or shorter steps, or in giving to his body a greater or less degree of velocity ; but Quadrupeds vary their mode of running, by tho different order in which they raise each foot, or bring it to the ground. The feet diagonally opposite rise simultaneously in the trot, and fall at once, each pair alternately, but in such a manner, that for a moment all the four feet arc off tlm ground. The sound of tho animal’s steps are therefore heard two and two in succes- sion, and a regular motion is produced. The Dog, Hare, and many other quadrupeds, can only run in the manner particu- larly denominated the full gallop, which is the most rajiid motion of tho Horse. These animals raise the anterior feet at each stop; the body is projected forwards by the extension of the bind-feet; the two fore-feet descend at the same lime, and are followed by the two hind-feet also descending together. By this means, the step* of the horse are hc^d by two beats at a time, differing in this respect from the common gallop, ulicre the two fuie-fcet are lifted unequally, and fall one after another, and from those other varieties of the gallop, where the horse’s footsteps arc licard by a series of three or four beats, from the hinder-feet falling to tho ground either both together or one after the other. Many animals leap by organs different from feet, hut they all agree in this respect, that the movement is occasioned by the sudden extension of several articulations. Serpents leap by foliUng their bodies into several undulations, which are unbent at the same instant, according to the degree of velocity wliich they wish to impart to their bodies. Only a few genera are assisted in this motion by the scales of the bcHy* which they are able to derate and depress at pleasure. Some Fishes leap to the tops of cataracts by bending tliclr bodies strongly, and then unbending them suddenly, so that they rise with an elastic and powerful spring. Several animals, which in reality leap, have been improperly said to fly. 'The Flying Lemurs, Flying Squirrels, ami Flying Phalangers, have membranes between the feet, but their toes arc not elongated. These membranes serve to support them for some time in the air, and enable them to take great leaps in descending ; but tim membrane acts merely as a parachute, as these animals camiot raise themselves in tb® air. In the same manner, the Flying Dragon, a small lizard found in the East Indit‘5» supports itself for some moments during a leap, by a membrane sustained by a bony rays, articulated to the spine of the back. 5Ian and various other animals possess the power of seizing objects, by surroun^l' ing and grasping them with their fingers. For this reason, it is necessary that the fingers should he separate, free, flexible, and of a certain length. Man has such fingers cn his hand only; but Apes and some other kinds of animals have them both on the hands and feet; hence they arc termed quadruviana, or four-handed. Man surpasses all other animals in the delicate operations wliich his hand is capable of performing. The Apes and Lemurs alone possess with him a thumb opposable to the other fingers, and forming with them a kind of forceps. They are consequently the only animals capable of holding moveable objects in a single hand. But it is pcnsable to perfect prehension that they should have tho power of rotating tlm upon the fore-am, and the bones of the shoulder must be placed so as to prevent the scapula or shoulder-blade from being thrown forwards. The Squirrel, Opossum, Rat, aud other animals, possess fingers sufficiently siwJ' and aexiblo to enable thorn to take up objects, but they can only hold them by iissistanea of both paws. Dogs and Cats, which have the toes shorter, and bosWe® arc under the necessity of resting on their foro-foct, can retain their hold of stances solely by fixing them upon tho ground with their paws. Those animaU the toes united and drawn together under the skin, or enveloped in horny hoofs, at'-’ incapable of cxercisiug any prehensile power. Climbing is greatly facilitated by a power of seizing and grasping firmly* 11^** but an indifferent climber, because he can only grasp with hU hands. His ftn’t chiefly adapted for supporting the body, and afford but an imperfect moans of it by the extension of the knees and heels. The arms form, therefore, the ’ means of drawing the body upwards in climbing. Aloiikcys, and other Quadrumana, are the best climbers. They can seize equ^ ^ well with their four extremities ; and the position of their hind-fo'A is still favorable to this action, as the soles arc turned inwards, instead of being dircc outwards. Aut-eators and Sloths have a considerable protuberance on tho which nearly accomplislics the same end ; and with the Opossums and Phalaug ANIMALIA VERTEBRATA— VERTEBRATED ANIMALS. 27 clrmbing is assisted by a thumb almost always directed backwards, and forming a kind of heel very powerful in its operation. The animals just mentioned, ns well as most of the Quadrumana, are assisted in climbing by their tail, which is capable of seizing bodies almost as powerfully a.s a hand. For this purpose, additional force is imparted to the common muscles of tho tail. The sharp and hooked claws found in animals of the Cat kind, enable them to climb with facility. Their nails are retained between the toes, ^vith the points elevated by two elastic ligaments, altogether independent of the will of the animal. When they wish to use the nails, either for tearing their prey or seizing moveable objects, tho nails are protruded by the muscle, which moves the last phalanx of the toe on the preceding one. In the Sloth, the ligaments arc differently disposed, and tho nails being naturally inflected, must be raised when tho animal wishes to use them. As the toes arc of an inconvenient form, being composed of two phalanges, one of which i^ very short, and the other entirely covered with tho nail, while the metacarpal bones are ossified to- gether, and immoveable, tho Sloths perform their movements with constraint and difficulty. The climbing birds arc enabled by their claws to fix themselves to tho inequalities in the bark of trees; and they perform this action by the assistance chiefly of the hindcr-tocs, which are used in supporting and preventing them from falling. Tho greater number of these genera have two hinder-toes, but tho Creepers and Nut- hatches have only one. The Woodpeckers, as well n.s the Creepers, arc assisted in climbing by tho quids of the tail, which arc stiff and capable of being fixed firmly into the inequalhics of surfaces. Some liirds can raise the food to their mouth by means of tho one foot, while they stand upon the other. Parrots have their toes conveniently disposed for this purpose, and also the Owls. Without this pronsion, the latter would frequently fall whenever they attempted to peck, in consequence of the great weight of the lie.ad, and the cor- responding elevation of their centre of gravity. But as most birds require both feet in order to stand firmly, they seldom use them for lioldhig .substances except during flight, when tho feet are disengaged. The Cormorant and Pelican will sometimes sw’im witli the one foot and carry some substance In tho other; ans adaptations for climbing, enjoyed by no other animals except the (Juadrumana. With a prehensile tail, and hands resoinbling forceps, he exhibits a degree of agility unusual with the Reptiles. Flying and swimming are leaps taking place in fluids, and the motion is produced by the resistance which the fluid makes to tho surface of tho wings or fins, when moved bj the animal with great rapidity. Leaping, however, takes place on a fixed sur- face, possessing the power of resi.stance, from its magnitude and firmness. If wo sup- pose tho ground to be either soft or clastic, leaping may still be performed; but there arises a diminution in the velocity of the leap, proportional to the resiliency of the support. It is necessary, therefore, that tho moving power dioul.l be increased in pro- portion, to produce an equal momentum by the extent of the vibrating surfaces, and by the rapuUty of their vibrations. The velocity with which the wings or fins must be used, depends on the rarity of the metlium in which they move. It is less in water, greater in air near the earth's surfuee, and increases as the luiimal ascends into the higher regions of the atmosphere. Birds cannot therefore fly above a certain height, dependent on tho strength of their muscles; and they are capable of rising to a greater height when tho barometer is high than when it is low. Tho muscles moving tho wings and fins, but especially the former, require a force vastly superior to that neces- sary to produce a simple leap upon a firm surface. As a flying or swimmiug body is entirely surrounded by the medium in which it is placed, it experiences an equal resistance in front as well as from behind on striking the fluid. An animal would be incapable of advancing, if it did not possess the power of greatly diminishing tho surface of its wing or fin, immediately after having struck the fluid. Flying and swimming arc sometimes performed by the same animal ; but the former is executed most perfectly by Birds, and tlie latter by Fishes. Some birds never fly. The Ostriches, Auks, and Penguins, arc possessed of small rudimcntnl wings, but they seem to have tliora but fur the purpose of conforming more nearly in external '■osomblanco to other birds. Some Mammalia can fly, although they have no wings. I’hc Bats possess a membraneous expansion, extending to the feet and to both sides the tail, hut supported chiefly by the humerus, the forc-arra, and the four fingers, 'rheso bones being greatly clongat(ul, serve to support the membraneous surface, which is of firmness and extent sufficient to riiisc and maintain these animals in the air, when ^ctod upon by the powerful musclcsj of tho breast. The first motion of a bird in atiempling to fly is an ordinary leap with the feet, Accordin'dv, those birds having the wings very largo and the feet very short, as wo observe in the Booby and the Marten-s, commence their flight with great ditliculty, as they cannot leap sufficiently high to obtain tho space nocc.ssary for tho extension of their wings. In flying, the resistance of the nir is in proportion to the mass struck at one time, this account the short-winged birds must repeal tlieir vibrations very frequently; they are therefore soon fatigued, and unable to continue thoir flight for a long time, '^'ben a birri attempts to fly, the humerus U first elevated, and then the entire wing, ''Inch had hitherto remained folded; while, at the same time, it is extended in a hcri- ^•onlal direction liy means of tho fore-arm and the last di\ision of the wing, corres- ponding to the foot of Quadrupeds. After the wing has thus acquired nil the super- bcial extent which it is capable of attaining, tho bird suddenly depresaos it, until it forms an acute angle with the vertical plane of the body, Bubtending tho ground. The air resists this motion, which is performed with groat rapidity, and produces a ^■paction of part of the force upon the body of the bird. Its centre of gravity then fise.s in the same manner as in other leaps. The wings may bo compared to a lever, ®f which the pectoral mu.sclca arc the moving power, and the body of the bird the "eight; while the air rcBisting, by its inertia, the action of the expanded wing, is the fulcrum. The impulse being once given, the bird refolds the wings by bending their joints, elevates them again, and gives a new stroke to the air. The force of gravi- tation diminishes the velocity which the body thus acquires in ascending, in the same manner a.s it affects every otlicr projectile. There consequently occurs a mo- ment in which tho bird neither ascends nor descends. If it seize this moment pre- cisely, and give a new stroke to the .air, Its body will acquire a new velocity, which will carry it as. far as that obtained hy the first impulse; it will then rise in a con- tinuous manner, and with a uniform velocity. If the second impulse of the wing commence before the impulse arising from tho first has been lost, the bird will ascend with an accelerated motion; or, if tho bird do not vibrate its wings at tho exact moment when the ascending velocity is lost, it will begin to descend with great rapidity. Yet tho bird may keep itself always at the same height by a series of equal vibrations, if a point be seized in tho fall so situate that the velocity which would have been acquired in descending, and the small space there would have been to reascend, reciprocally compensate and destroy each other ; but if it once allow it- self to descend to the point from which it departed, it can only rise by a much stronger exertion of the wings. In descending, the bird has only to repeat less frequently the vibrations of its wing.?. The darting of Birds of Prey is occasioned by their suppressing tho vibrations of tlie wings altogether, when the bird, being continually acted upon by the force of gi-avity, falls with an accelerated velocity. Wlien a bird in descending suddenly, breaks its fall, it is called a recover. Tho resistance of the air then increases in proportion to the square of the velocity, and the bird rises again. The preceding remarks apply only to flight when made in a vertical direction, either in ascending or descending. The Quails, Larks, and other birds which arc observed to fly upwards in a straight line, have the wings placed entirely horizontal ; but in the grc.'iter number of birds the wing is iuclined, and turned backwards. This inclina- tion may be further increased at the will of the bird. It is greatly assisted by the length of the quills, which enable the resistance of the air to act on their extremities with a mechanical advantage, while they arc the more elevated by it, from their fixed points being placed at the kisc. By this arrangement, birds are enabled to advance in a horizontal, as well as in a vertical direction, by a scries of oblique curves. The oblique motion upwards in flight may be resolved into two other motions, the one in a horizontal direction, independent of the force of g;!-avity, and the other in a vertical direction, opposite to that power. In flying horizontally, the bird rises in an oblique direction, and does not make a second movement of the wings until it is on the point of dcsccuditig below the line of the intended dirocUon of its flight. These par- tial movements, therefore, will not lake plaCe in a straight lino, but in a series of curves, nearly approaching to the straight line, and in which tl;e horizontal motion greatly prevails over the vertical. In ascending obliquely, tho wings move with greater ra- pidity; ill descending obliquely, their vibrations arc less frequent; and both of these motions are performed by a scries of curves. Some birds cannot sufficiently diininisli the obliquity of their wings, and with them the horizontal motion is always very considerable. "When tho wind blows strongly in the same direction with the flight of these birds, they arc carried to a very consi- derable distance. out of their intended ‘path. For this rcar.mi, those birds of prey which the falconers term nohhi are under tho necessity of flying against tho wind when they wish to rise perpendicularly upwards. The anterior quills of their wings being extiemely long, and their extremities pressing closely upon each other, the horizontal motion with them is proportionally greater than that of other birds. On the conlrary, w ith the ignohh birds the quills of tbe wings oi’O separated at their extremities, and permit the air to pass between them, which renders thu wing loss ca- pable of assuming the oblique position. De vialioiis from tho rectilineal path to the rigid and left, arc chiefly occasioned by tho unequal vibrations of the wings. When the left wing vibrates tho more fre- quently, or with the greater force, the left side moves mere rapidly, and the body necessarily turns to the right. Tlie rapid movement or groalor force of (he right wing produces a corresponding turn to the left. The difliculty of suddenly turning increases with the velocity of fliglit; and this arises partly from llie inertia of the body, which perseveres in its rectilineal course, and partly from the increased diffi- culty of making tho one wing to surpass the other in its velocity. For this reason, birds of rapid flight make great circuits in turning. Some will turn on the side, and make use of the tail as a rudder, when they wish to change the horizontal direc- tion. The tail of birds, when expanded, serves to sustain the hinder part of their body. When depressed during flight, the resistance of the air forms an obstacle wlildi raises tho hinder part of the body and depresses tho anterior; upon turning the tail upwards, a contrary effect is produced. As all Birds do not fly, so all Fishes do not swim, yet there ai*e many Birds which perform two motions, resembling those more particularly belonging to each clar-s. Aquatic Birds arc improperly said to swim; and tlie poet, describing tho swan sailing with tho breeze,” is perhaps not aware that Ida term is philosophically correct.' The bodies of Aquatic Birds are naturally lighter than water, from the great quantity of air which they contain within the abdomen, and from the feathers, which arc oily and impervious to moisture. They precisely resemble a boat, and have no further occasion for tho feet than as oars for moving forwards. As tho fore part of the body is completely sustained by the water, the legs are situate farther backw.irds than those of other birds, that thoir effect may be more lUrcct, as tlieir presence farther in advance would be superfluous. Tlie legs and thighs arc short, that ihc resistance of tho water to tho muscles may be as slight as possible. Tho tarsus, or instep, is compressed for cutting the water, while tho toes ai’c very much e.xpanded, or even united by a menibrauc, in order to form an oar of greater breadth, and capable of acting upon a greater surface of water; and when the bird inflects its foot in order to give a new stroke to tlie water, it closes the toes upon each other to diinhiish the resiatanco of the fluid. In diving, those birds arc obliged to compress tho breast with much force, in order to expel the air which it contains. Tho neck is then elongated, that the body may acquire an inclinatior forwards, while, by striking the feet upwards, it is forced 2S THE FIRST GREAT DIVISION. downwards. The Swan, and some other aquatic bird?, spread their vriiig.s to the wind, and use them as sails to diminish the labour of paddling. The body of the Fish is rendered of the same specific gravity as the water, by means of the air-bag or swimming-bladder. By the assistance of this organ, it can raise or depress its body in the water. When this air-bag is burst, the fish remains always on its back, and is unable to ascend. In an ordinary state, the fish is able to com- press the air-bag precistdy in the degree sufficient to enable its body to remain in equilibrium with the water, and to retain it. in the same horizontal plane. It com- presses the air-bag in a greater dfgrcc when it wishes to descend, and dilates this organ when about to ascend. This compressive force is accom]ilisliocl by the lateral muscles of the body, which tend to contract the bladder by elongating it. lu this man- ner, though the extent of its surface remains the same, the capacity can be diminished, since it is further removed from a spherical form ; and it is well known that the sphere possesses the greatest solid content of all bodies of equal surface. Some Fishes are capabic of having their air-bags so much dilated by licat, that when they remain for a long time on the surface of the water, exposed to the burning heat of a tropical sun, they cannot compress the bag in a degree sufficient to cuablo them to descend again. When the fish is in equilibrium with the water, and wishes to aflvance, its tail is bent in two different directions, resembling tlic letter S, by means of its strong and complicated lateral umsclos. It then augments the surface of its tail to the utmo.^t extent, by means of the dorsal, anal, and caudal fins. The tail is then extended with great velocity, the resistance of the fluid serves as a solid substance, a p-irt of this velocity is imparted to the fluid, and the body of the fish is propelled onwartls by the remainder of that velocity, diminished of course by the resistance of the fluid before the fish. But this Is not great, because the force with which it advances is much less than that employed io extend the tailj and also, when the tail returns to a right line, the fish presents to the fluid only the thickness of its body, which is by no means very considerable. It is necessary that the fish should bend its tail again to give a second stroke to the water. This motion, however, is directly contrary to the direction of the power by which the tail was extended, and produces in the fluid an equal resistance in the opposite direction. This resistance would be equally powerful, and would completely counteract the progressive motion of the Fish, if the surface of the body continued the same as before. But the anal and dorsal fins arc then laid down upon the body, while the caudal fin becomes folded and narrow. Again, the curvature of the tail takes place very slowly, wfiiln its extension is violent and sudden. On returning to the right line, the fall is bent a second time; but this takes place precisely in the opposite direction, and the impulse resulting therefrom h:is an equal obliquity only on the opposite side of that imparted by the first stroke. By this means, the course of the body is rendered straight; and, by striking the water more on the one side than on the other, the fish is enabled to move to the right or left, and to turn round horizon- tally. It docs not appear that the pectoral and ventral fins arc of very mneh use in the progression of Fishes, Tliey seem intended to aid in picserving them in a state of rest, or in equilibrium with the fluid, and they arc extended whenever it becomes ne- cesKury to correct the vacillations of tlie body. They arc used also in the slight turn- ings of their progressive motion, and in preventing themselves from falling on one side in swimming. Perhaps in those tribes of fishes where these fins are unusually large, they have some other uses, which a more accurate acquaintance with the habits of these fiahos would enable us to describe. Fishes williout air-bags experience a much greater difficulty in changing their ele- vation in the water. The greater part remain always at the bottom, unless the dis- position of their body enables them to strike the water from above downwards with great force. The Hays ('limuj elevate themselves wdth their large pectoral fins, which arc very properly termed wings, as these fishes use them in rai.sing themselves, precisely in the same manner as the bird elevalos itself in the air by means of its wings. Unlike the ether fishes, the Flat Fishes (I^leuronectes) arccmnpellcd to swim in an oblique position with the back on the one side and the belly on the other, in consequence of tboir eyes being placed on the same side of the head. In swimming, they acconliugly strike the water from above downwards. As both the Kays and Plcuronectes arc unable to strike the water conveniently to the right and left, they are compelled to make a succession of leaps in order to impart a horizontal dhvetion to the whole of their motions. The tail is struck downwards with great force, which elevates them sliglnly, and this force, combined with that of gravity, brings them back to the horizontal line after describing a curve. They depart from this lino by a new leap, in a manner similai- to the flight of Birds. The same means ore employed by the M'^hale and other Cetacea. It must be ob- sierved, tliat tlie boffius of these I^Iamnialia arc organized for swimir4ing as perfectly as those of Fishes ; but they differ from them in this respect, that the efforts of the tail arc made principally iu a vertical direction. The use of the air-bag is supplied by the lungs, wliich are compressed or dilatetl at will by the action of llie diaphragm and the muscles between the ribs. Serpents, and many of the Invcrtcbrated Aiiiniais having long bodies and no fins, swim in the same manner as Fishes, by suddenly in- flecting their bodies. The Quadrupeds, Aquatic Birds, and Reptiles, swim by means of their feet, which propel them onwards in precisely the same manner as a boat is moved by oars. When the oar b in a state of rest, it forms two angles with the side of the boat, and these may either correspond or be unequal. Ihe boatman moves the oar so as to render the anterior angle more obtuse, and the Idudcr one more acute. If the water did not resist by ils inertia, tho boat could not change its place; but as its resistance obstructs the motion of the oar, the angle iu question widens by the progressive mo- tion of the boat. When once tho iin|>ulst* has been given, tho boatman draws back his oar or turns its cd^e, that it may not interrupt the motion, and then repeats the same operation. The above dcscvq-.tion of the mechanical process iu rowing, is directly applicable to the animals just named, if we only consider their feet as oars, and their bodies as so many boats. The Seals, ISIorscs, and other Amphibia, swiiu the most perfectly of a:I the IMammalia; while they resemble the Cetacea and Fishes in the form of tlicir bodies more uearly than any other animals of the same class. In many Quadrupeds the mechanical power of the feet in paddling is greatly increased by membranes between the toes, as may be observed in the Otter and Beaver, but in general they swim simply by the action of the four limbs. Of these, tho hinder servo to urge the body onwards, and the anterior to sustain the fore-part of the body, which is tlie heaviest. As the weight of the head in Man is greater in proportion to the size of the body than almost any other of the IMammalia, he experiences greater difficulty in sup- porting his head when swimming than most of tiiesc animak, and he alone, of all Mammalia, seems incapable of swimming naturally, and without repeated trials. ANALOGIKS OF THE VEUTEBllATED ANIMALS. Idenihy of their Construction — Natural Scale of ^nhnal Orffa7iization Laws of Moiistrous Development, On stating, for the first time, to a person ignorant of Zoology, that all the Vertc- brated Animals are analogous to each other, he is apt to reject the assertion as para- doxical. He may ask, what analogy can exist between a Serpent and a Mainmiferou^ Qaadi'uped, or between a Frog and a Bird? If we answer, that they are composed of the same elements, of the same tissues, however different they may externally ap- pear, and that they arc all possessed of the same or nearly corresponding propcrticf, he may reply, that this is natural to all bodies possessed equally of life. It may be necessary Io explain that, when all the Vertebrated Animals are stated to be analogous, it is meant that they arc composed of tho same constituent mate- rials, and that, to a certain point, each similar organ is formed of the same number of pieces. By this it is not meant that the^c animals are all possessed rigorously of the same number of organs, or of parts of im organ; on the contrary, many are alto- gether deprived of certain parts which arc found well developed in other species. It is evident that the Boas, destitute of limbs, cannot resemble in this respect the Fishes provided with fins, or still less the Maniraalm, possessed of four limbs. It is only asserted, that when we investigate the corresponding organs of these animals, wc find them to he composed of the same materials, and of the same constituent pieces. It is unnecessary at present to allude particularly to the internal organs of animals, such as the muscles, arteries, and viscera, as every one is aware that a certain degree of analogy prevails in their internal parts or entrails. It is only necessary to point out some of the leading organs of the animal body, to be assured that there exist undoubted points of analogy in their structure. In attempiug to trace these analogous parts, it is convenient to select young animals, or rather tlie unborn embryos, in preference to the adult animals, because the identity and similarity of tho original and essential outline become gradually disguised by those characters, which afterwards form tho distinctions of genera and species. The exlmial coverings of the Ycrtebratcd Animals appear at first sight destitute of every pretoiigion to analogy. We are struck with the remarkable differences between the scales of the Fsh, and the feathers of the Bird, or between the shield of the Armadillo, and the glittering and delicate skin of the Eel. Yet, if we examine the first periods of the existence of these animals, they arc all equally covered w'ith a soft and thin membrane, — a simple or naked skin ; and, on tracing the subsequent changes which this envelope undergoes, wc arc led to perceive productions analogous to that same epidermis or cuticle, which invariably forms the external covering of each animal. Whatever changes the outward garb of the animal may undergo, whether it become hairy, scaly, feathered, cr covered with a shield, these arc merely subsequent modifications which the epidermis or outer skin undergoes in the course of its deve- lopment. In the skeleton, these analogies appear still more evident. Wc sec in all the Vcrlc- brated Animals a central column of bones, piled one over the other, called vertebra*; in all, certain projections or processes arise from these vertebra?; and among the greater number, these projections arc suflicienlly lengthened out in front of tho body to form ribs, and to constitute the walls of a cavity destined to contain the lieart and the lungs. All tliosc peculiaiitics appear greatly diversified in the different species of full-grown and perfect animals : but, if we look back to their origin, and investigate at the moment that ossification begins, wc find tliat tho first constituent elements arc identical — that the points of ossification are the same in all. This appears still more evident in the structure of the hc-ad# of animals. It seems difficult to conceive that the heads of the Crocodile and of the Sparrow are composed of precisely the same number of pieces as those of Man, or any other of the Mammalia, If we were only to compare the skulls of these several animals, iu their permanent .vlult states, we should be compelled to admit that their differences were more numerous than their analogies, ami they would then appear to differ as much in their details as in their general form when taken as a whole. But uponoxainining these several heads at the period when they first begin to ossify, they exhibit tho most perfect similarity in the number of pieces of which they arc thus originally composed. It would doubtless form a deeply interesting object of inquiry, to ascertain tho cause of this remarkable contrast in the results, while the materials aro identical, and whence it arises that so great an analogy among the elements finally produces sueli evident differences in ihc final structure, and in its progress towards comjdeiion. 'I’he cam*®* ho^YCver, is involved in impenetrable obscurity; such is the constitutum of Nature, and we arc only left to ascertain the facts, without venturing to speculate upon tbe cause. Thu essential pieces of tho skull are at first of the same number in all the Verte* brated Animals; but they have neither tho same form nor size. A certain pa^*’ which iu one species Is excessively reduced in .size, takes an extremely large volume in another; and this part, which in some is so greatly developed, occasions the neigh- bouring parts to become abortive. There are some heads in which the vomer and the bones of the nose arc as largo os the frontal bone ; yet these bones do not on tin* ANIMALIA VEllTEP.RATA— VERTEBRATED ANIMALS. 29 account lose their distinctive characters. Another cause of variety in the ultimate development, while there is a perfect similarity in the primitive elements, arises from this circumstance, that the dllToront portions of these honeys remain isolated in certain species, while in others the greater iiumher of scattered pieces become grouped to- gether, and coalesce into one hone. These modifications are pariicularly realized in the bones of the Skull; as it was especially necessary that this soliil covering should Iw modified so as to suit the pijculiaritics of the brain and the other essential organs, w hich it was destined to enclose and to protect. This instonco ts not solitary; the other pieces of the skeleton arc similarly modi- fied in their arrangement, to eoi respond with the adjustment of the more important organs. In the Fishes, for example, we find that the bones of the breast follow the respiratory organs into their appropriate situation, and are grouped along w'illi them in the vicinity of the head. AVithout disturbing the order of Nature, it was inipossiblo that tho air, when dissolved in water, could retain that cluslieity bedonging to its gaseous form; it la unablo to rush by its pressure within the body of the fish, and to seek out, as it were, tho blood in tlio ri'.spiratory organ, for the purpose of purifying it. The gills ai'c accordingly placed in the vicinity of the jaws and it is only a 'vn axis, or else round an imaginary axis passing through the articulation. This kind of motion can only be found when the articulated surfaces are plain or spherical, ^ud the latter are alone capable of motion in every direction. Flexion or bending takes place when the extremity of the bone, farthest from the joint, approaches the tone which is fixed. The different kinds of torsion have been assigned different names; there is the hinge-joint (GingUmufi)i the ball and socket-joint (J^narthrosis or Arthrodia)y and tho rotating joint (Trochmdo.s), The manner in w liieli the head is attached to the trunk, the lower jaw to the head, and the several pai-ts of tho limbs to each other, differs in the several classes of ani- w»als. The head of the Mammalia is united by a hinge-joint to the neck ; in the Hirds it is connected by u ball and socket-joint. Even among the Mammalia them- selves the ariiculafions are found to differ. In I\Ian, tho radius of the fore-arm is con- nected by a ball and .socket-joint with the hum(?i us, at its one extremity, and it rotates 'ipon the other. But in tlie Uodentia, and many Paehydermata, the radius is con- **ected by a hinge-joint with tho humerus, and is immoveable at its other extremity. In some species those bones are even completely united. The second class of articulation (Synarthrosis) admits of no motion whatever; it W said to form a suture when two flat bones join each other by the edges; to be squa~ when the thin edge of the ono bone covers that of the other; dcniiculary when the edges are notched and indented together; and harmonic^ when they simply touch each other. We find, in the bones of the face and bead of Man, instances of these ^fferent kinds of aiticulation. Tho manner in which tho bones of tho skulls belong- to the several Mammalia are joined together, bears a great resemblance to that •observable in Man; and wc find, in all, that they have a tendency to ossify as their ages increase. A variety of this kind of articulation is found in the teeth of JIan and Quadrupeds. These are inserted like wedges into the cavities of other bones. I’o this style of connexion the name of Gomphosis has been assigned. There is no instance found in the human skeleton corresponding to that singular ^‘^d of articuliitiuu observed in tho nails of the Cats. These are inserted into small cavities in tho last phalanges of tho iocs, and at the same time they receive a pivot, or aniinence of the phalanx, into a small cavity of tlieir own, prepared to receive it. This ^’irious contrivance is also found in otlicr quadrupeds with powerful (flaws. We also ^**d it ill the tu^k of the Morse, where a small pivot is observed to project from the of tho ulvculi. "Iho third kind of articulation (Jmphiarthrosis) admits only of a slight and rc- 'fricted motion. This is not occasioned by the form of the bones, which arc perhaps perfectly adapted for free motion, but by the cartilages and ligaments which are placed between tin; hones forming the articulations, and uniting firmly with them. The ver- 'ebrui of tlie back exhibit this restricted motion ; but the bones of the pelvis arc Joined in such a miumcr as scarcely to permit any motion whatever, 'i’he bones of W’risl and instep ore considered, by some anatomists, to belong to this class; for, ^*»«gh they appear to be provided with a few smooth articulated surfaces, yet they confined so greatly by the surrounding ligaments, that they move upon each other '''^ith great difficulty and through a very narrow space. In the second and third kinds of articulation, the edges or surfaces of tho bones either come immediately into contact, or else they are hound together by a substance which attaches itself throughout their entire parts of connexion. Also, the perios- teum is continued from one bone to the other, and is more intimately connected at the place of their junction than at any other part. In this respect they differ wholly from the kind first described. The muscles which set these bones into motion are as various as the movements destined to be performed. Those composing the trunk of tho Elephant are unrivalled for the union of strength, variety, and delicacy. As the snout of most animals is incapable of performing any considerable motion, we are naturally struck with asto- nishment at seeing an organ, which appears at first sight to be merely a prolongation of the snout, performing all the offices of the human hand. This delicacy is owing to tho immense number of minute muscles which are arranged in various directions, and thus enable the animal to execute the various movements of the organ. Upon mail- ing a transverse section of the proboscis, counting the number of short muscles, and then allowing the breadth of a line for the succeeding ones, which is considerably more than their thickness, some estimate may be formed of the number of muscles composing the trunk of the Elephant; and, upon adding these to the number of bundles comprising the horizontal layers, they are found to amount to between thirty and forty thousand. The snout of the Tapir is formed on a similar principle, with an additional muscle, corresponding to that which raises the upper lip of the horse. In Monkeys, the muscle w'hich frowns (^c.orTvyutor supercilii') is large, and is fre- quently used, but without expressing tho feelings indicated by that action in Man. In most quadrupeds the muscles, moving the external car, are more strongly developed than in Man. They arc thus enabled to give a great variety of attitudes to that organ, which enables them to collect sounds in every direction. Most quadrupeds, after an agreeable sensation, will erect their cars, and depress them when displeased, in the same manner as the Horse is in the habit of doing. Those animals which possess the pow’er of rolling themselves up, as the Hedgehog, have a number of curious muscles for that purpose. The muscles of tho tail are generally strongly developed; especially in the Kangaroos, which use them for standing and leaping, and in the Monkeys hav- ing prehensile tails. A certain degree of similarity prevails between tho muscles of Man and those of all the other Mammalia; but this resemblance is, upon the whole, greatest between Man and tho Quadrumana. But we cannot fail to remark tho small development in the calf of the leg, and in the buttock, among the Apes, as these muscles arc inti- mately connected with tho upright posture peculiar to Man, and the beauty of the human form. Many muscles, however, are found exclusively in Quadrupeds. Thus the fleshy panniclc (pannicuhis cnrnostts)y that sub-cutaneous covering of the body, is of very great size in the Hedgehog, Armadillo, Porcupine, and all animals possess- ing the power of rolling themselves up. This cutaneous expansion is even found in tho Cetaceous tribes; and the inhabitants of the Aluntnm Islands are said to fabricate a thread of great delicacy from the tendinous fibres of this muscle, procured from the Whale. Certain muscles arc distinguished for their very great strength. Tims the Horse is enabled to kick backwards with very great force, owing to the great development of the Gluteus medius and Gemellus muscles. 'Ihe Mole is enabled to burrow under ground, and to throw up the earth, by tho great magnitude of the pectoralis majory hitissimus dorsiy and teres major muscles. There is also a curious arrangement In the muscles belonging to the epiglottis of the several Mammalia. In the motion by which we elevate and depress the hyoid bone and the larynx, tho muscles acting on the bones, ami other hard parts, may be Compared to ropes drawing a resisting object in a certain direction. Innumerable muscles of a complicated form may bo seen in the tails of these ApUvS having that organ prehensile. It is said that no less than two hundred and eighty muscles were discovered by Mery in the prehensile tail of a Corcopithecus. Although the manner in which the bones arc artieulatefl determines the motions which they arc capable of performing, yet if is by the nunibor and direction of the imwclcs attached to the bones that the motions performed by each b(jnu are fixed. The muscles are attached to tho hones by tendons. Tho fibres of which the ten- don is composed are of a closer and denser texture than those of the muscles, and of a silvery whiteness. B(;ing penetrated by fewer vessels and no nerves, its substance seems altogether gelatinous. It possesses neither irritability nor sensibility, aiul forms tho passive link, by means of which the muscle acts upon the bone. Portions of teudou are found both inside and on the surface of several muscles ; and even those tendons, by which the muscles are inserted to the bones, penetrate a certain length into their fleshy substance, where they are interlaced in various manners. The term aponeurosis has been applied to those tendons which are broad and thin. 'J'he ten- dons have a great affinity for pliospbate of lime, which they often absorb with facility when their action is frequently repeated, and when employed to execute violent mo- tions. This frequently occurs with the Jerboas and other animals, which constantly leap witli their hinder limbs. It is considered probable that all the elementary muscles exercise an equal force at the moment of their contraction; but the degree of force with which a musclo can b© exercised greatly depends upon the manner in which its fibres are disposed, and the situation of the muscle itself, in respect to the bone or part it has to move. We therefore cannot estimate the force of a muscle by its mass, or by the number of fibres of which it is composed, but must also consider the com- position of the muscle and the method of its insertion. Tho muscles are cither simple or compound. In tho simple muscles all the fibres have the same disposition. The most usual are the ventriformy having all the fibres nctirly parallel, and forming a long bundle of a round form. The fleshy parts swell in the middle, forming the belly of the muscle, and becoming smaller at each extremity, where they terminate in tendons. Another kind of simple muscle consists of those that arc flat, and have parallel fibres, forming a sort of fleshy membrane, which is terminated by aponeuroses or tendinous membranes, instead of ending in small ten- dons. Both these kinds sometimes have ttmdons or aponeuroses in their middle, or in other points of their bodies. It is obvious that, in cither, the total action of tho muscle is equal to the sum of all the particular actions of the fibres; and that, if tho 32 FIRST CLASS OF THE VERTEBRATED ANIMALS. a/!tion experiences any mechanical disadvantage, it arises from the mode of insertion, and not from the composition of the muscle. This is not the case with the two other kinds of simple muscles, the radiated and penniform. The radiated muscles are those which have their fibres disposed like radii of a circle, and which proceed from a base more or less extended, while they incline to- wards each other, and are inserted in a s'.nall tendon. The penniform muscles have their fibres disposed in two rows, unitin'^ in a middle lino, and forming angles more or less acute, so that they resemble in some degree the arrangement of the feathers in a quill. The tendon forms the continuation of this middle line. It may be easily perceived that, in the two last-mentioned kinds of muscles, the total or resulting force is less than the sum of the component forces ; and that, if wo take successively the Icngtlis of every two fibres, which unite in producing one angle, as the measures of their individual forces, the diagonal of the ultimate parallclograra which may be formed thereon will represent the entire resultant, m quantity and direction, belonging to the fibres of the whole muscle. When several muscles unite in one common tendon, tho result is called a com-^ pound muscle. Those muscles may be similar in their nature, but sometimes they are formed of very different kiurls, such as the radiated and the ventriforra uniting to form one compound muscle. Wo may, then, estimate the particular action of each according to the preceding observations, and the total action can then bo estimated according to tlie degree of their inclination. Other muscles, again, are styled comp/i- cated: these may have only one belly with divided tendons; or they may have several fieshy parts, wherein the tendons are interlaced in several ways. The absolute force of the muscles is determined from these several dispositions; but it is their insertion which determines their real effect. Tiie muscular insertions may be referred to eight distinct classes: — 1st, the fleshy envelope; 2d, the sphincter or ring; 3d, the curtain; 4th, the rotatory; 5th, the rope; 6th, the lover of the first kind; 7th, the lever of the second; and 8th, of the third kind. The first four have a striking similarity, in their being all formed of a girdle, or portion of a girdle, which contracts upon the sun‘ounding parts. 1 . The diaphragm and abdominal muscles arc instances of the fleshy envelope. Being destined to compress thesoft parts contained in a certain cavity, they envelope that cavity in every direction, in the form of membranes or bands. When all the fibres act siinuitanoously, it is for excretory purposes ; but they usually act alternately, a:id then the effect is to enlarge one cavity and to diminish the other. Thus, at each iuspii'a- tioii the abdomen becomes wider and shorter, while the contrary happens on each expiration. The heart, arlcries, and intestines, have muscles of this'kiud; and the muscles moving the tongue in Man and Beasts must also be referred to this class. 2. The sphincter muscles are calculated to widen or contract some soft aperture. Some of them surround the orifico like rings, and others are inserted in a manner, more or less directly, upon the •edges of the opening. If the muscle bo uniformly dis- tributed around the orifice, it always preserves its figure, and is dilated or contracted always in the rame manner. But when these muscles have different directions, and make different angles with the edges they have to move, the form of the aperture is v(n*y variable, as wc may see in the lips of iM.m. No animal possesses so great a mobi- lity of this pai't, and none can therefore possess so expressive a physiognomy. 3. The curtain muscle is scon ii» the eyelids of lilan and other IMammalio. When these muscles arc placed in the body of the membrane, which is destined to cover some other parts, their structure is such as we have just described; but when they are situate externally, they have the form of very complicated pullics, as will be explained when we come to treat of the Eye in Birds. 4. The rotatory motion of the muscles may bo seen in the means by which the globu- lar mass of the eye is rolled and supported on every side. 5. The rope muscle has already boon alluded to, in speaking of the larynx, and may be rogardi>d as the most advantageous form in which a muscle can be applied. 6. 7, 8. ^^’hen a bone intended to be moved is articulated at any particular point, it cannot be elevated or depressed iii a direct line, but must be* considored as a lever having its fulcrum in the articulation. Thu bone forms .a lover of the first kind when tlio articulation is between the two extremities, and the muscles arc placed at one of them, as wc may observe in the muscles attached to the olecranon and heel-bone. But the most usual case is when the articulation is at one of the extremities of the bone; and then the most favorable position for the muscle is when it rises from another bone parallel to that which it has to move, or which forms with it only a very small angle. ThU is rhe case with the muscles between the ribs {iittcrcosiale^)^ and several others. Yet these muscles possess a degree of obliquity which considerably diminishes their power. The muscles closing the mouth of Man may also be com- pared to those just mentioned with respect to their small obliiiuiLy; but they are in- serted much nearer to the point of support than tlie former, a circumstance which also considerably dirainiahes their force. The most usual kind of insertion is where a miijcle attached to one bono is inserted into another, which last is articulated either mediately or immediately with the first, and may be extendofl until they both form a Unu, or inflected so as frequently to make a very small angle. This mode of inseiitioii appoiu's to be the roost disadvantageous of all in respect to mere force, on account of the obliquity of the insertion when the moving bone ia extended, and also on account of its proximity to the fulcrum. The first inconvenience is partly corrected by tho heads of the bones. Their articular extremities aro usually enhtrged, so that the tendons of tlio muscle, by turning round a convexity, in order to be inserted below it, form more obtuse angles with the lever, or body of the bone, than would be practicable if the head did not e.xifit. Uy this means tho obliquity of their insertion is diminished, and rendered less variable. The proximity of the fulcrum was necu-ssary to prevent the members from being moustrottdy large in the state of flexion, but particularly for producing a prompt and complete flexion. As the muscular fibre loses only a determinate fraction of its length by contraction, if the muscle were inserted at a greater distance from tho joiiii;, the moveable bone would only be approximated to the other by a small angular quantity. On the contrary, by inserting it near the apex of the angle, a very small contraction occasions a considerable approximation. Velocity is gained in proportion as the space through whidi the muscle acts is diminished. In this manner, muscles of this kind exorcise a power which surpasses all imagination. There are many instances of muscles inserted at a considerable distance from the fulcrum, especially in tho short bones, which must be completely inflected. The ver- tebr® and phaLiuges of the fingers arc in this situation. Muscles extended from the one to the other of those bones would not have produced a sufficient degree of flexion. In the phalanges, the fingers would have been two thick. It was also necessary that the tendons of these muscles should be attached to the bones over which they pass. If this were otherwise, it would happen that, whenever the phalanges were bent so as to form an arc, the muscles with their tendons would remain in a straight line, and form its cord. We may hence perceive the necessity of the annular ligaments, the sheaths and perforations. The last-mentioned arrangement occurs solely in tho fluxions of the fingers and toes of iilan, Quadrupeds, and some other animals, and consists in the muscles which have to extend farthest being placed near to the bones, while thoir tendons, perforating those of the muscles, are inserted at a shorter distance, and lio over the .first. When there are only three phalanges, there is but one perforation. The muscles moving the tail in the Quadrupeds arc placed at a great distance from it; but their long and slendjr tendons are inclosed in sheaths, which they do not leave excepting immediately opposite the points into which they are to be inserted. The whole of the Mamtnalia have flie upper jaw fixed to the skull ; and the lower one is composed of only two pieces, articulated to the tempo- ral bone, by a projecting part [called the condyloid process.] By the elongation of tho condyles, which fit into the z)'gomatic process of the tem- poral bone, this joint is nearly restricted to tho motions of a hinge, alternately raising and depressing, while the lateral motion is only just sufficient for the grinding of the food. There is a single or double bone, found in most Mammalia, called the intor-maxil- lary bone, but of which Man is entirely destitute. In these animals tho upper jaw- bones do not touch each other under tho nose, nor do they contain all tho teeth, hut the intur-raaxillary bone is wedged in between the former, and contains the incisive teeth of those animaU possessing them. The size of this bone varies surprisingly in the several orders and genera of Mammalia, being small in the Walrus and many Car- nossiers, but large in tho Beaver, Jlarmot, Hippopotamus, and Cachalot, but especially in the Wombat. In tho Ornithorynchus it is constructed of two pieces in the form of hooks. This bone is seen to exist in animals altogether destitute of tooth, and is also found in such Ruminantia as have no incisive teeth in the upper jaw. Some ana- tomists have doubted whether the upper jaw-bones and inter-maxillary bones are not the same, and that the latter is merely the anterior or incisive portion of the former. Thu latter opinion appears to bo the more probable, as the division is found in tho human fmtus, while, in some quadrupeds, the two bones are frequently seen to coa- lesce. Tiio lower jaw surpasses all other bones in the variety of its forms among the diflurent ^lammalia. It possesses very strong projections on the under side in the Wombat; .and we may remark in tho Cercopilhecus Beelzebub, and other Brazilian IVIonkeys, a remarlcablc lateral development of the bono, which assists tho larynx in the emission of that extraordinary deafening sound peculiar to these animals. In the Ornithorynchus, the anterior part of the lower jaw is shaped like a shovel. An intimate relation may be observed between tho kind of food with which an ani- mal is nourished, and tho motions performed by its lower jaw; and these again are greatly influenced by the form of its condyles. Thus, Mammalia living on vegetables possess a power of moving their lower jaws from side to side, so as to produce that grinding effect necessary for pulverizing and dividing grain, and for bruising grass. These animals are in this way able to move their lower jaw in almost every direction, by the form of the condyle, and of the cavity to which it is articulated. On the con- trary, with the Carnassiors, wo find that the lower jaw is altogether incapable of any other motion than simply downwards and upwanls, being destitute of that lateral grinding motion attendant on mastication in its most perfect form. Thus, while the teeth of the Herbivorous quadrupeds may be compared to the stones of a mill, the move- ments of the teeth, or rather tusks, in the Carnivorous quadrupeds greatly resemble the dividing motion of scissors. The neck consists of seven vertebrte, one species excepted [the tbree- toed sloth] which bus nine. A great variety is found in tho number of their vertebr®, excepting those of the neck. In the Cetacea, where the nock is very short, the bodies of the Cervical Ver- tebr® are extremely thin, and form by anchylosis one hone ; so that the original number of vertebrar, with their processes, can scarcely be perceived. In Quadrupeds having long and flexible necks, such as the Camel, and Camelopard, the spinous processes of tho vertebrre of the neck are small, or they are nearly obliterated. A peculiar sub- stance of great strength, called the Ugamcnlnmnncha:, is attached to the necks of the larger quadrupeds. By mcAna of this elastic body, the great weight of the head is sup- porteiL In the Elephant, it is of a very great size. The short-neckcd Cattle have double tr.ansveraa processes, and in the bodies of tho Cervical Vertebra*, both of Rumi- nating animals and Horses, there is a longitudinal rtdgo running along tho front. With Carnivorous animals, the ligamcnittm nuchts is small ; and as the pendent position of their heads require strong muscles for their support, the Cervical Vortebrjc have thoir transverse processes very large and flat, both in tho front and back, and thus afibrfl places of attachment for tho muscles of the neck, as well os for those which contribute to open their mouths. The length of the neck docs not depend upon the number of the cervical verte- brae; for, as wc have alrcaily observed, this is nearly always the same in most fupeds. In general, we find the length of the neck to be such, that, when it ^ added to the head, their united lengths am exactly equal to the height of the anim^i from the ground. Were this otherwise arranged, quadrupeds could not easily have reached cither the herbs on which they feed, or the water they must drink. 1 hulk of the head, in all those animals where this rule is observed, is very nearly an inverse proportion to the length of tho neck, else the muscles would bo unable t® elevate the bead. This rule, however, is not adhered to in such animals us lift ikorf THE MAMMALIA— MAN AND BEASTS. 