1889-90. MORPHOLOGY AND PHYSIOLOGY OF THE CELL. 253 



In Fig. 12 is shown a cell from the base of the epithelial layer, 

 which has certain peculiarities worthy of note. In one of its two nuclei 

 is a cavity containing an eosinophilous, dumb-bell-shaped structure. The 

 chromatin of this nucleus is very much condensed, but a portion of it is 

 extended into the cavity in the form of doubly-beaded rodlets. The 

 structure here reminds one strongly of that of the cytoplasm about the 

 parasites in the intestine of Dieniyctyhis as described above, and I am 

 inclined, therefore, to regard the dumb-bell structure as a parasite. The ele- 

 ments in the neighborhood of the second nucleus may be parasitic also. 

 Such a case as this .illustrates fairly well upon what slender grounds one 

 has to judge of the parasitic or non-parasitic nature of some intracellular 

 bodies. 



III. On Certain Structures in the Pancreatic Cells of 



Amphibia. 



In the pancreatic cells of Amphibia are structures which, since their 

 discovery by Nussbaum,* in 1882, have excited attention amongst a 

 number of cytologists, on account of their supposed participation in the 

 processes of secretion. From the fact that they presented resemblances in 

 position and form to structures described by v. la Valette St. George and 

 Butschli, as occurring in the testicular cells of some invertebrates, Nuss- 

 baum gave them for temporary use the name nebenkerne. It will be 

 seen from the description given below that these elements are not normal 

 portions of the gland cell at all, and, therefore, do not merit the title, which 

 has, since Nussbaum's paper was published, maintained its place in nearly 

 all the publications on the subject. I do not intend to discard the term, 

 however, because the full history of the structures have not been worked 

 out, and they may really belong to a stage of a Sporozoan parasite, whose 

 adult form may already be described and named. In that case the con- 

 tinued use of the term nebenkern applied to these elements is preferable 

 to the coining of a new word for temporary service probably, and I will, 

 therefore, not offer any further excuse for adopting it in this work. 



If the elements in question were normal, it might be advisable to give 

 them an English name equivalent to the word nebenkern, in which case 

 the words " paranucleus," or " accessory nucleus " might suffice. 1 he 

 word cytozoon, on the other hand, is precluded, since it has been adopted 

 by Gaule and his pupils to denote, according to their views, the elements 

 in certain stages of cell metamorphosis or cell rejuvenescence. 



According to Nussbaum's description, the nebenkerne are placed in the 



* Uber den Bau und die Thatigkeit der Driisen. Arch, fiir Mikr. Anat,. Bd. XXI., p. 296. 

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