260 TRANSACTIONS OF THE CANADIAN INSTITUTE. [VoL. I. 



ming's Fluid, though the cell structure and nucleus are well preserved, the 

 zymogen is dissolved out of all the cells except those at the immediate 

 periphery of the organ. This removal of the zymogen is due to the acetic 

 acid in the fluid, which penetrates where another constituent of the same 

 mixture, osmic acid, is unable to diffuse. The action of acetic acid in this 

 reagent enables us to distinguish between zymogen and other granules 

 which have the same staining capacity with eosin. The osmic acid, fur- 

 thermore, gives a dark tinge to the nebenkerne and unusual bodies in those 

 cells near the periphery and thus brings them out in clear contrast to the 

 other cytoplasmic structures. 



OBSERVATIONS. 



In sections made from the pancreas of Diemyctylus, which has been 

 hardened with Flemming's Fluid and stained with haematoxylin and eosin, 

 one observes in addition to the nucleus and cell protoplasm and, some- 

 times, zymogen granules, other structures which can be ranged in two 

 groups at least. One of these groups comprise forms whose fundamen- 

 tal structure elements are thick or thin fibrillae, either in sheaf shape, or 

 wound in a ball fashion (Fig. i). Sometimes the fibrillae may be so thick 

 as to merit the designation threads (Fig. 8). These forms are usually 

 but not always, placed between the nucleus and the membrana propria, 

 and they frequently sit, cap-like, on the nucleus, or the latter may be 

 indented by them. In the second group, which are, at the outset, unlike 

 the first, in that they are placed in cavities of the cell, are structures which 

 present a varied form and composition. They are sometimes eosinophil- 

 ous, sometimes chromophilous, and at times they present both characters. 

 They are numerous in the pancreas of a freshly captured animal, but are 

 not so much so as the members of the first group. 



The members of these two groups of intracellular elements have been 

 confused by other observers, and Ogata describes them as derived from 

 the plasmosomata migrated from the nucleus, while Steinhaus appears to 

 believe they are all parasites. In order to show that the views of these 

 observers are hasty generalizations from a limited number of results, I 

 propose to go fully into the description of the structure origin, mode of 

 production, and history of each group. As plasmosomata, migrated, or 

 extruded from the nucleus, are sometimes present, and as they have a 

 different history, they merit special attention as a third group. These 

 three groups may then stand in the order of description as follows : 



1. Parasites. 



2. The remains of broken down cells and nuclei swallowed by 



healthy adjoining cells. 



