ANIMAL KIXUliOM. 



AXIM.U. KINCDOM. 



from mineral*. That they are uiwymnu-trical, whilst mineral* are 

 > Mum-triad ; they grow irregularly, whiUt mint-rail increase in d.-lmitc 

 ctyiulliiie forma. Each portion Of a mineral, however uiutll, consist* uf 

 the Mine element*, whilst any part of a plant or animal may be differently 

 eompoeed to another part. 'The lino in fact U nowhere difficult to be 

 drawn, where the pretence or absence of oelU can be determined. 



The distinctions between animal* and plant* prevent greater 

 difficulties and perhapi no mere itnictural or formal difference can 

 be found. Looked at from one point of view, plant* and animal* form 

 a great organic unity, connected together by their common mode* of 

 cellular growth and function! ; and when thus regarded, there Mem* 

 to be no necessity for drawing an absolute line of distinction lietween 

 one and the other. Xaturalint* have however regarded them a* dutinct, 

 and the itudy of the two classes of objecta have constituted the sciences 

 of Botany and 7-x>U>fry. Rude definition! of various kind* have been 

 laiil down to guide the syntematist in his classification of the object* 

 belonging to each. Aristotle was one of the first who sought a 

 distinction, and in stating that an animal possessed a mouth whilst a 

 plant had no such organ, he gave perhaps the simplest and most 

 generally applicable dftinitii m that exist*. But Aristotle had not the 

 microscope to direct his inquiries, and by the aid of thin instrument 

 beings can be made apparent to which other distinctions must be 

 applied before they can be arranged in one kingdom or another. 

 Professor Kolliker describes an animalcule, the ArtiniJiryi tol of 

 Ehrenberg (' Microscopical Journal,' No*. L and ii.), iu which, though 

 no mouth is found, the function of digestion is carried on by an 

 indentation of its skin, temporarily formed for that purpose. Linmcus, 

 with no better success, gave the following definition : " Minerals grow, 

 plants grow and live, animals grow, live, and feel." To apply this 

 definition, we must define life and feeling, and this cannot be done in 

 such a way as to effect the object of the naturalist Cuvier thought 

 the possession of a stomach a sufficient distinction for the animal 

 kingdom, but the nature of a stomach must first be understood, and 

 here we have no absolute structural character to guide UK. It wax at 

 one tiuie a favourite distinction that animal* have tin- power of motion, 

 and that planU are fixed, but we know now that many plants move, 

 whilst many animals are fixed. One of the most recent and philoso- 

 phical of physiological writers says : " A plant is an organised being, 

 whose vital powers are directed solely to the performance of formative 

 operations, by which it* fabric u not merely lmilt up in the first 

 instance, but is continually receiving addition* during the term of its 

 existence; and any movements which it may exhibit are destined 

 solely for the furtherance of these operations, and must be regarded as 

 originating in physical or vital forces. On the other hand an animal 

 is an organised being, whose vital powers are not merely directed to 

 the construction and maintenance of its corporeal fabric, but are also 

 ubsenrient to the operations of the conscious mind, which involve a 

 continual disintegration of the structures that minister to them ; on 

 the repair of which, rather than on the extension of the fabric, after it 

 has attained its full development, the formative energy is chiefly 

 expended ; and of the movements which it may exhibit, though a 

 part are still to be regarded as directly dependent (like those of 

 plants) on causes inherent in it* material organisation, there is another 

 part, small though it may often be, in which the consciousness and 

 pontaneity of the individual are necessarily concerned, and wliirh 

 must therefore be distinguished as originating in psychical causes." 

 (Carpenter, ' Principles of Physiology.') 



In this way the naturalist and physiologist have tried to contend 

 with the difficulty. Within the last few years chemistry has invaded 

 the domain of the anatomist, and supplied him with materials for 

 determining the problem of the difference of animal and vegetable life. 

 The substances found in animal* and plants are found in a great 

 measure to be formed of four elements, carbon, hydrogen, oxygen, 

 and nitrogen. At oue time nitrogen was supposed to distinguish 

 animal from vegetable substances. It is now known, not only that 

 plants contain nitrogen, but that they supply this and the three other 

 elements to the animal system. It is found that these four elements 

 are always present in the yrotuplarm nuclnu, cgtoblatt, or primordial 

 ulrirlr, from which the cells of all plants and animals are first formed. 

 So that they are universally necessary in plants and animals, and have 

 hence been called Organic Element!. Three compounds of three of 

 these element*, carbon, hydrogen, and oxygen, and called cellulose, 

 sugar, and starch, were at one time thought to be peculiar to plant*. 

 It is now known that cellulose is present in many animals, and that 

 sugar Is very generally present in certain animal textures and fluids. 

 Starch yet remains to be found in the animal kingdom, and its 

 presence hi doubtful structures is still regarded as evidence of their 

 Tractable nature. 



It is clear however that no tingle character is sufficient to mark the 

 line between these two kingdom*, and that the collective functions 

 periVirmed by nitnal and plant*, accordingly as they are more or less 

 prominent iii organised beings, guide the opinions of naturalist*. 