33 food to tHc mouth by means of hands, or of feet constructed somewhat similar to hands. Neither do we find it in the Elephant, where the proboscis is substituted for hands, nor is it to be found in the Cetacea, which obtain their food in water: the latter possess the shortest necks of all the ^Mammalia. It appears singular that the number of cervical vertebraj should remain constantly the same, although the necks of different animals differ so very widely in length. In Msm, we sometimes observe the vertebrae of the back and loins to vary from their usual number, but never those of the neck. The Dorsal Vertebrae are very large and long in all quadrupeds with long necks and ponderous heads, especially in the Horse, Camel, Elephant, and Camelopard, which arrangement seems necessary to afford a place of attachment for the Ugamentum nucha. The number of Lumbar Vertebric varies exceedingly in different Mammalia; and when the length of the body is remarkably great, it is usually occasioned by a greater or less number of those vertebr® of the loins. Their motion is more or less restrained in nearly all quatlrupcds; and this is effected by the exterior side of each posterior articular process being directed backwards, so that the anterior articular process of the next vertebra falls between two prominences. The shape of the body in animals, whether slender, short, or thick, is chiefly determined by the length of the loins, and this again depends upon the number of the lumbar vertebrne. The anterior ribs are attached in front by cartilaginous portions to a sternum or breast-bone, composed of a certain number of vertical pieces. Some of the ribs are attached only by the hinder extremity to the spine, and are called yh/jc or shaking rihSj to distinguish them from the true, which are united to the sternum. The ribs of the Mammalia vary greatly in number. In no instance is the total number less than twelve, being the number in the human skeleton. The horse has 18 ribs, being 8 true and 10 false; the Elephant has 20 ribs, being 7 true and 13 false. The strength of the spinal column, and its consequent ability to sustain great weights, depend very much upon the size of the ribs, and upon the figure which they give to the rest of the body; accorilingly, we find that in the large herbivorous quadrupeds, which are usually employed as beasts of burthen, the ribs arc thick and broad. Those quadrupeds which have no clavicles have less curvature upon their sides than the others. Being never required to use the anterior extremity as a pre- hensile member, the chest h narrowed and flattened upon the sides, especially towards the sternum, whereas Mammalia with clavicles have their chest shaped nearer to the human form. The ribs are remarkably strong and compactly set in all quadrupeds destined to roll themselves up when attacked by other animals. In all Mammalia, they have only a very limited motion upwards and downwards, and their articulations are strengthened by a great number of ligaments. There are capsules at each articulated extremity of the ribs, which retain them upon the bodies .Tud transverse processes of the vertebraj. They are further secured by means of two ligaments, the one being inserted into tho transverse process of the superior vertebra on the inside, and tho other into tho low'er articulating projeetiem of the same vertebra, but on the outside. By this means the cavity of tho chest is rendered secure, as well as by tlie capsule which unites the ether extremity to the prolonged cartilage of the breast. There is also a ligamentous expansion between the ribs, connecting the lower edge of the one rib to the upper edge of the next. In all animals, excepting perhaps the I^Iai’mot, tho thorax or chest is narrower than In Man, and deeper from the spine to the breast. I’his peculiarity arises from the greater length of their breast-bone, and the less-marked flexure of their ribs. The flamelopard, and other animals having very long legs, possess the kecl-likc form of the chest in a rem:u'kable degree ; this is especially observable in the Door tribe. Tho Sternum, or Breast- bone, differs generally from that of man, in being composed of a greater nmubor of pieces, and in being rounder and narrower. It is also longer in proportion to the rest of tlio body. In tbe Mole, the sternum Is remarkably thick and strong. To enable this animal to excavate the eartli for the admission of its ^ody, the anterior portion of the clavicle is comj»rcssed upon the sides, so as to give it fho form of a ploughshare. It projects heyoiui tho line of the first rib, and thus enables the animal to burrow with singular rapidity. The anterior extremity of the Mammalia commences in a shoulder-blade, "hich is not articulated, hut merely suspended m the flesh; often resting On the sternum, by nu!ans of mi intermediate bone, called a clavicle. The anterior extremities, or f*acuum would, on the contrary, be formed between the pleura puhnonalis or external covering of the lungs, and the pleura costalis or internal lining of the ribs. But the lungs are highly elastic and free in their motion, so that atmospheric air rushes into and dilates the cells, exactly in proportion to the expan- sion of the area of the chest. When any cause prevents the air from rushing into tho lungs, death by suffotyitlon or asphyxia is occasioned. On examination, the lungs are found collapsed, as during expiration ; tho right cavities of the heart, and the veins ‘leading to them, are filled with dark blood, while the left cavities of tho heart and the arteries are nearly empty. In animals of the first class, which are hanged, death is occasioned by strangulation, and not by apoplexy, as is frequently supposed. This was proved by Gregory, who opened the windpipe of a dog, and passed a noose round his neck above the wound. The animal, when hanged, continued to five, and to breathe through the small aperture; but he died when tlic rope was attached below the wound. 31. Richerand asserts that a respectable surgeon in the Austrian army had informed him that ho once saved the life of a soldier by performing tho operation of opening the wmdpipc, a few hours before his execution. The soldier, feigning to be dead, was cut down, delivered over to tho surgeon for anatomization, and thus finally escaped. The glottis through which the external air rushes into the lungs, is so small that it may be readily obstructed when the epiglottis rises during the act of swallowing, and the substance swallowed may stop up the mouth of the larynx. Anacreon, tho celebrated poet, was in this manner suffocated by a grape seed, and Gilbert, also a poet, met his death in a similar manner. The organ of voice, in the Mammalia, is always at the superior extre- mity of the Trachaea or windpipe; — a fleshy prolongation, called the velum palati or palate-curtain, establishes a direct communication betw'een tlie Larynx and the back part of the nostrils. “ The human voice,” says Sir Charles Boll, ** commences in the Larynx, but rever- berates downwards into the Trachea, and even into the chest, whilst it may be directed with different effects into the cavities of the head, mouth, and throat. The organ of voice is neither, strictly speaking, a stringed instrument, nor a drum, nor a pipe, nor a horn, but it is all these together; and we will not be suipriscd at this complication', if we consider that the human voice is capable of every possible sound, that it can imitate the voice of every beast aud bird, — that it is more perfect than any musical instrument hitherto invented; — and, in addition to every vaiuety of musical note, it is capable of all combinations, in articulate language, to be heard in the different nations of the earth. The essential and primar)* parts of the organ are the vocal cords, or thyro-arytaRiioid ligaments. Tho membrane lining the larynx is reflected over these ligaments, so as to be drawn by them in their motions ; and this is what is meant when it is said the organ is like a drum, for those membranes must vibrato in tlie air. 1’be muscles of the arytaenoul cartilages draw tight the vocal cords and their attached mem- branes, and thus give them a certain tension ; and the air being expelled forcibly from the chest at the same time, they cause a vibration of these ligaments and incnibranos. This vibration is communicateti to the stream of air, and sound is produced. This sound may revorberat© along all the passages from the lungs to the nostrils; but unless there be a certain vibration in these cords of the larynx, there is no vocalization of the breath. For example, a man in whispering articulates the sounds of the mor® breath, without the breath being vocalized and made audible by the vibrations in the larynx. In singing, the vocalized bnKith is given out uninterruptedly tlirougb the passages, the rising notes in the gamut being produced, first, by the narrowing of tb® glottis, and secondly, by the rising of tho larynx towards the base of the skull. I*' the. graver notes, the larynx is drawn down, and the lips protruded; and in the higher notes the larynx is elevated to tho utmost and the lips retractetU” Tho various sounds emitted by different animals, to which we assign the terms roar, bray, bowb pm-r, scream, whistle, bark, grunt, snort, and hbs, are all caused by peculiarities the construction of their vocal organa, which will be explained hereafter. As the Mammalia [generally] reside on tho surface of the earth, wher® they are exposed to moderate variations of temperature, their coverinS ot hair is but moderately thick ; and in many of the animals inhabiting warni countries tliis integument is generally deficient. The Cetacea, wbid' live entirely in the water, are, however, the only species wherein it altogether wanting. The abdominal cavity of the Mammalia is hung round with a metn- brane called tile Peritoneum, and their intestinal canal is suspended to fold of this peritoneum, called the Mesentery, containing numerous con- globated glands, in which the lacteal vessels are ramified. Another pt®' duction of the peritoneum, called the Epiploon, liangs before and beneath the Intestines. Thp uses of these several parts are precisely the same in the other Mammalia as Man ; hut their form and extent depend upon tho convolutions and length vf intestinal canal; and therefore its reflexions, which form the omentum and tb® THE MAMMALIA— MAN AND BEASTS. 37 onvelopos of tlio intestinal canal differ greatly among the several quadrupeds. There are lateral omenta in some of tlio quadrupeds, which hybernate, such as the Polish and Alpine Sfarmots, in addition to the usual omenta of other quadrupeds. They arise from the loins, cover the sides of the abdomen, and advance nearly to its centre. These processes of the Peritoneum become loaded with fat. about the period that the animals remain torpid, and the fat is entirely expended during the time of their hybernation. The use of these lateral omenta is sufficiently obvious; yet it is very singular that other species which sleep during the winter, and are nearly allied to those just mentioned, such as the Garden Dormouse (Myoxus nitela) and the com- mon Dormouse (Myoxus aveUanarius) are destitute of them. L'urine, retciiue pendant qiielque temps dans unc vessie, sort, dans les deu-x sexes, a un tres petit nombre d’e.\ceptions pres, par les orifices de la generation. In nil the Mainmtdia [with the sole exception of the Monotremata] the generation is essentially viviparous. Immediately after conception, the fatus descends into.the Womb, surrounded with its membranes, of which the exterior is called the chorion, and the interior amnios. It is fixed to the sides of this cavity by one or more folds of vessels called the placenta, which establish the communication with the mother, from whom it derives its nourishment, and probably also its oxygenation. In the earlier periods of gestation, the foetus of the Mammalia possesses a small vessel, analogous to that which contains the yolk of the Oviparous ani- mals, and receiving supplies from the vessels of the mesentery in a simi- lar manner. Ils ont aussi une autre vessie exterieure, que Ton a nommee allantoide, et qui communique avee celle dc l’urine, par un canal appele I’ouraquc. La conception exigo toujours un accouplernent efiectif, od le sperme du male soit lance dans la matricc de la femelle. The young are nourished for some time after their birth by Milk, a fluid peculiar to this class, and produced by Mammj?, or Breasts. This secretion commences at the moment of birth, and continues as long after- W’ards as the young may require. It is from these Mammas that the class has obtained its name of M.vMJiii'iinES, or Ma.mmalia. This being a cha- racteristic peculiar to the animals composing this class, serves to dis- tinguish them more precisely from the remaining classes than any other external character. It remains, however, still doubtful whether the Monotremata possess nmmnite or not. hfockcl could find no traces of Mamtnm in tho male Ornythorynchus, hut thought he perceived them in the femiile. “ I detected, on the right aide of the .viidomini'il muscles," ho observes, “ ti smnll round mass, which at first bore the appeai-anco of a Vortion of intestine accidentally flushed into this situation. I was satisfied that this gland was a true Mamma, an ojiinion which was more forcibly impressed upon my mind from its slruc.liire and situation, from its marked development in the female, and the want of it in the male, or at least its existence in so minute a degree as to have hitherto eluded tho closest examination.” Oken and De niainville asserted, d priori, ttud without having ever examined a female Ornilhorynelms, tlial its Mamma) must exist, and would no doubt be discovered hereafter, on account of the very numerous analogies which this animal presents to the other Matnmalia. Sir Evorard Home describes tho Mamin.'o of the Ornithorynehtis in the Philosophical Transactions for IR02. On tho other hand, M. Geoffroy considers that these org.ans arc not real M:unmm, hut arc analogous oidy to tho lateral glands of the Museardin (^Myoxus avcllanarins.j Again, the Ornilhorynehus is either ovijtarous or ovo-viviparous, which properties are tdways connected with the absence of Mamma;, and its bill evidently appears unfitted for sucking ; so that, upon tho w hole, it must still be considered as doubtful whether those organs really perform the functions of Maniuuc. Although the .Alammie arc always found, with the above exception, in tho females, yet the males of many species tire destitute of them, as the Hamster (Cricctus vul~ Soris)^ and the Lemur mo/i^or, W'hilo in some others, as the Horse, they are found in ■tu unusual situation. Tlie Mamma; arc frequently less numerous in the male than in the female. Milk has often been secreted in the breasts of Blen, as well as of other "tale animals, such as tho Goat, Ox, Dog, Cat, and Haro. Blumcnbach describes a he-goat which it was necessary to milk every other day for the space of a year. It is Very common to finil milk in the breasts of newly-born children of both sexes; and ^hc same circumstance has likewise been observed in tho calf and foal. In the Oetacca and Marsupialia tho IMamma; do not project so as to form udders or breasts, but they lie flat under tho skin. In general the fliammni; arc very observ.ablo “d'y during the peiind of smdiling, at which time they are largely distended with ■"'Ik, exciqit in those .animals having them placed upon the (dirat, when they possess that graceful and delicate form observable in the human female of the Caucasian race during the bloom of youth. It is very difficult to discover them in the Marsupiiil ani- "'u's, except at tho period when the young are actually contained in tho abdominal I’oucli of ilie female. Tlie number, as well as the position of tlio Mannuoe, varies greatly in different animals. It would appear that there are frequently twice .as many *uats as tlm number of young usually produced by each animal. Yet this rule is not vutliout sevend exceptions, among wiiicli may be included tlm Guinea-pig (Coma and Domestic Sow. Indeed it is among tlie domesticated races tliat lose exceptions are chiefly found. Tims, according to Iluffon, tlic mammee of tho ‘‘Ow- vary from ten to twelve; of the Cow from four to six; of the Hat from cigiit to I”"' The Mare and Ewe may have from two to four, wliile tlie Ferret sometimes ‘US three on tho rigid side, and four on the left. From these examples wo may ri'adiiy perceive tlmt no fixed law' is observed in the number of tlio mamma;. 10 OlVISION or THE CLASS MAMMALIA INTO NINE ORDEE3. 1. Bimana — 2. Qitadrumana — 3. Carnassiers — 4. Bodentin — 5. Edentata — 6, Marsupialia — 7. Eachydermata — 8, Rummaniia. — 9. Cetacea, Those variable characters, which establish the essential differences of the Mammalia among themselves, are derived jointly from the organs of touch and from those of mastication. The forms of the hands or feet chiefly determine the degree of their agility and dexterity, while those of their teeth not only correspond to the nature of their aliments, hut draw along with them innumerable otlier distinctions, relative to the digestive organs, and even to the intellectual functions. The degree of perfection in the organ of touch is estimated by tho number of the fingers, their capability of motion, and the extent in which tlicir extremities are enveloped in a nail or hoof. A Hoof which entirely surrounds that extremity of the finger nearest to the ground, blunts its sense of touch, and renders it incapable of grasping an object. The opposite character is found in the Nail, composed of a single layei', which covers the one side only of the extremity, and leaves to the other the' utmost sensibility of touch. The nature of their ordinary food is determined by the form of the Molae or Cheek Teeth, and this always corresponds to the mode in which the jaws are articulated. In order to cut flesh, the Molars must be serrated, or saw-like, and the ja^s united in the manner of scissors, which can only open and shut. On the contrary, in order to crush grains, it is necessary that they should have Molars with flat crowns, and jaws capable of moving horizontally. It is .also requisite that the crown of these teeth should possess that kind of inequality which the millstone acquires, that its substance should be of different degrees of hardness, and that some of its parts should wear away more rapidly than others. All animals with Hoofs [thence called Ungclated] must of necessity be herbivorous, that is, po.ssossed of Molar teeth with flat crowns, because the structure of their feet prevents them from seizing a living prey. It is different with those animals said to be Unguiculated, from their possessing Nails. They are susceptible of several varieties, and may partake of different species of food; but they differ still more from each other in the extent of motion possessed by the fingers, and the delicacy of their touch. There is one characteristic which exercises a mighty influence on the degree of their address and means of industry — that is, the power of opposing the thumb to the other fingers, for the purpose of seizing smnll objects, which constitutes it a Hand, properly so called. It is in Man, whose fore-e.vtremity is entirely free, and capable of being employed in seizing, grasping, or holding, that this power reaches its limit of perfection. These different combinations, which determine rigorously the nature of the different Mammalia, have given rise to their subdivision into the following orders: — THE ONGUICULATED MAMMALIA. 1 . Bi.mana. — Man alone possesses hands solely at his fore-extremities, and at the same time is privileged in many other respects, so as to entitle him to the first place among the unguiculated animals; his lower extre- mities alone support bis body in a vertical position. 2. Quadeumana. — The order next to Man possesses hands at all the four extremities. 3. Caenassiees. — The third order has not the thumb free and oppos- able to the other anterior extremities. All the animals of the above orders possess three kinds of teeth, namely. Molars, Canines, and Incisors. 4. Rodenti.a. — Tlie fourth order differs but slightly in the structure of the fingers from tlie Carnassiers, hut it wants the Canine Teetli, and the Incisors are disposed in front for the peculiar kind of mastication, termed Gnawing. 5. Edentata. — Next follow those animals having the fingers very much confined, and deeply sunk into large nails, which are often very crooked. They also have the imperfection of wanting Incisors. Some also want the Canines, and others have no teeth at all. 0. Maesupialia. — This distribution of the Unguiculated animals would have been perfect, and might form a chain of some regularity, if Now llollmul [and .'America] had not furnished ns with a smidl collateral chain, composed of animals with I’oeches. All these genera resemble each other in the whole character of their organization, yet some of them correspond to the Carnassiors by the structure of their teetli, and the 38 FIRST CLASS OF THE VERTEBRATED ANIMALS. nature of their food ; others agree with the Rodentia in these particu- lars, and others again with the Edentata. THE CNGUEATE0 MAMMALIA. The animals with Hoofs are less numerous, and at the same time less various in their structure. 7. Pachydermata, or Jumenta, comprise all the hoofed animals which do not ruminate. The Elephant, though included in this class, would properly form a class of itself, which is allied to the Rodentia by some remote analogies. S, Rusiinantia. — The Ruminating animals form a veiy well-marked order, from their cloven feet, their four stomachs, and the absence of true Incisors in the upper jaw. THE SEA-EEASTS. 9. Cetacea Finally, we arrive at the Mammalia altogether desti- tute of hinder extremities. From their partaking of the form of the Fishes, and their aquatic life, we should be led to constitute them a separate class, did not the remainder of their economy resemble the Mammalia in every respect. These are the Fishes with warm blood of the ancients [the Sea-Beasts of the present day], which unite the strength of the othe'r Mammalia to the advantage of being sustained by the watery element. It is accordingly in this class that the most gigantic animals are found. The characters upon which these orders are founded will be seen more clearly in the following Analytical Table: — DIVISION OF THE CLASS MAMMALIA INTO NINE ORDERS. CLASS I MAM.MALIA. CONTAINING MAN AND BEASTS, WITH WARM BLOOD; HF.ART WITH TWO VENTRICLES; FEMALES SUCKLING THEIR YOUNG WITH MILK, SECRETED IN BREASTS OR MAMIDE; VIVIPAROUS, EXCEPTING THE MONOTREMATA, WHICH ARE EITHER OVIPAROUS OR OVO-VIVIPAROUS. Orders With nails or claws. Limbs Four, • I Without Marsupial bones. [With Marsupial bones, „ f With less than four stomachs. With hoofs, J , . L [ With tour stomachs. Limbs Two, r With two hands. • 1. Bi.mana. With three kinds of teeth, ^ With four hands. • . 2. Quadrumana. < (. Without hands. , 3. Carnassiers. Without canine teeth. « • • . . . 4. Rodentia. , Without incisors, « 5. -Edentata. 6. Marsupialia. 7. Pachtdermata, 8. Ruminantia. 9. Cetacea. GENERAL REVIEW OF THE MAMMALIA. External relations of the Mammalia to the other Classes, and to each other, — Usage of the terms Mammalia, Beast, Quadruped, Bimanous, Quadruinanous, and Cetaceous. — Further subdivision of the Mammalia into Families and Tribes. In the preceding outlines, the internal oi'ganization of the ULuumalia, and the leading principles of their classification, have been briefly explained. We shall now proceed to consider, in a general manner, their external relations to the temaining classes of animals and to each other. In those saperfleial characters, which strike the observer most forcibly at first sight, the Mammalia present many traits which aro to he found equally in the odior Classes, a fact which is not sufficiently adverted to in ordinary discourse. Thus, by tlic term Beast or Quadruped, it is usual to understand an animal covered with hair, and having four feet; and whenever a Bird or a Fish is referred to, the feathers of the former and the scales of the htter olfer themselves readily to the imagination. Yet these external characters by no means serve to distinguish the several classes of Vertebrated xknimals. The property of having four feet, which is possessed by a large and unportant portion of the Mammalia, is not confined solely to them. Many oviparous animals belonging to the Third Class ("KepIiVioJ possess the same character- istic; and in this respect the four-footed Beasts of the earth, which approach Man so nearly in their other characters, and occupy so high a place in the economy of N ature, are not superior to the Lizards and Frogs. Again, the Armadillocs (Dasijpus), instead of being covered with liair, are armed with a solid covering like the Tortoises, or even like the Crustacea. The animals of the genus Mauis are covered with scales not very different from those of the Fishes, and the same structure is found in the tail of the Beaver (^Castor Fiber.) The Porcupines (Hgstrix), and the Hedgehogs (Erinaceus), aro covered with a species of sharp quills, without feathery fibres on the extremity, but having the tube very like that of Birds. The Cetacea, or Sea- beasts, resemble the Fishes so forcibly in their external forms, that the uninformed portion of mankind persist in calling them Fishes in opposition to the universal deci sion of Naturalists. The Whale, Dolphin, Grampus, and other animals of this order, have nothing in common with the Fish, except the civcnmstanccs of their living in the same clement, in being destitute of hair, and in possessing that external form necessary for rapid motion in a fluid of considerable density. Yet the term MTiale- fishery will long preserve its usage among that numerous class of persons, who are apt to reject the critical observations of Naturalists, from their apparent over-refinement. • Nahire appears to evade, by the variety of her combinations, those obvious divisions which a superficial examination would lead us to form; and the Mammalia approach to the Birds, the Reptiles, the Fishes, and even the Crustacea, in the character of their external covering. This variety in the .superfioul appearance establishes clearly the necessity of seeking, in their internal organization, for the principles of classification. It has often been stated, that while Error lies on the surface. Truth must he sought deeply in the hidden parts ; and this assertion, which is only made mctaphoricaliy la reference to moral subjects, is literally true in Natural History. The Birds share their quills with the Hedgehogs atid Porcupines; and their long bills destitute of teeth, with their tongue, aro imitated by the trunk and tongue of the Aut-caicrs (Myrmecophaya.) The Reptiles are not alone armed svith a solid cover- ing. The Fishes share their scales with the Beaver and Manis, and their fins with the Seals (Phoca), the Morse (Tricheehus), the JIanatus, and the true Ceta- cea. The Birds have their powers of flight assigned also to the Bat; the crawling of the Reptiles and Eels is imitated in some degree by the slow movements of the Sloth (Bradypus) ; and the Fishes .share their powers of swimming with most Mammalia, but more especially with the tribe Amphibia, and order Cetacea. As the meanings of the terms Beast, Bird, Fish, and Quadruped, arc established by popular usage alone, they are necessarily destitute of that precision which should characterize the language of science. The term Mammalia, which has been gene- rally adopted by Naturalists, is much more wide in its signification than that of Quad- ruped; it agrees more nearly with the word Beast than perhaps any other term, although not exactly, as the latter term excludes Man, and the Cetacea are not always understood by the vulgar to be really Sea-beasts. The term Quadruped is still more improperly considered as synonyraons with Mammalia, with whiti, however, it is often confounded. In the last-mentioned class Man is included as well as the Cetacea, although he is a Biped, and they are altogether destitute of hinder limbs. The Ape tribes arc posse.»sed of four hands, and properly Quadrumanous. Even of those ani- mals which are, strictly speaking, Qu,adrupeds, from their walking habitually on four feet, many either frequent the water or are capable of supporting themselves in the air. The Seals and other Amphibia, although Mammalia, cannot properly be styled Quadrupeds, and the same observation applies to the Bats. The true Quadrupeds live exclusively on the land ; they may bo said to divide it with Man, whoso Nature they approach more nearly than that of the Birds, Reptiles, or Fishes. Bat we must observe that the term quadruped strictly supposes that the animal walks on four feet. If it be destitute of feet like the Maiiatus and true Ce- tacea, if it bo supplied only with arms and hands like the Ape, or if it possess wings like the Bat, the term Quatlrupcd ceases to be applicable. Man is the only Biped and Bim.anoas animal, because he alone possesses two feet and two hands ; the Mana- tus is only Bimanous, and the Bat is a Biped, while the Ape is Quadrumanous or four-handed. The Jerboas (Dipus), and Kangaroos (Macropus), cannot itropcrlj be styled Quadrupeds, because they can walk only on their hind-feet, in oonsequeneo of the fore-limbs being too short and weak. The signification of tiic term Quadru- ped is further restricted by removing all those animals which are able to use their fore-paws as a substitute for hands, such as the Bears ( Ursus), the Marmots (Arc- tomys), the Coatis (Nasua), the Agoutis (Dasyprocta), the Squinels (Sciurus), and the Rats (Mm); and those last-mentioned animals form a kind of intermediate class between the Quiulrupeds .and the Quadruinanous tribes. The term Quadruped is thus applicable only to one half of the Mammalia: it is totally inapplicable to at least one quarter, and is not strictly .applicable, in its full extent, to the remainder. The Quadrumana fill up the link which would .separate the form of Man from that of the Quadrupeds. Those auimal.<, with true clavicles, form another subordinate link between the Quadrumana and Quadrupeds; while the Bipeds with wings lead us tn the Birds. None of the vague terms of ordinary discourse correspond exactly 'sitk those nice distinctions which the philosophical student loves to trace m the works of Nature. As it is the leading design of classification to assist tho memory by a clear anJ lucid arrangement of Natural objects, it frequently becomes necessary to multiply suk' divisions in a few orders, which would be altogether superfiuous in the remainder. W this contrivance wo are enabled to arrive at general views in every department of Nature, and to remember a vast ma.s8 of phenomena not otherwise attainable. These subordinate divisions are termed Families or Tribes, and aro determined either bj some general resemblance prevailing throughout that whole department, or else by some particular character possessed by all the individuals included therein. Ik® THE MAMMALIA— MAN AND BEASTS. 39 selection of these characters is more or less arbitrary. No general rules can bo given for their institution, and they must depend chiefly on the skill of the Naturalist, Yet they are not altogether capricious, as will be readily seen hereafter. The gene- ral style of the objects under examination must be seized at a glance; and the groups must be strictly natural, or they will defeat the end for which they were insti- tuted. In the First Order (^Ttimana) Man alone is included ; and it admits, therefore, of no further subdivision. Tlie Second ( Quaclnmana) comprises the Monkeys, Baboons, Sapajous, Sagoins, Ouistitis, and Makis — animals which form a decidedly natural group, and all partake more or less of the same physical peculiarities. It is different with the Third Order {Carnassiers)^ being those IMammalia, without Marsupial bones, which have three kinds of teeth, and are destitute of hands. Among these wo find the Bat, the Mole, the Bear, the Cat, and the Seal; all which animals differ greatly in the subordinate characters of their 'structure, and consequently in their habits and external appearance. All the Carnassiers, as their name denotes, subsist either partially or entirely upon animal food. But some of them possess a remarkable fold of skin, w'bieh connects the sides of the neck with all the limbs, and the fingers of the anterior pair. This singular membrane confers upon the group the power of flight, exercises a remai*kablo influence over their general habits and struc- ture, and hcnco wo distinguish the first family. Cheiroptera. Of the remaining C.Triiassiers, some have their molar teeth with conical crowns; their habits aj*e subterranean or nocturnal, and they feed on Insects. These Car- nassiers form the second family, Insectivora, « We aie thus left only with those Carnassiers which arc destitute of a membrane fitted for flight, and whoso molar teeth are destitute of conical crowns. To these negative characters they join the positive one of being more decidedly Carnassiers, or of living mure exclusively on flush; for which reason they compose the third and last family, Carnii>ora. But this numerous and interesting family admits of further subdivision into Tribes. The rtontigrada walk on the entire soles of their feet. Tlie Digitigrada walk on tho ends of their toes. The Amphibia have their feet furnished with webs, which adapt them for an aquatic life. The Fourth Order (Rodenlia') is a very natural division, and docs not require to be subdivided, unless we wore to consider the presence or absence of perfect clavicles as a sufficient ground for tho institution of two tribes founded on this distinction. Tho Fifth Order (^Edentata) would remain undivided, did not the extraordinary peculiarities of tho Sloths (^Bradypua') authorise their separation from the ordinary Edentata, the former tribe being marked by its very long and crooked claws. The Sixth Order (^Marsupialia), among which we propose to include the Mono- tremata, forms a division of animals posses.sing marsupial bones, but at the same time partaking of tho characters of many of the preceding orders in general structure and habits. Their anomalous dentition renders any classification, founded upon this cha- racter, liable to some objections. It is, therefore, not without some hesitation that we venture to propose an arrangement, founded on the presence or absence of incisors and canines in the lower jaw. The first tribe (^Videlphida) has both incisors and canines in the lower jaw, and includes tlie genera DidelpliiSf 'ThijlacimxtSf Phascogalaf Easyurus, and Psi'ameles, all of which ai'o more or less carnivorous. Tho second tribe (^Macropoda) have incisors, but tho canines are either wanting altogether in the lower jaw, or else are very small. They live chiefly on fruits or herbs. In this tribe we propose to include the genera Phalangistay Feiaunts, Poto- rous, Macropus, LipuruSt and Phascoloniys. The third tribe coincides exactly with the Monolronata of M. Geoffroy St Hilaire, being destitute both of incisors and canines, and containing the two genera Eckidna and Ornithorynchits. Arriving at the Mammalia with Hoofs, wo find that, in the Seventh Order {Pachy- dermata), it is necessary to distinguish the remarkable proboscis of tho Elephant a character which establishes his claim to a separate tribe {Prohoacidea'), if not to a separate order. The solid hoof peculiar to the geuus Equus also gives rise to the formation of a tribe of SolipedxL, leaving the remaining genera to form a natural group of Pachydermata, or thick-skinned Mammalia. The Ruminantia or Eighth Order exhibit, in their four stomachs, and indeed in their entire conformation, that close resemblance which would render any intermediate divisions at present superfluous. The Last Order (^Cetacea) admits of further subdivision into the Herbivora, desti- tute of spiracles on the top of their head, and destined, by their dentition and general construction, to feed on marine vegetables; and the true Cetacea, with spiracles on the top of tho heath These subdivisions, and the leading characters on which they are founded, are shown in the following Table, with a few examples of each family and tribe, to enable the student to fix them more easily in the memory : Orders. 1. Bimana, 2. Quadiiumana, SUBDIVISION OF THE ORDERS OF THE CLASS MAMMALIA Families. INTO FAMILIES AND TRIBES. Tribes. 'With a fold of skin connect-' ingthe sides of the neck, with all the limbs, and the fingers of the anterior pair, 3. Car.nassiers,, ► 1. Cheiroptera, Without a fold of skin as above, Molar teeth, with ) ^ t . , >-2. Lvsectivora, conical crowns, J Molar teeth, with- out conical crowns Caunivoka, < "Walking on' Feet the entire with- solos of the I out feet. Webs, Walking on T the toes, J 1. Pl.ANTIGRADA, 4. Rodentia, Edentata, Feet with Webs, f Nails : I Nails 1 G. M. 7. P ARSDMALIA ACHYDEHMATA Nails long and bent, short, r r With incisors and canines, , J Lower jaw J With incisors, but tho canines wanting t t Without incisors or canines, . f With a proboscis ■; TTr-,, , L ■ f WiUi two or four hoofs on each foot, 1 Without a proboscis, , , , „ , „ ’ L I With only one hoof on each foot. or very small. 3- Ruminantia, 9 Cet icea I Without spiracles on tiie top of the head. Digitigrada, Amphibia, Examples. Man. . Monkeys, Lcniiu's. Bats, Flying Cats. . Moles, Hedgehogs, Slirews. Bears, Badgers. . Weasels, Dogs, Foxes, Cats. Tardigrada, Edentata (proper), Didelphida, . Macropoda, Monotremata, Proboscidea, . . Pachydermata (proper), SoLIPEDA, ( With spiracles on the top of the head. 1. Herbivora, 2. Cetacea (proper). Seals, Widrus. Squirrels, Mice, Hares. Sloths. Ant-eaters, ArmadiUoes. Opossums. Kangaroos. Ornithorynchus or Duck-bill. Elepliants. ' Rhinoceroses, Hogs. Horse. Camels, Deer, Sheep, O.xen. Dugong. Dolphins, Wliales. general review of the MA.MMALIA CONTINUED. Same popular and external characters of the preceding Tribes and Families. shall defer our observations upon the first order UniAHA, until wo come to treat of the physical history of Man. At present it is necessary to add a brief review of tbe superficial and external characters of those tribes and families which wc have onumcrated above. 2- QuAnauMANA Next to Man, but at a considerable distance below him, wo find the numerous tribe of Apes, from the Oran"- Outang to the Sagoins, all pos- S-ssed of hands on thcii’ hinder extremities, and if we except a few genera, also a thumb free and opposable. The latter characteristic gives them the utmost facility of climbing trees, and of grasping the branches. Accordingly, the Apes feed in general upon fruits and nuts. Some of the American species, such as the Sapajous, are capable of hanging to the trees by means of a prehensile tail, which twines around the branch, and enables them to swing with the head downwards. These animals, as well as the .Sagoins, are distinguished from the Apes of the old continent by a nose so broad and fiat, that both nostrils can be seen on either side. Among the Apes of the old Continent, wc find tho genera M.acacus, Inuus, Hilobates, Cercopithecus, tho ferocious Mandrills (7’opio), and several others. All these animals live in tiie forests of tropiov.1 countries, whore they form numerous bodies. They compose a 40 FIRST CLASS OF THE VERTEBRATED ANIMALS. tribe remarkable for its great resemblance to Man, and the natural propensity to imitate his actions — qualities which are combined with some degree of skill and intelligence, a singular liveliness of disposition, and innate fondness for mischief. It is said that they form regularly organized bodies in their native forests, and establish among themselves a kind of rude police for pillaging or gtiarding the fruits of the different districts. The females carry their young in their arms like the Negresses, and arc often observed to kiss them tenderly, and frequently to beat or bite them os a punishment. This close resemblance between the Ape and the human species when in the savage state, will hereafter become the subject of our consideration. The Makis, a branch of the Quadruraana, are diminutive like the Apes, whom they resemble greatly, both in manners and disposition, but are at once distinguished by their pointed muzzle. Tliey Uve mostly on Insects, and are marked by meagre and elongated fingers and arms. 3. Carn.\ssiers.— -After Ibis family we find the Bats, which bear a near relation to the preceding, both in general conformation,, and in having their mammae placed on the chest. Their wing-like arms, and their elongated fingers attached to a mem- braneous expansion, impart the power of flying, or rather of supporting themselves by a rapid succession of vaulting movements. They are all of a hideous aspect. The young cling to their mother, who gives them the breast even when flying. Unable, by the delicacy of their eyes, to endure the full blaze of day, they appear only at night, when they vault rather than fly after the insects which form their prey. In the warmer climates there are enormous Bats, which live also on the fruits of trees. All these animals hang by their thumb-nails in the depths of obscure grottoes, caverns, and other retreats, and in our climates they are observed to become torpid during the winter. The remaining tribes of Carnassiers follow the preceding races, and constitute two numerous, as well as interesting families. Among the Inscctivora, we find tlie Iledgehog-S (i?r first tribe of the Carnivora, we have the Bears ( Ursus)t the Badger (Mfles), and a few others — mostly animals of a surly and savage disposition, retiring during the wint^T into caverns and other obscure retreats. Among the Digitigrada, forming the second family of the Carnivora, we find the Weasels (il/uslc/a), the Otters (^Lvtra'), the Civets ( Viverrtt), possessed of a fine and glossy fur, a long and slender form, and a light step. Concealing themselves among crevices, they steal slyly upon their prey, whose blood they suck with delight. The animals of the Genus Alephitis exhale a most iDsupporl.ab]e odour. The Otters frequent the borders of streams or the sea shore, and seek their prey in the water. Among the move ferocious Digitigrada, we find the Wild Dog, Wolves, Foxes, and Jackalls ( Canw), with the Ilyajna — animals with a keen sense of smell, hunting togellH‘r in packs, and overcoming by force of numbers the most powerful beasts of prey. They present a haughty demeanour, an elevated head, and are tunment at onec for bril- liancy of instinct, and for sanguinary courage. In the. last quality they are only surpassed by the Lion, the Tigers, Leopards, Panthers, and the Lynx, all forming part of an extensive genus (^Fclis), of which our domestic Cat is considered the type. These animals arc enabled by their strong and retractile claws to climb with facility. Their head is round, their eyes glitter in the darkness of night, their tongue is roughened like a file, and their teeth are exceedingly powerful. They w.oit for their prey ; with a sudden spring they dash it to the ground, and enjoy with ecstasy the flesh yet throbbing from the breast of their victim, and the blood still warm from its heart. Among the Amphibia, which conclude the long list of Carnassiers, we find the Seals (Phoc- mal Kingdom, The chief benevolent emotions which the Carnivorous tribes present aro seen in the THE MAMMALIA— MAN AND BEASTS. 43 casual attachment to the females of their own species, the regard of the mother for her young, and that occasional language of signs by which they communicate their wants or their passions. If a Lion or a Tig(*r meet his mate at an unfavourable time, tiiey both become furious, and a conflict often fatal to one or to both ia the result. The circumstance of their both living by the chase renders them natural enemies to each other. This singular combination of love and hatred is wisely given by Nature to assist in preventing the too rapid increase of the more destructive animals. It is the organization of the Carnivora — the possession of teeth, of clawsi of short and narrow inicstinei — that imposes the office of Nature's executioners upon these ani- mals by an imperative necessity. The sharp teeth of thci Leopard or Panther might attempt in vain to grind plants : and even -when wc compel these animals to swallow bread and other purely vegetable substances, the gastric juice of their stomach is unable to dissolve them. On the contrary, the Lamb and the light Gazelle would refuse animal food with disgust. Their teeth arc not formed for tearing, and their entire economy is adapted to a vegetable diet. It is thus that we find, in the organization of the animal, the reasons for all its actions. This exquisite relation of all the parts of an animal to each other, enables the Na- turalist to describe the whole creature on seeing only a part. Thus, from knowing the size of a tooth, we can judge of the height of the animal which bore it; by the shape of the tooth we can tell whether it be carnivorous or herbivorous. Thence follow the general structure of the body, not only of tho stomacli and viscera, but also the form of their paw's, of claws with tho one, or of hoofs with the other, the livoUnoss of their passions, as well as the habits which attend this kind of life and constitu- tion. Besides the claws and teeth, which form the offensive arms of the Carnivora, they are endowed with superior strength, agility, cruelty, and treachery. The source of these qualities must be sought in the nature of their food — in the superior organization of flesh and blood. The herbivorous tribes want offensive arm.s in general, yet they are seldom of a timid or peaceful disposition. They love to unite together in social bands, to pasture on tke plains or by the mountain side, or else to hoard the common fruits of their industry. The carnivorous tribes, like tyrants, are unfitted for society by their ferocious and domineering tempers; they dread the rivalship of their own species, and the natural attachment of the. sexiw is witli them but a momentary passion. They can endure hunger much longer than the herbivorous tribes, wbo.se food is always spread out before them; and this power of fasting is necessary to animals obliged by their structure to overpower their prey by violence, to run them down by perseverance, or to surprise them by stratagem. They can fast for several weeks, but as their neces- sities increase they become bolder and more ferocious. Tho Wolf, with an appetite sharpened by famine, becomes an intrepid and formidable enemy. lie then invades the villa«-e.H, breaks into the stables during tho daytime, and even ventures to contend with Man. But when ho has found an abundance of nourishment, ho gorges himself for several days ; and, with an admirable sagacity, conceals tbe remainder under ground as a provision for future want. This continual use of animal food, and the high state of organization at which all tlie solid and fluid parts of their bodies have arrived, renders their flesh at once unpa- latable and unwholesome. Their excretions are all fetid, and the slightest check to the vital activity brings on a rapid decay. On tho contrary, the vegetable nutriment of the herbivorous tribes imparts to their flesh a high degree of delic.acy. Their milk is sw'cot, agreeable, and nutritious. Thus the herbivorous tribes yield an abundance of nourishment to Man, while he rejects with disgust tho flesh of those which are carnivorous. The natural antipathy of some of the carnivorous juiimals for each other, proceeds from tlieir rivalship in the chase. It is thus that tho Lion, Tiger, Panther, or Bear, permits no poachers upon his hunting grounds. These despots of the Animal King- dom allow few intruders to share their authority, and clear the forest of all those petty tyrants, whirh prey only upon small game; and which, like the inferior nohUssa of the inicUUe ages, oppicssed the lower ranks, and diminished the population. It is not among the larger animals of the forest alone," says Goldsmith with his usual elegance, “ that these hostilities are carried on; there is a minuter and a still more treacherous contest between ihn lower ranks of Quadrupeds. The Panther hunts for tho Sheep and tho Goat; the Catamountain for the Hare or tho Rabbit; and tho Wild Cat for tho Squirrel or tlio Mouse. In proportion as each carnivorous ani- uaal wants strength, it uses all the assistance of patience, assiduity, and cunning. However, the arts of these to pursue are not so great as the tricks of their prey to *^scape, so that the power of destruction in one class is itifevior to tho power of safety ■n the other. Were this ofhorwise, the forest would soon be dispeopled of tho feebler **aces of animals, and beasts of prey themselves would want, at one time, that subsist- ^•uce which they lavishly doalroyed at another. “ Pew wild animals seek their prey in the daytime; they are then generally de- terred by their fears of Man, in the inhabited countries, and by the excessive heat of the sun in those extensive forests that lie towards the south, and iu which they reign tile undisputed tyrants. As soon, therefore, as the morning appears, the carnivorous animals retire to tlioir dens; and the Elephant, the Horse, the Deer, and all the Haro l^'uds, those inoffensive tenants of the plain, make their appearance. But again, at ^•ght-fall the state of hostility begins, the whole forest then echoes with a variety of different Imwlings. Nothing can be more terrible tban an African land.'^cape at the close of evening; tho dccp-toned roarings of the Lion, thn shrill yelUngs of the 1'igcr, ^lic Jackal pursuing by the scent, and barking like a dog, the IlyEcna with a note peculiarly solitary and dreadful, but, above nil, the hissing of the various kinds of Serpents that then begin their call, and, as 1 am assured, malce a much louder sym- phony than the Birds in our groves in a morning. “ Beasts of prey seldom devour each other; nor can any thing but the greate.st degree of hunger nompol them to it. What they chiefly seek after is the Deer, or the Goat; those haiinloss croatiirea that seem made to embellish Nature. Tlicsc arc either pursued or surprised, and afford the most agreeable repast to their destroyers. most usual method, with even the fiercest animals, is to hide and crouch near some path frequented by their prey, or some water wiiere they come to drink, and seize them at once with a bound. The Lion and the Tiger leap twenty feet at a spring; and this, rather than their swiftness or strength, is what they have most to depend on for a supply. There is scarcely one of the Deer or Hare k’md that is not very easily capable of escaping them by its swiftness; so that, whenever any of these fall a prey, it must be owing to their own inattention. “ But there is another class of the carnivorous kind that hunt by the scent, and which it is more difficult to escape. It is remarkable that all animals of this kind pursue in a pack, and encourage each other by their mutual cries. The Jackal, Sya- gush, the Wolf, and the Dog, arc of this kind; they pursue with patience rather than swiftness; their prey flies at first, and leaves them for miles behind, but they keep on w’ith a con.stant steady pace, and excito each other by a general spirit of industry and emulation, till at last they share the common plunder. But it too often happens that the larger beasts of prey, when they hear a cry of this kind begin, pursue the pack, and, when they have hunted down the animal, come in and monopolize the spoil. This has given rise to the report of the Jackal's being the Lion’s provider; when the reality is, that the Jackal hunts for itself, and the Lion is an unwelcome intruder upon the fruit of his toil." It is in barren and unfrequented districts that the carnivorous animals are most fierce and sanguinary, because their prey is scarce, and the possession of it is continually disputed by a ho.st of famished rivals. From these continued scenes of violence their character acquires an unusual ferocity. The Bear of the Alps is a formidable and dangerous animal to the traveller. But the beasts that frequent the plains or fertile valleys find their food more easily, and when found it is less disputed. Their cha- racter being thus softened down by the comforts of life, loses that high degree of courage and asperity which distinguishes the mountain races. The carnivorous animals associate in troops only for the converdence of a combined attack; on tbe other hand, tho herds of herbivorous smimals seem intended only for their mutual defence. Placing the young ones in the centre, and the females in tho rear, the males advance to the front, united in a phalanx, and presenting their horns to the enemy, repel his attack with vigour, and generally with success. Most of the Frugivorous tribes, such as tlic Apes, the Makis, and the Loris, ramble about in numerous troops, for the purpose of pilliiging tho fruits of a district. Like expert marauders, they establish a regular order of pillage. They place sentinels in advance, and, forming a chain, pass the fruit from hand to hand. Upon the slightest alarm being given by the sentinels, tlie whole troop retreats to the woods or moun- tains, carrying off as much as they can hold in their hands and cheek-pouches. GENERAL REVIEW OF THE MAMMALIA CONTINUED. J)o)ncsiicated Animfxls are not Slaves — Methods of Taming Wild Animals — /«- Jlncnce of Mild Treatment — Hunger — Sweetmeats — Caresses — Chastiseyneni — Their Occasional llcvenge. Animals, whether domesticated or in a wild state, always preserve their real cha- racters, and act in a manner suited to their situation. The absolute submission which we are in the habit of requiring from our domestic animals, and that kind of tyranny which we exercise over them, have given rise to the belief that they are really Slaves. It is commonly supposed that our superior power compels them to resign their natural fondness for independence, to yield impli- cit obedience to our will, and to perform those offices for which they are adapted by their organization, intelligence, and instincts. We are in tho habit of attributing to our own influence tbe gulmiission obtained from these animals ; we are imagined to bo the source of those instmcls developed under domestication, and to have com- manded obedience, just as our superior power maintains them in captivity. This conclusion is, however, altogether fallacious. Judging from appearances only, we have confounded two things totally distinct in their nature, namely, Domestication and Slavery, Domestication is a state of freedom, and hence the difference between the human Slave and the domesticated Animal is as great as that between Slavery and Liberty. The domesticated animal makes use of its natural faculties within the limits marked out by its situation, in a manner exactly similar to the wild animal in the woods. Being never urged to act except by external causes, or by internal instincts, as soon as its will has conformed itself to the constraints of its situation, it makes no further sacrifice. The animal, iu fact, is not in reality in a different situation from what it would have been if left to itself. It lives, without constraint, in society with hlan, be- cause doubtless it was naturally a sociable animal. It conforms itself to the will of Man, within certain limits, because its herd would have had a leader in the strongest or most active animal, to whom submission would have been naturally paid. If a Dog is by our care rendered a good courser, it is because he was a himter by nature, and ^YG have only developed one of his original qualities. The same rule is observed in all the different qualities which wc impart to our domestic animals. They perform nothing which is not agreeable to their nature; in doing so, they only fulfil the ori- ginal purposes for which they were formed; they never acquire different qualities, and thus enjoy, under hlan, n perfect state of liberty. It is true that Man possesses an immense power over the domestic animals, and one which he often abuse.s. Yet he usually develops qualities natural to the animal; hence it acquires a degree of improvement unattainable iu its original state, and thus its condition really becomes ameliorated. Thus we may see tlie imnienso difference between Slavery and Domestication. The Slave is not only a social being, with the power of willing, but he is naturally a free being, whose mind cannot confine itself spontaneously to the situation in which ho is placed. Ho knows his condition, consi- ders its consequences, and feels its oppression. 'I he natural power which he pos- sesses of refit’cting upon liis situation, shows it to him in all its degradation. Ho fools that lie is in chains, that he cannot use his natural free-will, and that he is a (Ipjrvaded bcingi On the contrary, a domestic onhnal satisfies all its wants; hence it lives in a state of Nature, and is conformable to the situation in which it is placed. 