428 PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



Thus, when dried peas are given, traces of them are to be found in 

 the caecum after the lapse of twelve hours. After twenty -four hours 

 grain and dry forage are still to be found in the caecum, and after thirty 

 hours chopped hay still remains in the caecum. After seventy -two hours 

 the greater part of the hay had alread}^ passed into the colon. Thus, in 

 resume, twelve hours after feeding, forage is to be found in the stomach, 

 with some traces in the jejunum and caecum; after twenty-four hours, 

 principally in the caecum, with a certain amount of residue in the jejunum ; 

 after forty-eight hours, in the ventral colon, with some debris in the 

 caecum; after seventy-two hours, in the dorsal colon; and after ninety 

 hours, in part in the dorsal colon and rectum. 



As regards the functions of the caecum, it would appear that after 

 twelve hours already traces of food are to be found in the caecum, and 

 after twenty -four hours nearly all the alimentary mass has arrived at the 

 caecum, in which some is still to be found after forty -eight hours. Food, 

 therefore, usually remains twent3 r -four hours in the caecum of the horse. 

 The contents are always alkaline, highly fluid, and of a special odor. 

 The color varies with the nature of the food. 



From the fact that a larger amount of undigested food is found in 

 the caecum than in the colon, it follows that digestion must take place in 

 the caecum, its extent being placed by Ellenberger at from 10 to 30 per 

 cent, of the food ; the nature of this action is determined by examination 

 of the caecal contents. 



The acid reaction of the stomach and upper portion of the intestine 

 gives place to an alkaline reaction in the lower portion of the ileum, and 

 that of the caecum is invariably alkaline. In the colon, again, the reac- 

 tion may become acid from fermentative changes in food. 



Digestive changes are, therefore, merely the continuation of the 

 ordinary intestinal digestion. 



Bureau has succeeded in obtaining a secretion from the caecum of 

 the rabbit, but in such small amount as contrasted with the quantity ob- 

 tained from the small intestine by the same method (double ligature) that 

 he concludes that the digestive processes occurring in the caecum are due 

 to the action of the intestinal fluids which come down from above. 



In the duck, however, by ligating the caecum, after introducing small 

 fragments of cooked meat, a large amount of clear alkaline fluid may be 

 obtained, although the morsel of meat will have remained unaltered. 

 This fluid is said to have the power of converting starch into sugar, but 

 is without action on other food-stuffs. 



By making caecal fistulae in rabbits, Bureau found, in the first place, 

 that the reaction was invariably alkaline. Raw meat appeared to be 

 unchanged in the caecum, while cooked meat becomes somewhat softened 

 and reduced in volume. Boiled starch is converted into sugar. 



