xni.] THE FROG. 205 



a. Numbers of polygonal granular cells (h'patic 

 cells), with oil-drops in them, will be seen. 



/?. Treat with acetic acid : a nucleus, or sometimes 

 two, will be rendered apparent in each of the 

 cells. 



S. The stomach, intestine, pancreas and spleen. 



a. Cut away the front of the pelvis with a stout 

 pair of scissors, taking care not to injure the 

 urinary bladder: pass a probe from the anus, 

 through the cloaca, into the rectum: uncoil the 

 intestine and spread out the mesentery, so far as 

 is possible without cutting the latter. 



a. The spleen: a small red body lying in the 

 mesentery, near its attachment to the back of 

 the abdomen. 



/?. The stomach: an elongated sac on the left 

 side of the abdominal cavity: the narrower 

 tube (oesophagus] opening into its anterior end. 



y. The intestine: its length and varying diame- 

 ter; especially the great width of its rectal 

 portion : its posterior termination in the cloaca. 



6. The pancreas: a pale-coloured compact mass 

 lying in the mesentery near the commence- 

 ment of the intestine. 



e. The bile-duct. Slit open the duodenum where 

 the right end of the pancreas is attached to 

 it: a small aperture will be seen on the 

 mucous membrane of the intestine at this 

 point: this is the opening of the bile-duct: 

 pass a bristle into it. 



The mesentery: its width; mode of attach- 