44 FIRST CLASS OF THE VERTEBRATED ANIMALS. The Slave who is compelled to renounce his free-will is far from being in the same condition. Ho holds the same rank in the hloral as a mutilated being or a monster in the Physical World. The essential difference between these two states is further seen in the opposite means which are employed to enforce them. A Man can only he reduced to Slavery, and maintained in it, by violence; because it is the very nature of Liberty to be unre- strained. An animal can only be domesticated by kindness. Its will exists, and shows itself only in its wants, and it can only be acted upon through its necessities, cither by satisfying or enfeebling them. Violence is altogether useless in disposing a wild animal to obedience. As it has a natural aversion to IMan, from his being of a different species, it runs away, if at large, upon the first impression of fear which he occasions, and if captive, maintains a determined hatred towards him. It is only by restoring confidence that it can ever bo rendered familiar to him, and this can be effected only by kind treatment. It is thus that the social instinct of the animal becomes gradually developed, and its natural feeling of distrust of every thing which is new or strange becomes proportionately weaker. The methods to be adopted in taming an animal arc as various as the creatures themselves. Each process must be adapted to the peculiar likings of the animal. To satisfy its natural wants is one method which, iu the coarse of time, brings on its entire submission, especially when applied to a very young animal. The habit of receiving iU food constantly from our hands renders it familiar, and finally it becomes attached. But, except when very long continued, the attachments thus formed are but slight. The benefits which the animal thus procures it could have obtained of itself, had it been allowed to fulfil its natural disposition. As soon as we attempt to bend it to any particular service it runs away, and quickly returns to its original inde- pendence. It is therefore necessary, not only to satisfy its original and natural wants, hut, by creating in it new wants and cnjo}'ments, to render the society of JIan abso- lutely necessary to its existence. Hunger is one of the most powerful means of taming animals. As the extent of a benefit conferred is always in proportion to the want of the person relieved, so the gratitude of the animal is more profound according as the food jpven to it was the more necessary. This method is applicable to all the I^Iammalia. It gives rise to a feeling of affection on the part of the animal, and at the same time produces a physical debility w'hich reacts upon and enfeebles its WiU. It is thus that the education of Horses begins, when they have passed their first years in a wild state. On being first caught, a very small quantity of food is given to them, and at very long interva > of time. They hence become gradually familiarized to their keeper, and acquire a certain degree of affection for him, which he readily turns to his own advantage, and thus confirms his power. If to the influence of hunger that of delicious food be added, the empire of kind- ness becomes greatly extended; and this power arrives to a degree perfectly astonish- ing, if we can succeed in pleasing the palate of animals by any kind of confectionery or cookery, in a higher degree than could have been done by the best food attainable in their wild state. In fact, it is chiefly by means of dainties, especially of sweetmeats, that the herbivorous animals can be induced to go through those wouderful feats and exercises which may often be witnessed in the Circus. These delicacies influence the will of the animal to such a degree, that starvation and physical deprivations become no longer necessary. In a short time it acquires a high degree of affection for those who contribute to its enjoyment, and willingly per- forms whatever they may require. But the services rendered by animals do not always proceed from so selfish an origin. Caresses arc one chief means of gaining tlicir affection, which cannot be termed sensual, because these arc addressed to no particular sense. Their fondness for caresses is altogether an acquired taste. Ko wild animal requires them from others of its own species. Even among our domestic animals, we see the young rejoice at the approach of their mother, the male and female happy in each other’s society, individuals accustomed to live together pleased to meet again after having been separated; but these feelings are always accompanied W'ith much reserve, and they never extend to reciprocal caresses. It is from ISIan alone that they receive them, and their attachment to him increases with the strength of the acquired taste for them. The pleasure of animals maybe further heightened by a soft tone of voice, or even by touching their mommaj. All animals are not sensible to caresses in an equal degree. The Ruminating ani- mals seem but slightly influenced by them; the Horse, on the contrary, enjoys them with ecstasy; it is the same with many Pachydermata, and especially with the Ele- phant. The Cat is not indifferent to them; sometimes even it seeks them with ardour ; but it is unquestionably in the Hog that the influence of caresses produces the most marked results; and what is rcmaikable, all the other varieties of the genus Canis, which have been hitherto observed, shore this quality with him. M. F. Cuvier mentions,, that in the Menagerie rhi Roi there was a She-Wolf, upon whom caresses writh the hand and voice produced so powerful an effect as almost to amount to a state of delirium, and her joy was exhibited as much by cries as by move- ments. A Jackal from Senegal was similarly influenced when treated in the same manner; and a common Fox was so forcibly affected by them, that it was necessary to abstain from all demonstrations of this kind, as the result might have been fatal to the animal. It will be interesting to know that all these animals were females. It may be doubted whether we should consider the chanting of airs, or the sound of bells, amongst those artificial pleasures by means of which animals are gratified and captivated. The songs of the Camel-driver arc perhaps only the simple signs by which the Camels learn to mend or slacken their pace. That animals may continue to perform those acts of docility which we require from them, caresses must follow as w ell as precede their performance. The constraint employed in urging them to act would, if too long continued, have an injurious effect. It is then only by repeating their delicacies or caresses that the calmness and confidence is restored. When once familiarity and confidence prevail on the part of the animal by means of kind treatment, and that habit has rendered the sceioty of Man necessary to it, we may then venture to use higher degrees of constraint, and even to inflict punishment* But our means of severity are very limited. Wc can only use blows, with certain precautions to prevent the chastised animal from running away. Punishment always produces the same effect; it changes the disposition which we wish to suppress into fear. By the association of ideas, the former impression yields, or is entirely merged into the latter. It is alw'ays dangerous to carry the punishment of an animal to excess. Violent fear may either totally intimidate tho animal and render it for ever useless, or else it drives it to despair, and it becomes altogether ferocious and unmanageable. A Horse, naturally timid, if corrected imprudently, plunges in the madness of its fright, along with its rider, into the deepest abyss. The Spaniel when kindly treated is inteUigont, docile to its master, and in every respect fitted for sporting ; yet if an undue severity has been used in its education, it is undecided, hasty, or cringing. When once the severity of punishment has passed a certain limit, which varies in species and even in individuals, the animal begins to resist. In a moment, the instinct of self-preservation awakes iu all its force. Thus w© often see our domestic animals, and even the Dog itself, revolt against ill usage, and inflict the most cruel punish- ment on its perpetrators. Many instances might be adduced of vengeance inflicted by the domestic animals, especially by the Horse, against those who have ill-treated them, as well as the hatred shown by these animals, and the very long time for whicli this fueling of aversion has preserved its force. The cases are numerous and well known; and although they have long demonstrated that brutality is not the way to obtain ohe~ dience from animahj these creatures still continue to be treated as if it were unne- cessary to court their compliance. One example of an Elephant may be mentioned hero, which happencMl under the eyes of M. F. Cuvier. This auimal had been entrusted, when three or four years old, to a young man who took charge of it, and had trained it to perform various feats for the amusement of tho public. It paid implicit obedience, and seemed to feel a tender affection for him. It not only yielded, without a moment’s hesitation, to all his commands, but seemed absolutely unhappy without him. It rejected the attentions of any other per- sons, and even ate its food with sadness, when given by the hand of any other individual. While this young man remained under the eyes of his fatlier, who owned the Elephant, he always treated it properly; but when it was transferred to the Menayeris du lioU and that the young man was thus left to himself, his attentions diminished, the wants of the animal were neglected, anti in a moment of drunkenness ho wont so far as to strike the Elephant. The poor animal immediately lost its habitual gaiety ; it became so sad and dejected that it was supposed to be unwell. It, however, still obeyed the keeper, but no louger performed its exercises with the same alacrity as heretofore. Signs of impatience were sometimes shown, and then suppressed, as if two opposite feelings were in secret conflict; the animal became less disposed to obey, which in- creased the dbeontent of its lealor. It w.as in vain that order.*? were given to the young man on no account to strike tho Elephant, whoso former docility could only be restored by the kindest treatment. Vexed at having lost his authority, and in not being able to exhibit the feats of the Elephant with his former success, his irritation increased, and one day he struck the animal with so much brutality that it became excited to the utmost pitch of fury, and uttered such a yell that its terrified keeper, who heard it for the first time, was glad to escape its vengeance. Never afterwards would the animal permit him to approach; even at tho sight of him it became en- raged, and all attempts to manage it were un!iucccs.sful. It become wholly untract- able, and no longer could be induced to perform for the amusement of tho public. It thus appears that kindness on our part is absolutely necessary to dispose animals to obedience, and that interest as well as humanity agree in pointing out the same course for the proper management of their instincts. GENERAL REVIEW 0¥ THE MAMMALIA CONTINUED. Taming of the Mammulia^Forced Watches — Castration^SiLSceptibiUty of dif- ferent Tribes to the influence of Domestication — Formation of Domestic liucss — lielation to the Social Instincts. The different methods of taming wild animals pointed out in tho preceding section, arc completely applicable only to those animals which are susceptible of affection and of fear. Wlien animals feel a certain degree of attachment for kindness received, or when they dread the repetition of punishment, it is sufficient merely to rccal these emotions to produce an immediate effect upon their Will. It often happens, however, from the peculiar nature of individuals or of species? that certain habits or likings have acquired so powerful an influence, that no other emotion can maintain the ascendancy. With animals of this character, neither kindness nor punishment has any effect ; and if persisted in, they would tend but to increase iheir constitutional bias. It is only by acting immetliately upon their Will) so as to weaken the force of the ruling passion, that they can be rendered susceptible of gratitude or of fear. With tempers so refractory as these, the only means of domestication hitherto discovered are Forced Watches and Castration. Without proceeding to actual mutilation, it appears that of all methods Forced Watches exercise the most powerful influence in enfeebling tho Will of an animah and in disposing it to obedience, especially when united to a prudent combination of rew’ards and punishments. Animals may he prevented from sleeping by applying tbc whip more or less frequently, or still more effectually by a loud reverberating noise, such as that of a Drum or Trumpet, which must he varied so as to avoid the effect of uniformity. By keeping them long without food, and then feeding them slightly during their usual time of sleep, the same effect may also be produced. This method is applicable to all animals and to both sexes, although it docs n^t always produce the same result. The other method, that of Castration, applies to male individuals solely, and is absolutely necessary only with certain Huminatiug but chiefly with the Bull. THE MAMMALIA— MAN AND BEASTS. 45 All tho other animal appetites, which were given for the preservation of the indi- vidual, such as Hunger, Thirst, and the desire of Sleep, when opposed, load to an immediate physical debility on the part of the animal. Those passions, on the contrary, which were given for the continuation of the species, increase in proportion to the obstacles presented to their gratification. Hence it is only by depriving them of the organs from which those passions derive their source that we can bring them under our power. In fact, the Bull, the Ram, and other Ruminants, ran be domesticated solely after having undergone this mutilation. We may thus perceive the error of holding out the Ox and the Sheep as models of patience and submission. So far from this being really the case, the Bull and the Ram c.an only be used for propagation ; and we have merely succeeded in domesticating the females of these races. This operation is not necessary for Horses, although such as have undergone it arc generally more tractable than tlie others. The Dog loses by castration his entire vigour and activity; and this appears to be its usual effect upon other Caniassiers, for wo find tliat the domestic Cat is affected in the same manner as the Dog. It thus appears from the preceding observations, that we can only obtain an authority over animals by moans of their natural wants and propensities, by giving them a now direction, by developing, or else by annihilating them altogether. The very small number of animals which wo have hitherto succeeded in rendering practically meful, when compared with the total number of species, renders it ex- tremely probable that \vc have not yet carried the art of domestication to its extreme limit, and that hereafter we shall discover the means of training new species to our use, as well a.s more perfect methods of educating the old. It may easily be gathered from what has been alre.ady said, that the arts of taming present very different results when applied to animals of different species. There can be no comparison, for example, between the Dog and the Buffalo. The former is devoted in his attachments, submissive, and grateful; the latter wants docility, and indeed every benevolent affection. Between these two extremes, w’e may range in their order of susceptibility, the Elephant, the Hog, the Horse, the Ass, the Dromedary, the Camel, the Lamas, the Reindeer, the Stag, the Ram, and the Bull. Wo shall defer the further investigation of the peculiar characters of all these animals, until we come to dcsposition, which render them altogether incapable of yielding submission. Hence tiiey arc entirely excluded from the list of animals with whom Man could associate. A like exclusion must bo given to tho American tribes of Quadrurnaua, to the Maids, and to the Inscctivora, for the feebleness of their bodies would render them useless to Man, whatever suscep. tibility their dispositions might possess. But with regard to the Seals, it seems altogether surprising ihat Fishermen have not made use of tlioir instincts, or taught them to assist in fishing, in the same maimer as tho Hunter has brought up the Dog to aid in the chase. We inav pass ovt^r the intervening tribes ol Rodentia, Edentata, and Marsupialla. The feebleness of their bodies, and their limited intelligence, disqualify them from sharing our labors. It is different wltli the Pachydonnata, as most animals of this ordfU' liavc already been domesticated, or are fit to become so. The (fl'apir Amcricanus)i it is to be regretted, is still in an unreclaimed 48 FIRST CLASS OF THE VERTEBRATED ANIMALS. slate. Being very much larger than the Wild Boar, and at the same time much more docile, it would yield domestic races of far greater value than the common Pig, and of a different quality. Yet, as it presents but few means of defence, this valu- able animal is gradually becoming more scarce in America, where it is in great de- mand for the delicious flavor of its flesh as an article of food. Ik is probable that this important race, if not previously domesticated, will become totally extinct as America becomes more peopled. All the different kinds of Solipeda might bo rendered, with care, as domestic as the Horse or the Ass. The training and breeding of the Zebra (Eqjivs Zebra), the Quagga (E. Couagga), the Dauw {E. Montanvs), the Dzbiggiai {^E. Jlf^monns), would be a useful labor to society, and probably a lucrative undertaking for tlie pro- jectors. Nearly all the Ruminantia are social animals, living together in troops, and thus most of the species of this numerous tribe are fitted by their Nature to become domes- ticated. There is at present one species, perhaps two, which are now only partially domesticated in South America, and are nearly unknown in our climates. This is much to be regretted, as they would yield fleeces of great fineness, and at the same time be useful as boasts of burthen. The Alpaca (^Auchenia paco), and the Vicugna (Auclienia vicupna), arc more than twice as large as the largest races of our Sheep. The qualities of their fleece are very different from those of the ordinary wool, and might be made into stuffs possessing an intermediate quality between wool and silk. This would certainly give rise to a new branch of industry, and serve to extend the commerce of our nation. It has often been objected to the domestication of animals inhabiting warm coun- tries, that the differenc.^ of climate would form with us an insurmountable difficulty. This error might have been avoided, if the objectors bail been more aware of the re- sources of Nature in adapting animals to differences of temperature, as well as of our extensive influence over all living beings. In reference to the Alpaca and Vicugna this diflBcuUy could not exist, and the objection resolves itself into mere ignorance of their habitat; for these animals reside only on the very temperate parts of the Andes, in Peru and Chile. It is not even applicable to tho Tapir, although originally from the warmest climates. The nature of domestication has now been fully explained. We have seen that its foundation exists in the natural disposition of animals to live together in herds or troops, and to form mutual attachments; — that it can only be induced by kindness, chiefly by augmenting their wants and aftervi ards satis^ing them. Yet, by these means, we could only produce domestic individuals and not domestic races, if wo were not aided by one of the most general laws of living beings, — the power of transmitting their organic and intellectual modifications to their posterity. This is one of the roost rcraarkabla phenomena of Nature, and well worthy of profound attention. That an accidental modification of the body should become a permanent alteration of form is extraordinary, but that a passing desire or habit should become, in the course of time, an original instinct, is without doubt altogether astonishing. We have also seen the importance of studying animals in captivity, as connected with the progress of Zoological science. However the study of wild animals may serve to point out the part they have to play on the great theatre of Nature, it totally fails to discover their faculties and dispositions : we must resort to captive animals for this information. If it were true Uiat animals must he examined when at. liberty in order to ascertain their Nature, then the advancement of this branch of science is hopeless, as the difficulties of studjing wild animals .ire so great as to bo equivalent in practice to an impossibility. When at liberty they view with distrust every person whom they do not know, and either fly from or attack all who molest them. Again, animals could not be examined in savage and remote countries with wluch we arc altogether unacquainted. The mere circumstance of pursuing an animal alters its ori- ginal condition, and even then its natural state is as much disturbed as if it were really in captivity. If it be true that the state of an animal, in whatever part of the earth it may be placed, is the natural consequence of the faculties and instincts imparted by its Crea- tor, it follows, that if we have ascertained the latter, we may predict the former. As soon as we know exactly the general faculties and dispositions of the species, it is easy to state how it will act in every situation in which it can be placed. It be- comes no longer necessary for us to follow the animal into t)»e details of its existence, to visit the country of its residence, to find it out, and to hunt it down. Having once ascertained its Nature by Analysis, we can then apply the principles thus estab- lished Synthetically to every other possible case. This is the way in which all the sciences proceed, and Zoology can be properly cultivated only when it follow.^ a simi- lar course. Under whatever view the subject may be considered, we must arrive .at one con- clusion— that the examination of animals in Jlcnageries or Zoological Gardens is, of all methods, the best for studying and knowing them, as they ought to be investi- gated by the lover of Nature. GENERAL REVIEW OF THE MAMMALIA CONTINUEP, Analysis of the principles which guide the actions of Animals — Intelligence and In- stinct—Effect of Habit in transforming the character of Actions — /7i/c%c«cc of the higher Animals compared with that of Man. Before entering upon an analysis of the inward principles which determine the ac- tions of animals, it must, in the first place, be recollected, that our knowledge of the intellects or sensations of animals will rest ultimately upon tho consciousness of what passes in our own minds. It is only by examining that internal light which we possess within ourselves that we can arrive at any sati-ffactory conclusion. \Sc com- pare our own actions with theirs; we arc conscious of the internal cause which incites us to act, and we infer a similar cause in the animal. Should the Creator have be- stowed a faculty to animals altogether different from those we are conscious of possess- ing, it must remain concealed for ever from our thoughts. The boundaries of our own intellectual world form the limits of our knowledge regarding the causes which produce the actions of animals. Some of the principles which urge hlammalia to act arc evidently of the simplest kind. The cries of an Infant when in pain, or in want of assistance, — the determination of a newly-born animal to the brea.st and the action of sucking,— -the flight of a young animal when influenced by fear, although it has had no experience of danger, — its resistance when we attempt to aeixe it, — the attention of an animal just born to the cries of its mother, are all actions of this kind. AMiether simple or complex, they arise previous to all experience; and have been reg-arded, by the common consent of all Naturalists, as purely Instinctive. I’hey proceed from an irresistible and uniform internal power, which leads invariably to tho same course of action. But all the actions of animals are not of this uniform description. The Dog obeys and does not fly from the w hip which his master raises to chastise him. Ho seeks for the object which has been pointed out, instead of remmning indifferent to the order he has received. If he bo confined in a cage with wooden bars, he is agitated with rage and attempts to destroy them ; but if they are made of iron, ho lies down resigned to his confinement. All these actions ore Intelligent ; and it is the very nature of this Intelligence that it is capable of being modified by experience, and of conforming itself to the variable circumstances which incite it to act. Other instances of Intelligence may be mentioned. When a Horse has to choose between two roads, of which one is known to him, he always takes the latter, however long the period of time since he may have travelled thereon. The Dog leaps before his m.aster, and loads him with caresses, when he sees him preparing to go out, and wishes to accompany him. Tho same animal confines the flock, which has been en- trusted to his care, within tho precise limits marked out by his master, Tho Wolf attacks his prey openly and by force when in the recesses of the forest; but, if he be in the neighbourhood of a village, be approaches it cautiously, and attacks it by surprise. All these actions are evidently Intelligent, and not Instinctive. Tho slightest cir- cumstance would have induced the Horse to take the road which he had not previously travelled. If the Dog, by hia disobedience, had offended his master, instead of leap- ing before him with joy, he would crouch anti tremble at his feet. We also know that he acquires tlie remarkable talent of guarding the flock entirely from a previous education, and in being trained expressly for that purpose. On the contrary, it is the common character of Instinctive actions to bo fixed and invariable; ^o be constantly produced by the same causes and the same conditions. We accordingly consider the following actions as Instinctive ; — the Dog, when ho hides under ground the remains of his meal ; — the Horse and Reindeer, when they remove with their hoofs the snow which covers the earth, to expose tlie food of which they are in want; — the Cows, when they come together in a circle, upon the approach of an enemy, with their heads and horns in the circumference, anil their calves in the centre ; — the Beavers, when they build cabins and construct dikes, when they cut the wood necessary for their edifices, and repair the ravages which lime or an enemy has occasioned to their buildings; — the Rabbit, when it excavates its burrow; —the Bird, when it constructs its nest. All these actions, and many others, are presented to us with a certain degree of uniformity, essentially tho same in all its more important particulars. The Dog hides his food with the same blind Instinct, although its superabundant supply renders such a precaution unnecessary. The Horse or Reindeer that uncovers the gr.as5 or moss concealed under the snow, does the same thing when he sees the snow for the first time, and prior to all expe- rience; he acts in the same manner after a meal as when oppressed with hunger. The Beaver builds in all situations, under the closest confinement as well as when in the enjoyment of the greatest liberty ; when in the possession of the most comfortable abode, as well ns when in want of all shelter. The Cows, which exhibit so much ingenuity in defending their young when in a herd, do not change their plan of de- fence though surprised in a small party, and wiion this method becomes wholly insuffi- cient. The Rabbit which takes so much pains to burrow its retreat, knows not how to conceal it, or to adapt its construction to the changes of the seasons, to the cir- cumstances of the place, or to the nature of its enemies. Tho lower classes of ani- mals present instances still more striking and extraordinary of the blindness of their Instincts. Upon considering all the Instinctive actions of animals, we find that these are of » nature very different from their Intelligent acts. Instincts are exercised or exhibit themselves only at certain periods; theyarc always of a limited number in each species, but they go on increasing greatly in number and importance among the lower classes of animals, generally in pioportion as their organization differs from that of the human race. Numerous instances might be adduced in .support of those views. We at once per- ceive an immense difference between those intelligent actions which have already been enumerated, alike remarkable for their complexity, and those involuntary Instinct?, rJways of great simplicity, which arc ofcasioned by fear, passion, desire, or hunger. The hitter seem purely organic, — that is, they result from the direct influence of a superior Power, — ^whilo, to the former, Intelligcuco appears indispensable. It is also only at certain periods, and for a limited time, that those animals seek their females, prepare their abodes, or construct their nests. The Dog, the Horse, and the Bull present few actions which can be regarded as instinctive; yet their lives pass on with consi- derable activity. 1 heir intelligent actions nearly fill up their entire course, and arc sufficient for the numerous situations in which they are placed. We can perceive trace, among the Mammalia, of that diminution of Intelligence which results fro^’^ the prevalence of tho Instinctive acts. The Dog presents a great number of Intelli- gent actions, and only a small number of Instincts. The Bull, on the contrary, an active life within very narrow limits ; and though his Instincts are not positively numerous, they become relatively so, when compared with the very small number of his intelligent actions. But the marked difference between Intelligence and Instinct becomes still striking when we extend our views beyond the limits of the Mammalia, and consider 49 THE MAMMALIA- the entire Animal Kingdom. It is tlion wo shall perceive that the Quadrumana and Carnassiors, which stand at the head of the list, may almost he styled Intellectual, if compared-to animals of the lower divisions, whoso entire existence appears to he sway- ed by a uniform and constant force. Indeed, were not all analogies between mental and material phenomena altogether inadmissible, we would be disposed to compare tho Instincts of the inferior animals to those inert powers of Nature which form the prime movers of our own machinery. The most complicated Instinct of the Dog, requir- ing for its fulfilment the concurrence of the greatest number of intelligent acts, appears absolutely nothing in comp,ari3on to actions of this nature, which may he seen in tho Invertebratod animals, but chiefly among the Insects. In the Dog and other Mam- malia of tho higher orders, that Instinct which urges them to store up provisions for' future want, shows itself only in a few isolated acts. Among tho Insects, on the con- trary, their entire existence, however varied it may appear, seems composed only of one single invariable action, from which nothing external can divert them, and to which they seem invincibly urged by a superior power. None of the Mammalia exhibit in any of their actions such a combination of 3ag.acity, foresight, ,and skill, as might have been inferred from the industry of the Bee, did wo not sec in its actions, proofs of the existence of a Mind not its own, M^ero Man incapable of receiving evidence of a Creative Power in his own constitution, he must read it in that primiiplo which urges these lower animals to perform a complicated course of actions, continuing for days and months, — ever directed to one end, and that end invtiriably the same. He must Jtcrccive that Wisdom is not the sole property of Man, when ho finds profound com- binations, calculations of the greatest complexity, and tho most ingenious views, urging these lower animals to work with a degree of perfection which all his learning and experience, accumulated for a long course of ages, can scarcely equal. .\lthough we have said that Intelligent actions may be varied at the jdeasure of the animal, while, the Instinctive actions are irresistible, these assertions must bo under- stood with some qualification. While performing an Instinctive action, the animal always preserves tho power of using its senses, .and of exercising its Intelligence to tho degree natural to its species, and employs both in the manner most favorable for the execution of that Instinctive action to which it is actuated. •An animal is capable of exercising its Intelligence in a degree inversely proportional to the force of its Instinct. As the Instinctive wants become urgent, its Intelli- gence appears more fettered. 'I'heie is no comjrarisou, for e.xample, in the degree of Instinctive force between tho Hamster (Crtce/«»), which stores up magazines of pro- visions for the whiter, mid the Dog who hides his superabundant food. Nothing could divert, the H.imster from its purjiosc ; the slightest circumstance would cause tho Dog to neglect that precaution. Having pointed out the dilfercnce between Intelligent and Instinctive actions, we now come to draw the probable line of demarcation between the Intellectual powers of Man, and the Intelligence of the lower animals. We evidently perceive that animals, especially the higher classes, have the power of Attention ; that their senses receive impressions analogous to those we are conscious of experiencing in ourselves ; that their ideas follow each other in a certain regular order constituting a train of thought ; that a former idea can he recalled ; that their ideas are variously associated ; and that they can form some conclusions. This seems to ho the extent of their powers. We are, of course, reduced merely to conjecturo the intensity or qualities of their sensations or pereejitions, and are therefore unable to point out those qualities of tjodies which can ho perceived by Man alone. There is, however, one curious circumstance which may bo noticed in regard to the sense of Hearing. With animals it is a Sensation and not a Perception ; in other words, they are unable to refer sounds to an external cause. If a wild Bull or Horse feel himself struck violently, he makes no mistake os to tlie cause. He rushes immediately at tho person who has inflicted the blow, even when struck only with a stone nr other projectile, just as the Wild-Buar rushes upon tho Hunter, whoso ritlo-ball has struck him. But when captive animals, in course of taming, are tormented by a Drum or Trumpet to prevent them from sleeping, they have no perception cither of the in- strument from which tho sound proceeds, or of the person who plays it. They suffer passively, as if by some internal injury, where the cause of tho evil is within them- selves. It is curious that their head and ears are notwithstanding directed instantane- ously to tho precise quarter whenoo the sound proceeds. It is different wiih tho sensation of Colour. Tho Bull rushes at a piece of red cloth, in tho same manner as ho Would have done at an assailant ; from which we may infer, that when the Horse and Bull are unable to refer a .Sound to its proper cause, it is owing less to the distance wliioh separates them from tho instrument, than to the peculiar nature of their sense of Hearing. In other respects, they generally seem to have the same senses as ourselves, and to perceive analogous qualities in bodies. Their motions result from the qualities of their seu-sations; tiiey attempt to fly, to defend themselves, to seize, or to attack, iecording as they are moved by pleasure or pain. Being csp.ihle of forming certain relations to Man of a benevolent or malevolent character, they acquire a marked affection for those who treat them well, and a de- termined hatred to their tormentors. Some species form an attachment for each other solely from the habit of living together for some time, and frequently their mutual hatred arises from mere caprice. Tliese dispositions presuppose Mnniory, and at least some confused knowledge of the relations of thoso qualities which distinguish one person from another. They exhibit the internal affection of tlie moment by external signs, which are in general I'ery like those employed by Mall for tha same purpose. The Mammalia acquire from experience a certain knowledge of natural objects, of fiiosc which are safe or dangerous; they avoid the latter in consequence of this ex- perience, and of that memory from which it is derived, without being determined by mi Instinctive Attraction or Kepulsloii. This experience enables them to infer tha eenscquonce of their own conduct, when domesticated. They know that a certain ac- tion will be punished by their master, and that a contrary one will be rewarded. Their final determination does not proceed from any internal attraction, but often in direct opposition to some very powerful Instinct, and from the sole knowledge of the re« -MAN AND BEASTS. tvard or punishment which will follow. This knowledge, besides memory, also pre- supposes a power of reasoning from analogy, or of inferring that similar causes produce similar effects. Knowing well the power of their master, that ho can cither punish them or not, they assume before him a supplicating air, on perceiving him to be angry. Their passions and emotions react upon their involuntary functions in precisely tlie Same manner as with 5Ian. Surprise stops their respiration ; they tremble with Fear ; Terr-ir throws them into a cold perspiration; and Love agitates their frames. ■ They may be corrupted or improved by Domestication. Habits of ease or luxury create in them artificial wants unknown in the fields or woods. Education may fit them for actions for which they are not adapted by their structure. By proper training they may be rendered docile, mild, and active; or, if improperly managed, they may become more obstinate, passionate, stubborn, or lazy, than Nature had formed them. Ilacc Horses give evident proofs that they are actuated by Emulation, and Dogs dispute with each other for tho caresses of their master. The .Toalousy of tlie latter does not merely relate to the possession of their food or other enjoyments wholly physical, but also to tlie benevolent affections. ' The natural language of the Mammalia enables them to explain to each other the wants or sensations of the moment, and, in their intercourse with Man, they understand that more complicated language by wliich he makes known his commands. Not only do tho young know the cry of their mother when she gives notice of approaching danger, but they coiiiprchend a number of artificial words used by Man, and act in consequence. We have been acquainted with a gentleman who spoke to his Dog captivity. A most striking instance of tho inefficiency of mere force, in comparison to that con- fidence which is established by time, was often exhibited in tho Mi'magerie flu lUn. When the Moors of Barbary catch a young Lion, they are in the habit of bringing it up with a young Dog. These two animals become mutually attached, but especially the Dog to the Lion. As tho former grows faster than the latter, it ari-ives sooner at its adult state, that is to say, at that time of life when carnivorous animals acquire strength and courage. From this difference of growth, it follows that the Dog main- tains so great an ascendancy over the Lion as completely to direct the physical strength of tho latter, and he always preserves this power, especially if the Lion be of a mild and quiet temper. Other animals afford instances that muscular strength docs not always acquire the ascendancy; courage and perseverance are also means of obtaining the command. M. F. Cuvier hod a Cashmere Goat, which was placed in company with three other Goats, each of which was at least twice as largo and as strong as the former. Yet ilie little Goat managed to get the mastery over tho others, although in fighting he lost one of his horns, and thus was deprived of tho advantage whioh the others enjoyed of striking both to the right and left. But his fury and obstinacy were so great, that he ended by obtaining, through dint of perseverance, an authority os complete as if it had proceeded from an undoubted superiority of physical strength. Two of the Goats which be had subdued followed their little master every where, and when separated from him could not rest until ho was restored to them. Buffon relates a fact, authenticated in a letter from SI. Dumourticr, which show's how much the influence of animals over each otiicr is increased by time. “ The pater- nal authority among the Rabbits is much respected. I observe that all my Rabbits pay a great respect to their grandfather, whom I can easily recognise by his gray hair. His family have greatly increased. Those who have become fathers in their turn still preserve their submission to him. Whenever his sons fight together, whether for the females or for the possession of the food, the old grandfather, when he hears the noise 52 FIRST CLASS OF THE VERTEBRATED ANIMALS. runs at full speed to the spot. As soon as they perceive him, order is immediately restored ; and if he catches any of them fighting, he separates them, and makes an example of the refractory animals by immediate punishment. I may mention another instance of his influence over his posterity. For having always accustomed them to go into their holes on blowing a whistle, whenever I give the signal, however distant they may be, I observe the old grandfather to place himself at their head, and though he arrives first at the holes, he makes all the others defile in before him, and is always the last to go in himself.” It cannot be said that this authority on the one hand, and submission on the other, are instinctive. They depend upon accidental and variable causes. They often pre- sent opposite features in the same individual; and even the slightest change in the external appearance of the animals is sufficient to dissolve all harmony between them. A trifling circumstance of this kind would cause them not to know each other, and to recommence their battles. If two Rams which have long lived together in the most perfect harmony be shorn, they look at each other with furj', and rush together with such violenoc, that unless separated, they will fight until one of them either flies or remains dead on the spot. A boy belonging to thi^ Menagerie du Roi nearly lost his life only from changing his dress. He had acquired an absolute authority over a Bison from North America. His command alone was sufficient to make this power- ful animal go in or out of his stable, and the mere presence of the Boy made him tremble. One day having obtained from the tailor a new suit of clothes, a little dif- ferent in its colour and sbapo from that which he habitually wore, he went into the stable to perform some service for the animal, when the latter, having looked at him attentively for some time, made a sudden attack; and the young lad would certainly have been killed, if he had not had the agility to leap over the gate of the ward into which he had so imprudently cntereiL Having thus escaped, and suspecting the cause of this unexpected attack, he resumed his usual clothes. Tiio animal immediately re- cognized him, and regained his former fear and docility. Force, however, exercises a very important influence in all animal societies. We even see Us influence iu places where it might be expected that Nature would oppose some obstacle. In a flock of Goats, the She-Goat exhibits a remarkable care for her young, and is ready to defend them witli her life from the attack of any stranger. But if one of her kids receive blows from any of the other Goats of her own flock, she shows no opposition to their violence, and takes no notice of the cries of her young one, provided that they proceed only from the blows of the other members of her societj. Cunning is so often the attendant of weakness, that wo may readily expect all the young animals of a herd will possess a great share of it, M. F. Cuvier observed a remarkable instance of this in the conduct of a young Rhesus Monkey towards his mother. Although she treated him in the most affectionate manner while ho was suckling, she would never allow him to eat any thing. He could obtain nothing ex- cept by stealth ; and even after he bad filled his pouches, she wrould compel him to disgorge. In this way, the skill and cunning of the young Monkey became developed in a surprising degree. He used to watch the moment for seizing his food, when his mother was about to turn her head or eyes, and ho always anticipated her movements with remarkable accuracy. It may readily bo expected that a herd will separate when famine prevails. Then each animal is attentive only to its own preservation. Some species and individuals even devour each other if driven to extremities. This takes place among the Rats and also, it has been said, among the Field Mice (^Arvicola). A dissolution of tho society likewise occurs, when one of the Instincts essential to its existence cannot bo exercised. In densely-peopled countries, tlic Beavers, instead of constructing habita tions, lead a solitary life in the natural excavations of tho rocks on the banks of lakes or rivers. These several facts entirely confirm the correctness of those general riews which have here been laid down regarding the Social Instincts of animals; and M. F. Cuvier has contributed more, by his talents and industrj*, to e.xpose the character and manners of the Mammalia, than perhaps any other Naturalist. The preceding observations serve to show that there results from the instinctive union of several individuals in herds or troops, a certain mutual dependence, which passes into a habit, and becomes a necessary of life. The authority of one animal over the other originates in force, but when once esbiblUhed, it is maintained by confidence, until passions more powerful than the social instinct arise, and snatch tho authority from the chief, to vest it in a stronger and more courageous individual. It is in these mingled states of peace and war that the greater number of animal societies pass their existence, and they aro dissolved when the instinct of self-preservation becomes more powerful in each individual than the Social Instinct. Societies of this description have nothing cither Intellectual or Moral in their constitution. view, with mingled feelings of astonishment and admiration, a state of things in which authority is roaiutaiued without force, where harmony exists without the influence of Re.ison, and a variety of ojipositc wants and desires, without discord or dissension. We can ascribe ttiis solely to the great First Cause of all things. The animals themselves take no active part in it, and are, under this view of the sub- ject, but the blind and passive instruments in the hand of an invisible and all-powcr- ful Being. ^Vllen Societies of IMen approach this passive state, they bear a great resemblance in character to auhnal societies. It is sad to think that human nature can exist in such a state of degradation ; yet the accounts of enlightened traveUers inform us that the savage-s of New Holland, for example, lead nearly the same kind of animal life, where those faculties, which distinguish Man from tho other Mammalia, have scarcely received any development. It is only when the activity of Man is roused, that tho mere animal societies, which we have here described, assume a new appearance. Phenomena of habit then become piienomona of Mnscicncc. The same action which was formerly produced by mere likings or necessities, now results from the light of Reason. I ho authority of the strong and the submission of the weak become ennobled by the feeling of Duty. Thus Society, which among the other Mammalia is purely Instinctive, is transformed with civilized Man into an Intellectual and Jloral condition. GENER.\L REVIEW OF THE MAMMALIA CONTINUED. Tame Races have become wild — Alterations and Development of their Instincts and Intelligence vnder Domestication — Sensibility — Imitation — Sympathy — Inca- pacity to distinguish between. Justice and Injustice* The Intelligent Powers and Instincts of the Mammalia, which have formed the sub- ject of the preceding sections, may be made to undergo various modifications and alterations. There is a certain degree of perfectibility connected with each animal nature, and the changes induced may either affect individuals only, or be also capable of being transmitted permanently to their posterity. Hence arise the peculiar In- stincts and lutelligence of the differeni races or varieties of a given species. When the animals of an uninhaUtod country first encounter Mon, they exhibit no fear of his power, nor do they seem apprehensive of danger. The early navigators of the South Seas often allude to this innocent confidence of the Mammalia and Birds. Dr Richardson found the wild Slieep of the Rocky Mountains exhibiting that simplicity of character so often remarked in the domestic animal? ; and, in the retired parts of the mountains, where the hunters seldom penetrate, he had no difficulty in approach- ing them. He adds, ** where they have been often fired at, they are exceedingly wild ; they alarm their companions on the approach of danger by a hissing noise, and scale the rocks with a speed and agility that baffles pursuit.” Bat the young of all Mammalia, which have been much exposed to persecution, exhibit an Instinctive fear for strangers ; and this acquired Instinct, perpetuated by generation, may be ifiduced as well by any of the larger and fiercer Carnassiers as by Man. Thus Danger, whether proceeding from Man or other animals, may perform the converse of Domes- tication, and render those races wholly wild which had originally been tame. It has been often observed, that a certain resemblance exists between the characters of some classes of lilen, and of the animals with whom the}' habitually associate ; for example, betw'een tlie Drover and his Oxen, the Shepherd and lus Sheep, the Muleteer and his Mules, the Arab and his Steed. This modification is usually supposed lo have been undergone solely by the hlan ; but Ibis is not strictly correct, as the characters of the animals themselves insensibly approach that of their master and companion. jl!.lian has long ago observed the curious fact, that tho domestic animals, and espe- cially the Dog, acquire the faults and good qualities of the society to which they be- long. The Molossian Dog,” he remarks, “ is the bravest, while that of Caramania, like the people of that nation, is the most ferocious and the least susceptible of Domes- tication.” On comparing English Horses and Dogs with those of French origin, M. Dureau de La Malle observed certain well-marked national peculiarities which confirm the truth of .^lian s remark. In this way tho habits and manners of the domestic animals may form an index to the civilization of a great nation. Even among the different grades of society in the same country, wo find the animals adopting the peculiarities of iheir masters, and acquiring traces of their vices as well as virtues. The Dog which becomes so dainty when brought up in a Lady’s chamber, is ferocious with the Butcher, submissive in ihe poor man’s cabin, or thieving and cringing with tho beggar. When standing at tho Nobleman’s lodge, he even adopts the tone and manners of the great man’s porter. M. Edwards tells ua that he has often seen Dogs, educated by weak females, become excessively timid, and that this timidity was trans- mitted to their offspring. A Terrier-dog, born in the house of M. de La Malle, and treated like a spoiled child by a kind-hearted woman, who amused herself with speak- ing to it all day, had its sensibility brought at six month.s old to such a state, that when its mistress caressed the Cat, or pretended to scold tho little auimal, its large eyes would fill with tears, and it would cud by crying like an infant. In the wild and savage state, the lower animals and Man are possessed of much less sensibility than when domesticated or civilised. They also retain a much greater phy- sical power in resUting pain, and can endure without complaints the pangs of sickness, of deadly wounds, and all the evils arising from their original constitution or their want of civilization. The fortitude with which the sa\'agcs of North America and of Now 2ealand endure torments is well-known. According to Azara, the Charruas, a savage race of Paraguay, do not utter a complaint even while under the knives of their enemies. This feebleness and want of fortitude in civilized nations has many points of ana- logy among tho Wolves, Foxes, and proper Dogs, when they are placed in similar circumstances. The domestic Dog raises a most hideous yelping if a person tread on his paws, pinch his ears, or give him a whipping ; but if the wild Dog, the Fox, and the Wolf be wounded or taken in a trap, they suffer the sharpest pangs without utter- ing a cry, and expire without groans, in the midst of the mosbpruel torments. The observed habits of tho Dingo, or wild Dog of New Holland, perhaps the wildest of the species, bear the same relation to the domestic Dog in the scale of sensibility. The ancient Greeks and Romans endured pain more patiently than the moderns. The Turks have nearly the same fortitude, and the differences among the tenets of Paganism, Islauiism, and our own, are not the sole cause; for the colonists of Africa, America, and New Holland, and the sturdy peasants of our own country? endure pain more patiently, and with less complaints, than the inhabitants of towns. By this circumstance alone, wo might almost be able to determine tlio degree of civilization among the different classes of society, and it will be found to vary usually in the inverse proportion of their capability to endure pain. M. de La Malle says that tho English, of ail European nations, take the greatest care to preserve themselves from sickness; that they have the greatest dread of pain; and show the least forti- tude and firmness when the necessity for enduring the pain is not absolute. This if certainly a high compliment to the civilization of our nation, although made at tb« expense of cur fortitude. The cause is strictly physiological. As the nervouf system of Man becomes more susceptible to refined and vivid impressions, it acquires greater irritability; and when tho imagination, with the powers of reflection and fore- sight, are highly developed, wc may readily expect that the intensity of the pain will be increased. Habit with the Savage resigns him to pain; the civilized IMan either discovers a remedy or roars out with anguish. Some Instincts do not exhibit themselves until the animals have attained a cer- tain age. When gnawing a bone, the Dog does not know until two months old ho^ 53 THE MAMMALIA— MAN AND BEASTS. to hold it down steadily with his paws, and ho is ten or twelve months old before ho hides his superfluous food. The latter Instinct is also seen, accordin'? to Azara, in the Puma (Fclis Concolor), and in several other wild Animals of Paraguay. Many of the domestic animals, but especially the Dog, express their Contempt or Aversion for any object by rolling themselves over it. If they find the carcass of a Mole, a Shrew or other Insectivora, they immediately roll over it, which they never do upon the carcass of a Ruminant or SoUpede, of which they are very fond. M. do La IVlalle had two Spaniels, which devoured with pleasure the bones of Woodcock and Snipo ; but when ho threw into their mouths the gizzanis of these Birds, which had a very strong marshy flavour, they rejected them with well express- ed signs of disgust, and when the gizzards felbupou the floor, they immediately rolled over them. On attempting to urge them by commands and threats to eat the gizzards, they smelt them and rolled over them as before, nor could they be diverted from this Instinctive action either by the presence or injunctions of their master. This ex- periment wjis repeated several limes, and always with the same result. A remarkable instance of the force of Imitation is related by M. de La Malle of his Dog, named Fox, This gentleman had a male kitten, aged six months, when the Scotch Terrier, Fox^ then two months old, was given to him. It was of that variety with long and rough hair, with straight cars directed forwanls, which attaches itself to Horses, and is used for Fox-hunting. This Dog, when two years old, had never been out of the house where ho was allowed to run at large ; he had never seen other Dogs, and had received his education solely from the three (laughters of the porter, and from the Cat. The latter was the companion of his sports, and was with him con- tinually ; bonce these animals had acquired a singular affection 'for each other. The Dog had adopted the mildness and timidity of the females, who took charge of him ; but the Cat, being older than Fb.r, was his master in point of muscular force, and the Dog showed, in a marked manner, the influence of his preceptor. lie bounded like the Cat, and rolled a ball or a mouse with bis fore-paws in the same manner. He even licked his paw, and rubbed it over his ear just as he had observed in bis in- structor. The imitation was striking; it might have been expected that, in this state of isolation, the Dog being the more iutoUigent animal, would have acquired the greater influence over his companion; but the contrary happened. This circum- stance is easily explained from the power of Imitation being greater in the Dog than in the Cat. But although Fox had showed snch an attachment to his friend, it was not powerful enough to overcome his aversion to the species. If a strange Cat present- ed itself in the garden, immediately put it to the rout. The Cat also manifested his hatred to a strange Dog, which do La Mallo brought for the first time into the honse. The visitor could not be tanght to endure the caresses of Fox, but ex- hibited the utmost astonishment and aversion for his unnatural and Feline accomplish- ments. We are informed that M. Audouin had a Dog, which died in the year 1831, and had acquired all the manners of a Cat, particularly that one of licking his paw and passing it over the ears. It is well known that Dogs can open a latched door, and ring the bell for the por- ter ; this proves the faxnlltv with which they imitate the actions of Men. Many Cats axe known to leap upon the bell-rope when they wish to have the room-door opened. M. do La Malle had another Dog, which w'as brought to Paris when eight years old. On tho day of its arrival, it went ont of the hoiue, but being fatigued it w ished to return, and bjirkcd at the entrance for a long time without effect. At length a stranger rapped at the door by raising the knockor. Tho Dog observed the action, and came in along with him. That same day M. du La Malle saw it come in six times by raising the knocker with its paws. It must be observed, that there were no knockers at that gentleman’s country-scat, where the Dog had been brought up from its birth ; and also that it had not previously been absent from home. Signor Bcnnati, — a learned physiologist of Milan, who has written a curious me- moir on the mechanism of the voice during singing, and received the favorable notice of the Baron Cuvier in May 1830, — had a Water-Spaniel, which always came near the Piano •forte wlionever the S. Benuati stnigk tho chords, and seemed to show a taste for music. Tho learned Doctor, himself a skllfnl musician, was then studying the merits of Dr Gall’s system of Phrenology, and accordingly searched the Dog’s cranium very carefully for the bump of music, but without the slightest success. Not discouraged by this important circumstance, he tried to teach tlio gamut to the Dog. He began with the Piano, but failed; he then tried the Violincello, tho Flute, and Ihe Clarionet, also without success. At length he recollected that Dogs usually bark 'when a Bell is rung, and, therefore, concluded that Bells exert a peculiar action upon the Acoustic nervo of Dogs. lie procured seven diatonic Bells; and, by uiaking them vibrate with the bow of a Violin, succeeded in making the quadruped- K'usician sing tlie gamut very correctly after nine days’ lessons. He even brought ^ho musical education of the Water- Spaniel as far as to make him sing an accorapani- *nent in thirds to his own voice, wmich is one of very considerable power. These several facts show that we are still very far from being able to point ont limits to the intclligenco of animals possessed of tills remaikable faculty of imitation ; and, at the same time, they serve to exhibit tho influence of a rational course of cdu- <^tion upon domestic races so intelligent and so capable of improvement a? our Dogs. The iutolligexit powers of the domestic animals are thus capable of undergoing a much greater degree of development than is commonly imagined; and this improve- ment is not confined merely to tho faculty of Imitation, but cxlemls also to the otlier powers of Memory, Judgment, and Reasoning. The fne.ts observed during tho traiu- of Pointers, Setters, Slicpherd Dogs, and Water-Spaniels, arc evident proofs of that dcvclopmout of intelligtmce which increases with time, and may be induced by the care and skill of their instructor. One instance of intelligence in a Dog belonging to M. do La hTallo may be men. tioned here, as it shows that tho animal, judging from the impressions of its senses, ^•ombined their relations, and drew a just conclusion from the appearances and facts '^hich he had obsorxTd : “ I reside,” says tljat gentleman, “ when in the country, m a tolerably large Chateau, with a great number of windows, as w’ell in tho dwelling- house itself os in the offices. Tlie Spaniel, named PijranmSy to which 1 allude, sleeps m an open nicho in the wall at the end of a very large court-yard, and I am in tho Qabit of introducing him into my room during the night. This animal always finds some food in ray room, and a fire in the winter; he is, therefore, fond of his master, for Dogs, as well as Men, love society. I usually rise at midnight during winter, for I then retire to rest at five o’clock in the evening. As soon as I have risen and have lighted my lamp, I hear the Dog Pyramus under my window whining and howling gently. If 1 delay in opening the window, his cries become louder, with an occasional bark to give mo notice of his presence. On opening the window, and on telling him that I am going to let him in, he is silent ; but if I forget my promise, or am long in performing it, be begins in about half an hour his plaintive howds and barking. I have often observed him by moonlight, and when there is no light in the room, sitting with his eyes fixed on my window, but ahvays remaining silent, and neither expressing his wishes by cries nor any other sound. From these facts I draw the following conclusions ; — 1st, That the Dog, by means of the sense of sight, combined the appearance of the light with the idea of his master, and of the agree- able things he vpas in the habit of getting from him ; 2d, Tho absence of light indi- cated that his master either slept or was absent, and that then his cries would be superfluous. I may add, that my room is on an upper story, and though the Dog cannot get at it, except by a staircase and a long gallery with