PHYSIOLOGY. 
.Cjiialities and form a new compeamd, fit for 
ttie purposes of nourishment and growth. 
Animals alone are provided with digestive 
organs; all, from man to the polype, have 
an alimentary cavity, and its existence is, 
therefore, an essential character of animals. 
The loss which the body sustains in per- 
forming the various actions that take place 
in the living animal machine is supplied by 
meaiis of the food. Hunger and thirst ad- 
monish us of the wants of ,our frame, and 
the pleasures of the palate are a no less 
strong inducement to the procuring and 
taking of food. 
The cause of hunger has been placed in 
the mutual attrition of the rug® of the 
empty stomach ; in the irritation produced 
by the gastric juice, &c. Perhaps it may 
be derived more justly from a sympathy be- 
tween the stomach and the body at large. 
For when, in diseases of the pylorus, the 
food cannot be transmitted into the intes- 
tines, and does not therefore enter the 
system, great hunger is experienced, even 
although the stomach may be filled. Mach 
depends on habit, and on the operations of 
mental causes : hunger is felt at the usual 
periods of our repasts ; and, if it be not 
then removed by eating, will often cease 
spontaneously. 'J'hc man of letters, absorb- 
ed in meditation, often forgets the natural 
w’ants of his body. Whatever diminishes 
the sensibility of the stomach makes hun- 
ger more tolerable. 'I'hiis, the Indian and 
Turkish fanatics (Mollahs and Fakirs) are 
said to support their long fasts by the habi- 
tual use of opium. Thirst seems to consist 
more in a very troublesome dryness of the 
fauces and oesophagus, and in a peculiar 
irritation of these parts from the admixture 
of acrid, and particularly saline matters with 
the food. The necessity of obeying both 
these calls varies according to the age, con- 
stitution, and particularly the habits of in- 
dividuals; yet we may state, on the whole, 
tliat a healthy adult could not abstain fi om 
food for a whole 'day without bringing on 
considerable weakness ; and that this absti- 
nence could not be continued to the eighth 
day without the most imminent risk of life. 
Continued abstinence diminishes the weight 
of the body to a degree which becomes sen- 
sible in twenty-four hours, causes absorp- 
tion of fat, great prostration of strength, 
increased sensibility with watchfulness, and 
a most painful dragging at the epigastiic 
region. Hunger is more speedily fatal in 
proportion to die youth and strength of the 
-hulividital. Thus, the wretched father 
whose dreadful history is immortalised by 
Dante, sJiut with his children in a dungeon, 
perished last, on the eighth day of confine- 
ment, after witnessing the death of his four 
sons,, amid the convulsions of rage and cries 
of despair. We meet witli a large collec- 
tion of examples of long abstinence in the 
great work of Haller; but they do not seem 
to possess, in every instanpe, the requisite 
authenticity. Many of the subjects were 
weak and delicate women, living in a state 
of almost complete inaction, where the 
powers of life, almost extinct, were only 
evinced by a very low pulse and respira- 
tion repeated at long intervals. They might 
be compared to hybernating animals, where 
the waste, occasioned by the functions of 
active life, does not take place, and where 
consequently the usual supplies cannot be 
needed. Altfiough the admonitions of thirst 
are very imperious, yet drink does not seem 
so necessary to life and health as solid food. 
The mouse, quail, parrot, and several other 
warm-blooded animals never drink, and in- 
stances have been known ip the human sub- 
ject. Thirst always becomes greater wh,en 
any watery secretions are much aygmented, 
as in dropsy, and particularly in diabetes. 
In the dispute, whether man be naturally 
carnivorous or herbiverous, we are inclined 
to suppose that truth lies on neither side. 
That tlie structure both of the teeth and in- 
testines, as well as of the joint of the lower 
jaw, occupies a middle place between the 
two just mentioned, and constitutes Inm 
an omnivorous animal. This, indeed, seems 
to follow necessarily from the unlimited ex- 
tent of his habitation ; he can dwell in 
every country and climate of the globe ; 
and makes use, in various situations, of 
every variety of alimentary matter, furnish- 
ed by tlie animal and vegetable kingdoms. 
The food of man, and probably of every 
animal, is derived from organized matter. 
N othiug seems capable of furnishing nourish- 
ment that has not lived : the mineral king- 
dom, indeed, supplies some articles of sea- 
soning, which are mixed with our food, and 
various medicines and poisons, which do 
not seem to be nutritious. 
As man on the one hand is a most truly 
omnivorous animal, and capable of convert- 
ing into nourishment almost every produc- 
tion of the animal and vegetable kingdoms, 
so on the other side he may continue strong 
and healthy although using one, and that a 
veiy simple kind of aliment. A wonian, whose 
case is related in the memoirS'of the Medi- 
cal Society of Edinburgh, lived on vi'hey for , 
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