THE ABDOMEN AND ITS CONTENTS II3 



but very little dissection should be done on any of the portions 

 of the intestine or related organs until that organ, or part, is 

 to be studied specifically, as later outlined. 



The duodenum is the first part of the small intestine and its 

 ventral side is usually the outer or free edge of the compressed 

 intestine, when the stomach is in normal position. Turn the 

 stomach to the left side of the abdominal cavity, and beginning 

 at a point about six cm. from the pyloric end of the stomach 

 open the duodenum along the ventral or free side (as was 

 determined above) to the pyloric end of the stomach. Scrape 

 out the chyme with the blade or rounded end of the cartilage 

 knife so that a relatively large papilla, located about two cm. 

 from the pyloric valve, is plainly visible. This papilla is the 

 mouth of the common bile duct. Determine this by probing it 

 with the seeker. Note the plush-like lining of the intestine, 

 which is composed of the villi. 



The small intestine is comprised of the jejunum, which is 

 said to have the more vascular and consequently thicker wall 

 of the two, and the ileum (cf. ilium. Fig. 14, ILI). The 

 jejunum and ileum comprise the mesenterial section of the small 

 intestine. 



The cecum is very large in the rabbit. The outer loop of the 

 large intestine, as the intestines lie in situ, covers the dilated 

 end of the ileum, the sacculus rotundus, which forms a 

 vestibule before the ileocecal (ileocolic) valve. This valve 

 marks the caudal end of the ileac portion of the small intestine 

 and the beginning of the cecum and of the colon. That 

 portion of the intestine which continues from this valve to 

 end bhndly in a thick-walled vermiform process is the cecum, 

 while the colon is that portion of the intestine which becomes 

 saculated several inches from the ileocecal valve and continues 

 on to form the rectum and anus. Make incisions into the 

 various parts of the intestines in order to study the thickness 

 and character of the walls and other structures and pecuHarities. 

 In every instance (e.g., duodenum, sacculus rotundus), the 

 incision should be longitudinal and along the free margin of the 