many turnings, yet this animal never mistakes the position of my window, although it is exactly the same as’twolve others in front. And whether there be a light in my room or not, he re- gularly places himself at tho same hour under my window, alvrays silent when he perceives no light in the room, but calling me and asking to be let in whenever he observes the light.” It would be going too far to assert that well-educated Dogs can acquire notions either of Delicacy or Decency ; but there cannot be the least doubt that they possess powers of Memory, Reflection, .Tudgment, and Association of Ideas. They can even combine Relations, and draw just inferences from the notions received directly from the sense of sight. Many of their perceptions of sight arc also acquired. If a pup of two or three months old be called from an upper story w’hcn lying in a court, he knows not how to direct his eyes in the direction of the sound which strikes his car. He must first learn to combine the relations of these two senses, which in this respect have an intimate connexion. But when once he has by chance directed his eyes to the quarter whence the sound proceeds, he treasures up this fact ascertained by experi- ence; the result is fixed in his Memory, and he docs not again make tho same mis- take. The Domestic Pig, which is brought up with us only for the market, appears, when confined in its stye, to be excessively stupid and devoid of intelligence. Yet educa- tion, and the habit of living in the society of Man, develop his social character, and he exhibits some amiable qualities. At tho town of Brivcs-Ia-Galliarde, in France, Pigs are domesticated like Dogs, and live in society with the inhabitants. They go up-stairs even in houses of three stories high, and often sleep in the same room with their masters. From this treatment they have acquired singular habits of cleanli- ness, which are further improved by their mistresses taking them usually twice a-day to the river to be washed and rubbed. While undergoing this operation, it is curious to see them going voluntarily to the water, and turning themselves first on one side, then on the other, and then on their back, to assist her; and M. dc La Malle has scon them thank their mistress after their own fashion, when it was all over, by licking her hand. The Irish Pigs have long been remarked for their intelligence, and this is evidently owing to their living so much in the houses of the lower classes, and associating with the children. There is, however, no instance on record of their having been guilty of an equal degree of gratitude with their cleaner brethren of Brives-la- Gallinrde. The Intelligence of tho Elephant is capable of undergoing a very considerable de- gree of development under Domestication. An Elephant, at the Jardin du Itoi, was brought to understand the meaning of seven'll words. When his guide said “ En arridre,* without elevating his voice or making the slightest gesture, the animal backed immediately. A remarkable instance of foresight was observed in the War- Elephants of Cochm China, whicii is related here on the authority of an intelligent traveller, and an eye-witness of tho circumstance. Seventy Elephants were ranged against a Tiger ; and one of them, urged on by his Mohout or guide, advanced to the attack. The Tiger waited until the Elephant was in the act of striking with his tusks, and making a sudden spring, alighted on tho neck of the Elephant, with his hind paws inserted on the animal’s trunk. The Elephant was wounded, and fled; but all tbo other EUfphants who witnessed this conflict profited by the inexperience of their companion, and advanced against the Tiger with their trunks rolled up under their throats in the most careful manner, thus showing a degree of observation, fore- sight, and judgment, which might not have been expected in so large and heavy an animal. We shall only add here a few instances which servo to prove that the Domestic Dogs, from their living in society with Alan, havo acquired the power of reflection, of combining means to an end, and of foreseeing difficulties in thoir execution. They also learn the meanings of many artificial words. They communicato thoir ideas to each other by means of natural signs, and assign to each the part necessary to be performed, in a combined plan of action — qualities which require operations of their minds but little inferior to the results of tho Human Intellect. We shall oven show that they form plans when hunting by therasclvt^s, which exactly resemble those in- genious devices invented by Man, and practised by him in the Art of War. M. de PujT:nauriri, a fh'fmtt' or Member of tho French Parliament, had a female Water- Spaniel, whose education had been very carefully attended to, and it accord- ingly showed extraordinary intelligence. During the occupation of Paris by the alUed armies in 1814, General Stewart, who lodged in AI. Payinaurins house at Toulouse, remarked that the Dog would take nothing that was offered to it with the left hand, and he tried to deceive the animal by crossing his arms, and even by exciting its appetite by some marked difference in the quality of the food held in each hand, but without effect. Being determined to subject the Dog to a very peculiar experiment, he requested one of his Aides-de-camp ^Colonel Cameron), whose right arm had been amputated, to offer tlio Dog some food. The Dog approached, and without noticing tho hand containing, tho food, rose upon its hind-legs, and applied its nose to tho place where the Colonel s right arm ought to have been, as if to be 54 FIRST CLASS OF THE VERTEBRATED ANIMALS. rare that there was no deception, and betnj satisfied that the Colonel had only one arm, it passed on to his left hand and took the food. This fact was reported to M. do La Malle by M. Auguste do jPuymaurin, the son of the diputi, on whose authority it is inserted here. A well-trained Dog can often be brought to understand the meanings of words, even though spoken without the slightest gesture or alteration of tone. M. Edwards has been heard to mention an anecdote of a Dog, which was in the habit of seeking and bringing back Gloves. If in the course of conversation, when the Dog would appear to be paying no attention to what was going on, any mention was made of his talents, and the word Gloves {Gants) happened to bo used, the Dog was off im- mediately seeking out for them ; and when they were foimd, he again resumed his former position of careless listener to the conversation. Another Di>g, which belonged to an aunt of M. Audouin, was excited in the same way when Gingerbread cakes were alluded to, of which he was very fond. If this word (Gimllettes) happened to be mentioned in the course of conversation, and without any peculiar emphasis, ho was excited and ran to the cupboard where the cakes were shut up. This experi- ment was often repeated before several people, who would not at first believe the statement. M. de La Malle informs us, that one of his neighbours, the Count dc Fontenav, was engaged in some agricultural speculations relating to the breeding of the RIerino Sheep, jointly with the JIarquis des Fengerets, whoso property was situate about two leagues from his own. The Count had a very fine Pointer, possessed of great in- telligence, and as he had educated this Dog himself, it almost seemed to anticipate his wishes. One day he had an urgent message to communicate to Ins neighbour, and as no one was at hand to w'hom it could be entrusted, it occurred to him to try whether the Dog would carry it. Accordingly ho fastened the letter to SoUman’s collar, and told him carelessly, and without expecting him to obey the command, “ Carry that to Feugerets! ” (Porte cela aux Feugerets.J The Dog did as he was desired, and would permit no one to touch the letter except the Marquis. “ I have seen this Dog,” says M. de La Malle, “ for four or five years acting as messenger be- tween those two Chateaux with a remarkable quickness and fidelity. When the Dog delivers the letter, he goes to the kitchen to he fed. As soon as he has had his meal, he sits down before the window of the Marquis des Feugerets’ study, and barks at intervals, to show that he is really to take back the answer. On the letter bein" attached to his collar, he sets off and brings it to the Count his master.” It has been proved, beyond the possibility of doubt, that the property of pointing and setting game, which some races of Dogs are made to acquire by feeding them well, and then exercising a certain degree of comstraint and punishment, is transmitted unaltered to their descendants. M. Magendie, happening to hear that there was a race of Dogs in England which brought back game naturally, procured two adult Retrievers. These animals produced a female Retriever, which always remained under JI. Ala- genclie’s immediate inspection, and though it had received no instruction, it stopped and brought back game, from the very first day that it was led to tne field, and this it did with a degree of steadiness fully equal to those Dogs which have learned this art solely under the stern discipline of the whip and collar. When the Spaniards discovered America, they introduced Dogs as auxiliaries in their military expeditions against the Indians. Columbus first employed them for that purpose, and we are informed in his own Memoirs, that at his first conflict with the Indians, hb array consisted of 200 foot soldiers, 20 iiorsemen, and 20 dogs. These Dogs were employed in the conquest of several par'ts of the New World, espe- cially in Jlexico and New Grenada, wherever the resistance of the Indians was pro- longed. We arc informed by M. Roulin, that this race is still preserved pure on tile Plateau of Santa Fe, whore it is used for Stag hunting. This it performs with an extreme ardour, and still uses the same mode of .attack, which must have rendered it so formidable to the Indians. It consists in seizing the animal by the abdomen, and then overturning it by a sudden jerk, wliieli is given at the moment, when the weight of its body is thrown upon the fore-legs. Sometimes the weight of the animal thus overturned b six times that of the Dog. Without receiving any previous education, the Dogs of pure breed, naturalized in South America, bring to the chose certain disjiositions which the newly-introduced coursing Dogs, though of a superior European breed, have not yet acquired. Tims, the American Dogs never attack a Stag in front in the middle of its course, and even when the latter comes towards a Dog without perceiving him, the sagacious animal swerves to one side, and waits his opportunity to attack it in flank. A foreign Dog, who b unaccustomed to these precautions, b often left dead on the spot, from having the vertebral of his neck dislocated by the violence of the shock, Among the poor pimple inhabiting the banks of the Magdalena, this Dog has de- generated, partly from the cross of another breed, and partly from the W'ant of sufficient food. Even in this degenerate race, a new Instinct seems to become hereditary. R has been long used exclusively in hunting the White-lipped Pcecari {Dicotyles tabiatus). The art of the Dog consists in moderating his ardour, and in not attacking any particular animal, but thus keeping the entire herd in check. The very first time that these Dogs arc brought to the ehase, they show their knowledge of this art, which has been transmitted to them by their parents. A Dog of a different breed rushes into tho midst of the herd, is surrounded, and no mattew bow great his strength may be> he is ituvoured in an instant. Tiiose instances, where (llfierent varieties of the Dog unite their several talents while hunting, and form one combined plan of operations, are perhaps still more striking than any of the preceding. “ I had at one time,” says M. de La Malle, “ two sporting Dogs, the one an excellent Pointer -with a very smooth skin, and of remarkable beauty and intelligence. The other was a Spaniel, with long and thick hair, but which had not been taught to point, and only coursed in the woods like a Harrier. My Chateau is situate on a level spot of ground opposite to a copse-wood filled with hares and rabbits. When sitting ut my window, I have observed these two Dogs, which were at large in tho yard, approach and make signs to each other, and first glancing at me as if to see whether I offered any obstacle to their wishes, slip away very gently, then quicken their pace when they were a little distance from my sight, aud finally dart off at full speed when they thought 1 could neither see them nor order them back. Surprised at this mysterious manosuvre, I followed them, and witnessed a singular sight. The Pointer, who seemed to be the leader of the enterprise, had sent the Spaniel out to beat the bushes, and give tongue at the o]>- posite extremity of tho brushwood. As to himself, he made with slow steps the circuit of the wood, by following it along the border, aud I observed him stop before a pas- sage much frequented by the rabbits, and there point. I continued at a distance to observe how this intrigue was going to end. At length, I heard the Spaniel, which had started a hare, drive it with much tongue towards the place where his companion was lying in ambush, and the moment that tho hare came out of the passage to gain th# fields, the latter darted upon it, and brought it towards me with an air of triumjih. I have seen these two Dogs repeat the same inanceuvre, and in the same manner, more tlian a hundred times; and this conformity has convinced mo that it was not ac- cidental, but the result of a concerted agreement and combined plan of operations arranged beforehand.” Leroy was of opinion that Wolves do the same thing; but he foundeil his con- clusions solely upon the traces of tlieir foot-marks left on the snow or mud. The same thing has been said by Hunters respecting Foxes, but the truth of it is very doubtful. Indeed, these wild aniinaU which hunt during tho night, especially when timid, are so difficult to observe, that tliese assertions require further confirmation, especially when made of animals known to be of solitary habits. The fact that the domestic Dogs often eombiiie their different talents to execute one manoeuvre, is further corroborated by M. Louis Chateaubriand, nephew of the celebrated writer, who has witnessed tho same thing between two Harriers ami a Pointer. It is clear, that whatever differences there may be between this contriv- ance of the Dogs, aud the ambuscade of a skilful general who bides his forces in the woods or copses, and sends a small body of troops with orders to fall back before the enemy, and draw them on towards tho defiles, they both agree in being an ambuscade — a trick played upon the credulity of the enemy, and rcened in the case of the common Ferret, which is probably only a variety of tho Polecat {Mustela Futo Angora Goat has imparted his silky fleece to the . Swedish flocks, and they maintain this character for several generations. In Russia also, the Stallions with a frizzled and crisp hair, impart to their foals a similar coat .and of the same colour. The w ild, as well as domestic animals, also tend continually to main- tain their primitive forma in opposition to all the influences of climate and food, which arc wholly insufficient to induce this supposed degeneration and degradation of species. Whenever some accidental connate deformity or partial excrescence becomes hereditary, as sometimes happens, tho natural liberty of intercourse soon re-establishes the original form, and it is only by interfering with their unions that we can succeed in rendering permanent tho accidental varieties of our domestic animals. In the wild state also, tho females are led instinctively to prefer the most courageous of the males, tho most perfect, and the most masculine of their species. The males, like, wise, instinctively prefer the most beautiful of the females, and thus they both tend to transmit to their offspring tho most perfect form of their species. Since Nature then Ims placed an instinctive mutual aversion in animals of different species, — since she has rendered Hybrids cither sterile or weak and imperfect, if allied animals distributed in remote parts of tho globe are found to be inc.ipable of 60 FIRST CLASS OF THE VERTEBRATED ANIMALS. yielding fertile races, we have presumptive evidence that this supposed degeneration of species cannot have existed, and we derive from the known insufficiency of the present causes of change a positive ground for inferring their descent from distinct original types. The mere circumstance of our being able to induce by art and con- trivance a fertile union between two species, is not sufficient to counteract this evi- dence, when we see that these same species preserve themselves distinct in the wild state, and continually maintmn certain well-defined peculiarities. Pallas was led to infer that some of our domestic animals, such as the Sheep, the Goat, and the Dog, are factitious beings, not proceeding from any permanent origin, but from the union of several distinct species, such as the Dog from the Wolf, the Fox, and Jackal; the Sheep from the Moufion and Siberian Argali; and the common Goat from the Persian and Caucasian Goats with the Ibex. Wo know that these inimals have given rise to fertile hybrids ; and hence it becomes impossible to say now far their varieties may be owing to foreign contamination, or to the occur- rence of connate varieties in the original species. It is, however, useless to indulge in conjecture where data arc defective; but from analogy we might infer that a very small part of their variolies have been owing to foreign admixture. It now remains for us to notice the theory of the successive Transition of Species proposed by M. Lamarck. According to him, the habits and manners of life assigned to each animal do not follow from any original form peculiar to its species: but that, on the contrary, the form of each species is the result of its habits, its manner of life, and other influential causes, which, in the course of time, have consti- tuted the shape of tlie body and the parts of the animal. W'ith new forms, new faculties have been acquired; and thus gradually Nature has produced the animals as we now see them. Wo must in justice remark, that this theory has been censured in this country with undue severity, from its appearing at first sight to dispense with the agency of a First Cause in the creation of the several species of animals. But in reality, a creative power is as indispensable in maintaining the successive transition of forms, as in originally creating them. Lamarck himself was well aware of this, for ho observes, “ When I see that Nature lias placed the source of all the actions of animals, of all their facul- ties, from the most simple to those which constitute instinct, industry, and finally reasoning — in their wants, which alone establish and direct their habits; ought I not to acknowledge in this power of Nature, that is to say, in the existing order of things, the execution of tlie will of its Sublime Author, who has imparted them the power?” As an illustration of this supposed transition of species, we shall show M. La- marck’s method of explaining upon his theory, how it comes to pass that some Mammalia can fly. A very ancient race of common Squirrels had long amused themselves with leaping from tree to tree, and thence had acquired a habit of extend- ing their bmbs like a parachute. From frequent repetitions of this act, the skin of their sides became gradually enlarged, in course of time, and a loose membrane ex- tending from the fore to the hind feet, embraced a large volume of air, and broke the force of their fall. In a word, they acquired tho characters of the Flying Squirrels (Pterorngs). These animals, however, were still without membranes between their fingers. But a race of .Squirrels of much higher antiquity, after undergoing the preceding metamorphosis, had acquired a habit of taking still longer leaps than the former. Accordingly the skin of their sides became more ample, uniting not only the fore and hind legs, but even the tail with the hinder foot, as well as the fingers with each other. These now form our Flying Lemurs ( Galeopithecus). There was, however, a third race of Squirrels vastly more ancient than any of these, which had contracted a habit, in the course of time, of extending not only their limbs, but also their fingers. From this habit, long preserved and become inveterate, they not only acquired lateral raemhers, but an extraordinary elongation of the fingers of the anterior limbs, with largo intermediate membranes, so that at length they con- stituted those singular wings wliich we find in the Bats ( Vespcrtilio). “ So great is the power of habit,” observes M. Lamarck, “ that it singularly aflbets oven the conformation of the corporeal parts, that it imparts to those ani- mals which have- contracted certain habits through a long course of ages, certain faculties which other animals of different habits do not enjoy.” Upon this theory, it was requisite that the higher orders of animals should be re- garded as of tho greatest antiquity, a longer time being necessary for their transition from those simple forma, which were supposed to have been first created. “ I have no doubt, proceeds Lamarck, “ that all the Mammalia have originally sprung from the ocean, ana that tho latter is the true cradle of the whole Animal Kingdom. In fact, we still see tliat the least perfect animals are not only the most iinmerons, but that they cither live solely in tho water, or in thuso very moist places, where Nature has performed, and continues to perform, undiir favorable circumstances, her direct or spontaneous generations; ami there, in the first place, she gives rise to the most simple animalcules, from which have proceeded all the animal creation." — (Philoso- phic Zoologique, tom. 2, p. 456). Wo -must remark, that there has never y«t been, within the historical era, a well authenticated fact of any animal of one species having acquired organs, or faculties belonging to another ; nor are any spetpos known to have lost any of their senses or pow'ers to make way for new ones. It must further be observed that, while we have never found any ef these transitions in circumstances within tho sphere of our investigations, Lamarck places them precisely in those, where they cannot be proved or disnroved by direct observation. MTicre did these transitions begin ? In the abysses of tho Ocean, where Man has never penetrated, and where myriads of beings lie concealed from his observation, perhaps for over. What animals owe their origin to spontaneous generation? Animalcules, a class of beings the most remote from our observation, and whose forms can only be traced through the de- ceptive medium of the microscope. When did these transitions occur? Before the historical era, in those remote and inaccessible ages, whose existence is alone attested by tho organic remains imbedded within the surface of the earth. But, observes Lamarck, “ there is a very good reason why we do not see those changes sucuessively performed, which, hare diversified the known animals, and brought them to their present state. We see them only when they are finished, and not when undergoing the change ; and we very naturally infer that they always have remained as we see them.” This is a prejudice. “ If the average duration in the life of each generation of Men were only a second, and if there bo a pendulum mounted and in motion, each generation wonld consider this pendulum really to be at rest, never having seen it change in tho course of their lives. The observations of thirty genera- tions would not demonstrate any thing positive concerning the vibrations of this instrument.” We may remark, that our sole means of judging of unknown olqects is by compar- ing them with others which are known, and that it is unphilosophical to found a theory of what occurs, or has occurred, in remote and inacee.ssiblo parts of the creation, in direct opposition to what is seen to happen within our own sphere of observation. Tho earth appears to be at rest, if it be compared with objects on its surface; and we reason correctly, for, in respect to them, it is at rest. But on referring it to the .Solar System, wo at once perceive it to be in motion. Again, if we compare the entire Solar System with tho more remote heavenly bodies, analogy wonld lead \ts to expect that our system may be in motion towards the Fixed Stars, and that these Stars themselves may only be fixed, relative to our own limited means of observation. To suppose the Fixed Stars to bo really motionless, would be as great a violation of analogical reasoning, as those theories inflict which deny the permanent characters of species. All the sciences adopt this mode of reasoning when the contemplated object is inaccessible to direct experiment or observation. On looking abroad into Nature, tho Chemist finds every thing in a state of composition. He nowhere dis- covers pure oxygen, chlorine, calcium, or potassium, because nearly all the unions which simple substances were capable of forming spontaneously have already occurred. Tho Naturalist is disposed to imagine that something similar to this may have taken place among the species of animals and plants ; but the Chemist analyzes the com- pounds of these substances himself, and he sees their combinations going on before his eyes. 'Tho Naturalist cannot bring forward one single instance of the de^e- ncration or transition of species from one form to another. The weak point of the Lamarckian doctrine, in the absence of positive proof, is a violation of one of the first rules of analogy. Mr Lyell correctly remarks, in his recent criticism on this subject, that “ no positive fact is cited to exemplify tho substitution of some entireig new sense, faculty, or organ, in the room of some other rendered useless. All the instances adduced go only to prove, that the dimensions and strength of members, and the perfection of certain attributes, may, in a long course of generations, be lessened and enfeebled by disuse ; or, on the contrary, be matured and augmented by active exertion, just as we know that the power of scent is feeble in the Greyhound, while its swiftness of pace and its acuteness of sight are remark- able ; — that the Harrier and Staghound, on the contrary, arc comparatively slow in their movements, but excel in the sense of smelling. It is evident, that if some well authenticated facts could have been adduced to establish one complete step in the progress of transformation, such as the appearance in individmals descended from a common stock, of a sense or organ entirely new, and a complete disappearance of some other enjoyed by their progenitors, that time alone, might then be supposed sufficient to bring about any amount of metamorphosis. The gratuitous assumption, therefore, cf a point so vital to the theory of transmutation, was unpardonable on the part of i(s advocate.” We have now seen that some Mammalia are capable of undergoing a very consi- derable variation, not only in their Instincts and Intelligence, but also in their ex- ternal forms ; — that tho variations which each individual can bo made to undergo by the circumstances in which it is placed arc but very rarely transmitted to posterity, while connate modifications usually end in becoming hereditary; and that there are certain limits beyond which no species has been observed to vary, so that wo are fully entitled to conclude, that a certain form was assigned to each species at the origin of things. GENER.VL REVIEW OF THE MAMMALIA COKTINUED. Forms to which the Domestic Animals have reverted on becoming wild Their modifications during the Idistorical era. If it be true that tho numerous varieties of the Cow, tho Horse, tho Dog, and other Domestic Mammalia, are the effects of tho slow and continued influence of certain causes, which, in the first instance, induce a departure from the primitive type in the evolution of connate varieties, and afterwards tran.smit the.so variations to posterity, giving rise to their several distinct races ;— it ought to follow, that in all these artifi- cial beings, whose characters Man has for a time rendered permanent, there should bo a continual tendency, when left to their own resources, to assume the form of the original type. On allowing the domestic animals to run wild,— on permitting them to snbstituto the wandering habits and precarious subsistence of mountains and forests for the uniform and regular diet of the stable, we ought to find that thc.r acquired characters disappear, that all the individuals bear that marked resemblance to each other, which will serve to indicate both the identity of their species, and the original form from which tho races have diverged. The experiments confirming the truth of this conclusion have long been per- formed on the largest scale in the immense continent of America. It is well known that the Europeans, on the first discovery of the New World, sought in vain for any vestige of that animal creation to which they had so long been familiarized. Those useful animals, without whose aid, in the first instance, tho civilization of Mim might have been indefinitely retarned, had to be transported to America to supply the im- mediate necessities of the earlier colonists. Soon, however, the accidental flight of some animals to the woods, hastened probably by tho abiuidant supply of food, and a favorable climate, which, in increasing their fecundity, rendered a vigilant care of them superfluous, a large proportion became absolutely wild, and the establishment of wild individuals in the immediate neighbourhood of tho tame herds soon exerted a direct modifying influence over the latter. Hence, in America, wo may see performed, on a magnificent scale, the converse of that gradual modification which the domestic 61 THE MAMMALIA— MAN AND BEASTS. animals underwent in their original transition from the wild state ; and may farther compare those half domesticated herds, acknowledging only a partial submission to Man, with the humble individuals of their own species, which still yield him a patient and implicit obedience. It is evident that careful observations should be multiplied over the whole continent of America, in order to render this investigation complete ; but wo owe to M. Koulin the merit of having -traced some changes in a portion of this vast country. That learned physician, during his residence in Colombia for six years, has collected a number of interesting facts which were communicated to the Royal Academy of Science at Paris in the year 1828. These observations were made in New Grenada and a part of Venezuela, from the ad to the 10th degree of North Latitude, and from the 70th to tlie 80th degree of West Longitude. However limited this tract of country may appear, it offered unusual facilities for observation, being traversed throughout its entire course by the great Cordilleras of the Andes, which are here divided into three principal chains ; so that, within the distance of a few leagues, the same living animals were investigated, though resident in one district, where the medium temperature is only 30'’ Fahrenlicit, and in another where it varies from 77° to 86°. The Mammalia transported from Europe to America were the Hog, the Horse, the Ass, the Shuep, the Goat, tlio Cow, the Hog, and the Cat. It becomes import- ant to ascertain whether these animals retain the forms acquired in Europe, or whether they have undergone any considerable chango. By oarofully comparing these phenomena with the circumstances under which they have arisen, much light may be thrown upon those modifications which probably attended the transition of these animals from the wild to the domestic state. The first Hogs brought to America were introduced by Columbus, and became established at Saint Domingo in November 1493, being the year which followed its discovery. During the following years they were successively carried into all those pUcos where the Spaniaj'ds attempted to fix themselves, and, in the period of about half a century, they might be found wild from the 25tli degree of North, to the 40th of South Latitude. In no place do their important eliangcs appear to have been effected by climate, and they have reproduced every where with the same faci- lity as in Europe. Most of the pork consumed in New Grenada comes from tho warmest valleys, where the Hogs arc bred in largo numbers, from their maintenance costing but little. During some seasons they arc even supported wholly by wild fruits, and especially by those of the several species of Palms. From roaming constantly in tbo woods, the Hog h.-is lost in this district all traces of his former domestication. His ears are straight and erect, his head has widened and become elevated in the upper region. Tho colour has again bccoino constant, being entirely black. Tho young Pigs have several fawn-coloured stripes, like the European Wild Boar in its youth, and upon a .ground of tbo same colour. Such arc the Hogs brought to Bogota from the v.-illeys of Tocaymii, Cumlay, and Molgar. Their hair is scanty, and on this account they bear a striking resemblance to the Wild Boar of Europe, from a year to eighteen months old. This deficiency of hair is not, however, peculiar to the Hogs of Grenada, hut is also experienced by the common Wild Boar of Europe. M. Iloulin observed an instance of it in France, at a farm near Fougeres, where seven or eight of these animals were brought up together. One of them, being about two years old, had been fed iu a stable from tho beginning of spring, with the intention of fattoning it for the market. Though the animal had not been closely confined in this place, the good foeibng of the stable was sufiicient to induce it to remain at home. Its hair had almost wholly Men off from tho effects of the heat, and it exhibited a most perfect resemblance to the Hogs of Melgar above described, except that tlio two horizontal stripes on the sides of tho muzzle were more decidedly marked, and gave it a stronger expression of ferocity. Tho Hogs of tho Paramos, which are mountains at least 8,200 feet above the level of the sea, approach much more nearly in appearance to the Wild Boar of the European forests, from tho thickness of their hair, which has even become frizzled. Beneath, in some individuals, it has been observed to assume a Woolly appearance. Tho Hog of these elevated regions is, however, small and stunted, from tho want of sufficient food, ami the continued action of an oxcossivo cold. In some sultry districts, the Hog is not black Uko those above described, but red, like the Peccari, during its youth. At Melgar, and in the other places above mentioned, mstancos have been known where the Hogs are not entirely black ; but these arc comparatively rare. There is a variety called Cinchados, or girthed, because they I'ave a large white band underneath, which usually unites on the back, and always preserves a unifonn breadth; and the young individuals of tills variety hear the same ■'tripes as those of the pui-o black breed. The only Hogs in Colombia which re- semble tho common Pigs of Europe, have been imported within the last twenty-five years, and these do not come direct from Europe, but from the United States of •Auicrica ; and it must be recollected that in the neighbourhood of New York, where this race has long been domestioated, it experienced tho influence of a climate very t‘“avly tho same ad our own. The Horse has bccoino wild in several districts of Colombia, especially in the plains °f San Martin, among tho sources of tbo Jlota, tho Rio Negro, ami the Umadoa, ''■here sra.all troops of Chestnut Horses may bo observed. Their limited numbers, tho t’wrow range to which tliey are confined, and the immediate neighbourhood of the itiha- ‘”tod districts, have proveiitoU them from acquiring those peculiarities which Azara has ‘■“lated of the Wild Horses of Paraguay. They go about in snmll squadrons, com- posed of an old Horse, five or six Mires, with some Foals, and ouo squadron is com- pletoly isolated from anotlicr. luatcad of approaching the caravans to entice tho 'loraestic Horses, they run away on the first appearance of a 3Ian, mid do not stop their ‘ght until he is out of sight. Their raovemeuts are graceful, especially those of tho auer, but their forms, though not heavy, are wanting iu idegance. In the Hatos dea Llanos, tbo Horses arc almost wholly left to themselves.- The arus are assembled together at intervals to prevent them from becoming absolutely <1, to extract tho larva; of tho Gad-fly, and to mark the Foals with a red-hot iron, rom this independent kind of life, they begin to acquire the unifonn colour of the savage races. The Chestnut bay is not merely the prevalent colour, hut it is very Pearly the only one. Something similar to this has probably happened in Spain 16 with the Wild Horses (cavallos cerreros) which wander in tho mountains; for in the Spanish proverbs, the Horse is often noticed by the name of el bayo (the Bay), as well as the Ass by the term rucio (Gray). In the small Hatos which are found on tho plateau of the Cordilleras, the effects of domestication are more perceptible. Tho colours of the Horses become more various; there is also a greater difference in their height; and while many are more diminutive than the average of the species, only a few surpass the medium size. As long as they live continually in the fields, their hair is tolerably thick and long, but a few months’ residence in tho stable is sufficient to render it short and glossy. It is cus- tomary to cross this breed of Horses with the races from the warm valleys, especially with those of Cauca. On some properties where this precaution has not been at- tended to, the Horses have become perceptibly smaller, though the pastures have long been celebrated for their richness. The hair has grown to such a degree as to render their appearance absolutely deformed. In respect to the useful qualities, this breed has lost but little ; and the Horses belonging to one canton aro even celebrated for their swiftness. ^Vhen a Horse is brought from the Llanos do San Martin, or from Casanare, to the plateau of Bogota, he must be kept in tbo stable until he is accustomed to the climate. If allowed to run loose at once into tho fields, he grows thin, contracts a cutaneous disease, and often dies in a few months. The pace which is commonly preferred in the saddle-horses is thu amble; this they are made to acquire early, and the greatest care is taken not to allow them, when mounted, to take any other pace. In a short time, the limbs of these Horses usually become stiff; and then, if otherwise of a good form, they are allowed to run in tho Hatos as Stallions. FVom them a race has de- scended, in which the amble is with the adults the natural pace. These Horses are called aguilillas ; and they form a remarkable instance of the transmission of acquired habits from the parent to his offspring. The Ass has undergone very few alterations in its form or habits in all the pro- vinces visited by M. Roulin. At Bogota it is very common, being there used for tr-dnsporting building materials ; but being badly taken care of, and exposed to the inclemencies of tho weather, without receiving sufficient nourishment, tho race has become small and pitiful. It is covered with very long and uncombed hair. De- formed individuals are often seen, not only among the adults, which are loaded pre- maturely, and before they have acquired sufficient strength, but also among the Foals at their birth. Perhaps the latter circurastaneo may arise from the ill treat- ment of tho dams during the period of gestation. In the low and warm provinces this animal is less neglected, as it is required for the production of Mules. Being well fed. at least in these districts, it becomes larger and stronger ; its hair also is shorter and more polished. In no province, however, has the Ass reverted to its wild state. The Sheep was originally transported to the New World from Spain; and the earliest importation appears not to have been the Merino v.iriety, but another, which the Spaniards call de lana hurda y hasta (with wool coarse and rude). It is very common on tlie Cordilleras, at an elevation of 3,300 to 8,200 feet. In no place do the Sheep appear to have escaped from tho protection of Man, and hence we find that their manners have undergone scarcely any change; nor can any alteration iu their forms bo observed, except a slight diminution of stature. Within the limits above defined, the Sheep propagate readily, and almost without re- quiring any care; but tho reverse happens in the hotter districts. It appears that in the plains of Meta it is very difficult to rear Lambs; and no Sheep are to be seen from the river to the foot of tho Cordilleras, although thoir skin is very much in de- mand to make a kind of parchment, and that its price is as high as tho hide of an Ox. Ill tlie valley which separates the most eastern chain from tho central, they may perhaps be sometimes seen, but always in small numbers. The females are not very fruitful, and the L-imbs are difficult to rear. There is one very curious plietiomenon exhibited by the Sheep of this district. Tho fleece grows upon the Lambs in the same manner os in most temperate climates, provided they aro sheared as soon as it has ai-rived at a certain degree of thickness, in which case the wool grows again, and continues to observe the same order. But if the favorable period for stripping tlio animal of its fleece be allowed to pass, the wool thickens and becomes matted together, it detaches itself in flakes, and finally leaves behind — not, as we might expect, a growing fleece, or a naked and diseased skin — but, a short, glossy, and compact hair, exactly resembling that of the common Goat in tho same climate. Although the Goat is evidently best fitted for a mountainous region, it seems to thrive better iu the low and sultry valleys than in tho more elevated regions of the Cordilleras. In the former districts it multiplies rapidly, generally bearing two young at a birth, often throe, but never six, as some have boon pleased to assert. Its height is diminutive, but in other respects its form has greatly improved. Its body is more slender, tho shape of its head is more elegant, more pleasingly disposed, and usually less overloaded with horns. The agility of this animal, and^its taste for climbing and leaping, are also singularly increased. In the public square of a village, M. RoiiUn has often seen them leaping more than four feet upwards to tho mould- ings on tho pilasters of the church. The projecting place on which their feet rested was not tliroc square inches; yet in tliis position, so difficult to preserve, they re- mained for hours together, without any other apparent object than that of warming tliemselves in tho direct solar rays, as well as in those reflected from below. These Goats are covered with short hair, very glossy and thick ; and although they may be seen to possess all the shades of colour, yet the most common is fawn, with a brown stripe on the back, and black symmetrical marks upon the face. Tho She- Goats of Europe strikingly exhibit the influence of domestication in causing a great enlargement of tho udders ; for this acquired character has entirely disappeared in the She- Goats of America. Till! establishment of the larger Cattle in America must be dated, like that of the Hogs, from the second voyage of Columbus to St Domingo. In the latter place they multiplied rapidly, and tho island soon became tho nursery from which these animals were transferred to different points on tho coast of tho Mainland, and thence to the interior of the continent. Although these numerous e.xportatious must have 62 FIRST CLASS OF THE VERTEBRATED ANIMALS. diminished their mimbers considerably, yet we are informed by Oviedo, that within twenty-seven years from the discovery of St Domingo, herds of 4000 head of Cattle might frequently be encountered, and that there were even some containing at least 8000. in the year 1587, the number of hides exported from this island alone amounted to 35,444, while 64,340 appear to have issued from the ports of New Spain. This was the sixty-fifth year after the capture of Mexico, before which event the Spaniards were entirely occupied in warfare, and it strikingly evinces the extreme rapidity with which these animals will increase their numbers when placed under fa- vorable circumstances. While the Cattle were in small numbers, and grouped around the habitations of their masters, they succeeded equally well almost every where ; but as soon as their numbers became greatly increased, it was discovered that in certain districts they could not exist without the assistance of Man. Unless they were able to find a cer- tain quantity of Salt, either in the substance of the plants which formed their food, or in the streams which in some districts acquire a brackish taste from the saline particles contained in the soil, it was found to be absolutely necessary to furnish it to them directly. If this precaution were not attended to, they became stunted and poor ; many of the females ceased to be fruitful, and the herds rapidly disappeared. Even in those districts where the Cattle can exist without this assistance, it has been found advantageous to distribute salt at stated intervals to the herd. This is one principal means of attaching them to a particular spot ; and so great is the avidity with which they take this substance, after being for some time deprived of it, that when it has been distributed to them two or three times at the same place, they are seen running from all quarters to the spot as soon as they hear the horns which tho herdsmen sound before making the distribution. If, however, the country yields a sufficient supply of salt, and if the herdsmen neglect to assemble the Cattle from time to time, they become in a very few years wholly wild. This has happened at two places to M. RouUn’s knowledge, the one in the province of San Martin, in a property belonging to the Jesuits, at the time when this religious order was expelled, the other in the province of Mariquita at Paramo dc Santa Isabel, in consequence of the abandonment of some works where the natives washed for Gold. In the latter place, the Cattle have not remained in the districts where they were originally placed, but have mounted the heights of tho Cordilleras to seek the region of the Grasses, and there live in a temperature almost uniform of 48^ to 50° Fahrenheit. To this spot the peasants of the villages Mendez, Piedras, and some others situate in the plains, sometimes come to hunt them. They drive with knotted cords small divisions of the herd towards the places where snares havo been previously prepared. Whenever they obtain possession of one of these animals, it is often iippossible to conduct it alive from among the mountains. This does not arise from the resistance which the captive makes, for after a little time its violence begins to diminish ; but when the animal begins to perceive the futility of its efforts to escape, it is often seized with so great a tremor over the whole body, that it falls to the ground ; to make it rise becomes impossible, and it dies in a few hours. Tho want of salt to preserve the meat, the distance from any inhabited district, and tho difficult .nature of tho roads, prevent the hunters from deriving any other advantage from tho slain animal than tho portion which they can consume upon tho spot. These disadvantages render tho hunting of wild Cattle by no means frequent j and the hunters always run the risk of being surprised by the snow, which often falls in these ele- vated regions. When the snow lasts many days, those unfortunate men, accustomed to the continual warmth of the adjoining valleys, are sure to perish. If, how- ever, they are so fortunate as to bring one of these animals from the mountains, it is not difficult to tame j this is effected by confining it near to the farm, by supplying it regularly with salt, and habituating it to tho sight of Men, M. Roulin never had an opportunity of seeing one of these animals alive, but he tasted the flesh of a wild Calf which had been killed on the evening of bis arrival. Its flavour did not in any respect differ from that of tho common domestic Calf j the hide was remarkably thick, in other respects of the usual size ; the liair was long, thick, and rough. In the province of San Martin he, however, saw' a wild Roll of a chestnut colour, pas- turing in the Llanos in the midst of the domestic cattle. The Wild Bulls pass the moruinw in the woods which cover the base of the C-jrdilleras, and do not appear in tho Savannah until about two hours after noon, when they come out to feed. As soon as they perceive a Man, they hasten to regain the forest at a full gallop. The hide of the Wild Bull does not appear to differ in any respect from that of the domestic Cattle which inhabit the same districts. In both they are much heavier than the hides of the Cattle brought up on the plateau of Bogota, and the latter yield in this respect, as well as in respect to the thickness of their hair, to the wild Cattle of Paramo de Santa Isabel. In the warmest parts of the provinces of Mariquita and Neyba, there are some herds of horned Cattle with their hair extremely scanty and fine ; they are given, by antiphrasii, the epithet of Pelones. This variety is transmitted to their descendants, hut no care is taken to preserve the breed, as tho Polones are unable to bear tho cold of the elevated regions of the Cordilleras, where the cattle intended for con- sumption or exportation must remain for some time to fatten. There is also another variety of Cattle in this district called Calmigosy having the skin entirely naked like the Barbary Dog. As these animals arc more feeble and delicate, it is usual to kiU them before they are old enough for breeding. These never appear in tho cold districts. In Europe, where the milk of the Cow forms a very important article of rural economy, it is usual to milk her continually from the moment of the birth of her first Calf until she ceases to be fertile. This practice, continually repeated upon all these animals for a long series of generations, has had tho effect of producing permanent alterations in the species. The udders have acquired an extraordinary size, and the milk continues to be secreted even after the Calf has been removed. In Columbia, however, the introduction of a new rural system, the abundance of cattle in propor- tion to the number of inhabitants, their dispersion in pastures of very great extent, and a number of other circumstances which need not here be detailed, have counter- acted this effect of domestication. The organization and function of the udder soon resume their original state when freed from the long-continued influence of habit. At present if a Cow of Columbia be intended to yield mUk for the dairy, the first care must be to preserve the Calf ; it is allowed to remain along with its mother for the entire day, during which she is permitted to suckle it. They can be separated only at night, and the milk secreted during the interval of their separation alone becomes available for economical purposes, and accordingly it is abstracted every morning. If the Calf happen to die, the secretion of the milk is immediately stopped. In America, the Cat has scarcely undergone any alteration, except in its having no period of the year corresponding to tho rutting season. This peculiarity, which might naturally be expected in a climate always equal, exists also with the Hog, the Bull, the Horse, the Ass, and tho Dog. Although Kids and Lambs are born all the year round, yet there are two periods of tho year, Christmas and Whitsunday, when the number of births is greatly increased. These particulars, furnished by M. Roulin, though necessarily defective on many interesting points, enable us to draw several important conclusions, which servo to throw a light upon the past history of our domestic animals, and directly also upon the philosophy of species in Zoology. However, the extreme difficulty of distinguishing those phenomena which are due solely to domestication from those belonging to food, climate, and situation, lead us naturally to inquire whether tho records of ancient History can yield us any information regarding the progress of variation among our domestic animals. If wc can discover in these writings any traces of their gradual deviation from the form of the wild races, we have an additional evidence in support of those views which have here been laid down. Unfortunately tho notices of the domestic animals in the writings of the ancients are neither numerous nor full ; yet however scanty, they possess a peculiar interest and importance. It is true that wc find those civil and military events which attend the rise and fall of great Empires, or the establishment of different religions, and other historical events concerning the Human Race, recorded with a scrupulous attention; but the ancients may be said to have wholly neglected the minor histories of tho farm- yard and stable. The gradual modifications of their domestic auimals presented none of those brilliant events and striking positions which compose the ordinary pages of history, but, moving onwarils with a silent and almost insensible step, they escaped the notice of their contemporaries. Man, on becoming civilized, soon forgot, with char- acteristical ingratitude, those early companions of his labours, without whose aid his own progress might have been indefinitely retarded. It is only now by examining the aggregate of their changes through a long course of years, that we are led to perceive the extent of their modifications, and can fully appreciate the importance of their con- tributions towards the wealth and happiness of society. IHodern Naturalists have commonly supposed that the native country of our domes- tic Mammalia cannot be ascertained; yet it would appear that these animals wore all living in a wild state in Europe at the time of Aristotle. This great Naturalist himself attests the fact, and mentions the Horse, Bull, Hog, Sheep, Goat, and Dog, as familiar instances. We are also informed by I^Uny, after having alluded to the intercourse between domestic Pigs and the wild Boar, that there were no domesti- cated animals in his time, which could not also be found in a wild state. (In omnibus animalibus placidum ejusdem invenitur ct ferum). The concordance of these two passages is striking, and they prove that in the 450 years which elapsed from tho time of Aristotle to that of Pliny, the domestic auimal* had not been widely distributed over the globe, nor had they undergone much varia- tion. Indeed, as long as wild animals reside in the immediate vicinity of the tame herds, it is certain that the domestication of the latter will he exceedingly imperfect. The continual intercourse of the wild with the tamo animals, and tho contagious example of herds running wild in neighbouring mountains and deserts, must have diverted tho captive animals from those domestic habits to which the restraints of Man would otherwise have reduced them. In this rcs^icot, tlie partially domesticated races would have resembled those Indians of tho United States of America, which are taken from their tribes during their infancy, and educated in the midst of to^'ms, both in the religion and manners of the Europeans. At the age of twenty or thirty years, if they happen to encounter in the woods a tribe of Hunters of their own nation, so hereditary are their propensities, that they at once reject their fornn?*’ peaceable life, with all its advantages, moral and intellectual, and plunge without re- flection into the savage and adventurous life of their ancestors. Varro appeal's to confirm the opinion of the Greek and Oriental Philosophers, that tho Sheep, in consequence of its superior docility and mildnijss, was the first anini®^ which became domesticated. “ The Sheep,” says he, “ is not only of a very peaceful nature, but it is tho animal most fitted to supply the wants of ftlan, since it not only milk and cheese for food, but also its wool and skin for clothing.” “ several countries,” continues Varro, there still exist in the wild state some of th^ animals which we have rendered domestic. In Phrygia and Lycaonia, many flocks of Wild Sheep are to be found. The Wild Goat exists in Samothrace, and there are several in Italy, in the mountains adjoining Fiscellum (now Monte della Sibilla, Ahbruzo), and Tetrica (near tho most elevated point of tho Appenines in the jMarch of Ancona). In respect to the Hog, every one knows that he is desceu a from the Boar, which is found wild in all countries. There are still a great number of Wild Bulls in Dardania, Mysia, and Thrace ; there are Wild Asses in Phrygia- in Lycaonia, and Wild Horses in some parts of Hither Spain.” (Re Rustic, Il> ' 4-b'). This passage of Varro fully corroborates tho testimonies of Aristotle and and his evidence is important, as wo know that Varro himself travelled ^*****^'^^^0^^ the countries where he places these wild animals. Alodern researches have ven a part of Varro s declaration, and recognize tho origimil localities of the Ass. arc the mountains of Taurus and lower Curdistan, separating Persia from Afghuuw Here it still exists in the wild state, and tho pursuit of this Solipode has loug one of the chief amusements of the Persian Kings. . Buffon and other modern Naturalist differ in opinion from Varro and the Philosophers, regarding the priority of domestication with tho Sheep. The according to Buffon, was tho first animal which Man acquired for his use ; was by the assistance of this animal that he was able to seize and subdue all *'*'* “„. species necessary to supply the wants of an infant society. This opinion rests c upon tile extreme facility with which wild auimals of the Dog Genus are tamed, ari ” THE MAMMALIA— MAN AND BEASTS. 