492 



TEE DIGESTIVE APPARATUS IN MAMMALIA. 



Sheep and Goat, from 26 to 28 times ; the Pig, from 15 to 17 times ; the Dog, from 4J to 5J times ; 

 and the Cat, from 4 to 5 times. 



Accortling to Hering, the entire length of the intestines of the Horse averages 100 Wurtem- 

 burg feet, 70 of which are for the small intestine, and 30 for the large. In the Ox they are 

 150 feet, 120 being for tlie small intestine, and 30 for tlie large ; in the sheep they average 90 

 feet, from <15 to 70 being allowed for the small intestine; those of the Goat mtasure 95, the 

 small inte.stiue being 70 ; in the Pig they are 90 feet, 72 of which are for the small intestine, 

 and 18 for the large ; large-sized Dogs averaged from 23 to 27 feet, from 20 to 22 of which were 

 for the small inttstine ; small dogs had only 6 feet in many instances. The Cat has from 

 4 to 5 feet.) 



Comparison of the Intestines of Man -with those of Animals. 



Not unfreqnently the small intestine of Man is divided into duodenum and small intestine 



proper. The duodenum is from 9 to 11 



Fig. 292. 



the human intestines and superior mesenteric 



ARTERY. 



J, Descending portion of the duodenum; 2, transverse 

 ' portion ; 3, pancreas ; 4, jejunum ; 5, ileum ; 6, 

 caecum and appendix vermiformis ; 7, ascending 

 colon; 8, transverse colon; 9, descending colon; 

 10, superior me.senteric artery; 11, colica media; 

 12, the branch that inosculates; with the colica 

 sinistra; 13, pancreatico-duodenalis inferior; 14, 

 colica dextra; 15, ileo-colica; 16, 16, vasa intes- 

 tmis tenuis. 



inches in length ; is dilated at its origin, 

 and firmly attached to the posterior face 

 of the liver by a peritoneal fold, and to 

 the right of the sublumbar region by 

 connective tissue. It describes the arc of 

 a circle, in the concavity of which is 

 lodged the right extremity of the pan- 

 creas, and not the caecum, as in Solipeds. 

 Tlie small intestine jvoper is suspended 

 by a mesentery somewhat similar to that 

 of the Horse. Its length varies much— 

 from 13 to 26 feet. Its internal face has 

 a large number of transverse rugSB, the 

 valvulas conniventes. It also shows from 

 20 to 25 Peyer's patches, particularly in 

 the ileo-csecal portion. Its structure is 

 like that already described. 



In the large intestine are recognized 

 the caecum, colon, and rectum. 



The caecum is a t-mall reservoir placed 

 in the right iliac tbssa, a little obliquely 

 dowuwai ds and to the left. It commences 

 at the ileu-csecal valve, has an average 

 lengtii of about 2J inches, and terminates 

 by a rounded extremity with a small 

 hollow prolongation, averaging 3 inches 

 in length — the cxcal or vermiform appen- 

 dix. The mucous membrane is like that 

 of animals, and the muscular tunic is the 

 same. 



The human colon is regularly saccu- 

 lated, like the small colon of the Horse ; 

 it begins in the riglit iliac fossa, above 

 the valvula Bauhiui ; it ascends to the 

 lower face of the liver, passes abruptly 

 across from right to left, and, arriving 

 at the spleen, again ch;inges its direction 

 downwards to the iliac fossa ; it then 

 again describes the iliac S, to reach the 



mesial line, where it is continued by ihe 

 rectum. From this course, the colon has been divided into three portions: the ascending colon, 

 transverse colon, and descending colon. In the ascending and transverse colon are observed 

 three series of sacculi, separated by three muscular longitudinal bands; the descending colon 



has only two. 



There is scarcely anything special to note in the rectum and anus, except that they— and 

 especially the latter— are very rich in arteries and varicnse veins, and that the anus is separated 

 from the rectum by small cavities open in front, and which are found in the Dog; these are the 

 tinuses of Morgagni. 



