Digestion. 147 



of cellulose, where by churning, maceration, and decom- 

 position, this substance is dissolved and rendered fit for 

 absorption, and he likens it to the stomach of ruminants 

 and the crop of birds ; he further considers the caecum 

 exists owing to the small size of the stomach and the 

 rapidity with which the contents are sent along the small 

 intestines. It has also a large secreting surface, the glands 

 being like those of Lieberkiihn, and he considers that 

 absorption takes place from the caecum. 



This observer's experiments demonstrated that the entire 

 'feed' reached this bowel between 12 and 24 hours after 

 entering the stomach, that it remained 24 hours in the 

 caecum, and that during this time 10 to 30 per cent, of the 

 cellulose disappeared. The digestion of cellulose is no 

 doubt a very important matter, especially as we know that 

 the poorer the food the more cellulose is digested ; but I 

 am not prepared to admit that food remains in the caecum 

 24 hours, and I believe that cellulose digestion principally, 

 though not entirely, occurs in the colon. The gas found 

 in the caecum chiefly arises from the decomposition of 

 cellulose. 



My experiments on digestion have shown that ingesta 

 may be in the caecum 3 to 4 hours after entering the 

 mouth, and I am quite clear on the point that oats may 

 reach even some distance along the colon in 4 hours from 

 the time of feeding, though I regard this as exceptionally 

 rapid. 



I fed a horse, which had never had maize in its life, and had 

 not tasted oats for two or three years, with, first, 2^ lbs. of 

 maize, and 17 hours later with 4 lbs. of oats. He was 

 destroyed 4 hours from the time of commencing to eat the 

 oats. Much maize and a few oats were found in the pelvic 

 flexure of the colon, and a certain proportion of maize and 

 a quantity of oats in the stomach. This bears out what we 

 have said about gastric digestion slowing oft' (p. 115), and 

 proves how great is the distance food may travel through 

 the bowels in a short time, though I consider in this case 

 its progress was much more rapid than usual. 



10—2 



