234 J. L. Jomt: 



certainty, although it is legitimate from common experience 

 to postulate that all vertebrates at least possess these senses 

 too.) Tlie power to vomit is possessed by most animals. 

 Amongst ruminants and solipeds it is a rare occurrence, but, 

 after all, the nature of the food of these animals would un- 

 doubtedly exempt them from the necessity of ever rejecting 

 the contents of the stomach. But with man and the carnivores 

 particularly, the nature of their food, particularly the liability 

 to putrefaction and ptomaine formation, renders the existence 

 of the power to vomit a necessity, altogether excluding con- 

 siderations of the osmotic pressure of stomach contents, which 

 pertain chiefly to man, who, by an abuse of his intelligence, 

 perpetrates dietetic errors from which the low^er animals are 

 protected by their instinct, and senses of taste and smell. 



In connection with those hypertonic fluid foods w^hich are 

 normally admitted to the stomach of man, the following obser- 

 vations of mine are of interest. A definite volume of beer was 

 taken which gave a A of 2.246, evaporated to dryness and 

 then calcined. The ash was then taken up in the same volume 

 of distilled water, and dissolved almost completeh^, leaving a 

 snia.!! residue of calcium carbonate, which probably existed in 

 the beer as the soluble calcium salt of some organic acid. This 

 watery extract gave a A of 0.026^0.; and similarly with the 

 juice of the orange — 



A of juice ----- 0.990 

 A of aqueous extract of ash - - 0.132 

 These experiments are analogous to what occurs in the body. 

 The saccharine and alcoholic constituents of the food are 

 rapidly absorbed and burnt off, or stored in the body as inert 

 substances (cf. glycogen), while the saline constituents are left 

 to play their part in the osmotic pressure phenomena in the 

 body. Tlius w^e see that the kidney is constantly called upon 

 (in marine forms ahvays and generally in land mammals as 

 well) to excrete inorganic salts, which tend to produce a rise 

 in the osmotic pressure of the blood, and thus the urine is 

 generally hypertonic. Prima facie, this means work done, and 

 hence in metabolism experiments this work done should be in- 

 cluded in the energy balance-sheet, for in some cases the amount 

 of energy thus expended may attain considerable dimensions 

 when converted into terms of heat value or mechanical work. 



