CYTOPLASMIC STRUCTURES IN THE SEMINAL EPITHELIUM OF THE OPOSSUM. 71 



Nukleolen aufweisen, wahrend diejenigen Zellen, deren Plasmakiigelchen sich zu 

 Stabchen zu entwickeln angefangen haben, in der Regel gelappte Kerne besitzen." 

 As to the crucial point of the origin of the "Plasmafaden," I would suggest as a 

 possible cause of error the fact that Schreiner has made use of only such methods 

 as stain nucleoli and chondriosomes alike i. e., iron-hematoxylin and acid fuchsin 

 and not of Benda's method, which stains them differently. It should also be 

 recalled that other authors who have studied the fat-cells have declared themselves 

 for the cytoplasmic nature of then: chondriosomes; for instance Dubreuil, whose 

 completed paper (1913) Schreiner has overlooked. 



Taking for granted, however, that Schreiner's description is accurate, nothing 

 proves yet that his interpretation is correct, for the process described as an expul- 

 sion of substance from the nucleus might just as well be the reverse. And even if 

 we accept Schreiner's interpretation, we find that the question of the origin of the 

 chondriosomes has really not been touched, since these bodies are present, according 

 to Schreiner's own description, in all cells before the process he describes takes 

 place. 



These are the points which the preliminary account of Schreiner suggest to me. 

 I wish to add that the bibliographic review contains a number of omissions and 

 errors. Among the first I note, aside from the one already mentioned (Dubreuil's 

 paper), Schreiner's denomination of the theory of the cytoplasmic nature of the 

 chondriosomes as the "Meves-Duesbergsche Lehre." As a matter of fact, prac- 

 tically all cytologists agree on this point, one of the last to so express himself being 

 Maximow (1916). As to errors, we read, for instance, on page 148 that "die Anhan- 

 ger der Chromidialtheorie stimmen mit denen der Plastosomentheorie darin voll- 

 kommem iiberein, dass die Chromidien und Plastosomen die namlichen Gebilde 

 sind" an opinion never expressed by me (see Duesberg, 1912). Further, we find 

 that the criticism of Retzius (1914) is very highly praised. I have already pointed 

 out why Retzius can not be considered as an authority in this matter (Duesberg, 

 1915, pages 62-63) and would refer the reader also to Meves' answer (1914, 2) to 

 Retzius. On page 169, Schreiner writes: 



"Da ich das Material, bei dem Goldschmidt die Beobachtungen machte, welche die 

 Grundlage seiner Chromidialtheorie bilden (die Gewebszellen der Ascariden) nicht aus 

 eigener Untersuchung kenne, wage ich zu den verschiedenen Meinungen, die iiber die 

 Natur seiner Chromidialstrange von verschiedenen Seiten (Vejdovski, Bilek, Duesberg) 

 geaiissert sind, keine Stellung zu nehmen. Doch muss ich gestehen, dass es mir schwer 

 fallt zu glauben, dass sich Goldsmidt von seinen Praparaten derniassen hat tauschen 

 lassen, wie die genannten Autoren behaupten." 



To this, I would answer that I have expressed no definite opinion on Gold- 

 schmidt's "Chromidialstrange," as I recognize "dass es kaum moglich ist, sich 

 ohne eigene Kenntnis des Objektes kategorisch auszusprechen (1912, p. 907)." I 

 insisted, however, that all authors agree on one point, i. e., that Goldschmidt was 

 mistaken; and I would emphasize here that these authors are not only the ones 

 mentioned by Schreiner, but also Sjovall and Lundegardh (who declare themselves 

 unconvinced by Goldschmidt's description), Hirschler, Ehrlich, Jorgensen, and 



