488 THE DIGESTIVE APPARATUS IN MAMMALIA. 



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

 the Ox, in tlie vicinity of tiiis insertion, there are tracts of one of Peyer's patches. In the 

 Sheep and Goat, these patches are very numerous. 



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

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

 of elliptical convolutions, by at first makiuu' several concentric spiral turns, which leave a 

 certain interval between them fa- the reception of tlie ecceniric convolutions. The last spiral 

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

 the mi sentery 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 backwaids, 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, whicli, by its position, resembles 

 tlie large suspensory band of the floating colon iu Solipeds. 



The calibre of this intestine is at first rqual to tliat of tiie csecum ; but it soon becomes 

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



Fig. 288. 



B 



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



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

 intestine; D, ciEcum; E, its point directed backwards; f, fle.xure 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 arnngement as in the latter, 

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

 of tlie colon between th6 two layers of tlie 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 the left side, the promi- 

 nences of the spiral convolutions are found to ^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 cmcal division is well defined, hut the division of the colon into a large or double, 

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

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

 portion in the posterior extremity of the tube lying at first n gainst the sublurabar wall of the 

 abdomen, and afterwards suspended by the short inest nteric fraenum which resembles tiie great 

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

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



Measured tliroughout its whole extent, from the cjecal cul-de-sac to the anus, the large 

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

 but its cnpacity 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 which 56 go to the small, 

 and 16 to the large intestine. 



