GLANDULAR CELLS OF THE FROG'S PANCREAS 381 



Laguesse, Hoven ('12), Mislawsky ('13), and others, to which 

 the reader is referred for details. In the following the views 

 of various investigators concerning the origin of zymogen 

 granules will be summarized. 



a. Cytoplasmic origin. Langley ('84) and Carlier ('96) be- 

 lieve that zymogen granules are derived from the hyaline sub- 

 stance or hyaloplasm; an opinion which seems to have secured 

 few adherents among histologists. 



That the filaments present in the basal portion of the cell take 

 part in the formation of zymogen granules was first suggested by 

 R. Heidenhain as early as 1880. The similar filaments have since 

 been described by various investigators under the name 'Solger's 

 basal filaments' or 'Garnier's ergastoplasm,' and there has been 

 much discussion as to their significance, especially as to their 

 bearing upon the origin of zymogen granules. Moure t ('95, '05), 

 Laguesse ('99), and others believe that they are formed by disin- 

 tegration of the basal filament; hence the authors gave the term 

 'une substance prezymogene' to the filaments. Gamier ('00), 

 on the other hand, has made a study of various glands, inclusive 

 of pancreas, and has come to the conclusion that the filaments 

 are indirectly concerned in the formation of zymogen granules. 

 According to him, the process is as follows: the nucleus, first 

 of all, increases in volume, accompanied by the enlargement of 

 the plasmic nucleolus and by the diffusion of the chromatic sub- 

 stance through the nuclear sap. In the next stage the basal 

 filaments come in contact with the nucleus and then is acquired 

 the basophilic property. Gamier explains this phenomenon 

 hypothetically by assuming that the nucleus furnishes the 

 chromatic substance by osmosis to the filaments; he gave the 

 term 'excretion nucleaire' to the process. Next, the basal 

 filaments leave the nucleus, momentarily, and distribute the 

 loaded chromatic substance throughout the cytoplasmic retic- 

 ulum. Then, there appear basophilic granules at the nodes 

 of the reticulum, while the chromaticity of the basal filaments 

 decreases. Finally, zymogen granules make their appearance in 

 the meshes of the network. The conception of Mathews ('99) 

 includes the two views above mentioned : the cell-threads (basal 



