The Digestive System. 45 



ant stomach is concerned with secretion. Gastric juice is 

 a thin, limpid fluid, almost colorless, with a strong acid 

 reaction, due to the presence of muriatic (hydrochloric) 

 acid, it has an odor peculiar to the animal from which it 

 is got. It prevents putrefactive changes and contains 

 two ferments — pepsin and the mill' -curdling one, some 

 free acid (Hcl) and mineral salts. The milk-curdling 

 ferment is the active principle in rennet, is very power- 

 ful and may be found in watery extracts of the stomach 

 of calves or sheep. Gastric juice acts on albuminous 

 (proteid) material only, the fats and carbohydrates are, 

 reserved for the action of the intestinal juices. It is en- 

 tirely unexplained why the stomach does not digest itself 

 during life, after death such does occur. Gastric diges- 

 tion in flesh-eaters (carnivora) is more active than in 

 the herbivora, due to the large quantity of pepsin and 

 acid contained in the secretion. Pepsin will not work 

 in an alkaline medium, hence the acid, as it will be re- 

 membered that saliva was alkaline, and therefore unless 

 neutralization took place, digestion would be very imper- 

 fect. Albumen becomes more indigestible when cooked, 

 dogs often suffer from a fetid diarrluea due to boiled 

 meat, which is soon corrected by feeding the raw 

 article. Digestion in horses is characterized by the slow- 

 ness of the preparatory mechanical stage of digestion, 

 and by the rapidity with which the work of the stomach 

 is performed, the rapid passage of the liquid material 

 into the ccecum (blind gut ) and the hardness of the ball- 

 like form of the residue in the back parts of the bowel. 

 Chewing the food is a slow process in the horse, and is 

 completed at the time of the meal, consequently the 



