PHYSIOLOGY. 
Cojiparative Anatomy, which indeed he 
should peruse as an introduction to the pre- 
sent article. 
General View of the Functions exercised hij 
the animal Body. 
The term life denotes one of those gene- 
ral and obscure notions produced in our 
minds by certain series of phenomena, 
which we have observed to succeed each 
other in a constant order, and to be con- 
nected together by mutual Tclations. Be- 
ing ignorant of the bond of union which 
connects these, although we are convinced 
of its existence, we have designated the 
assemblage of phenomena by a name which 
is often regarded as the sign of a peculiar 
principle ; although it should indicate no- 
thing more than the collection of appear- 
ances, which have given rise to its forma- 
tion. Thus, as our own bodies, and seve- 
ral others, which resemble them more or 
less strongly in form and structure, appear 
to resist for a certain time the laws which 
govern inanimate matter, and even to acton 
surrounding objects in a manner quite con- 
trary to these laws, we employ the expressions 
of life and vital power, to designate these at 
least apparent exceptions to general rules. 
Our only method of fixing the meaning of 
these words is, to determine exactly in what 
these exceptions consist. With this object, 
let us consider the bodies alluded to in their 
active and passive relations to the rest of na- 
ture. Let us contemplate, for instance, 
the body of a female in the vigour of y outh 
and beauty : those rounded and voluptuous 
forms ; those graceful and easy motions ; 
those cheeks glowing with the roses of plea- 
sure ; those eyes sparkling with the inspira- 
tions of genius, or fired by the warmth of 
love ; that physiognomy enlivened by the 
sallies of wit, or animated by the fire of 
the passions ; all unite to form a truly en- 
chanting object. A single moment is suf- 
ficient to destroy this pleasing illusion : sen- 
sation and motion often cease on a sudden, 
without any apparent pre-existing cause ; 
the muscles, losing their plumpness, shrink 
and expose the angular projections of the 
bones ; the lustre of the eyes is gone, the 
cheeks and lips grow livid. These are only 
the prelude to still more unpleasant changes : 
the flesh turns successively to blue, green, 
and black ; it imbibes the moisture of the 
atmosphere, and, while one part is evapo- 
rated in pestilential emanations, the otlier 
melts into a putrid sanies, which also is 
speedily dissipated. In short, after a few' 
days, nothing remains but a few earthy etf 
saline principles ; the other elements having 
been dispersed in the air, or waters, to form 
new combinations. 
This separation is the natural effect of the 
action of air, moisture, and heat, that is, of 
all the surrounding external agents, on the 
dead body ; and it arises from the elective 
attractions which these agents possess for 
the materials of the body. Yet it was 
equally surrounded by them during life : 
their affinities for its component parts were 
the same ; and the latter would have' yielded 
in the same manner, if they had not been 
held together by a superior power, the in- 
fluence of which continues to operate until 
the moment of death. 
This resistance, then, of the laws which 
act on dead matter, is one of the particular 
ideas entering into the general notion of 
life, which seems, in a more especial man- 
ner, to constitute its essence ; for without 
it life cannot be conceived to exist, and it 
continues uninterruptedly until the moment 
of death. 
Almost endless disputes have arisen among 
physiologists concerning the. es.sential nature 
of this vital principle. Vitality is one of 
those attributes which can be more easily 
discerned and recognized when present in 
any object, than accurately defined. Defi- 
nition indeed would be more likely to con- 
fuse than to illustrate it. It i.s manifested 
most incontestibly by certain effects, refer- 
rible to peculiar powers, which are justly 
called living or vital, because the actions of 
the living body are so far depending on these 
powers, that they can, by no means, be ex- 
plained by the physical, mechanical, or 
chemical qualities of matter. Yet the ope- 
ration of the latter can be clearly discerned 
in many instances in the animal economy ; 
thus the humours of the eye variously affect 
the rays of light according to their figure 
and density : and the mechanical elasticity 
of the epiglottis, and the chemical affinities 
exercised in respiration, are further exam- 
ples to the same effect. Yet the energy 
and power of the vital force is most clearly 
evinced in resisting and overcoming, as we 
have already stated, the common laws of 
matter. Stahl and his followers, were so 
struck with the circumstance of living bodies 
resisting those affinities, which produce pu- 
trefaction in dead animal matter, that they 
made life itself to consist in this antiseptic 
property. The celebrated experiment of 
Borelii, in which a muscle, deprived of life, 
was immediately torn by a weight which it 