63 from their great sociability and their power of imitation. Azara mentions an Agua- rachay of Paraguay (Canis cinereo-arpenteus) which became as tame as a Dog, but ate up all the fowls. Yet the opinion of ancient writers regarding the prior domes- tication of the Sheep seems to bo by far the more probable. The Sheep lives habi- tually in large flocks ; the mildness of this animal, its simplicity, and disposition to follow its companions even to certain destruction, must have rendered it an easy prey to the savage in those first ages which followed the creation of Man. Its utility for food and clothing must have been evident. On the contrary, the Wild Dog lives in troops ; ho is a Carnassier, fierce, and daring ; he unites with his fellows to form a combined plan of attack and defence. He is as strong and more to be dreaded than the Wolf. No use could be made of his skin, of his flesh, or the milk of the female. Hence it is not very probable that the savage would have at once foreseen all the future advantages which he would derive from associating the Dog in his labours to reduce and subdue the other animals. JEven if he could have entertained this pro- ject, the difficulties and. dangers with which it was beset would have diverted him from the enterprise. In this case, we must admit, that the more simple and natural idea would first present itself to his mind. It may easily be imagined, that in those early ages, when the globe was less peopled than it is at present, the great work of Domestication must have been slowly and gradually accomplished. The remarkable property which these animals possess of transmitting their acquired qualities to their descendants, and ol perpetuating modi- fications of form, colour, and even of inteUigence, render their races singularly capable of improvement. The several races of Men are far less capable of undergoing this relative improvement than the domestic animals, which receive his influence iu innumerable ways. Yet we are not without some striking instances of the trans- mission of acquired properties even in Man. Among the Negro children of Sierra Leona, the offspring of the Negroes, who have long been liberated, and who are born in the colony, possess an immense relative superiority of intelligence over the chiUlren of Negroes which have recently been emancipated from their slavery. Their parents inhabit the same country; but the older liberated Negroes have commenced a moral and intellectual education, while the more recent Slaves have long endured a savage and degraded existence. It has, however, never been attempted to bring the Human race, like the Domestic animals, to a greater physiological perfection, by always uniting individuals, remarkable for the beauty of their forms, the goodness of their temperament, and the extent of their intellectual faculties. Absolute monarchs might, in the course of a long dynasty, have made this curious experiment, and en- deavoured to promote the good of their subjects, by improving the breed of their own ministers. Hence Man, considered as a race, that is, in reference to his physiological qualities, is much loss capable of improvement than the domestic animals. In consequence of this remarkable property of transmitting acquired faculties to posterityt the notices of the ancients, which (late back perhaps from twenty to twenty- five centuries, however meagre, become peculiarly important and interesting. Wants, dangers, and necessities, develop the more violent and fiercer passions of animals; the suppression of these exciting causes improves the milder and more useful qualities. From the descriptions of Aristotle, the passions of the domestic animals were formerly much more violent than they are at the present day. The progress of domestication, as recorded by the ancients, in respect to the Horse, the Ass, the Dog, and the Cow, presents many interesting facts. With the Dziggtai {Equus hem{onus)t domestication seems to have made a retrograde movement. Herodotus (iv. 52) informs us that Horses existed in the wild state on the banks of the Hypaiiis (now the Dniester). These Horses, he adds, were white. Further, also, that in Thrace, tho Paconiaus of lake Prusiaa fed their Horses and beasts of burthen with fish instead of hay. Strabo says that the Wild Horses were to be found in India, on the Alps, in Iberia, among tho Celtiberians, and finally in Caucasus, whore the intensity of tho cold had given them thick coats of hair. The last remark is confirmed by modern observations on the Norwegian and Lapland Horses, which have a thick and woolly hair like tho fleece of our Sheep. Pliny says that tlie North contains herds of Wild Horses. Strabo relates, on the authority of Alegasthenes, that the greater immbor of our domestic animals were wild in India. iElian makes the same remark for tho interior of India. Since Wild Horses thus existed in great numbers on several parts of the Old Con- tinent, the progress of domestication must have been very slow in all those places where they came iu contact with the tame herds. Azara observed, that tho Wild Horses which live at liberty in the pltuns of Pari^uay, in herds consisting of many thousand individuals, have an instinctive habit of seducing the domestic Horses. As Won as they perceive one, says this able Naturalist, even at the distance of two leagues, tliey form into an uninterrupted column, and approach at full gallop to entice him. They cither surround him on every quarter, or merely come along side ; they ^fess him by neighing gently, and always end in carrying him off never to return, without his offering them the slightest resistance. Tho inhabitants of that country hunt the Wild Horses very keenly, to drive them away from their own studs, for, without this precaution, the Wild Horses would seduce away all tho tame herds, ^crbillon notices the Wild Horses in tho desert of Chamo in nearly tho same terms. This fact may serve to explain one of the causes that in ancient times the herds of ^^ild Horses disappeared very rapidly when the population increased. According to accounts of those Missionaries who were best aciiuainted with China, M^ild Horses still to be found iu Western Tartary and in the territory of Kalkas. They live large troops in the neighbourhood of Ha-mi, and appear to resemble the common Horses. Grosicr, in his Description of China, mentions that if they meet a domestic Horse, they surround him on all sides, and, urging him onwards, draw him to their of Saghatur. A passage of Xenophon (‘ttsqI III.) alludes to this characteristic of tho ild Horses, so forcibly described by Azara and the Chinese Missionaries. His remark serves to show that, at the period of 450 years before tho Christian era, the domes- tication of the Horse was still recent, and had not yet overcome this primitive in- stinct. In speaking of a Horse broken in by tho groom, Xenophon observes, “ It is proper to ascertain whether, when momited, he will willingly separate from other wscs, or whether, when passing them at a short distance, he docs not attempt to join them.” Another observation of Xenophon, “ One can teach nothing to a Horse by word of mouth” (Ibid. VIII.), shows how imperfect their domestication must have been in his time. We have so many proofs and examples to the contrary, as to render an allusion to them only necessary at present. The modern Wild Horse, as described by Pallas, has his tail and mane very long and thick. He carries his cars depressed backwards, like a domestic Horse of the present day when preparing to bite. Xenophon and Varro describe a Stallion, the model of a War-horse, in words nearly synonymous to those used by Pallas in de- scribing the Wild Horse of the Russian Steppes (juba, cauda, crebra, suberispa, auribus applicatis). We have here an evident proof that the Domestic Horse, in the last century of the Roman Republic, still retained the characters now peculiar to the Wild Horses of the old continent. It must be observed that Herodotus describes the Wild Horses to be white while the dark bay has become the prevalent colour of the Wild Horses in America. Naturalists have generally concluded that the latter was the primitive colour of the species. This difference between the primitive hues of the Old and Now World is supposed by some to be owing to the excessive cold of the climate in some parts of the former, where it has been supposed that the temperature might act upon the Solipeda and Ruminantia in the same manner as it is known to do upon Hares, Rabbits, and other Rodentia. But Leo Afriuanus and Maxraol relate that the Wild Horses of Africa are small, and cither white or ash-colourcd. 1‘allas also informs us that the Wild Horses which inhabit the country between the Jaik and the Volga are fawn, red, or dun-eoloured. Aristotle attributes the changes in the colour of the hair of Mam- malia, as well as in the feathers of Birds, jointly to the cold and the influence of the water. The streams of Psychus, near to Chalcis in Thrace, according to him, caused the M'hite Ewes to produce Black Rams. In the neighbourhood of Antan- dros, he states that there arc two rivers, one of which causes the lambs to be white and the other black. We must remember that Aristotle belonged to Stagyra, and that he here mentions a fact which, it is probable, had fallen under his owm obseiwa- tion. The same remark is made by Varro, Pliny, jKlian, and by Anatolius (Hip- piatric, p. 59). It would be interesting to verify their declaration by observations made on the spot, as it seems to be rather of doubtful authority. The progress of education with the Horse, and the influence of domestication during 1800 years, are seen in the development of his paces both in number and permanence. The natural paces of the Horse are the walk, the trot, imd the gallop ; those which he has acquired from education, for the purpose of combining swiftness of pace with comfort to the rider, arc the amble, the pun relevc^ and the aubin of French authors. The pas relevc. consists in raising two foot on tho same side, not at once as in the amble, but successively. Jt is a close trot which beats tho ground, as in the walk, at four successive times. In tho auliny tho Horse gallops with the fore feet and trots with tho hinder. The Greeks and Romans had induced neither the pas rcleve nor the aubin. That pace which they call tolutarii, and which the Lexicons give as synonymous with is evidently tho amble, and seems to have been induced during the last century of the Homan Republic. It is described by V'’arro, Pliny, Nonius, and Vegetius, in a manner which leaves no doubt that the amble (tolutartm amhulaturani) was produced by training {iradiiur urtc). The race at that period had not been so long domesticated, that this property should have been transformed from an artificial acquirement into a permanent quality. It must then have been in tho interval of time which has elapsed since the days of Pliny and Varro, that the amble, the pas releve or trot with four beats, and the aubin, where the Horse gallops with the fore limbs and trots with the hinder, all of which are wholly artificial, had become natural paces, and were transmitted as such to posterity. At the present day, these acquired paces arc as permanent as the properties of pointing and bringing back game with the Setter Dogs and Retrievers. M. de la Malle has remarked more than a hundred times in the pastures of Normandy, that the Foals descended from a sire and dam endowed with the pas releve, or even where the sire alone possessed this quality, have exhibited this artificial movement in the meadow before receiving tho slightest education, or even leaving the side of their dam. As we might readily expect, the ancients were acquainted with very few varieties of the Horse. Only two distinct races, the Thessalian and African, can be traced on those ancient monuments which have reached our times. There are, however, two intermediate varieties, the Sicilian and Apulian races, formed probably from crosses between tho Thessalian and tho Wild Horse of Italy, and between tho Italian and the African races. The descriptions of authors agree precisely with the representations on the statues, the basso-relievos, and the medals, at least in respect to the tvfo pri- luitive races. We have the Thessalian Horse faithfully represented on the Par- thenon, iu tho equestrian statues and basso-relievos of the Greeks, and even on the columns of Trajan and other Roman sculphires, where this variety is always adopted as the type of the heroic Horse. The African race is seen on the medals of Carthago and on a medal of Mauritania, supposed to be a Juba (Catalogue de M. Mioimet, t. vi. Nos. 5 and 6). In tho time of Oppian, who was contemporary with Septimius Severus, the races of tho Horse had greatly increased in number, and he accordingly enumerates fourteen varieties. The Persian Horse of the age of the Ach.-emenides is figured on the monuments of Perscpolis. At the present day, in eonso(juenco of tho continual crossing of these races during twenty centuries of domestication, and the joint influence of climate and food, this species, so useful to Man, has been trans- formed into varieties almost innumerable. Tho Horse is now reared under domestication with greater facility than formerly. The foal, according to Varro, was suckled by its mother until the age of two years; —we separate them at six months. At throe years old the young Horse was exer- cised, and when he perspired, w'as rubbed over with oil. li the weather were cold, fires were lighted in the stables. The modern Horses do not require these minute attentions oven in our less congenial climate. The Ass, being less useful than the Horse, has been more neglected by Man, and consequently his physical and intelligent powers are not so highly developed. Yet there are some interesting conclusions which may bo drawn from an attentive com- parison of his ancient and modern history, and may serve to clear up some obscure 64 FIRST CLASS OF THE VERTEBRATED ANIMALS. points as to the causes which have served to retard the progress of his domestication. The imbecility of the Ass, and his imperfect education, may partly be owing to the cir- ctimstancc that the domestic species were continually united with the wild animals during many centuries. This practice was one chief cause of the slow progress of do- mestication among the ancients. Indeed, their rural system of large commons allowed a liberty almost absolute to their herds. Those animals passed the spring in the valleys, the summer on the mountains, and the winter on the plains. It was, there- fore, impossible to prevent tbe wild individuals, which then existed on several points of the globe, from accidentally uniting with several domesticated individuals of their own species or genus. This may probably explain the fable of the Mares of Boctica, said to have been fecundated by the West wind. Wild Horses were very numerous in Spain, and the ignorant herdsman, seeing products formed, with whose origin he was unacquainted, easily resolved the problem by referring it to a miracle. With the Ass, however, it was the constant practice of the Romans, according to Varro and Pliny, to select the Wild Asses (oiiagri) as Stallions. Luitprand, Bishop of Cremona, who wrote in 968, mentions that the domestic Asses of Cremona differed but slightly, in his time, from the Wild Asses of Asia Minor. The attempts of the ancients to produce Hybrids or crosses between different spo* cies were so common, that they had proper names to denote the Hybrids betwoen the Dog and the Wolf, as well as those between the Sheep and the Goat. They also had names for the cross between the Pig and the Wild Boar, and between the Sheep and the Moudon. To obtain a £ne race of Mules, the Romans united the Mare with the Wild Ass. Columella remarks, “ that the Mule, the immediate descendant of the Wild Ass, remains wild, difdcult to tame, and slender like its father ; but that the Stallion of this species is more useful in the second generation than in the first. For when a Marc is united with an Ass descended from a Wild Ass and a domesticated female, the savage nature of the IMule appears to have been softened down by the influence of time, and the product of this union combines the beauty of form and the mildness of its sire, with the courage and swiftness of its grandsire." Tliis impor- tant observation, of Columella strildugly exemplifies the influence of domestication, as well as the transmission of certain physical and intelligent qualities in the course of generations, and is the more valuable, as wo may at the present day search Europe in vain for a Wild Ass to repeat this interesting experiment. Those Chapters in the writings of Varro, PUny, and Columella, which treat of the production of Mules, contain minute directions as to the precautions which were necessary in their days to bring about an unnatural union between different species. The Ass, intended ultimately to propagate, had to be taken from its mother the mo- ment it was bom, and placed under a Mare without its perceiving the change. The IMare, on the other hand, had to bo deceived by keeping her in the dark, and her own foal had also to be removed. She would then suckle the Ass’ foal intended for propa- gating, and treat it as if it were her own offspring. In this way, the foal selected to be a Stallion formed an attachment to Mares from its infancy. It had to be constantly introduced into the society of Marcs even while yet at the breast, that it might be habituated to their approach at the e.irliost age. The above mentioned authors go on to describe that I’accouplcmont doit se fairo dans un lieu etroit, ferme, obscur, avee une jument liee, qui a dejh porte, et dont Ics desirs ont ete d’avance irrites par un ane commun qui les cvcUlc sans Ics satisfairos. These precautions clearly show that domestication had not yet induced that kind of depravity which is its consequence, nor bad it yet been sufficient to corrupt the manners of the Ass and Horse as at the present day ; for wo know that these Hybrid unions, formed between different species, can now be procured without the necessity of resorting to the slightest artifice. It must, however, bo recollected, that such unions can only arise among domestic animals of nearly-allied species, or between animals of which one sex at least is domesticated. The Rurainantia, it has been already cxphiined, arc those over whom domestica- tion has had the least influence. Yet among the Romans, it was found necessary to employ only the most robust and powerful men, of a loud and menacing voice, to con- duct their Herds of Oxen. Before yoking an Ox for the first time to the plough, it was requisite to tie him strongly to his manger, to put the yoke on his neck, to enfeeble him for four days by hunger and forced watches, and then to coax him with cakes, salt, and wine. At the present day these precautions are wholly superfluous ; and in any of our modern farms, a girl of fifteen years of age can induce the strongest Bull to obey her commands, although he may have lived for many years at large in the meadows. There is a singular fact recorded by the ancients respecting the food of the Ox, which was long considered to be of doubtful authority. iElian and Avhenieus have related, on the authority of Zcuothonus, that in a lake of Pzeonia, certain Fishes were produced, which the Oxen ate with as much pleasure they would have eaten hay, provided the Fishes were presented living and palpitating. When dead, the Oxen would not touch them. The singularity of this assertion, which would servo to break down the usual distinctions between the digestive functions of Herbivorous and Car- iMvorous animals, has, however, been removed by modern writers, several of whom relate, that in the cold countries of the North of Europe bordering on the sea the Oxen and Horses arc fed on Fish. In respect to Horses, there can be no doubt as to tbe fact, for tbe Horses which were brought in 1788 from Iceland to France, by lil. de Calonne, had no other food than Fish on the passage, as well as during their stay at the port of Dunkirk. M. du Petit- Thouars, who was garrisoned at the latter place, reported this fact to M. de la Malle, on whose authority it is inserted here. Torfiius (Hist. Norveg.) relates the same fact for the Norwegian Horses. The more recent experiments of M. Magendie have fully confirmed this omni- vorous property of the Domesticated Animals ; and it is perhaps one of the most curious consequences of their association with Man. Wild Animals apjicar, however, to possess this quality to a certain extent. AI. Roulin reports that th« Martin (taira) of Columbia will eat bananas and gretm maize, as well as Quadrupeds, Reptiles, Birds, and Insects. M. de la Malle has known a Polecat to devour pears, peaches, apricots, grapes, and other fruits of our garden trees, besides its ordinary animal food. These facts appear fully to verify the observations of Ailian and /enothemis. Another consequence of domestication, in modern times, may be remarked in the permanent secretion of milk with the Cows, Ewes, and She-Goats. The wild races only suckle their young (hiring the interval necessary to habituate the digestive organs of their progeny to other food. We have already seen that the domestic species, transported into the New World, have lost this property of their ancestors in acquir- ing their independence, and only preserve their milk as long as the calves end kids are kept along with their dams. We have a further proof of the imperfect domesti- cation of the Ass, in the circumstance that the secretion of milk in the female Ass does not remain permanent, but continues only during the time that the foal remains with its dam. An interesting pass^e of Aristotle appears to show, that one of the most im- portant consequences of domosrication, the permanent secretion of milk, which is at present maintained by an irritation of the Mammm almost mechanical, was first induced by a stimulus procured from some plants of the Nettle family ( Urticece). He adds, in reference to tbe She-Goats, that even when they have not been fecun- dated, it was customary to rub their udders with Nettles so violently as to excite pain. At first milk was drawn mixed with blood, then a quantity of purulent matter, and finally a milk as pure, as healthy, and in a quantity as copious, as tint rendered by a She-Goat which had just produced. The progress of domestication may, however, be seen more especially in the Dog, who has in all ages been the companion, the guardian, and we almost say the intimate friend of Man. Being possessed of a superior genius, and habituated to the society of his master, domestication has been truly wonderful in developing his natural capacity. The ancients were acquainted with but few varieties of the Dog, as far as we can gather from the descriptions of authors, and the figures on the monuments of antiquity. They had tbe Watch Dog, the Coursing Dog, the Shepherd’s Dog, and the little Maltese Dog, supposed to have somewhat resembled the French Bichon. The intelligent qualities of these varieties had been but slightly developed ; and the ancient Greeks and Romans were wholly unacquainted with those Dogs which set game, such as the Pointers and Spaniels, upon whom a modern education can produce results so surprising. The Water Spaniel or Poodle Dog, whoso fame is now widely spread for the constancy of his attachment and the extent of his acquirements, was wholly unknown to them. Aristotle and Xenophon have expressly declared, that animals can be made to understand nothing by word of mouth. Those who have witnessed the intelligence and dexterity of the modem Poodle Dog, will be able readily to appreciate the influ- ence of domestication when continued through a long period of time. These animals can be induced, at the word of command, to ring the bell, or perform many of the or- dinary duties of a servant, such as to shut and open the door, or deliver a letter. A black Poodle belonging to Robert Wilkie, Esq, of Ladythorn, in the county of North- umberland, would feign all the agonies of death in a very corret;t manner. When com • manded to die. he rolled over on one side, stretched himself at full length, and moved his hinder logs with a convulsive motion, first slowly and afterwards quickly, as if in extreme pain. After putting his head and body in motion with those affected con- vulsions, he would then stretch out all his limbs, or lie on bis back with the legs turned upwards as if he had expired, and remain motionless until the word of his master restored him again to his customary animation. These instances, and numerous others, which need not here be produced, clearly establish the important fact, that the education of the domestic animals has always followed a gradual progress, which may be ciclier slow or rapid, according to circum- stances. We may thence further expect, that future ^es, by bestowing more care as well as skill, and being aided by the influence of a longer perioil of time, may de- velop the intelligent powers of our domestic animals in a still higher degree. It appeal^, that with one species at least domestication has gone retrograde. The Dziggtai (^Eqvvs Hemionus) of Mongolia was once domesticated in Syria. Aris- totle declares (Nat. Animal, vj. 30), that “ in Syria animals are to bo foimd called Hemionus, a species resembling the mule in appearance, but being in reality different from it. These Hemionus are swifter than Mules. They produce among them- selves a constant race. Some animals, which still remain in Phrygia, where they were introduced in the time of Pharnaccs, the father of Pharnabazus, prove the truth of this assertion. Three animals now remain out of nine.” Although the later writers among the ancicoits generally confound the Hemionus with the different kinds of Mule, yet Ariatotle carefully distinguishes them. Thei'e was the Mule (ou^soj, or the Hybrid between the Ass and Mare; tbe Bordeau hinnus')^ or ilie Hybrid between the Horse and female Ass; and a cross of tho second degree (yivuoSi hinnulus^t between the Mule and the Marc- From all of these Aristotle separates “ the Hemionus (if^/ovof), which is not at all of the same species as the Alulc, notwithstanding its resemblance, since they propa- gate together, and continue their race.’ Theophrastus confirms this remark Aristotle; and more modern writers, such as Constantino Porphyrogenitus, Eustathius in his Commentary on the Iliad, remark, that tho Hemionus was formerly domesticated in that part of Asia Minor called l^apWagonia. Pallas has recently identified the Hemionus of Aristotle with the modern DzigS^* of Siberia. It is probable that this species may have been brought to Syria by som^ of the Tartar hordes, and that it remained there in domusiieatian until the era Aristotle; for after this time all notice of it disappears from the writings of ancients, and its place is supplied by the Horse and Alule. In certain parts of CcO' tral Asia, the Dziggtai is said to be domesticuted at tho present day. Thus, upon considering the domestic animals in reference to those phenom*?^^ which have attended their return from the domestic to the wild state, aiid upo^* investigating the records of antiquity, we are led to form several important sions which it may bo proper hero to recapitulate. In the first place, we find that tho numerous \'ariation5 of the domestic animalsi respect to the colour and quality of the hair, are brought back by a state of to a uniformity almost invariable- In the New World the common colour ^ hair is a chestnut bay for the Horse, a dark gray for the Ass, and black for the In the Old Continent it scorns to be gray for the Ass as in America, but a colour for the Horse, whicii here becomes white. Wc are hence entitled to infr’’ that all shades which diverge from these primitive hues are the evident THE MAMMALIA— MAN AND BEASTS. 65 of domestication. This discrepancy between tho original colours of the Horse in the Old and Now Continents is not, howetcr, without an analogous instance. Tlic Ox, on becoming wild in South America, appears, from the observations of M. Roulin, to have reverted to a chestnut brown, while in Britain we know that tho wild breed of the Ox, now exterminated, was entirely white, excepting a slight tinge of red on the ear, and a black inuarlc. Further, we find that the domestic animals on becoming wild reacquire other properties corresponding to their independent mode of life. Tho ears of tlie Hog arc diminished, and his skull is cnlai'ged j the speed and agility of the Horse are increased ; the courage of the Ass reappears especially among the Stallions ; and the petulance of tho Goat seems to bo augmented with tho ease and agility of his movements. We also find that the permanent secretion of milk in the Cow and She- Goat is an acquired property of domestication. In conducting these inquiries, it often becomes difficult to distinguish those changes which are entirely at- tributable to tho loss of properties fonncrly acquired by domestication, from those new changes induced by climate, food, and other physical conditions under which the animals are placed. It is to some accidental influence of this kind, that wo must ascribe the difference in the primitive hues of the Horse and Ox, which in America are chestnut bay and chestnut brown ; while in tho Old Continent white is the original colour. Yet, after making due allowance for tho joint or separate influence of food and climate, and after comparing the several races with each other, .ind with the circumstances in which they are placed, wo are compelled to admit the general prin- ciple, that habits of independence occasion the wild races to revert continually to- wards a primitive form and colour, which can he no other than those from which they have diverged in tho course of ages. In the second place, upon examining the waitings and monuments of antiquity, we find that all our domestic animals liave existed throughout Europe in the wild state. Most of them have undergone modifications dependent on the antiquity of their domestication. This progress can be traced in the Horse which has undergone perceptible changes during the interval of seventeen centuries from the age of Pliny to the present time. The pace of the pas-releve has been acquired by our Horses .since the time of the Romans, and this quality is now transmitted to posterity. Wo further perceive that while thti ancients were acquainted with only four varieties of the Horse, and but few of the Dog, the variations of these animals at the present day are absolutely innumerable. Tho influence of domestication in developing tho milder and more useful qualities of the Horse, the Ox, and the Dog, as well as in perfecting their intelligence, may be clearly traced. There also exists a tendency to break down the original distinctions between the carnivorous and herbivorous animals, by inducing a kind of omnivorous habit, especially when these animals are reduced to extremities. Tho dense fleece of the Sheep and the harking of the Dog have been considered to be the acquired results of Domestication. Hereafter wo shall investigate the grounds upon which those opinions s(*em cliiefiy to repose. Every where we are struck with that general tendency of the Mammalia, and in- deed of all living beings, to preserve the forms impressed upon them at the moment of their creation. As soon as the industry of the Horticulturist, or tho skilful precau- tions of the Grazier and Veterinarian, are suspended, both Plants and Animals alike feel the influence of tins aftieism, which leads them to revert to the forms of their remotest ancestors. The vegetable resumes its rustic garb, or tho bitter and use- less secretions of its wild condition, tho animal loses some of the most important and valuable of its properties. Both alike revert to a uniform tjqjc in their external and internal characters. Animated beings are soon stripped of those rich attributes which they had derived from the cultivation of the soil, or from civilization, tho abun- dance of nutritious food, a careful shelter from the inclemencies of the weather, or their habits of intercourse with the superior genius of Man, but above all, from his care in regulating their unions among themselves. A bountiful Nature is ever ready to sub- stitute qualities, which bear relation only to the w'ants of the animal, and tho part it should perform on the great stage of created existence, for those other properties, which doubtless were imparted only for the purpose of administering to the wants and necessities of Man. GENERAL REVIEW OF THE MAMMALIA CONTINUED, Jlc-capitulation — Rclaiion$ which the dimensions of the Maminalia hear to the pecu- liarities of their organizatioUf and the stations they are designed to occupy — Oc- casional difference of Size between the Sexes. That original types have been impres'^ed upon species at tlic moment of their creation, seems then to he one of the most general and important laws of Animated Nature. If the preceding observations have any force, the conclusions in which Lamarck and other experienced Naturalists have inferred the perpetual variation of species, and the indefinite extent of their modifications, during tho course of ages, become wholly inadmissible. Great as tho variations of Animals and Plants' may appear upon a superficial consideration, they seem, upon a more cautious investigation, to be in reality confined within certain very narrow and well defined limits. The care of tho Horti- culturist can modify tho secretions of a plant, and the relative magnitude of its parts; lie can obtain an extraordinary development of one part, at tho expense of another ; lie can transform the stamens into petals, and occasion a single flower to become double; he can import a delicious flavor to the fruit; or lead to the development of fleshy and tuberculous roots by suppressing the branches, shortening tho stalks, or diminishing the flowers. Availing himself of a corresponding law of Nature, the Grazier can modify the gecome progressively less .iccordiiig as there exists a progressive diminution of fe- cundity. Among tlioae domestic animals, whose fismales supply us continually with the inequality becomes enormous in the largest species, because frequent milk- is still more unfavorable to development than a very great fecundity. Good Cows fatten during gestation, and become lean when milking commences, whatever may the quality or quantity of their food. I he primitive cause of this inequality of size between the sexes seems to show a tendency to return to an equilibrium ; and we may thence infer that there formerly i^ Fahrenheit. The minute division of the food by mastication is a process indispensable to a lapid digestion. While the teeth and jaws are performing their function, the salivary glands of the mouth conlinuo to secrete a fluid in very considerable quantity. In Ruminantia, and generally iu itll animals living on a vegetable diet, these salivary glands arc very Urge, while in the carnivorous tribes they are very small. The entire length of the alimentary canal differs materially among the Mammalia. Its length, with the Ruminantia, is twenty-seven times that of the body, while it THE MAMMALIA— MAN AND BEASTS. 69 only from thrco to five times their length among the Carnivora. In omnivorous animals, such as Man, its length is intermediate to these, being six or seven times that of the body. Several experiments have been made by Sir Astley Cooper to ascertain the diges- tive power of the Dog. He found that this animal digested pork more easily than mutton, the latter moro rapidly than veal, and beef with greater difficulty than any of the othcr.s. lie found that fish and cheese were easily digested by the Dog, and boiled veal more readily than roast. The fat of meat seemed more digestible than cheese, codfish dissolved more readily than beef, and boef than potato. The order of digestion for the different parts of the same kind of animal food, was fat, muscle, skin, cartilago, tendon, and bone, the last being the least digestible. Young Dogs, when they have acquired strength, and are in good health, can digest bones; and what is remarkable, Spallanzani has observed that the gastric juice of their stomachs made an impression even upon the enamel of teeth. Hoerhaavo asserts the contrary, but the observations of Spallanzani have been confirmed. This power of dissolving bono is not peculiar to the Mammalia, but is also possessed by some animals of the other classes. Thus the Falcons, Eagles, and Crows, usually refuse bones; but when introduced into their stomachs, with proper precautions, these refractory substances are digested. Serpents and Adders also digest them, as has been remarked by Spallanzani. Only the smaller bones, however, possessing the least solidity, arc di.ssolvod entirely and rapidly ; the harder bones require to be minutely divided in order to be softened and dissolved, otherwise they merely undergo a small loss of substance. It must be observed, that before digesting they pass into a cartilaginous state, and resemble indurated gelatine, as if they hatl been submitted to the action of nitric acid. The Ruminantia, like the granivorous Birds, can digest herbs and grains, only when these substances have been previously divided, mashed, or ground. When entire herbs and solid grains are introduced into their stomachs, whether uncovered, or inclosed in linen, or perforated tubes, these substances undergo no digestion; they are merely moistened or softened, and this is the extent of their modification. The tame result is obtained oven when they are moistened with saliva. On the contrary, *f bags or tubes of mashed herbs or grains be introduced into the stomachs of the Ruminants, the digestion is then performed in a few hours. These experiments have been made upon Oxen, Sheep, and many other Ruminantia, and they present similar results for all this order of Mammalia, They have also been made upon the Horse, and with the same result, although ho does not ruminate. Many physiologists have attempted, with various success, to effect artificial diges- tions out of the body, by extracting the gastric juices from the stomachs of different animals, and afterwards mixing them with the food. Spallanzani, by these experi- ments with the gastric juices of different animals, obtained several important results, ^hen cold, the gastric juice produced scarcely any effect ; it merely opposed putrefac- tion, but did not exercise its dissolving and digestive power until it was raised to its proper temperature. It did not act upon grains and herbs until they were ground, niashed, and impregnated with saliva. The gastric juice of Man softened and seemed to digest beef in about thirty-six hours, when raised to a temperature equal to that of the stomach. He also observed, that the gastric juice of one species often acted opon a great variety of substances, and yet it did not always act upon substances ^hieh could be dissolved by the gastric juice of another species. From these instances of artificial digestion, wc may readily expect that the stomach, being lubricated by the gastric juice, will continue to digest after the death of the and even it lias been said to digest itself. Hunter first noticed the fact, that the gastric juice will act upon the sides of the stomach after death, and to this cause attributed the erosions and perforations which are somcliraes found in the stomachs human subjects. Spallanzani made several experiments upon Dogs and Cats with a similar result. Ho caused the animals intended for trial to fast for a long time, and then to be fed immediately before being killed. Their bodies wore placed in stoves which preserved their natural temperature, and in the course of a few hours found that the food in their stomachs was sensibly digested. The chyme, after being slowly formed on the surface of that alimentary mass which stomach contains, accumulates as it forma near the pylorus or intestinal opening the stomach. It is raised from this situation into tlie narrow pyloric entrance, by increased action of those gentle and almost insensible contractions which it had already experienced. Tho more violent contractions which are necessary to expel the phyme from the cavity of the stomach, usually originate in the duodenum or small •^testine, from which they are transmitted to the pylorus, and thence gradually to the ®>^tiro stomach. But this ascending movement of the chyme, during which some P0 removed. In this way, the duodenum is gra- ualiy each operation by the food chymified in the stomach. ^ terwards the course of the chyme is very slo^y in the intestines, and the same ob- ervation ajiplies to the intestinal movemcuis generally, c.xcept when excited by or mental emotion. *^l>o fithm.s of the tluodemtm favors the ! ! secretion of the hilo and pancreatic juices the T *"■ juices. All these now fluids being mixed with 0 cliyrao immediately cliange its nature. It almost wholly loses its acidity : its eoioaj. e' — - ■■ ... ^ ’ ness >• changes from gray to yellow, and it becomes bitter to the taste. This hitter- ^ U> some animals extends oven to the stoinachio product itself, especially in If tl punotrates through the pyloric entrance into the stomach, witl ^ contain fat or oily matters, those substances pass into the intestine fhem"**^ undergone any alteration in the stomach, but the bile uniting with »ndtl "I'inl' is easily dissolved. With the exception of herbs, iuis n't*° sultstances, the duodenum permits all bodies, which the stomach similar digested, to pass without altertition. The same aliments produce a 'ho h ° ‘“uu'nls of the same species when in health, and the changes which yme afterwards undergoes are equally the same. But the chyme produced 18 from animal food is thicker and more viscous than that produced from vegetables ; it is reddish, aud docs not curdle milk. Vegetable chyme, on the contrary, is al- most fluid ; it has a yellowish tinge, and curdles milk. Further, the chyme fur- nished by vegetables is less rich in nutritious matter, and it wants that albuminous substance, which is found in chyme resulting from animal food. Different kinds of gas are disengaged during the process, hut their nature varies according to the species of animal, its ago and state of health, the kind of food which is used, and especially according to the part of the intestinal canal from which they proceed. In a short time after the chyme has descended into the duodenum, and undergone the action of the bile, it divides into two parts. The one is a fluid termed c/iyle, which is the part destined to nourish tlie animal ; the other is more solid and coarse, and less homogeneous, and, being the useless residue of the aliment, is finally re- jected. This separation of the chyle, and even its formation, appear to he more especially due to the influence of the bile ; at least it is certain that digestion is always im- perfect, and that the chyle is either deficient or in small quantity, when the bile can- not mix with the chyme prepared by the stomach. -Vmong the greater part of the Mammalia, the time which the chyle takes to form, after the chyme has passed from the stomach into the duodenum, varies from two to four hours. This function is much slower among the Fishes, and still more so with the Reptiles. Well formed chyle has sometimes boon found in the white vessels which adjoin the stomach, and it Ijas been said in consequence, that the stomach can form chyle. But this has only been scon in certain animals, whoso bile frequently mingles with the gastric juice. The Dog appears to be an instance ; but it does not seem to be of frequent occurrence among the Mammalia generally. “ Les cxcremciis,” observes M. Isidore Bourdon, “ scparcs dn chyle qui les sur- nago ct dont 1‘absorption s’op&re dans le haut de I’intestin, perdent peu-a-pcu, I'l me- sure qu'ils dcscondent vers les gros intestins', la fluidite qu’ils avjiiont dans le milieu do I’intestin grCle. Le mucus des gros intestins cn feivorise la marche vers I’aiius, mais les leges que prese.ntent ces conduits do distance cn distance, cn prolongcnt le sejonr ot en accroissent la consislance. O est par 1 action des fibres musculeuses des intes- tins que les excremens son peu-4-pcu pousscs vers I’anus, et e’est par les muscles ab- dominaux qu’ils sent finaletncnt rejeles hors du corps. Cette expulsion resulte d’un mecanisme assez complique on la glotte, an moins chez les Mamif^res, jouo un role important. Le rejet des maticres fccales est bcaucoup pins facile chez les animaux ovipares et dans rOrnithorrhynque ; ct ce'.te difference resulte de ce quo ces animaux ayant un cloaquc, leurs urines s’amassont dans ce lien aussi bicn quo les excremens ; qu’elles dolayent. Les cxeremeiis diffiiront pour chaqne espiice d’animal ; mais la plu.5 grande difference s’ohservo surtout ontro les carnivores ct les herbivores. Le meme animal, s’il est omnivore, a des excremens tris differens, siiirant qn’il use d alimens vegetanx on d'alimens tiros do I’autro r6gnc. Les excremens provenant d’uuo nourriturc animale ont la propriele do fairc caillor le lait, et il n’e.xiste rien de semblable pour les feebs des alimens vegotaux. Cost absolument le contraire de ce quo nous avons dit pour le chyme des caniivores et dcs herbivores.” Bordeu has made several intorcstiiig remarks on this subject; the curiosity of an ingenious mind having overcome the natural disgust towards a study so repulsive. The researches of Prout are more precise than those of Borden. Complicated fluids are digested as well as solids, but a large part of them are ab- sorbed directly by the stomach. Water, alcohol, and other simple fluids, contribute towards nutrition, chiefly by Imparting their fluidity to some of the animal bodies. Those movements of the intestines by means of which they are traversed by the stomachic product, are termed pcristullic. There are, however, other movements, which are directed from below, upwards, in the contrary direction, and are hence termed anti-peristaltic. These movements produce various phenomena, such as Re- gurgitation, Rumination, and Vomiting. Among the Mammalia no animal vomits more readily than the Cat; there arc, however, few Vertebrated animals which do not possess the power of vomiting. The Horse cannot vomit in ordinary eases, be- cause the situation of the eardia opposes an obstacle to the return of the food towards the msophagns. It is ascertained that the chyle separates itself from the alimentary mass, after it has remained for some time in the distended cavity of the duodenum, and that in a short time the hilo and panercatio juices act upon it, although we arc ignorjint of the precise nature of the operation. With respect to tho characters and quality of the chyle, this substance is very plentiful in the Mammalia alone. Tho chyle 15 always of an opaque white, which has caused it to be compared to milk. When taken from the body, and left to itself, it separates into two portions ; the one is serous and saline, while tlie other is fibrous, in this respect nearly rcserablinn- the blood when similarly treated. If placed in an inert vessel, the chyle usually acquires a reddish tinge, which appears to bo owing to the action of tho oxygen in tho air ; and a thick kind of cream forms on the surface. This resemblance of tho chyme to milk 1ms led some physiologists to consider the one as the product of tho other. One thing is certain, that nothing tends more towards the abundant secretion of miik, in the female, than lliat plentiful production of chyle resulting from the abundant sup- ply of nutritious food. In other respects, the nature of the food with which the ani- mal is nourished greatly influences the chyle resulting from digestion. Different .substances do not produce the same kind of chyle; fat matters produce a chyle which is white, and more opaque than that yielded by substances which are not fat. Tiie chyme never acquires the hue of any colouring matter which may have been intro- duced into the intestine ; and it is even with difficulty that it can be made to acquire an odour. The chyle, wrheu once separated from the chyme, of which it may bo regarded as tho extract, flo.its on the surface of this matter, and accumulates by small rivulets in tho mucous valvules, with which tho interior of tho smaller intestines are supplied. It remains in this place for a few instants, when it is absorbed by the small vessels, which servo to bring it into the mass of tho blood. It is impossible to say in precisely what manner, or by what force or mechanism, this absorption of the chyle is effected, and to indulge in conjecture would but lead to certain error. On carefully examining, with tlie naked eye, the interior cf the intestine, at the moment when tho chyle is 70 FIRST CLASS OF THE VERTEBRATED ANIMALS. formed, there may he seen, at the lurface of the intestinal membrane, small eminences like spongiolcs, which appear to erect themselves, and become filled with the fluid. On compressing these spongioles or sm::U projections, the chyle exudes ; and when they are examined with the microscope, we may perceive them to be ramified with innumerable small vessels, and their surfaces perforated with minute pores like the point of a needle. These pores are conjectured to be the commencement of the white vessels or lacteals, which carry off the chyle, and that by their means the chyle is gradually pumped out or absorbed at the surface of the intestine. We are entirely ignorant of the nature of that power by which this absorption is effected, but it has been ascertained from experiment, tliat the chyle penetrates into the lymphatic vessels of tlie intestine, and traverses the glands of the mesentery ; that it is conveyed by proper vessels to the thoracic duct, through which it is finally carried into the blood. Once united to the blood, the chyle experiences the propelling force of the heart, traverses the organs of respiration, and comes in contact with the air always existing in the lungs. We may perceive many points of resemblance between the chyle and blood, in the spontaneous separation of their parts, in the fibrine which they both contain, and in their being similarly affected by oxygen, which colours them both red ; and wc ore fully entitled to conclude that this fluid, arising from the digested aliments, is actually changed into blood during its passage through the organs of respiration, for on leaving the lungs, the chyle has lost all those characters which formerly distinguished it from blood. As the blood is continually undergoing waste in its contributions towards the for- mation of the several secretions, as vtell as the reparation of the organs, this loss must be supplied by the aliment, without which life soon becomes extinct. The digested product of the food being altered in its properties, and completely animaliaed, finds its way into all the organs of the body, which it renovates and repairs. Thus, an iden- tification of now matter with the former substance of the animal body is finally effected, and this process constitutes the essential part of the function of nutrition. All portions of the animal frame undergo continual changes of dimemion, form, and structure, from the first period of their formation, until the body is finally subjected to the ordinary laws of inanimate substances. A part of the elements of which they are composed is incessantly dissipated in various ways, such as by respiration, perspi- ration, friction, and many others. Tliese losses in tho human frame amount to as much as several pounds weight of substance in the course of the twenty-four hours. M'ithout an adequate supply of nutriment, the strength of the animal soon becomes reduced, its bulk diminished, and it finally perishes. TUcre appears to exist a con- stant internal action, by which all the organs appear to be continually worn away and destroyed, only again to repair themselves, when supplied, through the food, with the proper elements for their composition. Such are the leading facts hitlierto ascertained, relative to tho obscure function of Nutrition. The necessity for a snpply of food is felt by all animals, yet it is not ex- perienced in an equal degree by all species, nor by animals of the same species, nor even by the same animal when placed in different circumstances. This appetite for food is heightened by youth, fatigue, long-continued want of sleep, by violent passions when the paroxysm has passed, by convalescence after a long illness, by a dry and cold air, and the influence of climates aud seasons. On the other liand, old age, prolonged sleep, hybernation, perfect repose, and hot baths, diminish the necessity for food. With the human species, luxurious habits lead to a loss of appetite, while it is heightened by labour ; and thus Hunger, which dcclioes tho invitation of the opulent epicure, comes an unwelcome guest into the hovels of the destitute. In general, the carnivorous .animals endure a long-continued fast with less incon- venience than the herbivorous. This remark must not be confined to the Mammalia, for it extends to the Birds of Prey, especially to the Eagle, to Serpents, and Spiders, all which animals can remain a very long time without food, and do not appe-or to suffer from their continued abstinence. On tins account they ai-e in general of a more meagre habit of body than such animals as live either on herbs or fiuits. There arc many instances on record of old Mon, but more especially of Women, who have lived for several weeks, some say months, without food. A mad enthusiast who imagined himself to be Christ in person, remained, it is said, during the forty days of Lent without using any food whatever ; but confined himself, without swallowing any thing, merely to washing his mouth with water or wine. These instances are not, however, always very well authenticated; and it would be difficult to prove, in this case, that tho fanatic did not actually swallow some of the fluid. Moisture, dark- ness, and repose, tend to diminish the usual effects of abstinence. A dog has remained alive under these circumstances for nearly fifty days without food. Persons of a vivid imagination, as well as frantic madmen, have in general a digestion extremely energetic, and they sometimes consume enormous quantities of food. Idiots also are freijuently tormented with a devouring hunger. Next to Sleep, which wholly sup- presses this appetite for the time, nothing tends more to drive away Hunger Hum tho long-continued exercise of deep thought. This appetite for food, which Man is enabled to confine within the bounds of Peason and Temperance, becomes in tho lower animals one of the leading principles of action. Indeed, if wc except the reproductive principle, and the principle of self- preservation from external danger, there are no others which approach in violence to the appetite for food, especially when heightened by abstinence. H'o obtain a sufficient supply of nourishment, is tho great end, to which a largo proportion of the instincts of each animal bear au immediate reference ; and wc commonly find, that those animals which posacss tho greatest facility in obtaining a subsistence, have the greater number of enemies to avoid. Such instincts as lead imineiliately to self- preservation from external danger, ore more developed in tho Herbivorous animals, than those other kind of instincts which relate more especially to their maintenance; and it is among the Carnivorous animals, whose existence depends solely upon their skilful exertions, that wo find the most ingenious devices to deceive and destroy their prey. The (iuadrumana, ospocialiy the IMonkeys, find an easy maintenance m the fruits of those warm countries, whore alone they have fixed their abodes. Secure on the tops of trees, they have few other eneraies to avoid than the Serpent tribes, which infest the lower branches. If wc except those marauding parties, which they aic sometimes compelled to form, in a great measure they are relieved from the cares which ha*- rass most other animals. But the Lemurs, being chiefly nocturnal, prey upon the small Birds and Insects while sleeping upon the branches. The Loris, favored by the darkness, steals upon its reposing victim, with a step so noiseless and excessively slow, that it is enabled to secure its prey with as much certainty as those Carnivora which depend for subsistence upon the extreme rapidity of their movements. Some of the Cheiroptera, such as the Roussetto Bats, feed almost wholly on fruits ; the remainder pursue the Moths and Gnats which fly about during the summer evenings. A few in South America venture to suck the blood of Man, and of the larger quadrupeds, but their bites are neither deep nor dangerous. During the day, and in winter, they bang securely suspended by their thumb-nails to the roofs otf caverns, and other obscure retreats. The Oaleopithcci, or Flying Cats, by means of their membranes, extended like a parachute, dart from the tops of trees, by para- bolic leaps, upon the small birds reposing on tho lower branches. Tiie liisectivora, as their name denotes, feed chiefly on Insects ; to these they add Worms, Snails, and tender roots. Some of these animals, such as the Mole, seek out their prey beneath the surface, by long mining operations; others, as the Sea- lops Canadensis, or Aquatic Shrew', add to their subterranean habits a mode of life almost subaqueous. Tho Planligrada, though omnivorous, differ in their tastes : some, as the Bears, arc partial to a vegetable diet, while others, like the Glutton (^Gulo arcticus)^ prefer animal food. The latter devours enormous quantities of flesh, and when urged by famine, conceals itself among the lower branches of a free, from which it watches for an opportunity to leap upon the back of some quadruped passing beneath, whose blood it continues to suck, until exhaustion compels the larger animal to yield to its more cunning enemy. The numeious genera of Carnivora arc compelled, by tho sagacity of their prey, and tlieir more exclusive propensity for animal food, to resort to many ingenious crhdps, into the ambuscade of some Lion or Leopard, while the band of Adtves witness the success of this other brigand with jealous eyes, and are left only to dispute tho mangled re* mains of the feast. Tlie Amphibia feed cUiefly on fish, which they always devour in the water ; though some species seem capable of living occasionally on Fuci. Those instincts of the Rodentia which refer to their self-preservation from ex- ternal danger, are mure remarkable than any others. No animals are so skilful in foiming subterranean retreats, which are usually executed by the combined labour of on entire settlement. One individual props wp the earth which threatens to fall, another divides a large cavity into apaitnients, and a third forms a water-proof roof, with a layer of clay, to preserve tho entire dwelling froux. the rain. One a}>artmcut is destined for the nursery, another for the granary-. Hero these animals amass, dur- ing die latter part of the autumn, a plentiful supjjly ot provisions, ar.d they find, on waking in the spring from th«>ir long winter sleep, that niainlcnanco which would otherwise have completely failed them, until the returning autumnal fruits and grains again permitted them to ama.ss another hoard. The Squirrels accumulate hazel-nuts, or the cones of the pine; the Dormouse gathers acoins and kernels; the Marmot seeks for different roots ; and many species of Rats select bulbous roots in particular. Other species penetrate into our graiiaiies aud stutehouscs, con»posiug a kind of ver- min, which nothing can entirely extirpate. Among the Edentata, the Tardigrada or Sloths feed chiefly on the leaves of trees, while tho proper Edentata, such as the Armadillo, prefer insects and carcasses, though they all seem on an emergency to be likewise capable of digesting vegetable food. None of these animals ruminate. The Sloth is enabled to endure a long-continued f^i^^ without inconvenieuce, and it never drinks, being supplied only with Vegetable fluids. Prevented by its singulai* organization from any rapid movement, tho Sloth devours every soft pai't of the tree within its reach, commencing with the loaves, following on with the buds, tender shoots, and bark, until the whole tree is left tirely bare. Here the animal lemains motionless and without eating for many day^» until extreme hunger finally compels it to sock fur food. Rolling itself in a ball, falling heavily from the branches upon the ground, it crawls with measured pace to the nearest tree. The Armadillo burrows under ground into the numerous Ant-hiU* of South America, and thu larger species fiequent the ucighbuurhood of burymg' grounds in great numbers. By means of subLerraneons excavations, they invade the graves of the inhabitants, unless carefully iirotected by boards from their incursionS- Thc three tribes of Slarsupialia present a great variety in their tastes for Among the Didolphida we find a strong partiality for animal food of every kind, THE MAMMALIA— MAN AND BEASTS. 