186 JOHN E. S. MOORE. 



The term "Nebenkern/' as I have before incidentally men- 

 tioned, has been applied by a variety of authors indiscri- 

 minately to all manner of foreign particles, from parasitic 

 bacteria and fungi, to globules of purely manipulative origin. 

 And the confusion thus arising has been so much deepened by 

 the involved karyokinetic phenomena in the tissue-cells of 

 adult animals as to make investigators, at least for the present, 

 wary of associating any variable structure with well- ascertained 

 bodies such as the central corpuscles and their radiation. 

 And it is probable that Flamming, while dealing with such 

 tissue, has through his habitual caution figured only that of 

 whose nature he was absolutely certain. 



Notwithstanding the apparently intimate relation we have 

 already traced between the archoplasm in the genital ridge of 

 the salamander and the '' sphere-attractive" of van Beneden 

 and Boveri (the homology between the first and the " Neben- 

 kern " of Platner needs no discussion), certain difficulties 

 remain as yet unexplained. 



In Hermann's figures of the archoplasm of the spermatocytes 

 there is no " medullary zone," and, as he goes on to say, '^ eine 

 sichere Diagnose eines Polkorperchens ungemein erschwert." 



The description I have given above, where all these parts 

 were present in the embryonic genital ridge — that is, in the 

 tissue which directly gives rise to the spermatocytes — shows 

 that this difficulty probably arises merely from structural 

 changes during maturation. 



Again, as Hermann himself points out, the " sphere-attrac- 

 tive" of van Beneden is duplicated, whereas the archoplasm 

 in the cells constituting the spermatocytes is invariably 

 single. It should, however, be borne in mind that the 

 " sphere-attractive " in some of Boveri's figures (27, 71, 73, 

 74) is certainly not duplicated ;^ whilst I have found besides 

 several traces of such division of the archoplasm ['' sphere- 

 attractive ") in the genital ridge of the salamander — one un- 

 doubted example (fig. 6). 



* T. Boveri, " Zellenstudieu," ' Jeiiaische Zeitschrift fiir Medicin,' Bd. xxii, 

 p. 685. 



