THE RABBIT 279 



the right anterior lobe. Turn the intestines as far as possible to 

 the animal's left without cutting the mesenteries, and fasten them 

 there. The dorsal wall of the abdominal cavity will thus be ex- 

 posed. Note the large right kidney on the right side, just back of 

 the liver ; it is usually embedded in fat, and lies in advance of the 

 left kidney. Two large veins may be seen (unless embedded in 

 fat), 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 kidneys, from each of which a prominent 

 renal vein will be seen going to it ; it passes forward through the 

 right side of the liver, on its way to the heart. The other prom- 

 inent vein is the superior mesenteric and its forward continuation, 

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

 the loop of the duodenum, its branches accompanied everywhere 

 by the branches of the superior mesenteric artery; the portal 

 passes to the dorsal surface of the liver, where it breaks up into 

 a number of branches which enter the various lobes. 



Lying alongside these branches of the portal vein are the much 

 smaller bile ducts, which collect bile from the lobes of the liver. 

 A duct from the gall bladder, called the cystic duct, joins these 

 bile ducts, and the union of all of these forms the common bile 

 duct, which lies alongside the portal vein and carries the bile to 

 the duodenum. Identify the portal vein and its branches ; trace 

 the bile ducts, the cystic duct, and the common bile duct ; if they 

 are not easily seen, they may often be made apparent by squeezing 

 bile into them from the gall bladder. 



Exercise 6. Make a sketch showing the dorsal and posterior surfaces 

 of the liver and the organs connected with them, so far as observed ; 

 the branches of the portal vein and the bile ducts, the gall bladder, 

 the cystic duct, and the common bile duct ; also the loop of the duo- 

 denum with the pancreas and the pancreatic duct and the branches 

 of the mesenteric vein and artery. Carefully label all the organs 

 observed. 



The study of the digestive system will be finished after that of 

 the portal veins. 



The Vascular System. This is composed of the following or- 

 gans: the heart, the arteries, the veins, the capillaries, and the 