71 tKey do not refuse fruits. Some live chiefly on the eggs of Birds, or on Crabs and Insects. Others devour carcassc.?, and even venture to make unwelcome visits into the houses of the Americans in search of food. The Macropoda, on the other hand, live almost wholly upon herbs or fruits. Of the Monotremata, the one Genus (^EchhU na) appears to feed, like the Hedgehog, upon land Insects and fruits j the other (Orniihojynchus) upon aquatic Insects, Worms, and Mollusca. The Pachydermata being in general of groat bulk, arc obliged, by their organiza-* tion, to feed chiefly on vegetables, while some of the smaller species, such as the Hog, seem almost omnivorous. Tlie larger sq^ecies 6nd their food either among the trees of the forest, or in the marshes bordering on large rivers ; the smaller generally seek with their snouts for the coarser kinds of fruit which fall from the trees, and lie con- cealed beneath the surface of the soil. All tho Solipeda are essentially herbivorous. Among the Ruminaiitia, the tasto for food b wholly limited to the vegetable king- dom. The Camels, whose callous feet are well adapted to the sandy soil of Arabia, find in these Dc.serts a scanty herbage of prickly trees or shrubs; for this purpose their gums and tongue arc almo.st cartilaginous, as a protection against the spinous pro- cesses of their food. The Rcin-Dccr, which is the sole sustenance of the Laplanders, Samoiedes, and Jakutes, scratches the snow for a supply of Lichens and Mosses, which is sufficient for his support. On the other hand, in the sultry plains of Ethi- opia, the colossal Camelopard pastures on the foliage of the highest trees. The Ox and the larger Cattle feed on the rich herbage of the plains ; some of the smaller, such as tho Sheep and Goats, arc satisfied with the more stunted ]dants of mountain regions. The Herbivorous Cetacea feed in numerous henb on the marine vegetables accu- mulated at the mouths of rivers, as well as on tho terrestrial herbs which float down tlie streams. Some, liowover, confine themselves to Fuci. The proper Cetacea are chiefly carnivorous, preying upon Fishes and Mollusca. Some, as the Dolphin, do not refuse vegetable substances; while others, as the Grampus (Delphinus gladiator) and Narwhal (Monodon moyioccros), carry on a deadly warfare against the very largest Fishes, and even upon their own order. Combining together in troops, they do not hesitate to attack the great Whale, apparently for the sole purpose of devour- ing his tongue, for which tho Narwhals seem to have a great partiality, leaving the remainder of his enormous body as a prey for epicures of a lower grade. In general, animals of the class Mammalia seek their food separately, or in com- pany, in which cases eacli individual labors for himself alone. It is only in a few species, such as the Beaver, Uaiustcr, and Economic JMouse, all of which construct dwellings of great complexity, that each individual assists in accumulating a common hoard. In this arrangement wo see one of the simplest states of society, where there exists community of goods, without any permanent division of labour. It is in Man alone that the Mechanic becomes distinguished from the Agriculturbt. Tims the MamtnuUa derive their subsistence from all inferior classes of living beings, as well as from their own; and hence tJiey exert a very groat influence in regulating the numbers of all other animals, and in establishing a universal cquili- hriuui among living beings in general. The earth, destitute of herbivorous animals, would soon be covered with a rank and dense vegetation. A few luxuriant species of herbs would wholly engross each Botanical province, and annihilate all others. Hence the herbivorous animals are requisite to curb tho exuberance of the Vege- table Kingdom; but as the herbivorous animals themselves would multiply, in their turn, to an inconvenient degree, even so far as to devour all plants to their very »*oots, the carnivorous animals are created to rcstiain the excessive multiplication of the herbivorous tribes, and thus become the indu’ect, yet necessary, allies of the Vegetahlo Kingdom. In respect to the kind of food which is most suited to each animal, and the relative facility with which dilTcrent substances are digested, tliesc arc questions which apply chiefly to Man. Each wild animal only uses that kind of food which is best suited to it ; and its aliments arc consequently very much restrained in their number. But Man is omnivorous, every kind of idimcnt can be rendeietiu.;tive aversion to deleterious substances, so necessary for ihcir preservation in the wild state. Dr Fleming remarks that Cows, 'vhich have been kept within doors during the winter, ami supported chiefly on dry food, when turned out to pasture in the spring, devour indiscriminately every green and frequently suffer for their iudiscrotion, Liunmus relates in his Lacliesis ^iipponica, that when he visited Tornea, the inhabitants complained of a distemper ^Hiich killed multitudes of their cattle, especially during spring, when turned out ^oto a meadow in tlm neighbourhood. He soon traced the disorder to the Water emlock which grew plentifully in the place, and winch the cuttle did not knoiv how lo avoid. In the Orkney Hlaiids, the Fox-glove becomes fatal to the Goslins, w hen iirst furned out into the hills to pasture. It is probable tliat, in a wild state, this instinct domains unim)iaircd, and directs them invariably to avoid tlioso substances which are ^‘i3uited to their digestive organs. Civilized Man appears to have lost, in a greater degree than any other animal, this power of discriminating between noxious and nutritious food. By means of the art of Cookery, which he alone knows how to employ, numerous substances, though in their natural state they may be nauseous to the taste or even poisonous, are rendered highly nutritious ; and thus tho original properties of substances become disguised or neutralized in endless variety. Habit soon modifies his taste ; and Man, being now left to the suggestions of Reason, is denied that Instinctive power of discrimination which the wild animals so largely enjoy. Many interesting facts relative to the comparative facility with which different substances arc digested, have been elicited from numerous experiments made on i\Ian and the other Mammalia. Milk being a fluid peculiar to the Mammalia, is, of all substances, the most nutri- tious to them. This proceeds from its containing the three ingredients essential to a perfect regimen. “ AU other matters appropriated by animals as food,” observes Dr Prout, “ exist for themselves, or for the use of the vegetable or animal of which they form a constituent part. Bat Milk is designed and prepared by Nature ex- pressly as food; and it is the only material^ throughout the range of organization, that is so prepared. In Milk, therefore, we ought to expect to find a model of what an alimentary substance ought to be — a kind of prototype, as it were, of nutritious materials in general. Now, every sort of Milk that is known is a mixture of three stamina] principles; that is to say, Milk always contains yksacchanne principle (sugar), a hulgraceous or oihj principle (butter), and a caseous^ or, strictly speaking, an alhnminoxt9 principle (cheese). Though in the milk of different animals these three principles exist in endless modified forms, and in very different proportions, yet none of tho tliree is at present known to be entirely wanting in the milk of any animal.” It has been remarked, that the following kinds of aliment are the most digestible for Man: — ^beef, mutton, veal, lamb, and chicken ; fresh eggs when half boiled, the milk of the Cow, JIare, Ass, Camel, and Goal; several kinds of Fish, when seasoned only with salt and parsley, but if used with oil or dripping, they are less diges- tible. Those vegetable substances easiest to digest arc spinage, celery (chiefly the root), young asparagus, hop-buds, the placenta of artichokes, the boiled pulp of fruits with stones or pippins, especially if they he sweet and aromatic ; tho farina- ceous seeds of the Cereal plants, wheat, rice, peas, &c. ; bread on the day after it is baked, but especially stale bread, and chiefly white bread; turnips; new pota- toes ; and gum-arabic. The following substances are loss digestible : — the flesh of pork, the different kinds of raw salad, cabbages, beet, onions, carrots, horse-radish, warm bread, figs, pastry, fried fish, and seasonings wit!) vinegar or oil. The stomach can attack these sub- stances but imperfectly ; and that digestion which it is unable to accomplish is finished in the intestine. Finally, wo may mention as the most indigestible substances, the tendinous and cartilaginous parts, and especially the membranes of beef, pork, veal, fowls, &c. ; bones, even when minutely divided; fat and oily substances; the white of egg hardened by heat ; mushrooms; truffles; oily seeds, such as walnuts, almonds, pista- chia nuts; the pippins of laisins, apples, See.; olives; cocoa; the different oils; raisins ; grape-skins ; the epidermis, or outer skin of different seeds and fruits ; the skins of peas; the bark of different trees; and many emulsive and ligneous grains. These last-mentioned seeds undergo so little change from the action of the stomach, that they germinate without difficulty on leaving the intestine. In this way many Blatits are disseminated from one country to another. There are several substances which serve to facilitate digestion, when mixed in small quantities with the food. The Ruminantia cannot exist without a supply of salt ; and Man experiences, with advantage, the moderate use of spices, w ine, liqueurs, cheese, sugar, and some bitter substances, particularly the products of the Cashew nut. Numerous other substances are in an eminent deg-reo prejudicial to digestion, and produce a tnore marked effect; such as the acids, Peruvian bark when taken after a repast, and the several emetics and poisons, in however small a quantity they may be used. Sedentary habits, excessive mental exertion, or violent emotions, also disturb or retard the function of digestion. Water, particulary when warm, if taken in large quantities after a meal, occasions the aliments to leave tho stomach before they are digested. It is by means of a well-regulated regimen, that IMan and the domesticated animals are brought to the state of the highest possible health. Race-IIorses, Greyhounds, and Fighting-Cocks, as well as Boxers, ILicers, and other Alhletie, acquire by this means an extraordinary increase of physical force, and are enabled to continue their exertions for a very lung time. This training of Men to athletic exercises produces surprising improvements in their external appearance. Their appetite is improved by this means, and digestion rendcreil more perfect. Giddiness of the head, after violent exertion, never occurs. The skin becomes clear, smooth, and well-coloured, and the veins are seen distinctly through it. The hones get harder and rougher ; they thence become loss liable to injury from blows and exercise, while tho shape is im- proved. But the most important effects of irainiiig are upon tho lungs, which ac- quire a free and powerful respu’ation, without which no animal can long maintain a vigorous action. The mental powers are aUo said to become improved ; tho atten- tion is more ready and tlie porcoplious more acute. These important effcels are pro- duced by temperance without ab.iteiniousiicss, and regular exercise in the open air. “ By these processes,” says Sir John Sinclair, “ the nature of the human frame is totally changed, and in tho space of two or threo months, the form, the character, and tho powers of tho body, are completely altered from gross to loan, from weakness to Vigorous health, and from abroathlcj.s and bloated carcass to one active and untiring. I'lius the very same individual, who but a few mouths before became giddy and breathless on tho least exertion, has his health not only improved, but is enabled to run thirty miles with the fleetnes-) of a Greyhouml; or, in a sboitness of time hardly to be credited, to walk above a hundred; or, varying the object in view, to excel in wrestling, or to challenge a jirofesscd boxer. '1 ho mind also becomes more courageous, corporeal sufferings are borne with patience ; a command of temper, and a presence of mind, are also acquired and preserved undisturbed amidst pain and danger.” it 72 FIRST CLASS OF THE VERTEBRATED ANIMALS. appears that these important results of training are produced by the most simple means, which every man may practise to a certain eatent ; general ill health might thus be commonly prevented, and many diseases wholly removed. It will be seen, from the preceding outline, that by far the greates number of Mammalia exist upon more than one kind of food ; and even in those species which are more especially restricted to an animal or vegetable diet, a certain degree of variation from their ordinary habits is allowed to them, by means of which they can subsist in unusual situations. Thus the Squirrel will sometimes devour Birds, and the Slarten and Pole Cat can subsist upon fruits. Domestication tends greatly to produce this omnivorous habit, yet there are some instincts connected with the food of animals which it fmls to overcome. The Dog continues to hide his food, though fed regularly and plentifully ; and civilized Man pursues the wild game with alacrity, although hunting has long ceased to be necessary to his subsistence. When the numbers of herbivorous animals are not kept down by other tribes, or when the cai-nivorons species fail in finding their prey, food begins to fail, and no resource remains to the famished animals but Migration from their native haunts. Excessive changes of temperature may be the nltimate causes of these migrations, by occasioning the destruction of those insects or plants from which the animals de- rived their maintenance. The IMamraalia are, however, in general sufficiently protected by their covering of haw or blubber from the changes of the seasons. They seek for shelter beneath the surface of the earth or sea, perhaps they sleep or hybernatc. But when animals are threatened with tamlne, either by a season excessively favorable to their multiplication, or any other cause, and their provisions in con- sequence suddenly become scarce, a simultaneous movement is the certain conse- quence. Migrations occurring in spring seem to owe their origin chiefly to this scarcity of provisions arising from an excessive population. Dr Richardson informs ns that the Black Bears of America migrate from Canada into the United States in very severe winters ; hut in milder seasons when they have been well fed, they remain and hybemate in the North. Among some of the sociable Mammalia, the force of han- ger, the confidence arising from the example of their fellows, and tire excitement of the Social impulse, ru-ge even the feebler and more timid animals to attempt mi- grations on the greatest scale of raagnitndo, and fraught witli the highest danger to themselves. The common Squirrels, compelled by a scarcity of provisions to desert their abodes, migrate from Lapland into lower latitudes in amazing numbers. On- wards they travel in a direct line, nor do rocks, forests, the deepest ravines, or the broailcst waters, disturb the invariability or iropotuosity of their course. Kumbers are drowned in passing large firths and rivers, or fall a prey to their numerous ene- mies. The Lemmings of Norway and Sweden often pour down in myriads from the mountains of the North and devastate the country. They move generally in lines, about throe feet from each other, and exactly parallel. The general direction of their march lies from north-west to south-east, and they pass directly onwards through rivers and lakes. Wdien stacks of hay or corn interrupt their passage, they gnaw through them instead of passing round. Pennant relates, that the Rats of Kamt- Bchatk.-! becoming too numerous at the commencement of Spring, proceed in great bodies westward, swimming over rivers, lakes, and arms of the seas. Many aro drowned or destroyed by Water-fowl or Fish. As soon as they have crossed the River Penchim, at the head of the Gulf of tho same name, they turn southward, and reach the rivers Judema and Ochot by the middle of July, a district surprisingly dis- tant from their point of departure. Mr Lyell has correctly observed, that the large Herbivorous animals which are gregarious, can never remain long in a confined region, as they consumo so much vegetable food. The immense herds of Bisons, which often blacken the surface, iii the great valley of the Mississippi, near the banks of that river and its tributaries, are continually shifting their quarters, followed by Wolves, which prey on the rear. “ It is no exaggeration,” says Mr James, “to assert, that in one place, on tho banks of tho Platte, at least ten thousand Bisons burst on our sight in an instant. In the morning we again sought the living picture, hut upon all the phaiii, which last evening was so teeming with .noble animals, not one remained.” Vast troops of Dziggtai, which inhabit the mountainous deserts of Great T.artary, feed during the summer in tho tracts East and North of Lake Aral. In the autumn they collect in herds of hundreds, and even thousands, and direct their course towards the North of India, and often to Persia. Bands of two or three hundred Quaggas are sometimes seen to migrate from the tropical plams of Southern Africa to the vicinity of the Maleleveen river. During their migrations they are followed by Lions, who slaugh- ter them nightly. Myriads of Springboks or Cape Antelopes pour down like a deluge upon the culthuted regions near the Cape, when the stagnant pools of the immense deserts sonth of tho Orange River dry up, which often happens after intervals of three or four years. The havoc committed by them resembles that of the African Locusts ; and so crowded are the herds, that the Lion has been seen to walk in tho midst of the compressed phalanx with only as much room between him and his vic- tims, as the fears of those immediately around could procure by pressing outwards. There arc certain secluded spots in tho neighbourhood of Melville Island, which are visited annually by herds of Vlusk-Oxen and Rein-Dccr ; during the short summer of the arctic regions, various plants put forth their leaves and flowers tho moment the snow is off the gromid, forming a carpet, spangled with tho most lively colours, and these animals travel over immense distances of dreary and desolate re- gions, to graze undisturbed in these luxuriant pastures. Mammalia which frequent the ocean, like the Wlialcs and Seals, or the air, like the Bats, possess unusual facilities for executing these periodical migrations. The Whales of the Northern Seas aro known to desert one tract of sea and visit an- other at a very remote distance. The Seals, according to Krantz, retire from the coasts of Greenland, in July, return again in September, and depart again in March, to return in June. They proceed in great droves northwards, directing their course where the sea is moat free from ice. This migration of the Seals must, however, proceed from some other object than a mere search for food, as they aro observed to bo very fat when they set out on this expedition, and very lean when they come home again. The Groat Bat ( VespertiUo noctula) visits England during the sum- mer, but retires in winter to Italy, where it hybernates. The daring manner in which Land animals attempt to cross large tracts of water IS an immediate consequence of the urgency of their wants. “ Rivers and narrow firths,” says Mr Lyell, “ can seldom interfere with their progress, for the greater part of them swim well, and few are without this power when urged by danger and pressing want. Thus, among Beasts of Prey, the Tiger is seen swimming about the islands and creeks in the Delta of the Ganges, and tho Jaguar traverses with ease the largest streams in Sonth America, Tho Bear, and also the Bison, stem the current of tlio Mississippi. To the Elephant in particular, the power of crossing rivers is essential in a wild state, for the quantity of food which a herd of these animals con- sumes, renders it necessary that they should he constantly moving'from place to place. Tim Elephant crosses the stream in two ways. If the bed of tho river be hard, and the water not of too great depth, he fords it; but when he crosses great rivers, such as the Ganges and the Niger, the Elephant swims deep, so deep that tho end of his trunk only is out of the water — for it is a matter of indiflcrcnce to him whether his body be completely immersed, provided he can bring the tip of his trunk to tho sur- face, so as to breathe the external air. Animals of the Deer kind frequently take to the water, especially in the rutting season, when the Stags are seen swimming about in search of the Does, especially in the Canadian lakes ; and in some countries where there are islands near the sea-shore, they fearlessly enter tho sea and swim to them. In hunting excursions in North America, tho Elk of that country is frequently pur- sued for great distances through tho water.” Without this power of shifting their quarters, a far greater number of animals would have become extinct than has ocenned under their present constitution. The mutual action and reaction of species is the necessary consequence of these general laws of Nutrition, by which all Living Beings are governed. Individuals maintain their existence for days or years — species for centuries and ages. Each arrives at its termination when its resources whoHy fall, from the influence of surrounding causes of change, and it is to their mutual struggles for subsistence we owe that equilibrium of animal forces which is found to prevail in all parts of the globe. In every place it is dccrcetl that tho demand for food shall bear a determinate ratio to tho supply, and Nature never hesitates to deal indiscriminate destruction on all individuals or species which transgress this law. It is evident from the mutual dcpcndance of animals upon each other and upon plants, that the creation of certain species has preceded that of others in the order of time. Vegetables must have become numerous upon the earth before the Frugivo- rous tribes made their appearance; while the Herbivorous animals must have multi- plied upon the earth, and become widely distributed, previous to the institution of predaceous types. The phenomena of nutrition thus clearly point out that the creative power has been exerted successively, imd probably at remote periods of time — a conclusion which is fully confirmed by the investigation of Fossil Remains. The mutual reaction of zknimals upon each other, and upon Plants, follows neces- sarily from the limited duration which is allotted to the existence of individuals and species. Had Living Beings not been subject to Death, there would have been no reproduction; the checks to reproduction would not have existed ; in a word, there would have been no activity, no prey to pursue, no enemies to avoid~no mutual re- action, in short, Life would lose that stamp of animation which marks its phenomena so distinctly from those of Inorganic Nature. The liability of Animals to Death i's thus tho ultiro.atc cause of their greatest enjoyments and sufferings. “ Tho law of universal mortality." observes Dr Buckband, “being the established condition on which it h.a3 pleased the Creator to give being to every creature upon earth, it is a dispensation of kindness to make the end of life to each individual as easy as possible. The most easy death is proverbially that which is least expected ; and though, for Moral reasons peculiar to our own species, we deprecate the tudden ter- mination of our mortal life, yet, in tho case of every inferior animal, such a termi- nation of existence is obviously the most desirable. Tho pains of sickness and de- crepitude of ago are the usual precursors of death, resulting from gradual decay ; these, in the human race alone, are susceptible of alleviation from internal sources of hope and consolation; and give exercise to some of the highest charities and most tender sympathies of human nature. But throughout the whole creation of inferior animals no such sympathies exist : there is no affection or regard for the feeblo .and aged; no alleviating care to relievo the sick; and tho extension of life through lin- gering stages of decay and old age would to each individual be a scene of protracted misery. Under such a system, the natural world would present a mass of daily suf- fering, boariiig a large proportion to the total amount of animal enjoyment. By the existing dispensations of sudden destruction and rapid succession, the fcchlo and dis- abled aro speedily relieved from suireriiig, and the world is at all times crowded with myriads of sentient and happy beings ; and though to many individuals their allotted share of life be often short, it is usually a period of uninterrupted gratification ; whilst the momentary pain of sinblen anil unexpected death is an evil infinitely small, >» comparison with tho enjoyments of which it is tho termination. <■ To the mind whicl. looks not to general results in the cconomv of Nature, the earth may seem to present a scene of perpetual warfare and incessant carnage; but the more enlarged view, while it regards individuals in their conjoint relations to the general benefit of their own species, and that of other species with which they are associated in the great family of Nature, resolves caclr apparent case of individual evil into an example of subserviency to universal good. “ I bo .appointment of de.ath by the agency of Carnivora, as the ordinary termina- tion of animal existence, appears therefore in its m.ain results to be a dispensation ot benevolence ; it deducts much from tho aggregate amount of tho pain of universal death : it abridges and almost annihilates throughout the brute creation the misery of disease and accidental injuries, and lingering decay; and imposes such salutary restraint upon excessive increase of numbers, that the supply of food maintains perpetually a due ratio to the demand. The result is, that tho surface of the land and depths of the waters are ever crowded with myriads of animated beings, tlic pleasures of whose life arc co-extonsive tvith its duration; and which, throughout the little day of existence that is allotted to them, fulfil with joy the functions for which they were created. Life to each individual is a scene of continued feasting in a region of plenty ; when unexpected death arrests its course, it repays with small interest tho large debt THE MAMMALIA— MAX AND BEASTS. 73 '^hicH it has contracted to the common fund of animal Nutrition, from whence the materials of its body have been derived. Thus the great drama of universal life is perpetually sustained; and though the individual actors undergo continual change, tlie same parts are ever filled by another and another generation ; renewing the face of the earth, and the bosom of the deep, with endless succession of life and happiness.” • GENERAL REVIEW OF THE MAMMALIA CONTINUED. The internal functions of the Mammalia in harmony with the revolutions of the Earthy and the laws of inanimate Natvre^General Relations to XAghtt Heaty and Electricity, It has already been shown, that the dimensions and forces of animals bear a certain determinate relation to the circumstances of their conditions*, — that the Creator has organized them so as to correspond accurately with their intended habitations. When an aquatic animal removes permanently to the air or earth, it receives an organization suited to that change. I’ho Frog is assigned the characters of a Fish while in its Tadpole state, and acquires those of a Reptile when it is designed also to reside upon the land. Rut this correspondence of animals to the circumstances of their condition is not confined merely to the media, whether air or water, in whicli they are intended to move; for their forces also bear a determinate relation to the earth, considered Mechanically as a mass of matter, or Astronomically in its relation to the other bodies of the Solar System. The dependance of all animal motions upon the attractive force of the Earth is suffi- ciently obvious. Each animal body is acted upon by Gravity, in proportion to its mass; in other words, it possesses weight; and in order that animals may exercise the power of moving, it is necessary that their forces shall bear a certain relation in excess to that of gravity, otherwise no motion could follow*. Their forces must also be proportioned to the resistance which gravity ofi’era to their exertions, or else ani- mals would lose their balance, their motions would proceed by jerks; at one time they would endanger their own safety by an excessive rapidity, at another by an excessive slowness; in all tbry would be devoid of grace, energy, and convenience. Animals would como into collision with other animals, or with harder substances than their own bodies; and this globe of Earth, like a machine out of order, would soon lie in a state of inactivity and disorganization. Mr "WhewcU remarks, that if the force of gravity were increased in any consi- akmg, Hunger, stales of Exertion or Repose, hear an immediate n-fcrcnce. The ^ ‘tenial clock-work of the anin'ml frame has been made to run for tivcuty-four iiours. when tho same states of the animal frame succeed each other in the same order, and in exact conformity with the revolutions of the globe. Besides this diurnal period of the animal clock-work regulated by tho diurnal revolution of twenty-four hours, there also exist periodical functions referring to divisions of weeks and months, as tho epochs of menstruation, also the incubations of Birds, which may endure for two or three weeks, and the gestations or internal in- cubations of tlie Mammalia, extending from three weeks to nine or eleven months. The year, or period of the Earth’s revolution round the Suu, is the most im- portant astronomical phenomenon in reference to organized beings. It is felt through every portion of animated Nature ; it measures the great epochs of their existence, and forms the limit of duration. t.o a multitude of animals of the Class of Insects in particular, and of Plants. All their functions are distributed in reference to the periods of the year. The annual species are horn in the Spring, the Summer be- comes the period of their puberty and reproduction, their fruits or productions appear in Autumn, and they die on the approach of Winter. Man, and the other persistent beings, from the Mammalia to 1‘rees and Herbs, experience more or less the influence of the seasons over their physiological functions. Spring, being the morning of tho year, is favorable to births and bodily growth ; it is in fact the period of youth, expansion, and gaiety. Experience proves that the human frame then undergoes, like Plants, its highest degree of growth and develop- ment. Summer, analogous to mid-day, is the season of heat, ardour, strength, and the highest development of the faculties. It corresponds with the age of puberty, and the impetuosity of the passions. The rutting period, with most animals, happens towards the summer solstice. Autumn is the evening of the year. Plants then yield their fruits, they aftenvards become ligneous and dry, and finally fade away. Animals, after performing the act of generation, cast their hair, skin, or feathers, and undergo that moulting which strips them of their more gaudy attire. This is the epoch when the faculties be- come concentrated, a period of melancholy and sadness. Vegetation ceases, and plants in general lose their foliage. Winter, the cold night of the year, renders the vegetable world dormant, and especially the cold-blooded animals. It is the season of repose, of nutrition, and internal repair, preparatory to future action. Animal bodies become inert, moist, and phlegmatic. Life is rendered at this period almost stationary and nullified; it remains either in a state of concentration, or in absolute torpidity. Thus, besides the nychthemeral periods, or diurnal revolutions, which regulate the daily functions of existence, the crises of maladies, the hours of repast or excretion, we have monthly periods of gestation and incubation, menstruation, rutting, and moulting, corresponding to the flux and teflux of the tides, to the periodical winds of the tropics, and the revolutions of the Moon. Again, tlie annual periods fix a limit to the lives of all annual and biennial species, and determine the periods of their gi'owth, the metamorphoses of Insects, with the phenomena of reproduction and decay among most animals. Thus the revolutions of our globe, and its relative situation to the heavenly bodies, maintain the circles of our existence in equilibrium with them. A philosophical Astrology may read our lives and destinies in the stars, which move in their curvi- linear orbits by tho same force that urges all Living Beings onwards in their physio- logical periods. Time, measured by the successive revolutions of our planet, draws onwards all the generations of Plants and Animals which decorate its surface ; it marks tho fatal hour to cacli individual, as it brings round the periods of love and tho necessities of nutrition. The f®tus of animals and the fruits of vegetables arrive to matui’ity at the appointed period. Each species of Mammalia has its fixed time of gestation, sufficient for the pro]>er elaboration of the foetus, which period may, how- ever, sometimes vary by a few es (Mycctes senecrtlus axid Reehelnil) are cither nocturnal or at leaat crepuscular, preferring tho twilight of the morning and evening for their time of feeding and exertion. It is the same with certain Makis, who have thence derived their name of Eemur, from their haunting the twilight liko the shades (leraurus) of the departed. Tho Cheiroptera or Bats, especially tho Genus Noctilio, with the Galeopithoci or Flying-Cats; the Insectivora, such as tlie Hedgehogs, Shrews, and Molcu; the Plantigrada, such as the Bears and Badgers ; also the entire genus of Cals ; the Weasels, Polecats, and many Opossums, .are strictly nocturnal ; and this quality seems eminently appropriate to all those Carnivora or Marsupialia, which watch for their prey, and endeavour to surprise them while sleeping. Like assassins and brigands of our own species, llicy bury themselves in silence and obscurity to render their blows the more deadly. We fin I many crepuscular or semi-nocturnal species among tho RoduntU; which / 74 FIRST CLASS OF THE VERTEBRATED ANIMALS. move in obscurity through fear of their enemies. Thus, the Hats, Dormice, and Hares, come from their retreats in the evening, or very e.Trly in the morning. The Edentata, such as the Armadillos, Anteaters, and Maiiis, are also nocturnal, through timidity and their want of offensive arms. The Pachydermata and Ruminantia, on the contrary, feed only during the day. With all these aiiimals, the remaining part of the twenty-four hours is devoted to sleep and repose. Crepuscular feeders sleep partly during the night and partly during the day, while diurnal sleepers arc nocturnal feeders, but in all cases the same round of functions succeeds in equal periods of twenty-four hours. Tlic time selected by each animal for its period of food or repose is capable of undergoing much modification, from the presence or absence of particular stimuli, such as the different states of the air, the states of electricity, moisture, and heat, at the several periods of the day and night. The presence or absence of Light and Heat seems chiefly to regulate the periods of activity and repose in all animals. Tiie Day being warmer than the Night, tends to establish in some of the bodies a movement towards the surface,— a period of waste and destruction of force, — the Night with these is devoted to a reparation and accumulation of energy. The dependance of certain functions of animals upon the presence or absence of Light, becomes more perfect when any particular formation of their visual organs specially marks them out for enduring Light of difl’erent degrees of intensity. When animals run into white varieties, as may often be observed in white Negrons, Albinos, white Rabbits, Mice, Dogs, Cats, Pigeons, and many others, their eyes are commonly red ; and these organs then become so acutely sensible to light, that they are unable to support the full blaze of day ; but at the same time, they can sec much more clearly in twdigbt than individuals which have not experienced this degeneration. The cause of this extreme sensibility in their visual organs is completely ascer- tained. If we examine the inside of the Sclerotica and Iris, which commonly form the obscure chamber of the eye, we shall find in the leucoso individuals, that these membranes are deprived of the black or brown pigment which is designed to defend the eve from the rays of Light, except at the transparent aperture of the pupil. The retina being thus insufficiently defended against the luminous rays, becomes easily dazzled in bright daylight, but receives a sufficient number of rays in the twilight for the animals to see clearly. An opposite clTect is produced in black or brown indivi- duals, such as the Negroes, in whom this pigment {pi^mentmn nigrum) which lines the interior of the sclerotica and iris, defends it perfectly from the entrance of lumi- nous rays, excepting at the proper aperture of the pupil. For this reason, Negroes, and generally all individuals witli black eyes, can easily support the full blaze of sun- shine, while the blue, gray, or ash-coloured eyes of the fairer inhabitants of Europe are so tender, from the intensity of the tropica! sun, that they require to be defended by coloured glasses, else they become affected with ophthalmia. IMcn and the lower animals, with very white skins and light hair, are thus destitute of that brown or black colouring matter, which not only lines the sclerotica and iris, but also impregnates the mucous tissue under the skin, and, passing onwards, tinges the hair or fleece of different colours. Black or chestnut hair usually accompanies an iris more or less brown. It thus follows, that black and dark-brown animals can endure the blaze of day, and that the light-brown or white animals, which are natu- rally better adapted for the cold and polar regions of the earth, become the most proper to see during the twilight or at night. All the nocturnal animals are further capable of dilating their pupils largely in the dark, in order to receive a larger pencil of rays tlian the diurnal animals; the latter, on the contrary, arc compelled to close the pupil to avoid being dazzled. The inhabitants of the polar regions possess this power of dilating and contracting the pupil in a remarkable degree, as they ex- perience, at one season of the year, the dazzling reflections of the snow, and at an- other, the long twilights and .Aurorjc Boreales of winter. When deprived more or less of this pigment, Man .md the lower animals have a very sensitive skin, the fibres of which ai-e delicate and slim, while their hair is light, fine, and silky. These individuals are easily overcome by the heat of the day and the intensity of its light ; they soon become exhausted during the day, and find the feeble rays of the night better proportioned to the delicacy of their temperament. Hence, hey transform the Day into a period of repose, the Night into one of activity and exertion. AVehave a further confirmation of the accuracy of these cb.^ervations in the fact, that with the greater part of the nocturnal animals, the colouring pigment of the skin is less vivid than in the diurnal races. It may generally be remarked, that animals with nocturnal eyes are clad in a raomnfiil and dingy vestment of gray or as-h-colour, striped with black or spotted, not only among the HJamraalla and Birds of Night, but even in the Insects, when we compare them to the allied diurnal species* We see a remarkable contrast between the tints of the diurnal Butterflies and those of the Moths and Sphinges. The Owls are sad luid sombre birds when placed against the Parroquets or Humming Birds, glittering in the brilliant sun of the torrid zone. Many atnniaU of the Cat kind, the Lemurs and Bats, cannot compare in these respects with the gayer quadrupeds. Nocturnal animals further possess the peculiar quality of advancing to surprise their jirey w ith a noiseless step. The almost imperceptible flight of Nocturnal Birds of prey is well kiionn to proceed from the soft feathers of their wings ; and the same eflect is produced by the wings of the Bats, and the nocturnal Butterflies. The cre- puscular Sphinges alone produce a humming noise by the vibration of their wings ; but they suck the nectar of fiow'crs, and the Bombyx and Cossiis do not take animal food. AU other nocturnal animals are, fur the most part, carnivorous, attack their prey by surprise — and Nature inspii'es tliera with the same instinct as the cow’ai’div assassin, who dues not dare to face his enemy in the blaze of day. In return, how- ever, they are often impregnated with fetid odours, which serve to announce their approach. It is thus to the peculiar constitution of their bodies that the nocturnal animals owe their property of sleeping during the day and waking at night, a peculiarity so opposite to other being?. An analogous state exists also in the Vegetable kingdom. Some flowers appear to close and languish during the heat of the day. The sun acts too vividly upon the frail texture of certain petals, and occasions the sap and nutritious fluids which fill their laminm to evaporate too freely; but during the fresh- ness of night the sap aud juices being less dissipated, accumulate in the tissues of these plants, their canals are dilated, and the flowers and leaves expand. Their ten- der organs of reproduction would soon become dossicated by the heat of the sun : hence the plant withdraws them from its influence, and displays them only before tluj pale light of the moon. Diurnal flowers also have, with animals, a more solid tissue than the nocturnal. The former require to be stimulated by light aud heat, that their reproductive organs may develop themselves, while the more tender nocturnal floweis resemble those animals of the night which shield their eyes from the dazzling influence of the day-light. Further, the sexual organs of Nocturnal Plants fade more ra- pidly than the diurnal: their monopctalous and polypetalous corollae are of a texture extremely frail, generally blanched and etiolated. Their evanescent perfume is exhaled only at night ; it fails during the day. In general, all nocturnal beings, whether Mammalia, Birds, Reptiles, Fishes, Ir>- sects, or Plants, present sombre and tarnished hues, while the diurnal species, under the fiery influence of the sun, assume garments of dazzling brilliancy. Light thus stimulates to activity, and is or4e of the principal causes of the development in organ- ized beings of animal and vegetable poisons and perfumes, when acting upon special constitutions. Darkness benefits those acrid, venomous, faded, and inert plants, whose juices, feebly elaborated, require its shelter : it is favorable to the development of animals generally at their birth — to the lai vm of insects in their dark asylum.s to mushrooms aud lichens, the mysterious product of evanescent sporulcs, in the deptlis of forests, and the hollows of caverns — and in general to all feeble and imperfect or- ganizations. The moisture and coldness of night are further unfavorable to the waste of living bodies, and hence it is the period when they experience the highest degree of growth and vegetation, provided that the cold be not too intense. In fact, the internal functions of nutririon and repair are performed more intensely during the repose of night, and the absence of external stimuli. Then the organs grow, and be- come replenished with nutritious fluids. Thus the mushrooms ai e mostly the offspring of the night, or multiply in the secret obscurity of subterranean excavations. Each day, like each season, distributes to every living being some portion of heat, light, and nutriment, and measures the rhythm of their functions of waking or sleep- ing, nutrition or excretion. When these are maintained in harmony with the movements of the globe, health and regularity are alike maintained. We find the influence of the periodic return of day and night in places where its presence could scarcely have been anticipated. According to the researches of Messieurs Burch, Quetolet, and Villermc, the mortality of the human species increases towards sun- rise, diminishes towards sun-set, and almost no deaths happen at nud-day. Further, it is observetl that births occur most frequently during the night, and deaths during the day. Births and deaths are generally most numerous between thehours of three aud six in the morning, aud least numerous from three to six in the evening, corresponding to the maximum and minimum of temperature. Tliis prevails as welkin the seasons the year- as in the hours of the day. Tlie greater number of births and deaths occur in the most stimulating periods of the day and year, being ilt six in the morning, and in the month of April. Those periods, on the contrary, when stimuli begin to fail, are most deficient in births and deaths, such as three o’clock in tlm afternoon, and iu the month of August. The paroxysms of fevers, aud the pains of an approaching accouchcmeiU, usually begin in the evening, while the crisis or result arrives towards the morning. Thus there exists a remarkable correspondence between the structure of animals and plants, and that periodical order of light aud darkness rcsul ,ing from the rotation of the earth around its axis. Although this succession of functions depends partially on the presence of the external stimuli of light and heat, yet there appears to be '* diurnal period belonging to the constitution both of animals and vegetables, and this structure corresponds with the astronomical day. The power of accommodation pcs-’ sessed by living beings iu this respect, is not sufficient to allow us to suppose that the periods of the day and night could be very greatly lengthened or shortened without causing their ultimate destruction. “ We may be tolerably certain,” says JL' Whewell, “ that a constantly recurring period of forty-eight hours would be too long for one day of employment, and one period of sleep, with our present faculties ; and all whose bodies and minds are tolerably a<;tivo will probably agree that, independently of habit, a perpetual alternation of eight hours up, and four in bod, would employ the human powers less advantageously and agreeably than an alternation of sixteen and eight, A creature which could employ the full energies of his body and mind unin- terruptedly for nine months, and then take a single sleep of three mouths would nut be a man. When, therefore, we have subtracted from the daUy cycle of the employ' mont of men and aiiimals, that which is to be set down to the account of habits ac ' quired, and that which is occasioned by extraneous causes, there still remaina a periodical character, and a period of a certain length, which coincides with* or at any rate easily accommodates iUelf to, the duration of the earth’s revo- lution. Wo can very easily conceive the Earth to revolve on her axis faster or slower than she does, aud thus the days to be longer or shorter than they are, without supposing any other change to take place. There is no apparent reason why this globe should turn on its axis just three hundred and sixty-five times while it describes its orbit round the sun. The revolutions of the other planets, as A*** as wc know them, do not appear to follow any rule by which they are connectcvl with the distance from the Sun. Mercury, Venus, and Mars, Imve days nearly the length of ours. Jupiter and Saturn revolve in about ten hours each. For any thing we can discover, the Earth might have revolved in this or any other smaller period, er "t might have had, without mechanical inconvcnieocc, much longer days than we ha'<* But the terrestrial day, and consequently the length of the cycle of light and darkno'* being what it is, we find various parts of the constitution, both of animals and veget- ables, which have a jicriodical character corresponding to tlie diurnal succession ^ exleruAl conditions; and wc find the length of the period, as it exists iu their co» stitution, coincides w ith the length of the uatur.il day. Tho want of colour, or Albinism, in animal and vegetable bodies, when they said to be leucosa or white, has its proximate cause iu the original want, or the diminished secretion, of the coloured layer of mucous uct-work placed immediately 75 THE MAMMALIA— MAN AND BEASTS. utider the epidermis, or outer skin of animals. With Plants, this is owing to tho inert secretion of tho green matter, or clirmnnh, and its ceasing to colour the cuti- c.ular tissues. In all species, softness and moisture are tho results of this albinism or whiteness. Its ultimate cause is the want of vital energy, arising either from the prolonged abscnco of the inlluence of Light upon the organic structure, or from the intensity of a long-continued cold. Its cfiect.s may be either absolute and total, or merely partial and local, even among the white varieties of animals and plants. Its general tendency is to effeminate all beings. Accidental albinism may arise from old age, or the want of a continued renewal of this coloured layer, wliieh communicates it.s hue to tho Hair, Feathers, or Scales. It may be even induced before old age by disease, or by the absence of the usual supplies of nutriment, or, among animals, by the violence of fear or any sudden emo- tion, wbie.h may serve to withdraw from the exterior of tiie body its secretions, and render tiie skin pale, or the liair white. Tiierc is also an accidental albinism from the mechanical injury of tlie raucous pigment, arising from the bruising or tearing of the skin, and on these spots, white hair or feathers will arise in tiie place of coloured appendages. An opposite state of deep blackness, or .IfedciwiV/n, when the surface is said to bo mefaiiose or blacky .arises from tlic superabuudauce of tlic mucous subcutaneous tissue in aiiimahs atid plants, in which carbon exudes towards the exterior. Sucli are Ne- groes, and all black or dark-brown animaks, lurid ami venomous plants, as the Solaneaj. This stale of the skin is well fitted for skies, resplendent with Light and Heat. It is attended in individuals with dryness, rigidity, and shortness of stature. Excessive cold, combined with the absence of Light, serves to drive the nutritive and repairing juices far from the skin. This kind of albinism is especially remarked in animals inhabiting the liighest mountains and the polar regions, where they become white in winter and coloured in summer. The large species of the Porcupine exhi- bit these alternate annulatioiis of white and brown, which are due to the alternations of summer and winter. A similar effect might be produced on live Sparrows, by pluck- ing tho feathers, and rubbing their naked bodies with Spirit-of-wine. The feathers which then succeed remain while, because tho alcohol prevents the secretion of the colouring subcutaneous matter, in the same manner as an excessive cold. A corre- siionding effect may be produced by simibir means upon the Mammalia. The colours of animals are intimately ooiiuected with the latitude of the place as well as with the changes of the seasons, and seem, in general, delicately sensible to the external stimuli of Light and Heat. In Mammalia and Birds, we find fliat the hotter regions of the globe, as well as the summer months, are favorable to deep and bright colours. Sir John Leslie's experiments on colour, as affecting the radiation and absorp- tion of Heat, afford the best explanation of tlio final causes of these changes. “ The rate at wliieh bodies cool is greatly influenced by their colour. The surface which reflects heat most readily suffers it to escape but slowly by radiation. Reflection takes place most readily in ulijects of a white colour, and from such, consequently, heat will radiate with difficulty. If wo suppose two animals, the one black, and the other white, placed in a higher temperature than that of their own body, the boat will enter the one lliat is hlaidc with the greatest rapidity, and elevate its temperature considerably above the other. Those differences are" observable in wearing black and light colour.'d clothes during a hot day. AVhen, on the other hand, these animals are jilaccd in a aituation, the temperature of which is consider- ably lower than their own, the black animal will give out its heat by radiation to every surrounding oiijcct colder than itself, and speedily have its temperature reduced; vvliile the white animal will jiart with its heat by radiation at a much slower rate. The change of colour in the dress of animals is therefore suited to regulate their tempera- ture by the radiation or absorption of caloric. Wliile it is requisite that tiie tem- perature of some species should be preserved as equally as possible, tiie cooling effects of winter are likewise resisted by an additional quantity of heat being generated in the system. An increase in the quantity of clothing takes place, to prevent that heat being dissipated by communication with the cold objects around, and tho dress changes to a white colour to pi-event its loss by radiation. In summer, the perni- cious increase of temperature is prevented by a dlmiuislied seeretion of heat, or the ■secretion of cold, increased perspinition, the ca^tinff of a portion of tlie winter cover- ing, and by a superior intensity of colour in the remainder giving it a greater radlat- mg power. The last character would, in the sunshine, by absorbing heat, prove a tiuurco of great inconvenienee, were its effects not counterbalanced by other arrange- ments, and by the opportunity of frequenting the refreshing shade, or bathing in the stream.” Animals become light or gray in old age, and thus the too great dissipa- tion of heat in their systems is prevented. If it were possible for any one to doubt the fact that the functions of ammaks and filants correspond with the movements of tho terrestrial globe, he would find a convincing proof in the influence of the seasons, upon the casting of liair among the ■Mammalia, tlic moulting of Birds, the changes of skin among the lower animals! and •ho defoliation of Plants. In the .Spring, all Nature is living and vegetating, exiianding and developing its I'i'oductions ; the earth is clothed with verdure, tho animals are dressed in their nuptial garbs, and their amours commence. The cause of tills external cxiiansion of all beings originates in tlie circumstance that their functions, long opiiressed hv the cold of winter, have actiuircd a superabundance of juices, sap, .and nourisliinent, ■"hieh only await the favorable mumeut of external heat to expand. Their germs are evelopod with extreme vigour. In the human race, there is at this season a doter- •nmatiou towards the skin, erupt ive maladies become more prevalent, and exanthemata sometimes ajipear as thougli budding were not exclusively conlim'd to the vegetahlo mgdora. 'Jhe Hair, Feathers, Homs, .Scales, and Epidermis of animals, as wcdl as >e Leaves, Flowers, and Fruit of vegetables, whicli have grow n and expanded dur- the Spring, assume their most glittering hues, if not during Summer, at least h( tueiiths of tho year, when in our climate the sun is most above the ^Tizon. But at the approach of the autumnal equinox, living bodies, whctlier mia s or I lants, are exhausted by the excessive action of their vital forces during fflmer, and their lunetions become less vigorous, in proportioti as Light and Heat diminish witli the enfeebled rays of the Sun. Those c.xtcrnal parts, proi'iic«l in Ih • preceding Spring, cease to receive nutriment from the body; tliey have furihei- arrived at the full period of their growth, and are incapable of receiving any more. Hence they dry up or fade away; others become detached and fall. Sooner or later at this season, we invariably witness the casting of hair, feathers, scales, horns, and epi- dermis, as well as the dropping of flowers, leaves, and fruit, when each Living Being enters into a kind of autumnal concentration prcjiaratory to the rigour of winter. In the southern hemisphere, our winter being then its summer, and reciprocally, the periods of casting or moulting are in each year opposite to ours. In the Torrid Zone, the Sun passes twieo a year from the one tropic to the other, so that it produces, to a certain extent, two winters and two summers. The winter IS there the season of continual rains ; it also determines twice a year tho casting or moulting period of anjinals and plants, and doubles the number of the rutting seasons, Fiom these circumstances, it arises that Living Beings experience a two-fold waste of vital force, and live in these waimer regions at a faster rate tlian elsewhere. Tliey arc continually producing or wasting; new flowers spring up next to the fruit ; new leaves replace the oid and faded; the Bird prepares its nest of eggs, and sings new cai-ols wilhin the hearing of its brood of six months old ; and the Quadrupeds con- sume ill a continual slate of generation, gestation, and lactation. In colder countries, and on the summits of elevated mountains, there exists another kind of change iu tho feathers of Birds and tho liair of Mammalia, which arrives at the period of winter. The white robe, the symbol of chastity and sexual indifference, is particularly fitted to these cold regions, in tlie same manner as the brilliant robe of summer is in corrospoiidenee with the full vigour and activity of the reproductive system. Thus the Hare of the Alps (Leptts turiabitis) and the Ermine, as well ils a great number of other Mammalia, witii an immense multitude of Birds of tlie Northern Regions, especially the M'aders {Grallm) and tfeb-footed Birds {Palmi- pedes), which arc covered in the summer season with hair or feathers of brown ami more brilliant hues, acquire a pale gray or uniform white during the winter. It has been considered by some, that the white garb of arolie animals serves to protect them from their enemies, by assimilating their colour with that of the snow. But Nature, pursuing a fair system of leeiprocity, imparts the same colour to the beasts and birds of prey, so that, in reality, this provision is less effectual than lias been commonly supposed. Hr Fleming has made the following observations on the cause of the change of colour in those quadrupeds, which, like the Alpine Hare and Ermine, become white in winter “ It has been commonly supposed that these Mammalia cast their hair twice in the course of tho year ; at harvest, when they part with their summer dress and m spring, wlien they throw off their winter fur. 