488 THE DIGESTIVE APPARATUS IN MAMMALIA. 



colon, without forming an arch, after having received the insertion of the small intestine. In 

 the Ox, in the vicinity of this insertion, there are traces of one of Peyer's patches. In the 

 Sheep and Goat, these patches are very numerous. 



The colon, sustained between the layers of tlje great mesentery, on the margin of which is 

 suspended the small intestine, is coiled upon itself in such a way as to form u certain number 

 of elliptical convolutions, by at first maiiinj; several concentric spiral turns, which leave a 

 certain interval between them for the reception of the eccentric convolutions. The last spiral 

 turn is a little distant from the others ; in the smaller Ruminants, it is close to the insertion of 

 the mesentery in the small intestine, which it follows to near the duodenum, in describing 

 regular festoons. On arriving near the trunk of the great mesenteric artery, this convolution 

 passes to the right of that vessel, and is directed backwards, then forwards, thus forming a 

 flexure, and turns back in company with the duodenal flexure. The colon then continues in a 

 direct line to the rectum, attached to a short mesenteric layer, which, by its position, resembles 

 the large suspensory baml of the floating colon in Solipeds. 



The calibre of this intestine is at first equal to that of the caecum ; but it soon becomes 

 constricted, and maintains a uniform diameter, which scarcely exceeds that of the small 



Fig. 288. 



OENERAL VIEW OF THE INTESTINES OF THE OX (RIGHT FACE). 



A, Origin of the duodenum ; B, floating portion of the small intestine ; C, termination of the small 

 intestine ; D, caecum ; E, its point directed backwards ; f, flexure of the large colon at its termi- 

 nation ; G, H, terminal portion ot the intestine. 1, Insertion of the ductus choledochus ; 2, 

 insertion of the pancreatic duct. 



intestine of the Horse. The muscular layer has the same arrangement as in the latter, 

 although it is not covered in all its points by the serous tunic, in consequence of the situation 

 of the colon between the two layers of the mesentery. In emaciated animals, however, it may 

 be remarked that the serous covering furnished by these layers to the muscular coat of the 

 colon is more extensive than at first we might be led to believe ; on tlie left side, the promi- 

 nences of the spiral convolutions are found to s-tand in relief on the surface of the mesentery, 

 and it is therefore more completely enveloped in the corresponding peritoneal layer. 



From this description, it will be seen that in the large intestine of the Ox, Sheep, and 

 Goat, the cxcal division is well defined, but the division of the colon into a large or double, 

 and a small oi floating portion, can scarcely be made out; unless we regard as the large or 

 flexured colon, the spiral folds contained between the layers of mesentery, and see the floating 

 portion in the posterior extremity of the tube lying at first Rgainst the sublumbar wall of the 

 abdomen, and afterwards suspended by the short mesenteric frtenum which resembles tlie great 

 colic mesentery of Solipeds. It is worthy of remark that the great mesenteric artery goes to 

 the first, and the small mesenteric to the second portion, as in the Horse. 



Measured throughout its whole extent, from the csecal cul-de-sac to the anus, the large 

 intestine of the Ox is from 33 to 39 J feet. It is, therefore, longer than that of the Horse; 

 but its capacity is much less, for it does not exceed from 6J to 7J gallons. 



3. The Intestines of the Pig. 

 The average length of the Pig's intestines is about 72 feet, of whicli 56 go to the small, 

 and 16 to the large intestine. 



