SECRETION. 



175 



the loss of the granular material, so that the cell as a whole is smaller in 

 size than in the gland from the fasting animal. It seems evident that during 

 the hours immediately following a meal that is, at the time when we know 



FIG. 76. Pancreas of dog during first stage of digestion ; alcohol, carmine (after Heidenhain). 



that the gland is discharging its secretion, the granular material is being used 

 up. After the period of most active secretion that is, during the tenth to 

 the twentieth hour after a meal in the case of a dog fed once in twenty-four 



FIG. 77. Pancreas of dog during second stage of digestion; alcohol, carmine (after Heidenhain). 



hours the gland-cells return to their resting condition (Fig. 77). New gran- 

 ules are formed, and finally, if the gland is left uustimulated they fill the 

 entire cell except for a narrow margin at the basal end. 



Similar results are reported by Kiihne 1 and Lea from observations made 

 upon the pancreas cells in a living rabbit. In the inactive gland the outlines 



1 TJntersuchungen aus dem physiologischen Institut des Universitdts Heidelberg, 1882, Bd. ii. 