'lids opinion, however, doe! not appear to be supported by any direct observations, nor is it coentenanoed by ana logical reasoning. If we attend to the mode in which the human hair becomes gray as we advance in yeius, it will not be difficult to perceive that the change is not pro duced by the growth of new hair of a white colour, hut by a cl.aiige iirUie colour of the old hair. Hence there will he found some hairs pale towards the middle, and white towards the extremity, while the base is of a dark colour. Now, in ordinarv cases, the hair of the human head, unlike that of several of tiie inferior animals,' i's always dark at the base, and still continues so during the change to gray ; hence 'we arc disposed to conclude from analogy, that the cliange of colour, in those animals which become white in winter, is efi'ected, not by a renewal of the hair, hut by a change m the colom- of the secretions of the reie-mticosum, by which the hair is nourished, or peiliaps by tliat secretion of the colouring matter being diminished or totally suspended.” An Ermine shot by Dr Fleming in May 1814, in a garb inter- mediate to its summer and winter dross, confirmed this view of the subject. In all the under parl.s of its body, the white colour had nearly disappeared, hi exchange for the primrose-yellow, the ordinary lingc of these parts in summer. The upper “parts had not fully acquired their ordinary summer colour, which is a deep yellowish-brown. There were still several white spots, and not a few with a tinge of yellow. Upoii examining those white and yellow spots, not a trace of iiitorspersod new .short brown* hair could be discerned. This would certainly not have been the ease if the change of colour is eflccted by a eliaiige of fur. Besides, while some parts of the fur on the back had acquired their proper colour, even in those parts numerous liairs could he observed of a wax-yellow, and in all the intermediate stages from yellowish-brown tlirough yellow to white. These observations leave little room to doubt that the change of colour takes place in the old hair, and that tlie change from white to brown passes through yellow. If this conclusion he not admitted, then we must suppose that this animal casts its hair at least seven times in the year. In spring it must produce Iirinirose-yellow hair, then hair of a ivax-ycllow, and lastly of a yellowish-brown The same process must he gone through in autumn, only reversed, and witli the ad dition of a suit of white. The absurdity of this siiiipositimi is too apparent to he furllier exposeil. Thus the hair, as long as it remains connected with tho body, participates in llic general life of tho system, and is influenced in respect to its colom- by tho secretions of the mucous net-Mork of the skin. There exists a general tendency iu all living bodies to develop themselves from within, outwards. 1 Ids evululioii of living bodies is the ultimate cause of tho.so changes wliieh the external surface of their bodies undergoes during tlio several pe- riods of their existence, and determines the variations in the quantity of their cloth- ing : the proximate causes of cliange are the external stimuli of light and heat. As each appendage ol the animal body is endowed with a vital power peculiar to itself, it must have its peculiar periods of youth, perfection, decay, and death. When anv organic portion of tlic body is completely dead, it separates and falls, because a livinir suhstaiiee cannot eo-exist with a dead one. 'i'he casting of hair, and all other kinds of moulting or external change, is nothing more than tlie natural deatli of a certain liortion ol an animal body, in consequence of the development of other parts interior to it, and lliis kind of function is regulated by fixed laws. The external parts of animals and plants w hith are renewed each year are of two kinds. They may liavc a peculiar organic conformation, as we find in hair, liorns teeth, leathers, and loaves, or tlii'v may Imve a simple structure, scalv or foliaoeous as We find iu the epidermis or outer skin, shells, and memhraucs. 76 FIRST CLASS OF THE VERTEBRATED ANIMALS. The changes of ail these bodies partake more or less of the same general character. A tree may be considered as a body composed of an infinite number of germ.s wliich are successively developed. Besides the fruit produced each year, it pushes forth an immense number of loaves, which extract their nutriment from the sap, expand, and uirive at their full growth. Then having received all the nutriment which the ariolse of their tissuo can maintain, they dry up, become yellow or brown, the leaf ceases to extract the sap, and dies of old age. The vessels of the petiole are broken by this drying up aud obstruction, and the leaf falls. This is observed generally in autumn with the trees of our climates, and happens altm in the ever-grecn trees, the only difference being, that in these the new leaves are repaired as fast as the old ones fall, so that the tree is not at any one time completely destitute of verdure. The same thing happens witli the feathers of Birds, and the hair of the Mam- malia. The bulbou-s root of the hair is penetrated by a blood-ves.sel, and that portion of nutriment and growth necessary to its development is thcncc communicated to the shaft. When the root dries, and the canal ceases to admit nutriment, the hair falls ; the nutriment finds its way to other bulbs, the germs of hairs yet in embryo, con- cealed beneath the epidermis ; and a new coat of hair succeeds to the former. Thus the hair is a kind of plant, which has its bulb or root, and its shaft or stalk, com- posed of long shcathy tunics, one within another, like the tubes of a telescope. The casting of hair among the Mammalia arrives at differ cut seasons, according to the peculiar constitution of each animal in reference to Heat, and in general its de- gree bears an immediate reference to the temperature of the district, whether arising from the season of the year, the latitude of the place, or the degree of elevation. “ In the warmer regions,’* says Dr Fleming, “ it is reqmsitc to have the temperature of the body diminished, in the colder regions, the very opposite object is aimed at. In the former case the hair or feathers are thinly spread out, while in the latter, they form a close and continuous covering. In the Dogs of Guinea, and in the African and Indian Sheep, the fur is so very thin that they may be almost denominated naked. In the Siberian Dog and Iceland Sheep, on the other hand, the body is protected by a thicker and longer covering. The clothing of animals, living in cold countries, is not only different from that of tlie animals of warm regions in its quantity, but in its arrangement. U we examine the covering of Swine of waj*m countries, ave find it consisting of bristles or hair of the same form and texture ; while the same animals, which live in colder districts, possess not only common bristles or strong hair, but a fine frizzled wool next the skin, over which the long hairs project. Between the Swine of the South of England and the Scottish Highlands, such differences may be observed. Similar appearances present themselves among tlie Sheep of warm and cold countries. The fleece of those of England consists entirely of wool, while the Sheep of Shetland and Iceland possess a fleece, containing, besides the wool, a num- ber of long hairs, which give to it, wlien on the back of the animal, the appearance of being very coarse. The living races of Rhinoceros and Elephant, inhabitants of the warm regions, have scarcely any hair upon their bodies; while those which for- merly lived in the Northern plains of Europe, the entire carcasses of which have been preserved in the ice of Siberia, were covered with fur similar to the Iceland Sheep, consisting of a thick covering of short-frizzled wool, protected by long coarse hairs. These species, now extinct, possessed clothing, suiting them to the climate where they lived, and where they became at last enveloped in Ice. Had they been transported by any accident from a warmer region, they would haro exhibited in the thinness of their covering, unequivocal marks of the climate in which they were reared. By means of this arrangement, in reference to the quantity of clothing, individuals of the same species can maintain life comfortably, in climates which ditfer considerably in their average annual temperature. By the same arrangements, the individuals residing in a particular district arc able to provide against the varying temperature of the seasons. The covering is diminished during winter, and increased in summer, as may bo witnessed in many of our domestic quadrupeds. Previous to winter, the hair is increased in quality and length. This increase bears a constant ratio to the temperature ; so that, when the temperature decreases with the elevation, we find the Cattle and Horses, living on farms near the level of the sea, covered with a shorter and thinner fur th.m those which inhabit districts of a higher level. Cattle and Horses, housed during the winter, have shorter and thinner hair than those which live constantly in the open air. The hair is likewise shorter and thinner in a mild, than during a severe winter. The approach of the hot seasons of each year, by occasioning the development of new hair, transfers to them that nutrition which the former coat was in the habit of receiving. Hence, as the summer advances, the hair falls off, aud the animal be- comes sleek ; and the warm covering of winter is excliangod for a lighter and more commodious garb. The Sheep in our climates casts its fleece before the end of June, aiid the Mole about the end of hjay. The time when the wild annuals, whose furs are used in commerce, acquire their wnnter coats, corresponds with tho hunting sea- son. “ During the summer months the fur is thin aud short, and is scarcedy ever an object of pursuit ; Avhile, during the winter, it possesses in perfection all its valu- able qualities. ^Vhen the beginning of winter is remarkable for its mildness, thelur is longer in riperjirifft as the animal stands in no need of the additional quantity for a covering; but as soon at the rigours of tho season commence, the fleece speedily increassa in the quantity and length of tl.e hair. This increase is sometimes very rapid in the Hare and the Rabbit, the skins of which are seldom ripe in the fur un- til there is a fall of snow, or a few days of frosty weatlier ; the growth of hair in such instances being dependent on the temperatoro of the atmosphere. In the northern idamls of Scotland, where the n/iears are never used, tho inhabitants watch the time when the fioeco of their Sheep is ready to fall, and pull it off with their fingers. The long hairs, wliich Ukewise form a part of ihe covering, remain for sover-al weeks, as thev arc not ripe for casting at the same time as the fine wool. Tho operation of puUlng off the wool, provincially called rooinr/, is represented by some writers, more liumane than wcll-iiiforraed, as a painful process to the animal. That it is not even disagreeable, is evident from tho quiet manner in which the Sheep lie during the pulling, aud from tho ease with which the fioecc separates from the skin. The shedding of those antlers, which are produced each year on tho Stags, and oth'T' I'ecr, may be explained on the same principles the shedding of hair, and other external appendages. As long as the bony protuberances on the forehead of the Stag continue to absorb the nutritive fluids holding phosphate of lime in solution, and permit them to penetrate abundantly into the parts yt»t soft and gelatinous, the horns grow in tho form of antlers of various shapes. But when these horns, being completely filled with phosphate of lime, refuse to admit anymore, the latter accumu- lates in a lump at the root of the horns, and obstructs the nutritive canals. These soon die, and the passage from within outwards, being thus interrupted, the antler dies and falls like the withered leaf or the dead feather. In a similar manner we may explain the shedding of the milk teeth in the Human infant and the other Mammalia. The germs of the second teeth, before they appear externally, exist at the root of the gums, in the form of small capsules, which receive their nutriment from the blood-vessels of the maxillary arteries, and their sensation from the dentary nerves. When the first teeth have attained their full growth, and cease to admit any more nutriment, tho latter is diverted to the other germs of teeth situate below. The second teeth, having thus acquired more force, expel the others and assume their place. From these instances, it may be seen that the shedding of teeth, horns, hair, feathers, or scales, is the same phenomenon of organization ; and that these bodies resemble leaves, or rather those parasitical animals and plants, which draw their nutriment from a body larger than themselves, on which they grow or live. So exact is this com- parison, that the Hair and Nails maintain a separate Life on the corpse of Man or other Mammalia, and continue their growth until the dead body, by being entirely decomposed, ceases to supply them with a nutritious lymph. Thus the moults and changes which living bodies undergo at the surface, in differ- ent periods of their existence, depend upon the general fact that organized bodies develop themselves continually from within outwanls, so that the matter composing them never remains the same. 'J'hc nutritive parlioles dt-rivod from the food, after being assimilated to our bodies, and incorjioratcd into our proper substance, are ever transitory, and tend to undergo decomposition and waste at tho surface, so that as fast as the internal organs are repaired, the vital force impels the nutrition towards the exterior, where it is decomposed and finally rejected. Each portion of the indi- vidual participates in the general nutrition; but besides this general life which the organs enjoy in common with the entire frame, each organ partakes of a special living power, which can maintain itself distinct from the whole, or even occasion a growth at the expense of the other parts. Hence each animal appendage h-ns its special birth, age, and limited duration, besides those which it derives from the entire body, as we find in the organs of generation, the teeth, hair, feathers, and the leaves of plants. Those appendages, though developed a long time after tlie birth of the indi- vidual, perish notwithstanding before it, and various external germs develop them- selves successively. Thus, the special vital forces of particular parts possess a much shorter duration than tho general Life of the body. Further, these productions w hich succeed each other, whether hair, fi'athers, or teeth, may neither have the same form nor colour. The radical leaves of Plants often have forms and colours very different from those of the branches and floral peduncles. Tlie featliers of the winter plumage are more downy and thick than those of summer, or the nuptial period of Birds. The second teeth of the Mammalia have very different roots from the for- mer ; an old Stag receives a more formidable defensive weapon than the Fawn whose first horns are beginning to shoot. 1 hus, Nature has implanted in animals and plants different kinds of germs, appropriate to the several epochs of Life, as well as the external circurastauces of their situation, and even in reference to their relative situa- tion in respect to the heavenly bodies. The rich variety which we find in these arrangements at once demonstrates the admirable economy of Nature, which operates incessantly in evolving or developing, according to fixed and determinate laws. Every one is compelled to acknowledge that organized bodies arc formed in exact corres- pondence with the physical agents which surround them, otherwise the harmony and concourse of all portions of Nature could not subsist. Living bodies are not only formed in direct co-relation to Air, Food, and Moisture, but also with the laws of Light, excepting, perhaps, in cenain subterranean animals and plants, and require the influence of a moderate Heat. Electricity, and that form of Electricity which we commonly term Magnetism, may also contribute towards the vital action in certain circumstances. So close is the co-relation of Electricity with the vital power, that several later writers have confounded tho one agent with the other. Although it is impossible to admit that Life is the same as Electricity, yet their intimate connexion is undoubted. Animal bodies are in this respect delicate electro-vital machines, and acutely sensible to the electrical state of surrounding bodies. Animal electricity has been shown by Mr Faraday to be identical with al! the others, only that it resides in those imperfect conductors which compose the aninial tissues, in the same way as Voltaic Electricity penetrates into the metallic substance, and the ordinary Electricity exists at the surfaces of bodies. In fact, all these Elec- tricities may be converted into each other, and Magnetism itself is only a particular form of Electricity. There is no phenomenon among the Mammalia which can compare in intensity to the electric batteries of certain Fishes. The presence of Electricity is, however, demonstrated in various ways. The Hair and Skin of Man, when heated, have been accompanied, under certain circumstances, by remarkable electric and luminous sparks. Hales and BelUngeri have shown the different states of Electricity in the humours of the Human Body. Friction can draw electrical sparks from tho Fur of the Cat and several other Mammalia, chiefly carnivorous. The same thing has been found with the plumage of certain Birds, as the Parrots. It was conjectured by Humboldt, and confirmed by tho experiments of Prevost, Dumas, and Edwards, that every muscular contraction, and every act of tho Will or volition, is accompanied by a kindnf electrical discharge of the nerve* which animate it, and that the nerves servo to deposit and distribute an clcctro-vH'** fluid. 1’ho scintillations and corruscations which emanate from the eyes of certain P'frm- malia when in the dark, arc phenomena of a very different kind from that gem’ra pi*, isphorcsccnce which prevails over the entire bodies of many Fishes, Mollusca, Cru< THE MAMMALIA— MAN AND BEASTS. 77 tdrea, and Zoophytes. They seem to depend upon a certain state of the nervous expansion of the retina, when tlie anin.al is under the influence of rage, love, hunger, or any violent emotion, especially in the more furious species of Cornivora. This )iroperty of the retina is not pecuiiar to the Jilammalia, hut is also found among the Molluscu, Arnthnides, anti Crusliicta. The enormous eyes of certain Cephalopoda, as the Cuttle-fishes (5(7>!a), appear luminous in the middle of Uie Ocean, and ten'ify the Fishes, their prey. 'J'he eight eyes of the Tarantula Spider, a voracious and nocturnal species, arc also luminous, according to Jl. Leon Dufour. We also find this property among several Sauriati Reptiles, sueh as the genera Anolius and Gecko, whose eyes scintillate in the darkness of night, and the same assertion has heen made regarding the Alligators, which are thus said to frighten their prey. The ancients have related many fables concerning the jiiercing looks of the Basilisk Serpents, and modern authors have given credit to the fa.«cinating powers of the Rattlesnake. Certain credulous believers in Animal Magnetism have also attributed the mo.st ter- rific effects to the glances of the Toads, and have illustrated their credulity by examples. When carefully considered, these examples only prove a nervous state of tlie imagination when under the inlluene.e of fear. Such effects may be induced in sensitive frames by the approach of a hideous or dangerous object, and may be ob- served in the lower animals where these involuntary sensations occasion them even to tremble and faint- The eftect which the Painter Dog produces upon the Partridge is a striking instance. But the greater part of the Carnivora being nocturnal in their habits, such as the Cat genus, as the Lions, Lymx, Ounce ; the Dog genus, as the Wolves, Foxes ; the Miu-tcns, and probably also the Bats, with the Mocturnal Birds of Prey, have luminous eyes in the dark, whether during the night, or during the day, when confined in a dark chamber. Tliese animals then dilate their pupils, so th.at llie expanded surface of the retina at tlic back of the eye sliiiies vividly, and illuminates tlic external chamber of that organ. Light is thus projected i'rom witbiu upon those objects on which the animal fixes its gaze, that one can distinguisli them very well at the distance of more than a foot and a half. This emanation appears clearly to proceed from the exp.andcd extremity of the optic nerve. It lasts nearly for a minute at the pleasure of the animal, or even involuntarily when under tlie iii- llucnce of violent emotions. Certain Apes, a.sthe Kocthora trimrgata, and the How- lers (Mgeeta'), have nocturnal eyes possessed of tliLs radiating property. Inflamraa- lion, in various discase.s of the Eye, gives to some Men a temporary power of seeing in the dark, or of emitting luminous rays. The eye when rubbed, or when it receives a blow, becomes ilazzlcd by the sudden influx of blood into this organ, and not only do scintillations appear, but there is a luminous emission when these animals are enraged, like tliat proceeding from an electrical discharge. The luminosity of the retina does not proceed from a simple reflection of those scattered rays of Light which may ehanec to fall upon the Eye, as Treviraims and Jionj. Prevost have considered probable, for these phenomena can be observed in the most perfect darkness. The Cat, when irritated, darts forth fiery rays of liglit; its eyes sparkle intermittently when enraged, according to Esser and Rengger; and Gruithuiseu remarked that the rays acquired a greenish tinge when the animal was caressed. Dogs, when enraged, impart to their ocular r-idiations a tinge sometimes yellowish and sometimes hlueish. Their corruscations vaiy with individuals, but the luminous emanations appear to he most brilliant in animals with black or ash-coloured hair. They neither proceed from the crystalline tior vitreous humours of the Eye, for these can be altogetlier removed without destroying their luminous property, which only then acquires a more greenish hue. But on wounding the optie nerve, or on scraping the retina, the radiation becomes extinct ; tlms proving that it pro- ceeds neither from the cornea or uvea, or indeed from any of tlie transparent portions of the Eye. • GENlillAL REVIEW OR THE MAMMALIA CONTINUED. ■Phenomena of Sleep — the llyhernation of some Species. The phenomena of Sleep hear an immediate relation to the most general law's of Na- ture, and form an important illustialioii of the fact, lhattlio periodical motions of tho anim.al economy are in direct currcspondcnce with the inoveinents of our planetary system, and especially with our situation relative to tliat Sun wliich regulates tlie pe- riods of the day and ye.ir. “ All our wants reappear,” says Cabanis (Rapports du I’hysique et du Moral de ITlommc), “and all our functions execute themselves, in fitted and iso-clironous periods. The duration of the functions is the same in each period ; the saiiic .'ippclites or the same wants have the hours marked for their retiu-n ; »iid it commonly happens, when these wants are not immeilialely satisfied, they dimi- nish and disappear for a certain time, only to return again with the greater force and ‘mportunity at the next sueeoeding period, which ought to produce a return of the 'niprcssion. This character of periodicity is particularly remarkable in the returns and duration of sleep, which commonly reappears during each astronomical day .it the same hour ; continues nearly for the same period of time ; and according ns it is re- Rular in its periods, slumber is the more easy, while the repose which follows is the *nore salutary ami r(‘fresUin{5^” 'There are two principal states of vital activity, of which all animals partake in dif- ferent degrees. When tho vital excitement exists to its full extent, the animal is said to be awake ; when the functions of life arc suspondcil, citliei wholly or parlially, 13 said to he uslcp. From this waking state, when life exists in all its plenitude, here may be many ilegroes of its diminution, called Uererie, Delirium, Dreamiiit/, Sleep, Torpor, Stupor, Asphy.via, Lethargy, according to their intensity, of which states the last is hut one degree removed from absolute death. The principal occasions on which these states of vital repose naturally present them- selves to our observation are, Isf, When the body and mind of an animal languish cither from the return of their period of natural repose, or through excessive exer- tion. Off, When the cold of winter, or perhaps also the heat of summer, acting on yecial constitutions, suspends the animal functions of life either partially or entirely, le former phenomenon appears daily, while the latter is of annual recurrence. The first of the Wliicl: so occasions, or Sleep properly so called, differs from Death, with 1 it has often been compared, in the circumstance that all the involuntary 20 functions of life continue their action uninterruptedly. It may be recollected that, animals have two kinds of vital fuiictions ; the one vegetative and internal, which continue, with tho exception of gencr.ition, to exert tliemselves during the entire existence of each individual, and the ether purely animal, which refer to external ob- jects. T he former being essential to their existence, are never suspended ; the latter are intermittent in their action. If the heart ceased to propel the blood through tile arteries, if the lungs ceased to respire air, if the functions of nutrition and secretion were discontinued, or if they depended upon the mere Will of tho animal, life would soon become extinct. But all these internal actions arc involuntary, .and hence it is only the external and purely animal functions of life which can have their periods of action and repose, of waking and sleeping. These latter actions are therefore less essen- tial to life than the former. An animal, when profoundly asleep, is reduced to a state very analogous to that of a plant. Though dormant, he is still a living being, for he con- tinues to perform tlie functions of nutrition and secretion even more perfectly than svheii awake ; but he is destitute both of sensation and motion, and must awake be- fore he can fully resume these functions peculiar to aniuials. Thus animals have two states of existence, waking and .sleeping, while a plant has only one. The state of the latter may, however, be more or less active, according to the different degrees of heat or light to which it is exposed. There can ho no diiTerence with plants between the activity of the internal and external laiictions, and they always appear to be plunged in a state of repose more or less profound. Slany of the lower animals, such as an Oyster or a Zoophyte, when considered superficially, appear to exist in a continued slate of torpor, rather than to possess an active life, because they maintain but few relations to external objeo'.s, and hence are commonly considered rather as vegetatinu- than as living, although Plants .are possessed of life as well as animals, but only in different degrees. Sleep, ill fact, consists in the suspension of the organs of sense and voluntary motion, qualities which chiefly serve to dEtiiignish animals from plants. All the vo- luntary muscles rejiose completely, and the sleeping animal maintains no active rela- tions with external objects. The functions belonging to vegetable life continue their existence, hut tlie consciousness of existence is lost. The heart and the lungs con- tinue to act without intci ruption, wliile tlie organs of thought and sensation possess hut a temporary action. It is thus jirecisely tliose organs which are the most inti- mately comieeted with tho Mind, namely, the organs of thought and sensation, which most require repose, and tho human Soul, though immortal, when entirely sejiarated from the Body, cannot now maintain its consciousness uninterruptedly for twenty-four hours together. Night, or the absence of light, is favorable to the sleep of all animals not natu- rally of noeturiial habits. Silence, repose, the absence of noise, and in general every thing which interrupts the relations of the animal with external objects, are favorable to sleep. As long as the purely animal fuiictions continue to be stimulated, they maintain their action, until an exue,ss of action prcdmies a contrary effect. A violent exertion of the body, profound thought, or any powerful sensation, disposes for sleep. Often the fatigue of a single sense brings on the sleep of all the senses, thrmi-rh that intimate cuimexion maintained among all the parts of the body. The monotonous murmurs of a brook, the bowling of a forest, bad music, protracted reading, bad verses, or a lung lecture on r.n uninteresting subject, gradually fatigue the sense of hearing or sight, and lead the vital forces of these organs to seek in sleep for an accession of energy, ami the repose of the entire animal functions speedily follows. '1 he inclination to Sleep is amiounced by a slowness of motion, by languor of the Attention and Will, and by the gradual stupefaction of the senses. But tho different kinds of functions are suspended in a certain order of succession, according to their nature and relative importance. The muscles which move the arms and legs are relaxed and cease to act before those which sustain the bead, and the latter before those which support the spine. M'hcn the sense of sight is first suspended by the falling of the eyelids, the other senses still maintain tlicii action. The sense of Smelling is obli- terated before the taste ; Hearing after smelling; and Touch last of all. Even during the most profound sleep, the sense of touch continues to suggest ditlerent movements and changes of position, when tlio long duration of the same posture renders it disagreeable. At length animal exertion is at an end; the muscles, excepting tliose of Circulation and Respiration, ccasu to act; and the body sinks down, obedient to the ever-acting force of Gravitation. T hesc phenomena of Sleep are very analogous to that insensibility of particular organs, during our waking moments, when the .Attention is fully engaged. A pro- found Jlatheniatician, when absorbed in a calculation, neither sees, hears nor feels ■ all The functions are a.sleep except the organ of thought. Other Men, like mere machines moved by liahii, perform tlie same operation a thousand times with their hands, while the thinking jirinciplc remains buried in a profound lethargy. At Uie [irecisc moment when the Mind loses its consciousness, tlierc results a ge- neral relaxation of .all tlic muscles. If the body be at rest and m health, this sudden change in its state of obedience to the Will is attended with no marked result. But if tho liody be fatigued, or in an uneasy posture, or if the joints or muscles be pain- ful, this first result of Sleep has the effect of removing it entirely. Hence arises the lUffieulty of sleeping in a sitting posture, or during an attack of gout or rheumatism . Thu pain which the sudden starting of the muscles occasions is often so great in these diseases, that SIceji can only he induced by strung doses of opium or some other narcotic. It also follows from this relaxation of tho muscles, that the limbs become bent during Sleep, and that a substance grasped firmly in the hand, falls at tho instant when consciousness is lost. During Sleep the character of the Respiration is altered ; it becomes less frequent and deeper. The heart also beats more slowly, but the pulse is stronger. The Heat of the surrounding air, when imperfectly renewed, tends, however, to increase its movements. The heat of (ho body is not naturally higher during Sloop; on the coiki,„j, diminished re.spiratioii tends to lower the tempora'ure. It usually liappens. however from external circumstances, that tliere is an apparent rise of temperature, from tho body being surrounded by imperfect conductors of heat, and from the circumambient air being but slowly renewed. 78 FIRST CLASS OF THE VERTEBRATED ANIMALS. As the stomach is a muscular organ, and as the passage of the food through the pylorus depends upon the rapidity with which the almost insensible contractions of the Stomach are performed, it follows that Sleep retards digestion, while, at the same time, it renders it more complete. This slowness of digestion is further increased by the sUte of rest in which the body remains, as nothing tends more to excite a rapid digestion than the gentle motion of the limbs, or of the entire body. The same phenomena take place in the intestines, where the aliments remain ahnost inert in the several portions of the alimentary canal. However, the slowness of this movement favors the formation of chyle, and renders its absorption more compleU. Absorption is very active during Sleep, and the danger of slumbering in noxious air hence becomes very great. Travellers are usually advised to avoid sleeping in marshy situations, such as the Pontine Marshes of Italy, especially in the warm sea- son of the year. Perspiration also is performed more easily, because the pores remain open during the state of muscular relaxation. “ 0ne nutrition plus efficace, la re- paration graduelle des forces qui cn resulte, et aussi la replkion de la vessie, toutes ces choses reveiUent en nous, durant le sommeil, des idees de jouissance et des sou- venirs de volupte. As all the senses do not fall asleep at the same time, so they differ in the order in which they awake. Taste and Smell commonly resume their functions last of all. The sense of Sight is roused with greater difficulty than that of Hearing. An un- expected noise will often awaken a Somnambulist from his lethargy, upon whom the strongest rays of light will have had no previous effect, although his eyes continue open. Touch, as it was the last sense to become dormant, so it appears to be the most easily roused. The same person who cannot be awakened by very loud noises, will rise instantly on being gently tickled on the soles of the feet. Often the mere approach of the respiration of another will be sufficient to rouse the soundest sleeper. The positions which the Mammalia assume during .Sleep are very various. The young animal sleeps with its limbs gathered together, in a posture most resembling that of the foetus in the womb. This situation is very favorable to the renewal of the animal forces, by permitting the relaxation of all the articulations, and in preserving the heat of the more sensitive parts. For the latter reason, the Dog and Cat sleep with their bodies forraad into a circle. Some Mammalia sleep in the open air, while others retire to caves and sheltered places. Many repose without any covering, while others prepare a bed of sonte imperfectly-conducting substance, to preserve the temperature of their bodies, which would otherwise fall during Sleep below the na- tural standard. It is usually on the right side that Man reposes. This posture favors the action both of the heart and stomach, as the vibrations of the former would reverberate through the body from the reaction of the substance upon which it reposes, and the latter would be compressed by the weight of the liver. After sleep, all the organs, being refreshed, repaired, and completely nourished, acquire a greater size ; thus Man and other animals which commonly hold the spine more or less erect, are taller in the rooming than in the evening after the fatigues of the day. Sleep is not always profound ; some of the animal functions continue to act ; ideas succeed each other, and the animal is said to dream. The power of dreaming is falsely ascribed to Man alone ; other Mammalia dream likewise, because they are capable of thought, and possets a certain degree of intelligence. Sometimes the Dog is observed to howl, struggle, and perspire copiously. Moving his tail and limbs rapidly, be pursues the Hare in imagination, and, on the point of seizing it, closes his teeth and lips as if in the act of dyeing them in blood. Some Birds are also known to dream, as the Parrots. Those animals which are most easily excited dream more frequently than the others;. thus the Horse is more liable to dream than the Bull. According to Chabert, this phenomenon among Cattle is observed only in the Bull, the Ram, or in Cows which are suckling. It is possible to protract the usual period of sleep by an unusual excitement ; but if the stimulus be long conlinned its effect goes off, and then nothing can prevent sleep ■ as long as the health continues good. In fact, sleep, once in the twenty-four hours, is as essential to the existence of the Mammalia as the momentary respiration of fresh air. The most unfavorable conditions for - sleep cannot prevent its approach. Coachmen slumber on their coaches and couriers on their horses, while soldiers fall asleep on the field of battle, amidst all the noi.se of artillery and the tumult of war. During the retreat of Sir John Moore, several of the British soldiers were reported to have fallen asleep upon the march, and yet they continued walking onwards. The most violent passions and excitement of the mind cannot preserve even powerful minds from sleep; thus Alexander .the Great slept on the field of Arhcla, and Napo- leon upon that of Austorlitz. Even stripes and torture cannot keep off sleep, as cri. minals have been known to slumber on the rack. Noises which serve at first to drive away sleep, soon become indispensable to its existence ; thus a stage-coach stopping to change horses, wakes all the passengers. The proprietor of an iron forge, who slept close to the din of hammers, forges, and blast furnaces, would awake if there w this period, the mildest animals acquire new fierceness, bow formidable must those be that subsist by rapine! At such times, no obstacles can stop their ravage, and no threats can terrify ; tho Lioness then seems more hardy than even the Lion himselt- She attacks Men and Beasts indiscriminately, and carries all she can overcome reck- ing to her Cubs, which she thus early accustoms to slaughter. Milk, in tho Caf' nivorous animals, is much more sparing than in others; and it may bo for reason, that all such carry home their prey alive, that, in feeding their young» blood may supply the deficiencies of Nature, and serve instead of that milk, which they are so sparingly supplied. The choice of situation in bringing forth ** also very remarkable. In most of the rapacious kinds, the female takes the utmost precautions to hide the place of her retreat from tho male, who, otherwise, pressed by hunger, would be apt to devour her Cubs. She seldom, therefore, straj far from the den, and never approaches it while ho is in view, nor visits him till her young are capable of providing for themselves. Such animals as are tender constitutions, take the utmost care to provide a place of warmth, as well safety, for their young. Some dig holes in the ground ; some choose the hoUo'^ a tree ; and all the amphibious kinds bring up their young near the water, and custom them betimes to their proper element. The rapacious kinds bring forth the thickest woods.” THE MAMMALIA_MAN AND BEASTS. 83 The young are at first nourished entirely by the Milk secreted from the Mammae or breasts of their mother. Each mamma is a conglomerate gland, covered with a tenacious cellular tissue ; it is formed of rounded grains, separated from each other by fat, and surrounded by spongy and cellular tissues. In the midst of this gland, a number of lactiferous canals cross each other, being semi-transparent, susceptible of dilatation, andro-uniting in several leading branches towards the nipple. Besides this general conformation, there are several thoracic, epigastric, or hypogastric arteries, independently of numerous lymphatic vessels, which carry their ramifications through- out these organs. They are also very numerously supplied with nerves, for their sensibility is very great. The nipple, which is only covered by a mucous tissue, with a very fine skin and epidermis, is delicately sensible to the slightest touch. “ Elio est formce il’un tissii vasculaire particulier qui jouit do la propricte d’entrer en uno veritable Erection analogue a cclle de la verge et tlu clitoris; car ces organes ont beaucoup dc sympathie entro eus. Elle rcfyoit de sang et devient rouge et tres-sen- sible alors. Les conduits s’ouvrent et sont prets a falrc jaillir le lait do meme que le spormc est fjacule par los canaux excretcurs des vcsicules seminales. En effet, ii y a unc grande rcsscmblance enlre Taction de la glando inamraaire et colic des organes de la generation.” The mamma? nmy be placed, acconlin ^ to the species, on the breast, the groin, or the abdomen. Their number is often relative to that of the young. In the larger species, which have only one or two young at each birth, there are usually but two mammfe, whether pectoral or ventral. AVith the species of medium size, there are most commonly eiglit ; although some may have as many as fourteen. 1'lifi Carnivorous animals most commonly liavc from six to ten placed longitudinally under the abdomen ; the 0])ossums and Kangaroos have four to eiglit, fixed within a fold of skin, or inguinal purse, within which the young lodge securely. The Elephant, as also the Quadrumana, usually have two upon the breast, as in Man. Tliu female Hog has from ten to twelve, and the Ruminantia, whose milk seems to bo more sub- stantial than lliat of any other domestic animals, have generally two to four mammro. Tlie.se numbers point out the maximum limit to the number of young, which each female, when in a healthy state, is capable of nourishing without inconvenience. Among the gregarious tribes of Mammalia, the young recognise their mother with surprising accuracy by the sound of her voice, or by the smell, in the mitlst of the most numerous flock. Those young possessed of the greatest vigour will, however, take milk from several mothers, at the expense of the weakest, which are thus de- prived of a portion of the food intended for them by Nature. Some unnatural mothers drive their young away on first approaching their udder, without exhibiting the slightest compassion for the unprotected state of their offspring, which are thus in general left to perish. With the greater number of Mammalia, the young take and leave the breast ac- cording to their wants ; but it is different with tho IMarsupialia, the young of which attach themselves m forcibly to the mammie, that they would rather permit them- selves to be decapitated than leave the nipple. They remain continually in this position until their bodies become entirely covered with hair, and they possess strength sufficient to gambol around their mother. Among most species of this singular (dass of Mammalia, the skin of the abdomen forms a purse or pocket containing tho mam- mas and to which cavity the young resort for refuge, oven after the time when they cease to derive their sustenance from tlicir mother’s milk alone. Only two species of Mammalia, the Ornithorhyuchus and Echidna, are without any apparent raarama? ; but many interesting questions regarding their habits, and especially tho cares wdiich they bestow upon their young, still remain unsolved. It has been said that tho young Elephant sucks with its trunk. This, however, is an error, as it makes use of its mouth, in nearly the same manner as other Mam- malia. The time of suckling varies with the period of gestation, as well as with the time necessary for the growth of the young. Thus it is prolonged as long as the ninth or tenth month in Man, the Horse, and the greater part of the larger quadrupeds, while it is very short with the Uodontia, which have in each year a considerable number <^f births. With the Guinea-])ig, which is the most fertile of known Mammalia, the period of lactation terminates in about twelve or fifteen days. After having fed their young during the days immediately succeeding to the period of birth, entirely with the milk of their niammfc, the females of the Carnivorous animals take themselves to the chase, and bring home to their young different kinds of prey, so as gradually to accustom them to the use of a more solid food. At this tunc they seem to lose their natural ferocity, and gambol with their young ; but on being attacked, they are only thereby rendered the more formidable. After liaving fried every possible means to place their family in a place of security, they fight witli fhe most determined obstinacy and courage. The particular history of each species exhibits, in general, many interesting details relative to the care which the female lakes of hqr young, until they are sufficiently strong to provide for themselves. As *0011, however, as they have attained this period, the mothers are often seen suddenly change their feeling towards their progeny, and drive away, with the greatest *^bstinacy, the same young ones which had so long been the continual objects of »eir warmest attachment. This is particularly tffiservablo in all those species which ®^perience a rut at a particular period of tho year, and also most remarkably among 0 larger Carnivorous animals, who would soon become pinched for want, if too '^xny Wore permitted to reside together in the same district. It is commonly during the interval which elapses between the termination of lacta- tion and the commencement of puberty, that tho first or milk teeth are replaced by Qrs* This only happens to those species which have simple teeth, fixed by true oots. It begins with the incisors, and ends with the nmlars, while it often happens the latter are not changed until long after the age of puberty. The Hog never its first teeth, as they do not fall, but always continue growing. In certain tho teeth continue to grow during the whole course of their lives, *amc incisors of the Rodentia, tho compound molars of some animals of tho teeth those of the Elephants. The same property is observed in tho niol ** Idling, iroos as well as in the Elephants, but with this difference, that the 3 are developed from tlie back, of each jaw forwards, and do not grow out of the gums as in most other Mammalia. There are, however, numerous variations in these respects among the several genera and species, as well as in tho forms, which the teeth present, according to the respective ages of the animals. Thosci Mammalia which change their teeth, and especially the Caimassicrs, experience at this critical period the most painful nervous affections, which often prove fatal. In general, the term of life among the Mammalia is in direct proportion to the time which they severally take in arriving at their full growth, exclusive of the period of gestation. Buffon calculated, from many observations, that they lived seven times the period of growth ; but it is very often only six times this period. Among the most remarkable exceptions to the above rule, we find Man, with whom the average duration of life is far less than that of other species, relative to his time of growth. As he does not attain his full size until about the ago of twenty years, his life ought to average a duration of 120 to 140 years. Several individuals have attained these ages, and some have even passed them ; but of those few who survive the first years of infancy, by far the greater number do not pass beyond the ages of seventy or eighty. This anomaly to the rule of Buffon is due to a multitude of circumstances, which it would bo premature to detail at present; such as the mode of life, the abundance and excess of food, the want of temperance, and other results of an imperfect and misdirected civilization. For the same reason, the relation which tho period of grow'th bears to the whole term of life, is not without many exceptions among tho domestic animals. On the one hand, they receive the influence of a superabundant nourishment, and on the other, are more frequently preserved from those excesses to which this abundance might have given rise. Hence, the duration of life is often prolonged among the domestic animals beyond the term already specified. The growth of the Horse being commonly completed in about four or five years, it lives twenty-five or even thirty-five, provided the natural term of its existence has not been sliortencd, as happens too frequently by ill treatment of every kind, by violent fatigues, as well as the want of attention and suitable nourishment. This animal presents, notwithstanding, several instances of remarkable longevity, and some individuals have been known to attain the advanced ages of sixty and even seventy years. As the Ass takes nearly as long as the Horse in reaching its full growth, the duration of its life ought to bo nearly the same ; yet it often breaks down before that period through injuries or neglect, which it receives most undeservedly from all quarters. It is observed that animals, naturally disposed to chastity, live longer than those of different propensities. The Mule and Bardeau are usually unable to procreate, and accordingly they live longer than either the Horse or Ass. Very fre- quently Mules die at the age of forty, and one has been known to attain the age of eighty years. The Bull takes about two or three years in growing, and the natural period of its life terminates at fifteen to twenty years. The Buffalo approaches the farmer very nearly in both of these respects ; yet it appears to take a little longer time in reach- ing its full growth, and hence lives to a more advanced age. The Sheep has nearly the same period of growth, and also a corresponding period of life. Tho Goat ap- proaches to the same terms, both in respect to its growth, and tho durafion of its existence; yet the extreme attachment of these two last-mentioned species to sexual propensities serves to abridge tho ordinary period of their lives, in those few cases where Man does not terminate their existence suddenly for his own advantage. The Hog being two years in attaining its full development, may reach the age of fifteen or twenty years, if not fattened before the term of puberty, as is most commonly done, though some old Boars have been known to pass far beyond the above-men- tioned terms. We may thus perceive that the relation of the period of growth to the duration of life does not remain constant among the domestic animals. It is, however, more precise with the wild I^Iammalia. Tlu* Lion lives twenty-five years according to Buffon, though several Lions of the Tower Menagerie of London lived in confine- ment to the extraordinary ages of sixty-three and seventy years, on tho authority of Shaw. The Mococo (/.emar catta) lives at least twenty year-*, llie Rabbit eight or nine ; the Haro seven ; the Mouse only a short time. The Elephant, it is said, lives for two hundred years; the Bear thirty ; and the Wolf fifteen or twenty. Further, the Dog usually lives fourteen years, though the lives of some individuals have been prolonged to twenty ; the Cat lives nine or ten years, and the Dromedary forty or fifty. . Nothing positive is known regtarding the ages to which the Seals and the Cetacea respectively attain ; it is, however, probable, from their near approximation to the Fishes, in external characters, that they resemble them also in the average duration of life ; in other words, they live to a very advanced age. This presumption is fur- ther confirmed with the Seals, by the fact that they take a very long time in growing. GENERAL REVIEW OF THE MAMMALIA CONTINUED. 2Vie Structure of Teeth — their growth — the phenomena of successive dentition — their varieties of form. The teeth among the ^laramalia are always found upon the jaws or maxillary bones, which is far from being tho case with the lower classes of vertebrated animals the Rep- tiles and Fishes. Though useful auxiliaries of digestion, they are by no^ means essen- tial to that function ; for some animals are wholly destitute ot teeth, and in others, they are far removed both from the mouth and the intestinal canal. Their existence is no: exclusively proper to the vertebrated animals, nor are they always confined in them to the. bones of the mouth. The teeth of animals may be defined as bodies, generally bard or of a calcareous appearance, produced by the secretion of special organti, fortifying the onlerior parts of the alimentary canal, and by tho assistance of which, the greater part of these ani- mals seize, rctaiti, or divide the food with which they are nourished, while some em- ploy them further as weapons of offence and defence. The teeth of tlie Mammalia, 84 FIRST CLASS OF THE VERTEBRATED ANIMALS. with which alone we are at present concerned, may furtlier be restricted by the cir- cumstance already alluded to, that they are only found upon the margins of the maxil- lary bones. It was for a long time supposed that the teeth were bones, that they were produced in the same manner, and had a similar structure. This view of the subject has been wholly abandoned, since the publication of the admirable treatise of the Baron Cuvier upon the grinders of the Elephants, in the Annales du Museum dTiiatolre Naturelle, tome viiij in the year 180(i. Although the diSerence.^ between teeth and bones appear to be very numerous and essential, there seems, however, to be a cou.siderable ana- logy between them, especially when considered in a point of view purely anatomical. When physiologically considered, they possess many peculiarities in common with the horns, nails, and hair. At first, the constituent matters of the teeth and bones are precisely the same ; and if we revert to the first formation of these bodies, it appears that they are equally secreted and deposited by proper vessels. Under this point of view, the teeth may be considered as bones, the vessels of which are united in a single mass, and deposit the osseous matter around them ; while the bones may, on the other hand, be viewed as teeth, within which the minute subdivisions of the vessels cause this matter to circulate in every direction. At their origin, and during the greater part of their existence, the teeth arc com- posed of a secreting organ and a secreted substance. The former, or secreting organ, is always concealed in the lower part of the tooth, or in the interior; and when en- tirely formed, consists of three, or at least two other organs. It is essentially com- posed of vessels and nerves, which communicate directly with the remainder of the organization. The latter, or secreted substance, is merely deposited outside tbo first. It is composed of a greater or less number of different substances, and being deprived of all vessels and nerves, bears no necessary or immediate connexion with the other organs. The secreted substance is of a calcareous appearance, and composed of two parts ; the one e.KternaI, called the croini (fust or conronne) of the tooth; the other being more or less concealed, is termed the root (racinef The intermediate point is dis- tinguished by the appellation neck (collet). ^ The crown of the tooth may be composed of different hinds of matter, deposited one over the other. In the most complicated kinds of teeth, three of these may be obtained by a mechanical analysis. The central part is termed the ivory; the second the enamel, and the most external part the cortex. These three substances are found combined in four different ways. Some teeth are composed of ivory, enamel, and cortex; others only of ivory and enamel. Some, again, are formed of ivory and cortex, the enamel being wanting ; others of ivory alone, this last being never observed to be deficient except in those Mammalia which are wholly destitute of teeth. The root may bo real or apparent, in the first case, it is formed of ivory alone, as in Man, the Caruassiers, and the Ruminantia; or of ivory and cortex, as in the Cacha- lots. In the second case, the root is merely a continuation of the crowm, and has all the characters of the latter. Such are the roots of all tusks properly so called, the incisive teeth of all the Rodentia ; the molars of Hares, of Guinea-pigs, and of the Cabiais {Hydrockfcrus). The secreting organ of the tooth or dentary capsule, according to M. Frederic Cuvier, appears to be dependant on, or produced by, the nerves and maxillary vessels. It is not, however, without relation to the contiguous parts, being even united to the gums ; but rnu<;h leas than some authors have imagined. It is certain that the secreting organ of the second teeth, for a long time after its formation, is altogether independent of these parts, aud it is only subsequently that it becomes united to the gums. The dentary capsule corresponds, both in its structure and functions, with the substances or materials of which the teeth are composed, in such a way, that it is more simple in teeth formed of one substance alone, than in those composed of two or three. It is the same with its forms, as well as its growth, in relation to tho forms and growth of tho teeth, ihe one always being the eonsequenco of the others. The most complicated kind of dentary capsule, being that observed whenever tho teeth arc composed of three substances, is itself formed of three very distinct secret- ing organs. The central one, called the bnlhi produces the ivory ; the second, under the form of a membrane, secretes the enamel, and may thence be termed the enamellaiing membrane ; and tho third, which sunounds ail the other parts, produces the cortex or external ivory. The last may be termed the exlcnial membrane. The bulb which secretes the ivory by its external surface, appears to be entirely composed of nerves and vessels. Several arterial trunks, which extend from the one extremity to the other, are ramified infinitely before arriving at its extremities, where their divisions sometimes form tufts and fringes of an almost imperceptible degree of fineness. This part of the teeth may be studied with tho greatest facility when they first begin to form; it is then found to be naturally injected, and is net exposed to injury during the abstraction of those bony portions in which the teeth are enclosed, while a very slight degree of maceration is sufficient to extract tlie bulb from the coating of ivory by which it is surrounded. It seems to be homo- geneous throughout, and always has the same shape as the tooth will ultimately have. In fact, it is the mould upon which the tooth is modoUed. The enamellating raembratie produces the enamel by its internal surface. It sur- round? the bulb entirely, and follows all its circuitous outlines, thus possessing the same form, except at tho h&se of tho bulb, corresponding to the neck of the tooth where it abuts and terminates. IM. F. Cuvier was unable to detect any vessels in this membrane. It is transparent and brittle when thick and about to deposit <’«amel; but it soon softens, becomes of a milky whiteness and great elasticity. Finally, it cutis by disappearing altogether, when it has no longer any function to discharge, that U, when the external membrane, by depositing the cortex, resumes its place. The transparency of this membrane, its extreme thinness thereafter, aud its final obliteration, in those teeth where the ivory is formed, have been tUc cause that many Naturalists have failed to observe it. But it may be seen very easily upon tho parts contiguous to tho molars of the Ruminantia, aud especially on the hinder ones, at the moment when those animals are born ; and, if once remarked here, it becomes easy to detect it upon all teeth possessed of enamel. The external membrane, like the bulb, is of a nature essentially vascular, and may be considered as an external bulb. It is homogeneous in respect to its intimate structure ; but its two faces have not always the same forms, nor do they perform tho same functions. It deposits the cortex by its internal surface, and follows all the contortions of the tooth. In the compound teeth it juts outwards, whenever they present any hollows. The parts which line these cavities are not merely mem- branes, at least when the cnrtical matter is about to be deposited, for they then have the same Ihickuess as these cavities, and this gives them all the appearance of bulbs. Before the above period, it is sufficiently thin upon the surface of the compound teeth, and this observation U applicable to most teeth. But it may be presuin€*d that tho external membrane is always of a great degree of thickness in the capsules of those teeth where the ivory has to be covered with a great thickness of cortex, as may probably happen in the molar teeth of the Cachalots. Its external surface is always simple, being merely the protecting aud uniform envelope of the entire den- tary organ, and its form when complete is always more or less spherical. It is pierced at its summit by the evolution of the tooth ; but its margins arc attached to the gums, and become in some measure a continuation of them. These three pares, comjmsing the dentary capsule, are intimately united, and be- come confounded together towards the inferior part of this organ, at the point where the vessels and principal nerves are introduced, at least from the time when the roots begin to develop themselves, and to become distinguished from the crown. It appears that all the three parts originate from this point, and likewise all the cssen* tial vessels which traverse and nourish them pass from thence. Their other portions are from the very commencement entirely independent of each other. The external membrane may be raised without occasioning the slightest injury to the enamellating membrane, which detaches itself without effort from the layers of enamel just deposited ; and the bulb may be separated from its cones of ivory' like a blade from its scabbard ; or if the cones be broken, it may be disengaged and displayed without being destroyed, or in any way injured. This capsule, however, is not entirely formed before the teeth are secreted, in those at least which have roots. It develops itself successively, and in proportion as the different parts are formed, beginning from the summit of tbo crown, and finish- ing by the extremity of the root. The bulb and enamellating membrane seem to deposit simultaneously the matters which they respectively secrete ; and tho first molecule of ivory receives the first mole- cule of enamel. It is ouly at a later period, that tho external membrane deposits the cortex, being at the time when the crown is already formed, and when the bulb, as well as the enamellating membrane, cease to deposit matter in this part of tho tooth, for these secreting organs have still to give birth to tho roots. The above detailed analysis of the most complicated kind of dentary capsule, cn* ables us to pass rapidly over those destined solely to secrete the ivory and enamel, or the ivory and cortex, or the ivory alone, aud being consequently of a more simple structure. Those capsules intended to form tooth composed of ivory and enamel alone, arc not, on that account, depriveti of the external membrane, but this body always ap- pears to be thinner, instead of being thick, as in the preceding kind of teeth, when about to deposit the cortex. It is raised with difficulty and by shreds, aud seems only to be intended to protect the function of dentition ; it accordingly envelopes tin* organ in every part. Tho enamellating membrane presents itself in these capsule's with all the general characters which have been assigned to it. Tho bulb does nnt differ from that belonging to teeth composed of three substances. With respect to those teoth which are composed of ivory and cortex, such as the molars of Cachalots, we also find tho external membrane in them to be of a cer- tain thickness, in addition to the bulb, which is never svauting. Having thus shown that the dentary capsule of the most coinpUcat<‘d kind of teetln produces three distinct and different substances which can be accurately separated from each other, it now' remains for us to consider tho secreted bodies themselves, composing, as they do, the proper substance of tho teeth. The ivory forms the essential and fundamental part of the tooth. -As it covers the organ by which it is secreted, it is deposited from without, inwards, aud not appear to be absolutely identical in all kinds of teeth. In some, as tlic tusks of the Elephants for example, it is deposited by concentric beds, in such a manner that they are composed of cones, the one encasing another, and being numerous m proportion to the length of the tusk. This conical appearance is especially show'U in fossil tusks, as the cones themselves do not appear to have been separated artifi- cially. Other teeth have a more homogeneous kind of ivory, but tho differences of texture which this substance presents are very numerous. These tusks of the Blo- phants show on their transverse sections a iiurabor of segments of circles regularly disposed, which intersect each other, and form a waving mark, bv which the true ivory may always be recognised. ITie teeth of Man, the Quadrumana, and Carna^- siera, possess an ivory of a silky appearance, appaienlly composed of fibres. ThoaU of the Cetacea, the tusks of the Hippopotamus and otliers, have their ivory simph' and of the most uniform texture; tliose of the Rat-!Moles (Bathyeiyui;) formed of longitudinal and parallel liiires, like those of a rush. 