1889-90.] MORPHOLOGY AND PHYSIOLOGY OF THE CELL. 265 



generally, of the pancreatic parasites in young Amblystoinata, if an expla- 

 nation is desired of the latter phenomenon. Furthermore, the degenera- 

 tion and disintegration of the pancreatic parasites and the complete 

 absence of the reproductive processes show that some other ti.ssue is the 

 breeding ground of the parasite, and their presence in every pancreatic 

 cell points to the blood as their source. 



The destruction of such large numbers of the parasites in the pancrea- 

 tic cells seems to indicate that the pancreas of Amphibia is a pro- 

 tective as well as a secretive organ, and that it plays this part specially, 

 since the parasites have not been found in any other organ after the most 

 careful search. 



2. Karyolytic and Cytolytic Products. 



These elements are 'iQw in some Dieniyctyli, abundant in others, the 

 latter especially in freshly captured animals. They are found only in 

 groups of the cells at certain spots in the sections and they present cha- 

 racters which definitely distinguish them from the elements described 

 in the foregoing section. Probably the best representation of these torms 

 is given by a glance at Figs. 6 chm, 4 rcJic, pineg, 5 pm. 



Their form is usually spherical or approximately so, and their size, as 

 well as their structure, varies. They often consist of chromatin and eos- 

 inophilous substance, or simply of protoplasm which has a special affin- 

 ity for staining reagents. Less commonly, they may contain eosinophi- 

 lous granules like the zymogen granules, or these may be present with 

 the chromatin masses. Apart from the occurrence of eosinophilous 

 granules and the slightly stained protoplasm, the structure of these bodies 

 is mostly varied by the quantity of chromatin present and the form which 

 it takes. Sometimes the whole of the structure seems composed of chro- 

 matin (Figs. 3 and 6 chm), but more frequently the latter forms a small 

 oddly shaped mass irregularly placed in the structure. One may see 

 rings, rods, crescents, hooks, and spirals formed of this substance and 

 variously disposed in the protoplasmic mass carrying them. These bodies 

 usually lie in the cavities in the protoplasm of the containing cell, a pecu- 

 liarity which readily brings them to view when their affinity for staining 

 reagents is very slight. These elements are sharply distinguished from 

 the parasitic bodies in that they never fibrillate and they, moreover, have 

 a different fate. The latter can only be studied in the pancreas of freshly 

 caught animals, and in those in which the various phases of the resting 

 cells are being developed. In the active gland they may be numerous 

 but as the resting phase of the gland cell is step by step being estab- 

 lished they are found to become correspondingly smaller, the staining 



