INTESTINES IN THE OX. 107 



and iliurn ; while the great intestines include the csecum, the 

 colon, and the rectum. The principal coats of the intestinal 

 tube are three namely, the external serous, derived from the 

 peritoneum ; the middle muscular, in two layers of fibres, the 

 outer longitudinal, the inner circular ; and the lining or mucous 

 membrane. The peritoneum, in its passage from the upper 

 part of the abdominal cavity to reach the intestines, forms the 

 fold, consisting of two layers of the serous membrane, termed 

 the mesentery. At the free margin of these layers that is, 

 where they take the form of a sling the intestine is contained. 

 Between these layers, the arteries, veins, nerves, absorbent 

 vessels with the conglobate glands, belonging to the intestine, 

 are supported in their course. There is a considerable pecu- 

 liarity in the mesentery of ruminants as compared with the 

 mesentery in the horse and many other animals. In the horse, 

 as in man, the great intestine is supported by a separate doub- 

 ling of the peritoneum, termed the meso-colon and meso-rectum ; 

 but in the ox a great part of the colon is contained in the 

 same doubling of the peritoneum which forms the mesentery 

 that is to say, the small intestines hang in the concavity 

 of the sling, while the great intestine lies above the small in- 

 testine between the same two layers, in the free margin of 

 which the small intestines are suspended. In the caecum of 

 the ox the longitudinal muscular fibres are very well developed ; 

 in the colon the longitudinal muscular fibres are arranged in 

 broad bands, between which are narrow intervals, and in these 

 the circular fibres of great strength are visible. The lining 

 mucous membrane of the small intestines has no doublings, 

 except in the duodenum, where these are transverse. The villi 

 here resemble fine scales. At the lower part of the small intes- 

 tines, this membrane shows Peyerian patches to a very con- 

 siderable extent that is, a glandular structure named after 

 Peyer, and well known in the human body. The mucous 



