ON THE DIGESTIVE FUNCTION, ETC. 



pound of it fo be poured forth every twenty-four hours. " The drink," 

 says he, " taken into the stomach may be two pound^ in twenty-four hours ; 

 the saliva swallowed may be one pound in the same period, the gastric 

 juice another, the pancreatic juice another. The bile poured into the 

 intestines Haller supposes about twenty ounces, besides the fluid secreted 

 through the whole of the internal surfaces of the intestines which 

 Haller calculates at not less than eight pounds in twenty-four hours, — a 

 calculation nevertheless that Blumenbach regards as extravagant.! 



The quantity of the gastric juice, however, seems to vary very con- 

 siderably, according to the demand of the system generally, or the state of 

 the stomach itself. In carnivorous birds, whose stomachs are membranous 

 alone, and consequently whose food is chymified by the sole action of the 

 gastric juice, without any collateral assistance or previous mastication, 

 this fluid is secreted in much larger abundance ; as it is also in those 

 who labour under that morbid state of the stomach which is called canine 

 appetite ; or when, on recovery from fevers, or in consequence of long 

 abstinence, the system is reduced to a state of great exhaustion, and a keen 

 sense of hunger induces a desire to devour food voraciously and almost 

 perpetually. I 



Such was the situation of Admiral Byron and his two friends Captains 

 Cheap and Hamiltpn, after they had been shipwrecked on the western 

 coast of South America, and had been emaciated, as he tells us, to skin 

 and bone, by having sufl^ered with hunger and fatigue for some months. 

 " The governor," says Admiral Byron, " ordered a table to be spread for 

 us with cold ham and fowls, which only we three sat down to, and in a 

 short time despatched more than ten men with common appetites would 

 have done. It is amazing that our eating to that excess we had done from 

 the time we first got among these kind Indians had not killed us ; we were 

 never satisfied, and used to take all opportunities, for some months after, 

 of filling our pockets when we were not seen, that we might get up two or 

 three times in the night to cram ourselves. "| 



When pure and in a healthy state, the gastric juice is a thin, transparent, 

 and uninflammable fluid, of a weak saline taste, and destitute of smell. Ge- 

 nerally speaking it is neither acid nor alkaline ; but it, appears to vary more 

 or less in these properties, not only in animals whose organs of digestion are 

 of a different structure, but even in the very same animal under difierent 

 circumstances. It may, however, be laid down as an established rule, that 

 in carnivorous Siud graminivorous animals possessing only a single stomach, 

 this fluid is acid, and colours blue vegetable juices red ; in omnivorous 

 animals, as man, whose food is composed both of vegetable and animal 

 diet, it is neutral ; and in graminivorous ruminating animals with four 

 stomachs, and particularly in the adults of these tribes, it has an alkaline 

 tendency, and colours blue vegetable juices green. 



There are two grand characteristics by which this fluid is pre-eminently 

 distinguished ; a most astonishing faculty of counteracting and even cor- 

 recting putrefaction ; and a faculty, equally astonishing, of dissolving the 

 toughest and most rigid substances in nature. 



Of its ANTISEPTIC POWER abundant proofs may be adduced from every 

 class of animals. Among mankind, and especially in civilized life, the 

 food is usually eaten in a state of sweetness and freshness ; but fashion, 



* Anat. of the Absorbing Vessels, p. 106. 

 t Physiol. Institut. xxvii. §410. 



t Voyage, p. 181. See also Hunter's Animal Economy, p. 19§, 



