ANIMAL. 



175 



with the whole chain of the organized world. The 

 great discoveries in chemistry, magnetism, electri- 

 city, and galvanism, have shown that those elements 

 and principles on which rest the laws of life, prevade 

 nature in the most various forms and combinations ; 

 that there is no harsh and abrupt distinction between 

 the animate world and the inanimate, but, on the 

 contrary, an intimate connexion between the energy 

 which makes the crystallizing mineral follow the 

 law of the strictest regularity, or the stone fall from 

 the height, and that which makes the heart of man 

 beat. The difficulty of defining animal life has, 

 therefore, been greatly increased. What is animal 

 life ? What constitutes an animal ? Since mankind 

 began to cultivate philosophy, they have sought in 

 _ vain for a definition of life. It would require much 

 more metaphysical discussion, to enter at all satisfac- 

 torily into this subject, than the character of the pre- 

 sent work allows ; and we are constrained to offer the 

 reader only the following remarks on this most inter- 

 esting subject. Linnaeus defines an animal an organ- 

 ized, living, and sentient being. An animal is indeed 

 organized; but are not vegetables organized also? 

 Animals are endowed with sensation ; but are all, 

 without exception ? and do not some plants possess 

 this faculty ? Locomotion is not a more certain 

 characteristic of animals tlian life or irritability, for 

 many animals are destitute of this power, and vege- 

 tate like plants, the images of torpidity and insensi- 

 bility. Neither are the chemical characters of ani- 

 mal substances more distinct ; animals are chiefly 

 composed of azote, and vegetables of carbon ; but, 

 among the latter, some are, like the former, compos- 

 ed principally of azote. In whatever point of view 

 we consider these two kingdoms of nature, we find 

 them blended in so many ways, and separated from 

 each other by such imperceptible gradations, that it 

 is impossible to draw a line, at which we can affirm 

 tliat animal life ends and the vegetable begins. We 

 cannot, therefore, give a rigorous definition of the 

 animal kingdom, but we may point out certain gen- 

 eral characteristics, which clearly distinguish this 

 from the other kingdoms of nature. There are two 

 kinds of motion in animals, one of which is voluntary, 

 and the other mechanical- The latter is involuntary, 

 and belongs to the vegetative life of the animal. By 

 this the vital actions are carried on independently of 

 volition. By this the heart beats, the blood circulates, 

 the food is assimilated. The former is voluntary, 

 and is peculiar to animal life ; it cannot exist with- 

 out a nervous system, or something equivalent, by 

 which the animal perceivesand wills. However feeble 

 the manifestations of this will may be, it neverthe- 

 less exists in proportion to the simplicity or complex- 

 ity of the organization of the creature which perceives 

 and wills. Thus the vibrio and the monas, although 

 apparently destitute of viscera, organs, and locomotive 

 apparatus, when they avoid or pursue surrounding 

 objects, act by virtue of the will as completely as the 

 highest orders of organized creatures. One sense is suf- 

 ficient to produce voluntary motion, and, therefore, to 

 constitute animal life ; the vibrio and the monas have 

 at least one sense analogous to that of touch. This 

 kind of motion may exist without locomotion, as in 

 the oyster. There is no one organ which character- 

 izes the animal kingdom ; there is none which is 

 found in all animals. The head, the stomach, the 

 system of circulation, in a word, all the complicated 

 apparatus ot the mammalia, for example, disappears 

 in other classes, or undergoes a thousand various 

 combinations of form and proportion. The organ, 

 of which the slightest injury in one animal produces 

 instant death, may be wounded or even extracted 

 from another without fatal consequences : whilst some 

 are killed by the loss of some parts of the body, others 



may be cut in pieces, and each fragment becomes 

 a perfect animal. M. de Lamarck lays down the 

 nine following characteristics, as common to all ani- 

 mals, and peculiar to them,andconstituting,therefore, 

 the distinction between theanimal and vegetable king- 

 doms: 1, that they have parts susceptible of contrac- 

 tion of themselves, and thus the power of mo ving them- 

 selves suddenly and repeatedly ; 2, that they have 

 the power of changing place, and of acting at will, 

 if not completely, at least to a great extent ; 3, that 

 they perform no motion, total or partial, unless in 

 consequence of certain motives, and that they are 

 able to repeat the motion as often as the exciting 

 cause operates ; 4, that they betray no perceptible 

 relation between the motions they perform and the 

 exciting cause ; 5, that their solid as well as fluid 

 parts partake of the vital motions ; 6, that they nour- 

 ish themselves with compound substances of a dif- 

 ferent nature from themselves, and that they digest 

 these substances in order to assimilate them; 7, 

 that they differ from each other in their organization, 

 and in the faculties resulting from this organization, 

 from the most simple to the most complicated, so 

 that their parts cannot be mutually transformed into 

 each other; 8, that they are able to act for their 

 own preservation ; 9, that they have no predominant 

 tendency in the developement of their bodies to grow 

 perpendicularly to the plane of the horizon, or to 

 preserve a parallel direction in the vessels which con- 

 tain their fluids. Linnaeus was the first who ventured 

 to include man in the systematic classification of 

 animals; and though he was violently assailed for 

 thus degrading the dignity of the human race, he 

 has been followed, in this arrangement, by succeed- 

 ing philosophers. Cuvier has, however, assigned 

 him a distinct order, bimana, by which means he is 

 separated from monkeys, with whom Linnaeus had 

 classed him. Linnaeus divided the animal kingdom 

 into six classes, as follow : *. Such as have the 

 blood warm and red ; the heart with two auricles 

 and two ventricles. I. Mammalia ; viviparous ; 

 suckle their young. II.Aves, birds ; oviparous ; have 

 neither teats nor milk. **. Such as have the blood 

 red and cold ; single heart, with one auricle. III. 

 Amphibia ; oviparous ; without teats, milk, hair, or 

 feathers. IV. Pisces, fishes ; breathe by gills, a 

 sort of external lungs ; oviparous ; their organs of 

 locomotion, fins ; their covering, scales ; they emit 

 no sound, and inhabit the water ***. Such as 

 have a single heart, without auricles; blood cold 

 and white, consisting of a sort of transparent lymph. 

 (These characters have since been found to be in- 

 correct ; for some of these animals have red blood, 

 and some have no heart at all. ) V. Insects ; pro- 

 vided with antenna ; breathe by lateral stigmata ; 

 all have feet, most have wings, and undergo trans- 

 formations. VI. f'ermes, worms; provided with 

 tentacula ; no feet or fins. The progress of natural 

 history has revealed some defects in the system of 

 Linnaeus. Cuvier has corrected its errors and sup- 

 plied its deficiencies. His system is as follows : *. 

 Vertebral animals. They have an internal skeleton, 

 composed of a series of bones attached to each otlu r, 

 and called the vertebral column. It is perforated by 

 a canal containing the substance from which the 

 nerves, or organs of sensation, take their rise. This 

 column is terminated at one end by the head, (which 

 is, perhaps, only a vertebra fully developed), and at 

 the other by the os coccygis, or tail. Two cavities, 

 the chest and the abdomen, contain the principal or- 

 gans of life. The sexes are two, male and female ; 

 testicles belong to the former, ovaries to the latter ; a 

 spleen, liver, pancreas, jaws incumbent, transversal, 

 and provided with teeth (which are imperfectly de- 

 veloped in the beak of birds), not more than four 



