152 



THE BIOLOGY OF THE FROG 



CHAP. 



''**<^:^ 



peptones. The latter differs from pepsin in that it acts in an 

 alkahne or neutral medium ; in a strongly acid medium its 

 action is entirely stopped. 



The Liver. — The liver is a massive gland whose secre- 

 tion, the bile, is conveyed to the intestine through the bile 



duct along with the 

 fluid secreted by the 

 pancreas. The or- 

 gan is of a dark red- 

 dish color, and is 

 divided into a right, 

 a left, and a middle 

 lobe. The middle lohe 

 is small and con- 

 cealed from view by 

 the heart. The left 

 lobe is divided by an 

 oblique incision into 

 an anterior and a pos- 

 terior portion, the lat- 

 ter occupying the 

 middle of the poste- 

 rior part of the liver. 



Fig. 42. — Liver and pancreas of frog. Dc, '^"^ greater por- 



common bile duct; Dcy, cystic ducts; Dh, tion of the liver is 



Dh\ hepatic ducts which with the cystic covered by a closdy 



ducts combine to form the common bile -^ ■' 



duct; G, gall bladder; L, D-, L^, L?, lobes adherent layer of per- 



of the liver turned forwards; Lhp, hepato- itoneum which is 



duodenal ligament; M, stomach; P, pan- . 



creas; />!, pancreatic ducts entering the COntUlUed tO form at- 



common bile duct; Py, pylorus. (After tachmentS with the 



Wiedersheim.) ... , 



pericarduim, ventral 

 body wall, dorsal body wall, and the stomach and intestine. 

 The bile duct is formed by the confluence of the hepatic 



