160 ELEMENTARY PHYSIOLOGY. [XV. 



a. The granules are fewer, being absent from 

 the outer part of the cell, thus forming an 

 inner granular and an outer non-granular 

 zone. 



h. ^e spherical nucleus is more obvious (partly 

 in consequence of the disappearance of the 

 granules) and is situated chiefly or entirely 

 in the non-granular zone, the nucleolus is 

 usually distinct. 



c. If the gland has been taken after very active 

 secretion the cells may be nearly free from 

 granules, the remaining granules "will be 

 smaller and the lurifiina will be more obvious. 



3. I'repare sections of an active pancreas which has 

 been hardened in spirit, stain with carmine and 

 mount in acid glycerine. 



The division of the cells into granular and non- 

 granular zones will be seen as in the osmic acid 

 preparations ;, the inner zone however appears as 

 a aonfusedly granular mass instead of as an 

 aggregation of separate spherical granules ; the 

 outer zone appears homogeneous and stains more 

 deeply than the inner zone. 



six hours after a full meal for the active state ; ahout twelve hours 

 after a full meal for the resting state. With the frog the pancreas 

 should be taken in eight to ten hoiors after a fuU meal for the active 

 state, in one to two- days for the resting state. Worms serve best for 

 feeding frogs. In unhealthy frogs and in frogs which have long 

 fasted, the pancreas-cells have usually a distinct outer non-granular 

 zone. In, all oases the pancreas should be placed in osmic acid 1 p.o. 

 for two to twenty-four hours as convenient, then washed, and trans- 

 ferred to- 75 p. c. Erleohol. 



