SPLANCHNOLOGY. 195: 
duodenum, the process of digestion is completed; the chyme is mixed with 
the biliary and pancreatic juices, and a separation takes place between the 
chyle and the excrementitious matter. 
-8. Tae JEJUNUM AND ILEUM INTESTINES are partly concealed by the 
omentum. ‘There is no exact division between these two portions, the upper 
two fifths being named jejunum, and placed higher in the abdomen than 
the remaining ileum. From the duodenum the jejunum first passes forwards 
and to the left side; it then descends into the middle of the abdomen, is 
folded upon itself over and over again, extending into various regions ; 
finally, the terminating portion of the ileum rises out of the pelvis from left 
to right, and joins the coecum at an acute angle convex upwards. This. 
portion of the intestinal tract is well supported by the mesentery, so that 
while possessing sufficient freedom of motion, and the power of accommo- 
dating itself to the various displacements produced by muscular action, it is 
securely tied in its place. “ 
The large intestine, from four to five feet long, is divided into ccecum,; 
colon, and rectum. It differs from the small, not only in size but in being 
cellular or sacculated when distended; small processes too, appendices 
eptploice, are attached to it. Three strong longitudinal eee bands -— 
be observed, puckering it and causing the cellular appearance. 
The cecum, or caput colt, is a cul de sac in the right iliac fossa, with it 
nearly fills. Tt joins the colon at an obtuse angle, although diare iS NO: 
exact limit between them. On its external surface there are three irregular 
protuberances, one anteriorly and the other posteriorly. The appendix ver- 
miformis proceeds from the left side of the lower and posterior part; this is 
a small tortuous cul de sac about the size of a goose quill, and may be con- 
sidered as representing the more highly developed coecum of other animals: 
The ileum joins the left or inner side of the coecum at an acute angle, its 
mucous coat protruding into the cavity of the ccecum to form two valves. 
The inferior or tlio-cecal valve is the larger; it secures the ileum against 
regurgitation from the coecum; the superior or z/2o-colic valve is smaller, and 
prevents regurgitation from the colon. These two valves are united at their 
commissures or extremities, and from each commissure a fold is continued 
round on the inner side of the ccecum ; these folds are the frena or retinacule 
of the valves. 
4, THE CoLon extends from the ccecum to the rectum ; it is divided into 
four portions. The right or ascending colon extends from the ccecum to the 
inferior surface of the right lobe of the liver. The transverse arch of the 
colon turns off at a right angle from the last, and extends tortuously from 
the gall bladder, transversely as far as the spleen in the left hypochondrium. 
The left or descending colon extends from the spleen to the iliac region behind 
the small intestines, and the segmoid flexure or the fourth division mine oriee 3 
brid colon to the rectum. 
. THE RECTUM, or straight intestine, extends from the sigmoid. flexure 
of dis colon to the anus. It is more Bpinldzieal and Jess sacculated than 
the colon; it is usually found much dilated about an inch above the anus. ~ 
The mucous coat of the small intestines, although continuous with that 
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