'I'hese ebarac ters arise doubtless from the peculiar structure of the bulbs which secrete these d* ferent kinds of ivory ; yet their essential differences have not been determined b) experiment, but will probably be ascertained hereafter, when these bulbs are su mitted to a more minute investigation. This central part, being the most Important and considerable portion of the crow of the teeth, is chiefly formed of a very compact gelatinous substance. Fhe reous matter which gives it the external appearance, is merely deposited in the mes of this substance, and composes only the smallest portion. It may be abstrac! ,lcd by and of the means of a small quantity of dilute acid, and the gelatine remains pure, same form as the ivory. This calcareous matter, the only part of the tooth rea J destitute of life, is a phosphate of lime. The Enamel is deposited in a manner contrary to tho ivory, being from ' > outwards, and always immediately over the latter; this it appears to do by a km crvstallizing process. On being examined upon a section of a tooth, it is tmi THE MAMMALIA—IVIAN AND BEASTS. 85 havs Uio appearance of brilliant ncedlos, porpondiculai* to tbo surface of the ivory. I’hc ivory an I onaniel do not form one body, although they aro united to;;cthcr very C'losi'ly, for the enamel can be detached from the ivory without injuring the latter, and reciproeally. But the essential distinction between them consists in the circum- stance that the enamel does not possess gelatine for its base ; for, although it contains some traces of that, substance, they are always very minute in quantity. The enamel, on the other hand, is essentially composed of Huato of lime, which contributes its stony character, and imparts a degree of hardness superior to that of any other por- tion of the teeth, and indeed of any animal substance. The Cortex, like the Enamel, is deposited from within, outwards; but it cannot bo discovered upon teeth possessed of enamel until the latter is entirely formed. M. F. Cuvier is of opinion that, in tcetl> composed of ivory and cortex alone, it is deposited over the? ivory like the enamel. Tlu* intimate nature of cortex is absolutely the same as that of ivory, on which account it might with propriety bo termed the ^‘Xiernal ivory. Gelatine forms its principal base, ami phosphate of lime is deposited between the meshes of that substance. The cortex is found in layers more or less thick. It is of an extreme thinness on tho projecting surfaces of the molars in the Uuminanlia, but is much thicker in the liollows found on the summits of their crowns. It is observed, however, to possess a still greater thickness in the crowns of tho teeth belonging to Cachalots. In this place it equals the ivory in quantity and thickness ; for (he whiter substance, which surrounds the centra! part of these teeth, is not enamel, as some Naturalists have supposed, but a true external ivory. It commonly happens tliat the cortex contains nothing but gelatine and phosphate of lime. In some cases, however, it contains some colouring matter in addition to these, as may be seen in the teeth of several Ruminantia, and in the incisors of the Beavers. I’acas, Agoutis, Porcupines, and some others. The colour of the anterior part of these teeth depends upon a very delicate layer of true cortex, as M. F. Cuvier ascertained by many careful experiments. Tlie colour becomes brown only on that part of the tooth which projects from the gums, while the portion within them is of a dark green. It has been said that this colour is owing to the presence of iron, and that the change which it undergoes from the contact of the air is a true oxi- dation. The above details regarding the structure of the dentary capsule, which produces the teeth, as well as the composition and structure of tho teeth themselves, have been hitherto demonstrated upon a very small number of Mammalia, and they are applied only by analogy to the remainder. In fact, the teeth of Man, of some Car- tiassiers, Hodentia, and Ruminantia, with the Solipeda and the Indian Elephant, have alone been studied in respect to their dentary capsules, and the substances of which the teeth are composed. It is probable that a special investigation of teeth belonging to other Mammalia may lead to the restriction or extension of some of the preceding observations. The above remarks explain to a certain extent the manner in which the crown of the tooth is formed. As the dentary bulb is the mould of the crown, and as the matter which it secretes is deposited upon its surface, tho crown cannot fail to exhibit the same projections, hollows, and angles — in a word, to have the same identical Hguro ; but there is nothing in the structure of this bulb which can explain the form of the roots. By the terra root is commonly understood, that part of the tooth contained within the gums ; but it is essential, as has already been explained, to distinguish those in- »ortions which differ from the crown neither in structure nor form, from the roots properly so called, which begin from the neck of the tooth, and diminish gradually, '^ntil they terminate in a point more or less obtuse, and more or less irregular. The first are not real roots, but arc formed merely by the prolongation of the crown ''■'ithin the gums. When the time at which the true roots have to be formed has arrived, the ena- ^^'ellating membrane ceases to maintain its activity, and even bccotnes wholly obli- terated. The bulb and the external mcmbniue alone continue to grow and to pro- duce roots, which usually correspond, in number and situation, with the principal tubercles of the crown, and appear to be numerous in proportion to the number of I^'ading branches which the maxillary arteries transmit into the bulb. It seems probable that these vessels and their branches form an inferior prolongation of the I>ulb, as soon as the crown has been deposited ; or, in other words, that the bulb continues to develop itself under their influence, which is restricted to the points *niruodiately surrounding them. Under this point of view, the roots of the teeth be regarded as the evanescent crowns of tho same teeth, reduced to a rudi- *tieatary state; for we can easily see how they might bo continued, if the vascular system did not become obliterated. In fact, those teeth, where the capsule never leases to reproduce the crown as fast as it wcais away, and which are consequently destitute of true roots, only become such in consequence of the undiminished vitality their bulb, wliich continually maintains its vigour and activity as at the com- ‘’fienceinent. Thus we sec that teeth possessed of roots, obtain them at periods of Ificir existence more or less advanced. Among the herbivorous animals, the Horse example, tho vitality of the bulb continues for several years, while it ceases in a short time with the Carnassiers. In this respect, the Mammalia offer a great ^i^riety of examples. There are several circumstances which serve to confirm the accuracy of those As long as the dentary capsule is wholly occupied in depositing the crown. See, at the precise point where tho membranes composing it reunite and become Unfounded, a uniform disc, supplied with au immense number of vessels, which distinguish it readily from all the adjacent parts. It is from this surface that the '^^psule continues to grow uniformly, until the crown has acquired its entire height. *^he latter period, however, it undergoes a total change ; the isolated portions of vessels disappear, and those which remain compose little circles, more or less *"j^tueruu3, and distinct from each other. From these circles the roots grow ; during ich operation, the external membraue detaches itself from the bulb on all the in- ^■‘“ediato points of tho partial circles. The crown is then terminated by the dc- P*^sition of ivory between tho roots and beneath both the crown and the bulb ; further, * deposition takes place from different points of the circumference of the tooth, 22 it is at the internal surface of the roots that it reunites. The little circles continue to diminish ; suinetimes they divide after a certain grow th has taken place in the root, causing them to appear more or less forked ; and they end in disappearing gra- dually, so as to occasion all the roots to terminate in a point or thin layer. By this growth, the bulb, now reduced within very narrow dimensions, remains inclosed within the crown, and the roots are found to be pierced through their entire length by those vessels and nerves which formed them; thus connecting them with the bulb on the one ham), and on the other with tho maxillary vesseds and arteries. The first traces of the dentary capsule can bo discovered In the fmtus, it is said, during the earliest days of its life. There can be no doubt, however, that the teeth are in a great measure formed at the period of birth in a large portion of the Mam- malia, and the young animals are even compelled to use them before the perioil of their lactation has entirely terminated. Physiologists are not, however, agreed as to the nature of the process carried on within the jaws, in those parts which are traversed by the teeth, before leaving the gums. Some have supposed, that there exists a natural passage, leading from the capsule, out of the gums; and it is imagined, that this cavity is enlarged by the expansive force of the tooth, aided by the elasticity of the adjacent parts. Others have conceived, that the tooth tears everything which opposes its passage; and they have even attributed to this c.ause, some of the accidents which occasionally accompany the dentition of young animals. The former of these views is opposed by the observed plieiiomuna of the sccono dentition, where another set of teeth is developed immediately beneath tho first, in such a way, that the second cannot appear before the fir.st have fallen. No such na- tural passage has been observed; and it ought not to be presumed before adequate proof, that Nature has employed two different methods of evolving these organs. It should rather be inferred, that if the second teeth are able to surmount the obstacles presented to their growth by the first teeth immediately above them, these will also be able to overcome the resistance of the membranes and cjirtilages, when they aro required to leave the jaws, to satisfy the new wants of the young animal. It further appears, that teeth of tho most complicated form, having their crowns terminated by many tubercles, and having bctw'een them many intervals of considerable depth, ob^ trude themselves, by the summits of their tubercles, on several points at the same time, beyond the gums; yet tho gums still continue to occupy the intervals which se- parate their tubercles. The liypothesis of a violent tearing is still less admissible than that of a natur.il passage. During the time that the teeth are growing, not the slightest trace of such a phenomenon can be observed; and analogy does not appear to justify this second supposition. ■ Nature appears to have a surer and more effectual means than tiiese mechanical hypotlieses would lead us to infer; for the present is, in reality, only a, particular case of a very general law, of which it forms one of the most exact appli- cations. There is no truth in Physiology better established than this, that the nutritive power of any organic part is enfeebled, when it receives the continued mechanical action of any foreign body whatever, and the nutrition of the part may even be wholly mtcrnipted, if this action acquire a certain degree of intensity. It seems, that in the perpetual interchange of particles which constitutes life, the new molecules become incapable of replacing the former, whenever a foreign body compresses the parts from which the others have escaped. It may be said, either that the place of the first bodies has ceased to be occupied, or that the assimilating force, which ought to have sup- plied new molecules, has ceased to act. The consequence is, that the part becomes obliterated; and the molecules, which should have nourished it, are dissipated, or go to supply the adjacent parts. There can be little doubt that the development of tho teeth is a phenomenon of this description. When the crown of a lootli begins to be formed, and still more, before this period, all that part of the gum, which is intended to he opened for its pas- sage, is tliick and filled with vessels. As the tootii grows, this part becomes smaller, and the time at length arrives, when it consists of nothing more than a compact and dry skin, which soon disappears in ortler to allow a free passage to tlie tooth. This view of the subject is, however, incapable of explaining bow' it happens that the pressure of the teeth is exerted contrary to the gums, rather than in the opposite direction. Although the tooth begins at first to form only on the side next to the crown, this circumstance does not completely account for the fact that the tooth tends exclu- sively to emerge on this side. The reaction of a tooth growing in the direction of its root, is equal to its action in the direction of the crown ; and if the degree of firm- ness possessed by the adjacent parts be regarded in this question, instead of piercing the guirts, the teeth ought to descend on the side where the roots arc afterwards found ; for the inferior pans of the capsule and Its bulb would offer much less resist- ance than the denser structure of the gums. It is therefore probable that wc ought to attribute the natural direction of the teeth to some special impulse which the cir- culation impresses upon the dentary organ, as well as to the mere growth of tho capsule by its interior part. The addition of matter to the inner extremity of the crown is far from being sufficient of itself to explain this phenomenon. The pressure of the gum upon tho teetli would even bo sufficient wholly to arrest it, and it is, on the contr.ary, the life of the gum which would thou have to bo suspended. While the teeth are growing, the vital action of their capsules is raised to an intense degree, the blood is directed towards them with great force, their irritation becomes extreme, and hence probably result the fatal consequences which frequently occur to young animals during the period of their dentition. Tiie protrusion of the teeth from the sockets, in consequence of their secretion and growth, is not the sole movement which these organs present. Other changes suc- ceed, the object of which being the mastication of the food, is rather more obvious than the causes which produce them. Among these may bo ronsidered, in the first place, the secondary movement of the crown in teeth with distinct roots, after tliey have emerged from (he sockets, The capsules of all these teeth being entirely inclosed within the jaws, have their lower parts, which correspond with the neck of the tooth, much below the deniary margin of these bones ; but when tho teeth are entirely formed, the neck is on a level witn this same border that is to say, the inner part of the crown, which in some manner S6 FIRST CLASS OF THE VEIITEBRATED ANIMALS. has been formed in the bottom of the jaws, ultimately finds itself on a level with their exterior margin. This protrusion of the crow'n appears to be owing, at first, to the growth of that part of the capsule which is about to give birth to the roots — a growth which does not make its appearance until after the formation of the crown. Subse- quently to this, it must be attributed to some special impulse of the circulation, which maintains itself in a high degree as long as the dentary capsule preserves its secreting power. Further, at this particnlar period of its growth, the gum no longer opposes any resistance to the growth of the teeth. There is seen in the molars of the Horse a second kind of movement, which they probably possess in common with all other herbivorous animals as well as the Ruminantia. It consists in the continued obtrusion of their teeth, even when completely formed, and opposed by others in the opposite jaw, against which thev act during mastication. This moveraet.t was fully demonstrated by Tenon (Acatlemie des Sciences, an. 6), who, however, did not investigate its cause. It may be regarded as a continuous ossification of the jaws, — on operation which only erases with the life of the animal. In fact, a third movement of these teeth exhibits this ossification tending continually to expel the teeth from their sockets; and this occurs when a tooth, not being opposed by others, is pushed out of the jaws. As no force then opposes the continued secretion of bone, the sockets become tilled, and the teeth are driven from the place which they occupied, as if tliey were foreign bodies. This movement, which is prejudicial to most animals, has one advantage for those which are obliged to wear out their teeth in grinding their food ; for, al- though the wealing out of the teclli in these Mammalia is nften very unequal, the duntarv organs do not on that accoant remam uneven at their summits ; and the con- sequence is, that the grinding of the food may be continued to the most advanced periods of life. There is a secondary movement in the incisors or front teeth of the Rodentia wholly opposite to the preceding, and still more difiicult to explain. Thai part of the tooth which corresponds in sitmition with the root, is placed much less towards the front of the bones containing them, among young animals, than among the old. ^hesc teeth continually fall back at their extremity where the bulb is placed, in pro- portion as the animal grows, while they advance forward by the other extremity. M. Frederic Cuvier, who observed this singular phenomenon in the Rabbit and Guinea-Pig, supposes that the bulb continues to grow by its binder part, being in- (luenced by the nerves and vessels which thence derive their life ; and this pbeno- nicnon appears to be common to all teeth approaching to tusks in their general cha- racter. Another problem connected with the incisors of the Rodentia is much less diili- eidt to solve, we mean their curvature, and the peculiar curves which they affect. To produce an arched tooth, it is sufficient that the capsule he arched; but if the curvature of the capsule remain always the same, these teeth, which can grow in- definitely when no obstacle arrests their course, would present in this case the form of a re'-ular circle, of which frequent examples are found. Instead, however, of this curve, the incisors of the Rodentia exhibit one nearly approaching to a spiral, where the first portions of the teeth are inclosed in those that follow. It is necessary, therefore, that the capsule producing the teeth should change iU curvature, and that it should approach continually towards the right lino, as these animals advance in a»e, up to a certain point, perhaps, when it ceases to be further modified. We may also remark, that these changes of curvature arc tlic same in the incisors of both jaws ; for these teeth, at all periods of life, preserve among themselves the same relations. The appearance of the teeth beyond the gums usually commences, among the Mam- malia with tlie period when the milk begins to he insufficient for the nourishment of the voung animal ; but it very rarely happens that they are all developed at the same time” In this respect, great differences are found among I hem ; and Nature, in most cases fails to impart at one time all the teeth necessary for the use of each animal. There are very few, we may almost say, no Mammalia, where some of these organs are not renewed ; that is to say, that certain kinds of teeth fall, and are reproduced, or rather replaced, once or oftener, by the successive growth of other teeth beneath, behind, or before the former. These first teeth, which give place to new ones, are distinguished by the term ■milk teeth, or teeth of the first dentition ; those which succeed are termed the second teeth. But these terms, founded upon what has been observed in the human species, ought not to be taken in the strict sense when applied to other Mammalia ; for among these, it will be seen that the milk teeth may fall before birth, or a long time after the adult age. To avoid the mistakes to which the ambiguity of these terms might give rise, it will he proper to employ the terms first, second, and third teeth, to de- note the order of their appearance. This department of Natural History, which shows the succession of the teeth, their mutual iiifluenec, the coincidence of their appearance with other parts, and with the new Wiints of each animal, as well as the relations of form and number between the teeth of different dentitions, has, unformnately, been much neglected, and it is only now beginning to receive that attention winch it merits. In a Zoological point of view, a knowledge of the dentary system in different ages is almost indispensable; hat we arc still without a series of drawings, showing the teeth of young Mammalia, cor- responding to the valuable lithographic sketches of M. Frederic Cuvier (Sur les DeuU des Mamraiferes), made from adult specimens. Before explaining the few particulars that have hitherto been nseertuinod on this subject, it will be proper to premise a few words respecting the different kinds of teeth, as well’as to explain the system of notation which we intend to use in describing ihcm. The teeth of the IMammalia emerge solely from the inter-maxillary and maxillary bones. The incisors, or front teeth, make their appearance first ; .and these may be followed either bv the canines or molars. The last are subdivided into false molars, camassiermolars.and tuborculons molars: while the tuberculous molars themselves may be further distinguished bv their having simple, compound, nr proper tubercles. (1.) The Incisor, or Cutting Teeth (Ineisores or Primures), are somewhat broad ami long, with their margins often parallel, and cut away obliquely at their free ex- tremity. Wc see them so, for example, in the front teeth of Man ; but this form is still more strongly marked in the Rodentia or Gnawers. This term Incisor ought properly to be applied only to those teeth which have a form especially fitted for cutting ; but it has been extended not only to all such as arc found in the incisive or inter-maxillary bone, but even to those opposed to them in the lower jaw, although the latter often have neithiT the form nor use of true Incisors. (2.) The Canines (Laniarii), or Tearing Teeth, have the genersal form of those teeth which appear most prominently in the Dogs. They arc longer than all the others, and always hare a single root and a single point to the crown. i\s these teeth are usually ]>]aced in the upper and lower jaw, immediately behind the Incisors, the term Canine has been extended to all teeth which appear to occupy this place. They are likewise called Corner teeth ; .ind, from the chief use to which they are applied, have obtained the name of Laniariii from laniure, to tear. (3.) As the names of most parts of animals are derived from the corre.sponding parts in Man and the Ruminantia, which were principally dissected by the ancient Anatomists, ll»e term Moltr (^Molares) is correctly applied only to those which act, as we may remark in the Ruminantia, almost like a mill-stone — (in Latin wio/«, a mill). IJencc, we understand Molar teeth to be compound, semi-compound, or even simple teeth, having the crown broad and flat, with broken projections and small eminences corresponding to each other in both jaws. Afterwards, however, the term has come to be applied indiscriminately to all teeth situate behind the Canines, and occupying the entire inner extremities of the dentary lines, although they some- times possess no other character of molars than the place they occupy. Thus, in the Cats, whetc these teeth are trenchant, and correspond in each jaw, so as, in fact, to act in the same manner as true Incisors, they are not on that account deprived of the common appellation of Molars. Hence it becomes necessary further to distinguish the diiTerent kinds of Molars from each otlier. In many IMammalia, the IMolars difier greatly both in size and form, and have on that account been divided into False and True Molars. false Molars, being most commonly the anterior ones, we understand such as are small and pointed. True Molars are considered to be tliicker and larger, with ilicir crowns studded with several points, or altogether flat. In the Carnivorous animals, there is found a very large Molar, which more especially fulfils the tearing purposes of these animals ; and this tootli is further distinguished by the terms carnussier Molar. The importance of possessing a good system of Nomenclature for the teeth becomes sufiiciently obvious, as soon as the necessity of defining clearly the different kinds and combinations of teeth, both in respect to their forms and relative position, has been made apparent. In stating the dentary systems of animals, two methods of notation have hitherto been employed ; for example, the adult teeth of the human species, being eight inci- sors, four canines, eight false molars, and twelve tubcrculou-S molars, have long been represented thus : Incisors^; Canines ; Molars = 32. In his work on the Teeth of the Mammalia, M. Frederic Cuvier expresses the same thing, under the following form : 32 Teeth. ! IG upper. IG under. 1 4 Incisors. 2 Canines. 10 Molars. 4 Incisors. 2 Canines. 10 IHolars. The former expression, besides its inconvenience from the smallness of the figures, does not represent the nature of the Molars. Tl»c latter is not compact. In bolh> the teeth on each side are confounded together unnecessarily. As a new system of notation, which will combine the advantages of brevity and clearness, yet remains to be proposed, wc venture to suggest the following, which possesses, in our opinion, some of the most essential requisites. Let M represent anv Molar tooth ; C a Canine ; F a false Molar j and C' a carnassicr Molar. Let a number annexed to an explanatory letter denote that there arc as many teeth of the kind, represented by the letter, as there are units in tlie number. Further, let a number without an explanatory letter denote an Incisor, or front tooth, and a Molar, unless otherwise expressed, be always understood to be tuberculous. Then, adopting the ordinary signification of the Algebraical symbols, the deiitary system of the AduU Man will be conveniently icpresented as follows; ^2 + C + (2 F + 3) M _ _ I'i + C + (2 1' -f- 3) M 16 where the numerator denotes the number, nature, and relative position of the teeth on one side of the upper jaw, and the denominator of those on one side of the lower* The small figure in the corner indicates that each expression must be doubled represent both sides of each jaw, and the vertical line on the left hand shows the medial axis of the body, passing in the middle of the front teeth. To avoid repetitious, only one side of either jaw is alluded to in referring to p^'*' ticular teeth ; and what is said of one side must be understood of the other, which precisely resembles the first in all its relations. It is always customary to count from the anterior extremity of all the parts which bear these organs. Thus, the first Incisor among the Mammalia is tltat tooth found nearest to the suture, by the inter-maxillary bones are united. This suture is represented m the formula* the vertical line. All extraordinary cases are excepted, such as the appearauc® teeth before birth or in extreme old age, while the ordinary and most natural proc^- of development is always understood to be meant, unless otherwise expressed. In the human species, the first dentition generally takes place from the or eighteenth month to the age of two years or two years and a half, and it u^o commences with the lower jaw. The first Incisors precede all the others, and tie_^ are followed by the second ; so that, towards the end of the first year, all the lU ^ sors are developed. The first tooth which pierces the gums after tho incisors ^ molar ; and it is subsequent to this that the Canine, though placed before it» iiake* THE MAMMALIA— MAN AND BEASTS. 87 its appearance ; finally, the first dentition is terminated by a second Molar, It must bo remarked that Molars, and not false Molars, immediately follow tho Canine ; and this is contrary to what is observed in the final dentition of the human species. The general law, of which this is only a particular case, will come afterwards to be ex- plained. The formula for the Milk-teeth, or first teeth of the Infant, is therefore »| 2 + C + 2 M _ 10 _ I 2 + C + 2 M 10 All ^.he tcela of tne first dentition fall exactly in the same order as they have ap* peared. The Incisors and Canines are replaced by Teeth of the same nature as themselves, only stronger and larger than the first. On the contrary, the two first Molars are replaced by false Alolars oi ly Tliis operation is finished towards the twelfth yeai*, and tho first tuberculous molar, being tho third in the order of time, shows itself about the sixteenth or eighteenth year. This tooth is larger than any which preceded it, or even than those which follow. Finally, tho last of these teeth, commonly termed wisdo7n (eeth, and which may not improperly be styled a third dentition, make their appearance a few years later, though sometimes they are de- layed as long as the tliirtieth year. All the teeth of the second dentition are formed, according to the import.ant re- searches of M. Serros, by the vessels and nerves of a special dentary canal, developed beneath the first, and which replaces it as soon as the first set of teeth begins to fall. We may thence conjecture that, at the time when tho other Mammalia change their teeth, an analogous phenomenon takes place. Wlien the teeth of tho first dentition fall, it is observed that the greater part ot them have lost their roots, and that the lower part of the crown is tinged black, and covered with asperities which seem to be the effget of a species of corrosion. It will be proper, however, to postpone further notice of this curious phenomenon until the subject of successive dentition has been concluded. The Apes of both continents present nearly the same phenomenon as the human H^cmes, in respect to their first and second dentition. Tho Makis and Insectivora have not yet been studied in these respects, but some Carnivora have been satisfac- torily examined, and especially the Dogs and Cats, in which two dentitions are recognised. The first dentition of the Cats consists in the upper jaw of three incisors, one Canine, one rudimentary false Molar, one carnassier, and one small tuberculous Molar ; in the lower jaw of three incisors, one Canine, one false IMolar, and one <^arna5sicr. Or, 3 + C + (F + C'+\) M ^ _I4 ^ 26 I 3 (J ( b -4“ C IVl 12 In the second dentition of the Cats, tho incisors and canines are replaced without ^tiy important changes, by teeth similar to them in nature. It is also the same with the first two false JSIolars ; but the carnassiers are replaced by the second false Molars, and both are. developed immediately after tho others, so that, from being second IMolars in the first dentition, tho carnassiers pass onwards to be third Molars ‘n the second ; that is to say, in the upper jaw, tho carnassier Molar has taken tlie place of the tuberculous Molar, which in the second dentition appears in the fourth and last place, while the carnassier of the lower jaw is developed in the place where tooth was found in the first dentition. This will he readily under.stood on com- paring the following formula of the second and adult dentition of the Cats with the preceding. S|3 + C-i- (2F4- 16 _ I 3 + U -1- (2 F -f CO M 14 In the dontitiou of the Dogs we find phenomena very analogous to ihe above. On ^■’^mpleting their first dentition, they have in the upper jaw three incisors, one Canine, falsG Molar, one carnassier, and one large tuberculous Molar; in the lower jaw, ^Hree incisors, one Canine, two false Molars, and one carnassier. Tlie formula for the l**‘st dentition of the Dogs is therefore 2. ;^4.C + (F+C^+1)M ^ ii ^ os I 3 -j- C -f- F C^) M 14 ^ Iri the same manner as among the Cats, we find that the incisors and canines of the are renewed, at the second dentition, in both jaws, without any important change, ^^ediately after the canine, in the upper jaw, there appears a rudimentary false molar ^ spot whore no tootli had previously existed. The false molar of the first dentition ^‘^pUced by a tooth similar to itself ; the carnassier by a third false molar, and tho ^**’^ulous molar by a carnassier. Finally, a tuberculous molar, v^ith a second or ^’^allei- one, appears art<’r the carnassier. In the lower jaw, as in the upper, theru a rudimentary fa!.so molar .after tho canine. The two false molars of the first dion are replaced by teetli which resemble them, and the carnassier by another ttjolar. Kext follosvs the new carnassier, ami immediately behind it, one largo 7^^<=uious mol, dui ■ mmodiatoly behind it, one largo place where no tooth had appeared , and one rmlimentary ^ the first de ® l^ollowiug formula of tlic adult dentition in the Dogs witii that last given. the first dentition. These changes appear obvious to tho sight, on contrasting 3 -I- C + (3 F + CM- 2^ _ — 3 -j- C + (4 F + C' + 2) M “ ‘22 ~ are ^ t follows from this, that in the second dentition of the Dogs and Cats, the teeth ^ tiot only more numerous, but the carnassier molars are placed at a muCli greater from the eanino teetli than in the first dentition. Perc-'^ is equally applicable to all Carnassiers, and it is not difiicult to design of Nature, in thus altering the position of these teeth, which are Qf , t.o animals feeding almost exclusively on flcah. T6 render the action the ■ f^lways powerful, they are'brought nearer to the fulcrum or hinge of i„ ^hus the effect which tho jaw would otherwise produce from its growth, ‘‘"ishitig tlieir ptjwer, is effectually counteracted. As the Rodentia do not possess different kinds of molars, they cannot present these changes which we observe in the Carnassiers. Excepting the Cabiais (ITydro- eharu8)i their teeth of the second dentition are developed immediately under those of the first, and the latter entirely resemble the former. The Cabiais, on the con- trary, possess a peculiar mode of dentition, in common with the Elephants and Ethio- pian Hogs (^Phacochoertts), It has not yet been ascertained, whether the incisors of the Rodentia fall, and are replaced. The Baron Cuvier has proved, that all species of Rodentia which have only three molars, possess only a single dentition ; and that there is a second denti- tion only among those species which have more than these throe teeth ; that is to say, all molars surpassing three in number, and placed before them in the jaws. He has further made the singular observation, that tho teeth of the first dentition fall, in the Guinea Pigs, while these animals arc yet in the womb of their mother. In spe- cies of the liarc genus (Lepws}, the first teeth fall a few days after birth, and this phenomenon is found even in those rudimentary incisors, which are known among all animals of this genus to develop themselves behind the principal incisors. Wo proceed to the Pachydermata, as the Edentata have not yet oflered any im* poitant observation in this branch of the subject. The first dentition of the Hippo-* potamus consists of two incisors and one canine in each jaw, of three false molars and three tuberculous molars in the upper jaw, and of two false molars and three tuberculous molars in the lower. Or, »|2 + C + (3 F + 3) M _ ^ ]2 -j- (J -J- (^2 F ”1“ 3) M It) In the second dentition, the incisors and canines of both jaws experience no change. The first of the three false molars in the upper jaw falls, and is not replaced; the two others arc replaced by teeth the same as themselves, and a false molar succeeds to the first real molar. But, at the same time, another molar is developed at the extremity, so that the number of these real molars remains always the same, not- withstanding the fall of the first real molar. In the lower Jaw, the first false molar falls without re-appearing ; the two following arc replaced by teeth of the same kind,' and then, as in the other jaw, the last molar appears. The second dentary system of the Hippopotamus may, therefore, be represented thus ; ^12 + C + C-t F + 3) M ^ ^ _ 38 I2 + C + (2 F + 4) M 18 We may apply the same observation which has already heoii made regarding the Carnassiers to the Hippopotamus ; and it is, probably, for a similar rc.oson, that the first real mo^ar of the first dentition is replaced by a false molar in the second. The Ethiopian Hogs ( P/mcocAfiTtts) exhibit a new mode of change, which they possess in common with the Cabiais (^JIi/drocha.Tuii). Their last molar possesses a movement from behind towards tlie front, so that, when entirely grown, the two small teetli which preceded it have disappeared, and it alone occupies the ji»vs. The Elephants have a mode of dentition resembling the Cabiais and Phacocha'ru?. Their molars begin to show themselves by the fore part, and continue to advance from behind forwards ; from which it follows, that these animals liave at first only one molar in each jaw, afterwards two, then only one, then two again, and so on. It appears that this movement is the consequence of the growth of eight teeth. The first, which occurs soon after birth, has not fallen when the second makes its appear- ance. At the age of two years, the latter remains alone; and this continues until the appearance of the thiri’, which remains alone until the sixth year. At nine years of age, it also disappears to give place to the fourth, and so on. It should be noticed, that these teetli always appear at first by their fore part, which, on that account, is much sooner worn out than the hinder. Passin‘» to tho Horses, we return to the mode of dentition first described. The teeth of the second dentition develop themselves immediately under such of the first as are intended to fall; that is to say, under all the incisors, the canines, and the first three molars. The only particulars requiring notice at present are, tliat the first teeth arc narrower than those which succeed, and that the last molars appear as soon as the first have fallen. The Ruminantia present analogous phenomena. All the incisors and canines of the first dentition give place to teeth of the same nature as themselves; and of the six nu>lars found in each jaw, the first three are replaced by the same kind of teeth, being only less complicated. It is then, also, that the last molars, which are very complicated, present themselves ; and wc may thus perceive the same design of Na- ture, already noticed, in respect to the Carnassiers and others. Among nil these animals, the greater part of the teeth, at the time of falling, )»rc- sent nearly the same appearance as those of Man. Their roots have disappeared; and from the ii regularities in these teeth at their innermosl surface, it might be im- agined that they had been corroded ; and further, that being composLul of different substances, some of them were less accessible than others to the action of the corrosive substance. As spots or black stains arc perceived on the whole extent of this surface, they might appear to exhibit manifest traces of a kind of corrosion, and forcibly recall the appearance of caries, or decay of the teeth, as has often been remarked. Many hypotheses have been proposed to explain this singular phenomenon. Vet it is not easy to perceive how a corrosive lluid, if it really existed, could spare the adjoining parts, and especially the teetli of the second dentition. I'lie mechanical action of the second teeth upon tho first has also been supposed, and of all attempts to explain the phenomena, this is undoubtedly the most unfortunate. One tooth can- not wear out another without wearing itself out likev\ise; and the second teeth arc always in their most unblemished state at the time when the first have fiillen : finally, this has been attributed to a power of absorption ; and the last opinion is most gciu*- rally adopted. It is not unUkely that caries, or decay ot the teeth, tuny be produced by a similar cause. From the observations which have already been made, on the complication of ilie dentary cajisules, on the variety of substances of which tho teeth are composed, on tho care which Nature takes in supplying the places of those teeth destined to fall, on the different situations which they occupy, and the names they h.ave received, will 88 FIRST CLASS OF THE VERTEBRATED ANIMALS. lead the student to perceive the importance of these or^jans, and the different func- tions which they are destined to fulfil. But a much more enlarged view is acquired by studying the different forms of the teeth, in their relations to each other, as well as to the nature and habits of the animals possessing tliem. It remains for us to give a rapid outline of this part of the subject. On placing before our view the teeth of all known Mammalia, we soon perceive that they admit of being classified under a small number of different forms. With some of them, as we have already remarked, there is no (hffercnce between the root, or rather, the parts inserted within the bones which bear the teeth, and the crown, or part beyond these bones. Teeth of this nature have no real roots, in the proper acceptation of the word ; that is to say, the crown is continued inwards as far as the dentary capsule, which never produces anything but the crown, as long as it remains free and active a circumstance occurring with some animals during the whole course of their lives. Among others, on the contrary, the roots are very distinct from the crown; they maybe either simple or complex, but do not, in general, exhibit in their forms that constancy of character which is always to be recognised in the forms of the crown. This circumstance arises naturally from the different manner in which each of them is formed. Hestricting, therefore, our view of the teeth solely to their crowns, we find that there exist three principal forms among them. These may be almost infinitely mo- dified, and some transformed into others, in such a manner, that it becomes impossi- ble rigorously to determine the precise point where the one form passes into the other. This manner of classifying the teeth must be regarded as nothing more than a purely artificial method, for enabling us to speak of their forms without too much obscurity and confusion, by restrmning, within their proper limits, the observations necessary to be made. The crowns of all teeth may be regarded as conical, tren- chant, or tuberculous. (1.) The Conical Teeth vary in form from the cylinder, more or less compressed, terminated by a point, more or less obtuse, to the oval or ellipse. Some are straight, some angular, others curved. Those of an elliptical, or oval form, are the least common, and are observed among the Cachalots. The conical teeth, which comprise , the Canines of the Carnassiers, the tusks of the Elephants, Hippopotamus, &c. are the most numerous. Finally, the cylindrical may be seen in the molars of such Edentata as are possessed of teeth. Among the Conical teeth, only two kinds of composition can be observed. Some are formed only of ivory and cortex, such as the Molars of the Cachalots ; for although the external part of these teeth possesses a whiter tinge than the central, it is not formed of enamel, as some have thought. Both substances arc ivory in reality, and it is the same w'ith the tusks of the Elephant. Others are covered with enamel, such as the Canines of the Carnassiers, and many others. In this class of conical teeth are found by far the greater number of those destitute of roots, such as nearly all tusks ; and of those, wherein the root is distinct from the crown, only a small number have been observed with many roots, as the Canines of the Moles, for example. (2.) The Trenchant or Cutting Teeth may be presented under a simple or com- pound form. Among the former may be placed the Incisors of the Rodentia, which belong as much to the first division as to the second, the Incisors of the Quadru- mana, the Carnassiers, the Ruminantia, and others. In this division we may place the false and carnassier molars of the Carnivorous animals. There are, how- ever, many among the former vshich approach nearer to conical than to trenchant teeth. All teeth of this class are composed of ivory and enamel, though some also have cortex. These last are the incisors of the Rodentia, which present the singular anomaly of having enamel only on their anterior surface. They are with simple or multiple roots ; and those of the Rodentia alone are possessed of the same peculiarity as tusks, in having no roots properly so called. (3.) The Tuberculous Teeth present the greatest variety of form, and are all Molars. The simple tubcrculoiia Molars are those of the Quadrumana, the hind - most molars of some Carnassiers, the grinders of Squirrels and Rats, those of the Babyroussa, or Indian Hog. The proper tuberculous Molars arc found in the Insectivora, &c. The compound tuberculous molars belong to a great num- ber of Rodentia, such a* the Beavers, the Pacas (^Ccdogeny.%\ the Agoutis, the Hares, the Guinea Pigs, and others. The simple tubcrcnlous molars arc always formed of ivory and enamel, while they arc all possessed of several roots. This observatioti is equally applicable to the proper tuberculous molars. Among the compound tuberculous molars there are perhaps none which do not possess the cortex, in addition to the ivory and enamel. Some of these teeth arc found with several roots, as in the Beavers, Elephants, Horses, and Ruminantia ; and without roots, as in the Hares, the Cabiais, the Lagomys, and other Rodentia. The uses which animals make of these different forms of teeth are exceedingly various. To some they are powerful arms, by means of which they attack their prey, or any enemy that threatens them, or else defend themselves when attack<*d. In others they seem rather to he intended to retain a prey, which has already been seized. Some kinds are used for dividing the food like pincers ; others for cutting it like scissors. Again, we find another class of teeth which grind like the stones of a rail), or which triturate their food, like jagged pestles fitting into mortars as jugged as them- selves. Sometimes they crush by a single jerk, or pressure. All these forms and different modes of action find their final object in the ever-varied substances, which may serve for the nourishment of animals. The kind of food which each animal re- quires is determined by iU nature ; this again regulates the influence which it exer- cises upon other beings, and determines its station in the scale of creation. The different kinds of teeth are found combined together in different manners. In many Carnassiers, wo find conical, trenchant, and tuberculous teeth, all united in the same individual. Among the greater number of the Ruminantia, we can discover only the trenchant and tuberculous teeth. The conical teeth alone are found in some Edentata, and in the Cachalots and Dolphins, while only the trenchant and conical teeth arc found in the common Seal. In fact, wo find in almost all Mammalia at least some of these forms — simple teeth, semi-compound, or compound, with one or more roots— conical, compressed, pointed, with fiat crowns, tuberculous or trenchant. At present it is unnecessary further to enumerate the different possible combinations of teeth, A general idea of the sub- ject may be obtained from the following SYNOPSIS OF THE MAMMALIA, EXHIBITING AN OUTLINE OF THE NATURE. FORM, AND POSITION OF THEIR TEETH. Instances. [■ of va- rious forms Teotli Calcareous in both jaws of one form only |_in one jaw only ■completely lin- ing the mar- gins of both jaws not completely lining the mar- gins of both jaws, leaving a . vacant space 'of three kinds not very strong- ^ ly defined (Anomalous) r in the middle, both above and below [ f tubercles blunt Man, Orang-Outang. molars simple J pointed Lemurs, Flying-Cats. I very sharp ...Hedgehogs, Shrews, Moles. .molars compound Aiioplotherium (fossil). f Apes generally, the Ouistitis. f .u 1 • j 11 1 c j ^xT IS 1 nearly all C.vbnassieus, HiP' of three kinds, well denned (Normal) ■ L Opossums. C really Rodentia, Asiatic Rhinoceros- (apparently ...Horse, Kangaroo-Rat. r both above and below Sloths, Morse. r Elephants, Mastodon (fossil)- the front ...•<; below, and in the middle above i Diigong (adult), Manatus I ( (young). (above, and in the middle below Ruminantia. c Armadilloes, Oryctcropus, 1 Megatherium (fossil), Afr**-*'*'’ ( Rhinoceros, Manatus (adult)- all Conical or Canines Dolphins generally. f the upper Narwhal, some Dolphins. I the lower Cachalots? all Molars Iloriiv Wanting ■ in both jaws Ornithorhynchus. in the upper jaw only Whales. f Manis, Ant-eaters, Echidna, I some Dolphins ? These varied forms and positions, and even the number of the several kinds of teeth, often afford the best speciffo characters for determining the Mammalia ; in all cases they offer the surest characteristics of the genera, and oven of other divisions of a higher order. In this way. one of the Mammalia may be immediately recognised by a simple inspection of its teetli ; and, reciprocally, wo may determine the nature of the animal to which a single isolated tooth has belonged. The importance of this study towards the knowledge of fossil animals, as well as for establishing the generic groups of fos- sils, has been forcibly illustrated in the celebrated work of the Baron Cuvier, on the Fossil Bonos of Quadrupeds t^Sur les Ossemens Fossiles), and liy MJI- Fr*^ Cuvier and llligor. The teeth may, indeed, be regarded as one of the most ant subjects in Zoology, and one of the most certain marks for ascertaining the ture of animals, and the relations established among them. They are, in foundations of the science ; and, hence, should occupy an important place in system of classification, as they serve as an index to the order of facts and lations ; and, hence, may be considered as indispensable to the existence of tb“ THE MAMMALIA. MAxV AND BEASTS. 89 GENERAL REVIEW OF THE MAMMALIA CONTINUED. Tht Structure of Skin , Hair, Iforns^ Nails, Scales, and other inteiyumejits. Thk entire surface of all organized bodies is terminated by an envelope of a peculiar nature, varying in thickness according to the species of animal or plant, or the dif- ferent parts which it covers. In animals, this iiitegnment commonly receives the name of skin, and seems to bo esseiilially the samo in all the \ertGhrated animals, the external difleronces being merely owing to the development of certain additional parts. One of its surfaces is always intimately united to the body of the animal or plant ; while the other, remaining unattached, bears immediate and various relations to the surrounding bodies. In the Mammalia generally, the skin is composed of four substances, more or less distinct, and varying in their properties. The roost external is termed the epidermis or cuticle ; the second from the surface is the mucous tissue or veto viiccnsum ; the third is the /ja^i7/rtry or rtervous substance; and the fourfh, or innermost, forms the true skin, chnri.on, cutis, or dermis. These successive layers may be of greater or less thickness, and some of them may not always be present in the several species of animals belonging to this class. The epidermis or cuticle is the most universal of all the layers, being found on iho bark of trees, the stalks of herbs, the petals of flowers, the pellicle of the fruit, — as well as upon the entire surface of all animals. It appears to be an intermediate sub- stance between horn and true skin, being nothing more than a tliin membrane, form- ed by the hardening and drying up of the most superficial layer of the mucous tissue immediately beneath it, and of the albuminous fluids with which the latter is impreg- nated. It does not possess life in common with the other animal tissue^ being merely composed of a greater or loss number of inanimate layers placed one over the other. This cuticle is not confined to the surface of the body, but extends into its several apertures, protecting them, as well as all the nerves of the body, from a prejudicial contact with the media of air and water, to which they arc con- tinually exposed. The consistency of the cuticle varies with the nature of the cir- vumjacont fluid; thn", it is observed to be dry and almost horny in animals living permanently in the air, while it is viscous and mucous in the aquatic species. The cuticle appears to be folded in a variety of ways, among tlioso Mammalia, which re- main continually exposed to tlie drying influence of Iho air. Sometimes these folds take the form of circles, wrinkles, or spiral curves, corresponding to the elevations and depressions of the skin, or that part of it called the. imieims tissme. The thick- ness of the cuticle becomes considerable whenever a part of the body i.s exposed to a continuous friction ; for example, upon the solo of the foot, the palm of the hand, and other parts used for holding or grasping, such as the prehensile tails of some Ameri- can apes. The holes through which the hairs protrude may be perceived in the fur- rows of the cuticle. These appc.ir to be conical elongations, forced outwards by the hairs, to which they serve as rudimentary shearhs. The epidermis is very thin in Man, excepting on those parts which cover the palm of the Irnnd and the solo of the foot. Yet it may be considerably hardened, and even changed into a substance nearly approaching to horn in consistency, either by fric- tion, long exposure to a dry air, or to certain chemical agents, while the .sense of touch becomes deadened in consequence, and almost wholly obliterated. We see frequent instances of this in the hands of hard labourers, of blacksmiths, dyers, or in those nativ