52 



PHYSIOLOGY OP FARM ANIMALS 



[CH. 



Digestion continues in the colon and is therein terminated, 

 but the process is carried on either by ferments passing into it 

 along with the food from the anterior part of the gut or else by 

 bacterial disintegration as happens in the horse. It has been 

 shown that bacteria may hydrolyze cellulose, and that in the case 

 of oats there is evidence that a digestive ferment is present in 

 the food itself. In the horse particles of corn and other com- 

 paratively unaltered food substances are found in the first part 

 of the colon, but as we pass on the food becomes more and more 

 fluid, then firmer again, and in the last part the contents are like 

 thick pea soup containing finely comniinuted particles. In 

 ruminants the function of the colon is only subordinate, since, as 

 already mentioned, cellulose digestion is carried on at the anterior 

 end of the gut. In the pig also the colon is of relatively small 

 importance. 



Fig. 31. Colon of horse (from Smith, Messrs Bailh^re, Tindall and Cox) 

 1 first colon, 2 pelvic flexure, 3 suddenly enlarges, 4 diaphragmatic 

 flexure, 5 commencement of single or small colon. 



