The Liver and Pancreas. 



173 



condition of the cells, and the latter are seen crowded with 

 granules which are so arranged as to form on the margin 

 next the basement membrane a clear or fairly clear zone, 

 and within this an intensely granular zone. When activity 

 commences the granules appear to pass centrally towards 

 the alveolus, leaving the cell comparatively clear, excepting 

 that portion immediately abutting on the alveolus, which, 

 even in the exhausted condition, is still granular. These 

 changes have resulted in the cells becoming distinct and 

 clearly defined from each other, and moreover, as they have 

 emptied their granular contents into the alveolus as pan- 

 creatic secretion they have consequently become much 



Fk;. 11.— A Portion of the Pancreas of the Rabbit (Kuhne 

 and Sheridan Lea). A, at rest ; B, in a state of activity. 



a, The inner granular zone, which in A is larger, and more closely 

 studded with fine granules, than in B, in which the granules are 

 fewer and coarser, b, The outer transparent zone, small in A, 

 larger in B, and in the latter marked with faint stria?, c, The 

 lumen, very obvious in B, but indistinct in A. d, Indentation of 

 the junctions of the cells seen in the active but not in the resting 

 gland (Foster). 



smaller; the narrow clear zone seen in the resting gland 

 now becomes a broad, clear one, the choked alveolus 

 becomes readily defined, whilst the nucleus of the cell 

 hidden in the charged condition, is now clearly seen. These 

 changes have been worked out on the pancreas of the living 

 rabbit by Kiihne and Sheridan Lea (see Fig. 11). 



Amount of Secretion. — From the investigations of Colin 

 and others we know that in the herbivora the secretion of 

 pancreatic juice is continuous, though not uniform, reach- 



