THE PHYSIOLOGY OF DIGESTION 177 



matter," by citing the ease of the West Indies negroes who grow fat 

 on sugar at certain seasons when they are at work on the cane. The 

 absorption and need of water and " calcareous earth " is also discussed. 

 The author reaches the conclusion that water not alone supplies the 

 waste of fluids, but also goes to form the solids of the body. He says : 

 Dr. Foi'dyce informs us he put a gold-fish in a glass vessel, and supplied it 

 with spring water; the fish lived in this manner for fifteen months, grew to 

 more than double the size it was when first confined, and threw out much 

 feculent matter. Lest it should be supposed the fish lived on substances held in 

 the water by solution, he used distilled water and impregnated it with the air 

 of the atmosphere, and put other gold-fish in the water thus treated, and kept 

 them six months,' during which time they threw out feculent matter, and thrived 

 as before mentioned. 



In referring to the " action of the mind " on the secretion of saliva 

 Young makes the following comment in a foot-note: 



Is not the secretion of the saliva and gastric juice synchronous? It is 

 highly probable from long habit, the actions of these two sets of vessels become 

 associated; hence, when the stomach and its vessels are irritated, as in nausea, 

 there is always a flow of saliva, though nothing stimulating has been applied 

 to the mouth. The excitement of the vessels of the one seems to keep pace with 

 that of the other ; when the nausea is so great that vomiting is just at hand, the 

 flow of the saliva is proportionally increased; and when we make an unsuccess- 

 ful eff"ort to vomit, we generally throw out a mouthful of saliva. 



Is it far-fetched to recall in this connection the comparable psychic 

 secretion which has been described in recent years for both saliva and 

 gastric juice and the probability of a common stimulus for the produc- 

 tion of each? 



Let us now consider more particularly Dr. Young's observations on 

 the processes in the stomach. He assumes that sufficient evidence was 

 already at hand from experiments on animals to permit plausible, if 

 not conclusive, inferences concerning our own digestion. He writes : 



It would be unnecessary to recite particular experiments, to prove the 

 solvent property of the gastric fluid, this being admitted on all hands. . . . The 

 effects of solution are most remarkable in such animals as swallow their food 

 without mastication; we will, therefore, relate a few experiments made on some 

 of these. 



Our common large bull-frog (Rana ocellata) was chosen in order to observe 

 the effects of the gastric fluid, as they swallow all their prey whole. They have 

 a large membranous stomach, which when distended, occupies the whole anterior 

 part of the abdomen: the oesophagus is very wide, so that their food can be 

 examined at pleasure. Two of a very large size were procured, and their 

 stomachs were found to be greatly distended with food: being desirous of seeing 

 what was their natural aliment, and the efl'ects of their digestive power upon 

 it, by means of a pair of forceps, one of their stomachs was easily emptied of 

 its contents; and to my surprise, and that of others who witnessed the fact, it 

 was found to contain a common sized spring frog, and aflforded a fine oppor- 



' One is reminded of J. Loeb's demonstration nearly a hundred years later 

 that certain fishes can be put into distilled water without the least injury. 



