THE CAT 215 



is not sharply separated from the colon; its posterior end is 

 constricted. Note the mesentery which joins the large intestine 

 with the dorsal body wall, but do not cut it. 



In order to study the hinder end of the rectum, the pelvis must 

 be split in the midventral line,— an operation easily accomplished 

 with a scalpel by cutting the midventral suture. Grasp one of the 

 legs firmly in each hand and bend them sharply back, thus making 

 a space an inch or more in width between the two halves of the 

 pelvis and exposing the rectum. 



Exercise 7. Draw a sketch of the abdominal cavity with the great 

 omentum removed, showing the natural position of the organs 

 exposed. Carefully label all. 



Study the form and position of the liver and pancreas, but with- 

 out cutting them or any of their connections. The liver is divided 

 into the two main lobes, the right and the left lobe, between 

 which is the suspensory ligament. Note carefully the minor lobes 

 into which each of these lobes is divided. Turn the hinder end 

 of the liver forward and pin it there, and observe its dorsal and 

 posterior surfaces. Note carefully the lobes which appear in this 

 view. The gall bladder will be seen in the right lobe. 



Turn the entire intestine as far as possible to the animal's left 

 without cutting the mesentery, and fasten it there. The dorsal 

 wall of the abdominal cavity will thus be exposed. Note the large 

 right kidney on the right side, just back of the liver, usually em- 

 bedded in fat. Two large veins will be seen, the larger of the two, 

 and the largest vein in the body, being the postcaval. This vein 

 lies in the median plane near the dorsal body wall between the 

 two kidneys, from each of which a prominent renal vein will be 

 seen going to it. It passes forward into one of the divisions of the 

 right lobe of the liver, on its way^to the heart. The other vein is 

 the superior mesenteric vein and its forward continuation, the 

 portal vein. The superior mesenteric lies in the mesentery, in the 

 loop of the duodenum, alongside the pancreas ; the portal lies in 

 front of the loop and passes to the dorsal surface of the liver, 

 where it breaks up into a number of branches which enter the 

 various lobes. 



