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<iuld tlicso golden wheels of 
animated nature he inert and motionless, if they were not influenced by this prime- 
mover, formed of a coarser, hut more energetic material, which supplies the fuel to 
their fires, aud enables them to maintain undiminislied the original vigour of their 
motions. ° 
SECl. X GENERAL REVIEW OE LIVING BEINGS CONTINOED. 
riicir Unity and Perfection — Symmetry — Mutual Dependence — Classification of 
Liciny Beings, 
All living brings are orgaiiizod; that i;;, they are composed of different organs, each 
performing its separate function, and in its own peculiar manner. These organs col- 
lectively form a whole, perfect in oaeli being; and tho .aggregation of those actions 
compoae all that we are permitted to know of Life. V/ilhout the healthy state of tlie 
body, life cannot exist; yet the organs remain after life has ceased. We behold e 
body, wliich has just been deserted by tho breath of life; wo perceive an exquisite 
macliine, wlicre notliiiig seems defective; the whcol-work remains entire, but it wanrs 
the propelling liand of tho workman. We may admire the sublime mechanism of that 
mighty Being who formed it, but the moving power ever escapes our rrsoarch. ' 
