DIGESTION. 183 



stomach, and termed the Gastric juice. This 

 fluid has, in each animal, the remarkable pro- 

 perty of dissolving, or at least reducing to a 

 pulp, all the substances which constitute the na- 

 tural food of that particular species of animal ; 

 while it has comparatively but little solvent 

 ix>wer over other kinds of food. Such is the 

 conclusion which has been deduced from the 

 extensive researches on this subject made by 

 that indefatigable experimentalist, Spallanzani, 

 who found in numberless trials that the gastric 

 juice taken from the stomach, and put into glass 

 vessels, produced, if kept at the usual tempera- 

 ture of the animal, changes to all appearance 

 exactly similar to those which take place in 

 natural digestion.* In animals which feed on 

 flesh, the gastric juice was found to dissolve only 

 animal substances, and to exert no action on 

 vegetable matter ; while, on the contrary, that 

 taken from herbivorous animals, acted on grass 

 and other vegetable substances, without pro- 



* The accuracy of this conclusion has been lately contested 

 by M. De Montegre, whose report of the effects of the gastric 

 juice of animals out of the body, does not accord with that of 

 Spallanzani; but the difference of circumstances in which his 

 experiments were made, is quite sufficient to account for the 

 discrepancy in the results; and those of M. De Montegre, 

 therefore, by no means invalidate the general facts slated in 

 the text, which have been established by the experiments, not 

 only of Spallanzani, but also of Reaumur, Stevens, Leuret, and 

 Lassaigne. See Alison's Outlines of Physiology and Pathology, 

 p. 170. 



