348 S. SAGUCHI 



1. INTRODUCTION 



The pancreas forms a favorable object for the study of the 

 activity of secretory cells in general, and has been used by vari- 

 ous investigators who have studied the minute structure of the 

 pancreas cell in relation to the secretory process, since the com- 

 plete processes which take place in the pancreas cell during the 

 production of secreting matter are to be followed with great 

 clearness. In looking over the literature, there can be found 

 three important steps in the development of the structural par- 

 ticularities in the cells in question. The first step was taken by 

 R. Heidenhain ('80). He divided the cell-body into two distinct 

 zones; one, a light, apparently homogeneous outer zone turned 

 toward the basement membrane, and the other, dark granular 

 inner zone near the lumen. He suggests that the expenditure 

 of the matter which is accompanied by the transformation of 

 zymogen granules into secretion is going on in the inner zone, 

 while the deposition of the nutritive material and the elabora- 

 tion of zymogen granules take place in the outer zone; thus giving 

 us an idea of the fundamental importance of the process going 

 on in the pancreatic cell. The second step was taken by the in- 

 vestigations of Mouret ('95, '05), Laguesse ('99), Mathews ('99), 

 Gamier ('00) and others, who attached considerable importance 

 to the fibrillar structure first observed by Pfliiger, in 1869, and 

 assumed the participation of the filaments in the formation of 

 zymogen granules. Structures of this kind have since been of- 

 ten described under the name of 'Solger's basal filaments' or 

 'Garnier's ergastoplasm,' the significance of which is not yet 

 decided definitely. Benda ('97-'03), Meves, ('07, '08) and 

 many others, finally, advocate a theory which makes the granules 

 or filaments, named either 'mitochondria' or 'chondriocontes,' the 

 most important morphological constituents of the cell. These 

 structures were also found in glandular cells, and have formed 

 a problem for various investigators which is still far from a 

 satisfactory solution. 



The questions as to whether these structures and others, 

 above all the intracellular net-apparatus form essential constit- 



