DIGESTION. 
very little reliance om the aceufacy of the ayes which 
ee hitherto been made of the gaftric juice. - «* It is,”’ fays 
, “different in different animals, but it is a very dificult, 
ie not an impofile tafk, to obtain it in a flate of purity. 
Various attempts have, indeed, been made by very ingenious 
philofophers to procure it; but their analylis is fufficient to 
thew us that they have never obtained it ina ftate o 
The methods which have been adopted to pro re galtri ic 
juice, are, firft, to k:ll the animal whofe gaftric juice is to be 
‘examined, after it has fafted fome time. By this method 
Spallanzani eo halts 37 oes from the two firit ftomachs 
ot afheep. It w a green ore undoubtedly owing 
. the grafs acs aie animal had eaten. He found alfo 
half a {poonful in the ftomach of fome young crows, which 
he killed before they had left their nett. 
Smali tubes of metal, pierced with holes, and containing 
wed by animals; and when 
ne by the {ponge is fqueezed 
By this method Spallanzani ‘alle 481 grains of 
_ gaftric juice from the ftomachs of five crows. hird 
thod confifts in exciting vomiting in morning, when the 
ftomach is without food. ieee tried this method 
twice upon himfelf, and colle Ged one of the times 1 02. 32 
gr. 0 liquid ; ; but the pain was fo great, that he did not 
anaes Proper to try the experiment a third time. Mr. Goffe, 
ould excite vomiting whenever he thought proper, by 
fwallowing air, has employed that method to colle& gaf- 
tric juice. Ina ws thefe means it muft be contaminated by 
the admixture of iva mucus, bile, food, &c. I 
Be 
cr 
m 
may, too, 
be queftioned, whether any gaftric j as at all can ha pean 
by thefe methods i as the ule o t flui conver 
the food into cae, | in all probability i it is one yen od, 
when food is prefent. 
According to ee the eae juice of carnivorous 
animals, as hawks, kites, &c. has an acid and refinous odour, 
is very bitter, and not at “al epee and is compefed of an 
uncom ined acid, a refin, an animal fubflance, and a {mall 
ty of muriate of foda n herbivorcus animals, on the 
contrary, as goats, fheep, gc. it is very watery, a little muddy, 
as a bitter alah tafte, and ase ni tay ana ay 
xtract, and a pretty a = y of muriate of i 
Carminati found the fam ofed co 
part 
_of the food, and that the galtric juice in thefe animals is 
therefore of an acid nature. 
In man it has fometimes been found of an acid nature, at 
other times not. The experiments of Spallanzani fhew that 
this acidity is owing to the food. e never found any aci- 
dity in birds of prey, ep frogs, or filhes. Crows gave 
an acidulous gaftric juice only when fed on grain ; and he 
obferved the fame fact in dogs, herbivorous animals, and do- 
meftic fowls. Carnivor 
fibly diminifhed in t ac 8, even when od 
in perforated tubes. OS aiaaatl {wallowed — fub- 
ftances enclofed in tubes; and when h a vegetables 
and fruits, they were fometimes altered, as a little di 
"When poured on the carbonate 
ee har it caules no effervefcence. 
he influenc ce of the fo od on 
re nature of the e gaflric j ees is prac ed ftill more indifpu- 
table by the experiments o mas (Principe de Phyfiologie, m 
tom, 4. ch.9.) Having procured gaitric juice from a dog 
a 
ed, no predominant quality net: 
ifec 
-the gzftric juice was aint, infipid, thick a 
With refpeé to the fubltanees cme in he omach, 
fheep, invariably contains uncombined phofphcric a as 
Macquart and Vauquelin have democitrated. ‘The fecond, 
milk ; that is to fay, more than 685: 
and yet, in all probability, its weight was not much dimi- 
a 
eepe 
wafhed with aca ftiil furnifhes a liquor,on infufion, w 
coagulates milk : , ound that a 
fo} 
"The moft remarkable property of gaftric juice, is the very 
fingular adtivity of its folvent power. The hardeft bones 
yield to its influence; and it aéts as a real menftruum on 
thofe fwallowed by the dog, uniting with their organifed 
and gelatinous parts, and leaving a calcareous refidue, 
is the material, of thofe excrementitious concretions to whic 
the older f album Grecum., 
The folvent energy of this fluid ts in an eal ratio tothe muf- 
cular ftrength of the coats of the ch; and where thefe 
i d 
e 
vity. In the numerous c 
agent of digeftion, as the food undergoes no preliminary 
peacauans this, indeed, is alfo the cafe in many other in- 
ftances. It is always more adtive when affifted by warmth, 
as Trembley obferved in the polype, which, according to his 
obfervations, digefted in twelve hours in the — what 
occupied three days in colder times. inca and 
holothuria it deftroys even the fhells of nals which thofe 
: gia the furface of bodies, unites to 
seine alia s off,,and from which 
operates with more 
ory 
me s not mere 
cer fmell are quite cured: its fenfible cen are de- 
ttroyed, and it acquires new and very different ones. It does - 
not aét asa ferment; fo far from it, that it is a powerful 
antifeptic, and even reftores flefh a putrified. Onlya - 
few air bubbles make their efcape, w ere to the Xi 
mentary matter, and buoy it up to abe = a are probas 
bly hehiniae by the heat of the folutio 
wever powerfully the gaflric juice aay a& in oe 
pee the coats of the 
neuer fubfances, it does not 
r power of r nee ce 
ach itfelf; which probably ow 
oe ee vitality. 
which : 
The faba vidi are very tender, are - 
Not . 