 The structural characters of typical animal* are so evidently different 

 from the corresponding forms of plant*, that we need not dwell on 

 them here ; but a view of the functions which animals and plants 

 perform dependently on one another, will give the best possible notion 

 of their antagonistic nature. One of the great functions performed 

 by the animal kingdom is that of Retpiralion. During this process 



the oxygen of the atmosphere ie brought iu contact with carlHin in 

 the blood of the animal, and the result in a union of the i-m-lui MI<! 

 oxygen, and the formation of carbonic acid gas, which U being 

 constantly thrown off from the structure of the animal from the 

 whole surface of the body in the lowest animal*, from the gill* of those 

 that live in water, and from the lungs of those that live in air. It 

 thus consumes oxygen and give* off carbonic acid. The great function 

 of plant* is antagonistic to this. They take from the air carbonic acid 

 gas ; it is a part of their food. In the tissue* of the phut the 

 carbonic acid is decomposed. It* element* are separated ; the carbon 

 is retained in the plant, and the oxygen is set free. It thus consumes 

 carbonic acid and gives off oxygen. As far as we at present know 

 there are no exceptions to this law. On tracing tin- supply of >!,. 

 carbon which is contained in the animal system, and which combines 

 with the oxygen, we find that it is derived by the animal from tin- 

 plant. The food of the whole animal kingdom is derived from the 

 vegetable kingdom ; and the other three element*, as well as the 

 carbon, which are found in the animal, are thus obtain* 1 The 

 animal, in like manner, throws off its nitrogen in the 'onn of 

 excretions, more especially those of the kidney*, which, on decom- 

 posing, yield ammonia, a compound of nitrogen and hydrogen ; and it 

 is from thia substance that plants principally derive their nitrogen. 

 Thus, whilst the animal derives the constituent of its body from the 

 vegetable kingdom, the plant derives its element* from the mineral 

 kingdom. The animal takes up starch, sugar, and protein, from i!..- 

 plant, but the plant takes up carbonic acid and ammonia in their 

 mineral form. The tissues of the plant are engaged in converting 

 mineral into organic substances, whilst the tissues of the animal are 

 engaged in converting organic substances into mineral. 



In their relation to the great physical forces, heat and light, we see 

 the same antagonism between plant* and animals. Light and heat are 

 essential to the growth of plants. The productions found in their 

 tissue* are but the expression of the amount of heat and light tin v 

 have as it were appropriated. Many of the substance* thus 1 

 are taken into the system of animals as food ; and whilst in the 

 of the animal, the heat and the light are again set free in the form of 

 the peculiar vital animal forces. 



It is then by regarding the Animal and Vegetable worlds as exhibiting 

 a combination of antagonistic and dependent forces in the great circle 

 of nature, that we shall best form au idea of the real differences that 

 exist between these two kingdoms of nature. Having said this much 

 with regard to the nature of the Animal Kingdom, we shall now 

 proceed to consider some of the methods which have been employed 

 by naturalists to arrange the various members of which it i* com- 

 posed into groups, for the purpose of exhibiting the relation of one 

 animal to another, and of facilitating the study of the whole. 



In a crude shape, zoology, or the arrangement of animals, must have 

 been one of the earliest sciences that forced itself upon the attention 

 of the human mind. The very necessity for finding names for tin- 

 more obvious divisions of living being* must soon have produced a 

 classification into the natural groups of Quadrupeds, Birds, Fishes, 

 and Insects ; and certain subordinate sections, as, for inxtancc. 1 1 

 distinction between herbivorous and carnivorous beasts, gniuivorou* 

 and carnivorous birds, harmless and poisonous reptiles, must have 

 followed aa a matter of course. 



We have in the Bible, and in the engraven and pictorial Egyptian 

 records, the earliest evidence of the attention which had been paid to 

 Natural History in general. The 'navy of Tarahish' contriUitrd to 

 the wisdom of him who not only " spake of the trees, from the cedar 

 of Lebanon even unto the hyssop that spriniMh out of the wall,' )<ut 

 " also of beasts, and of fowl, and of creeping things, and of fishes " 

 (1 Kings iv. 10); to say nothing of numerous other passages showing 

 the progress that zoological knowledge had already made. 



The Egyptian record* bear testimony to a familiarity not only with 

 the forma of a multitude of wild animals, but with their habit* and 

 geographical distribution. 



Although it must be admitted that Herodotus was behind the 

 science of his day in physical knowledge, he who, despising the 

 sneers of the half-learned at his wonderful stories, will bring to the 

 perusal of his works a fair share of scientific acquirement, uill fin<l 

 many instances of zoological information which have been tii 1 

 the mere tales of this excellent traveller and historian. Imt which 

 modern investigation has confirmed. But it is to Aristotle, justly 

 termed the father of natural history, that we owe the first dawning* 

 of system founded on the only sure basis the organisation or physio- 

 logical character of animal*. 



Aristotle's method was founded on a division of organs, which may 

 bo arranged, first, with reference to natural groups (xara ytrot or KOT' 

 <r8oi), Bird* or Fishes, for instance, which depend on a similar structure 

 of part* ; secondly, according to their excess and defect (naff vwrpoxh* 

 KCU fAAfii^ii'), OK, for example, a <li\ i-ion of I'.ir.ls into those with long 

 bills anil those with short liilli ; those having crest* and those having 

 none; thirdly, according to their analogies (KOT' avaAiryfav) ; bike, for 

 instance, the comparison of a hoof with a claw, the wing of a bird 

 with tl. .fa quadruped, a feather with a scale ; and, fourthly, 



according to their situation (Kara f>iaa>) ; take, for example, animals 

 which have pectoral mamma) : man, apes, and elephants; and animals 

 which have abdominal mamma? ' dogs and oat*. 



