148 A Manual of Veterinary Physiology. 



Colin believes that in the caecum starch can be converted 

 into sugar, fats emulsified, and that active absorption of 

 assimilable matters occurs. 



It is remarkable how the material finds its way against 

 gravity out of the caecum. The capacious folds in the 

 intestine are likened by Colin to the buckets of the Persian 

 water-wheel, by which means the fluid is handed up and 

 passed on into the colon. 



In the absence of experimental evidence, I would hardly 

 like to suggest that food may pass directly from the 

 opening of the ileum into the colon, but I certainly have 

 reason for thinking that this may occur. 



The Colon. — The direction taken by the colon of the hors ■ 

 is remarkable. It commences high 'under the spine on the 

 right side, its origin being very narrow, but it immediately 

 becomes of immense size. It descends towards the 

 sternum, and, curving to the left side, rests on the ensiform 

 cartilage and inferior abdominal wall. The colon now 

 ascends towards the pelvis, and here makes a curve, the 

 bowel becoming very narrow in calibre. The pelvic flexure 

 having been formed, the bowel retraces its steps towards 

 where it started from ; running on top of the previously 

 described portion it descends towards the diaphragm, 

 gradually getting larger in calibre, and then ascends 

 towards the loin, being here of immense volume — in fact, 

 at its largest diameter ; it then suddenly contracts, and 

 forms the single colon. The object of the difference in 

 the volume of the double colon appears to be for the con- 

 venience of its accommodation in the abdominal cavity. 

 The double colon may be divided into four portions for con- 

 venience of description : the ingesta in the first and third 

 descend, in the second and fourth they ascend. We find 

 that the physical characters of the contents are not the 

 same throughout. In the first colon the food is fairly 

 firm, and the particles of corn, etc., can be readily recog 

 nised. In the second colon I lie material is becoming more 

 fluid, whilst at the pelvi<- flexure the contents are invariably 

 in a liquid pea-soup condition, and the particles composing 



