Metazoa Rana. 



281 



highest importance, and will be described in connection 

 with the circulatory system. 



One Other digestive FlG - T 44- FOUR HEPATIC CELLS WITH 



f COMMENCEMENTS OF A BILE-CAPIL- 



gland may be referred to, LARY. (Quain.) 

 viz. the pancreas. This 

 organ lies in the fold of the 

 duodenum, and is the 

 agent in the formation of 

 pancreatic juice. It con- 

 sists of a series of closely 

 packed tubules, lined by 

 cubical glandular cells 

 which have the power of 

 abstracting the constituents 

 cf the pancreatic juice 

 from the capillary blood- 

 vessels distributed in large 

 numbers through 

 its tissue. The 

 secretion differs 

 from that of the 

 stomach in being 

 alkaline (that of the 

 stomach is acid), 

 but, like the gastric 

 juice, it has the 

 power of rendering 

 proteid substances 

 soluble which have 

 escaped the action 

 of the gastric se- 

 cretion. It also 

 assists in the ab- 



. r r ^ j a > secret ory tubule ; d, origin of a pancreatic duct. 



sorption of fat, and, 



in addition, transforms staj-h intp .sugar a function in the 



higher animals mainl^g^faled by "the secretion of the 



FIG. 145. SECRETORY TUBULES OF THE PANCREAS. 

 (Quain.) 



