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 
