170 



BIOLOGY. 



[Book ii. 



the first portion of the Sliiall intestine or duodenum. In this 

 same region and very near the origin of the choledochal canal 

 opens, in man, the principal excretory canal of another and 

 very important gland of cluster-shape, foi-med also of small 

 clusters or acini, each diverticule whereof is terminated in a 

 cul-de-sac. It is also clothed with epithelial cells. We shall 

 have to speak of the digestive office of this gland called 

 pancreatic. 



In certain vertebrates the pancreatic canal opens at a certain 



Fig 13. 



Isolated cells of the 

 liver ; a, with simple 

 nucleus, 6, -witli 

 douUe nucleus. 



Fie. 14. 



Arrangement of the cells of the liver in a lobule cut 

 transversally, with the section of the hepatic vein 

 in the centre. 



distance from the hepatic canal, but generally below, about 

 from 30 to 50 centimetres (rabbit, hare, beaver, porcupine, 

 ostrich). 



The pancreatic gland already existg in the most inferior 

 vertebrates— the fishes : but in them it is generally smaller 

 and of a simpler structure. Its culs-de-sac [bliad ends] are 

 wider, more or less independent. The pancreas of divers ver- 

 tebrates (lizard, and so on) is joined to the spleen as in the 

 superior mammifers, the biliary gland is joined to the glycogenic 



