THE DIGESTIVE APPARATUS IN MAMMALIA. 



ileum occupies the posterior border of the mesentery, reaching the cjecum by keeping on the 



right of the colon ; its insertion is oblique. 



Among the peculiarities of the small intestine, may be cited the presence of an immense 



Peyerian gland, which occupies the latter portion of the canal, where it figures as a band 



measuring from 5 to 6^ feet in length. 



The cmcum is directed backwards, and shows, on its internal surface, some Peyerian 



patches ; it is sacculated, as in the 

 Fig. 290. Horse, and is furnished with three 



longitudinal bands. The colon is 

 not comprised between the layers 

 of the mesentery, except in its 

 latter portion ; for the remain iler of 

 its extent it is on the left side of 

 the mesenteric layer, where it 

 forms a distinct mass. It describes 

 three turns from right to left, and 

 three turns from left to right; it 

 then passes forward, and, crossing 

 again from right to left, insinuates 

 itself between the duodenum and 

 pancreas. It has two of these 

 muscular bands in a portion of its 

 track, and even three towards the 

 csecum. 



The rectum is situated above 

 the convolutions: of the colon, at 

 the border of a special mesenteric 

 layer. 



4. The Intestines of Carnivoea 

 (Figs. 290, 291). 



The intestines of the Caruivora 

 are remarkable for their shortness 

 and small volume. In a Dog of 

 ordinary size, they scarcely measure 

 more than 14 lectin length, of whicli 

 only from 24 to 28 inches are for 

 the large intestine. In the Cat, 

 the latter is about oue-half this 

 length, and the entire extent of the 

 viscus is equal to about 6 or 7 feet. 

 With regard to capacity, Colin gives 

 the following averages : for the 

 Dog's small intestine, 1 quart; tliat 

 of the Cat, ^ of a pint ; for the 

 large intestine in tiie Dog, nearly 

 1 quart, and in the Cat, a trifle more 

 than J of a pint. 



The small intestine, suspended 

 at the extremity of a mesentery 

 similar to that of Solipeds, rests 

 on the inferior abdominal wall. It 

 is distinguished by the thickness 

 of its parietes, the length and 

 number of its \\\\i, which cover its 

 inner surface, and which are even 

 found accumulated on Peyer's 



patches. These latter number about 20 in the Dog, and 5 or 6 in the Cat. 



The csecum forms only a small, spirally twisted appendix, lined by a plicated and very 



follicular mucous membrane, particularly in the Cat, and shows at the bottom of the cul-de-sac 



a true Peyer's gland. 



INTESTINES OF THE DOG. 

 a, Stomach ; h, duodenum ; c, jejunum ; d, ileum ; e, caecum ; 

 /, ascending colon ; g, transverse colon ; h, origin of de- 

 scending colon ; i, great omentum ; k, spleen ; I, mesentery : 

 m, pancreas. 1, Aorta ; 2, great mesenteric artery ; 3, 

 artery of the duodenum ; 4, artery of the large intestine ; 

 5, small mesenteric artery. 



