CYTOPLASMIC STRUCTURES IN THE SEMINAL EPITHELIUM OF THE OPOSSUM. 69 



designated as "vordere Halsknotchen." In figure g this last term is correctly used, 

 but in the same figure, as well as in figure/, the chondriosomal sheath of the middle 

 piece is referred to as "Spiral-faden und -hiille;" in the guinea-pig, however, the 

 chondriosomes do not form a spiral filament. I must add that I am not by any 

 means responsible for these mistakes. 



DISCUSSION. 



As to the ultimate fate of the chondriosomes in spermatogenesis, the present 

 investigation leads to the conclusion, readily foreseen, that the chondriosomes 

 build a part of the spermatozoon in this case a spiral filament surrounding the 

 middle piece. 



As to their origin, Jordan's assumption of their discontinuity and their nuclear 

 nature in the seminal cells of the opossum can, in my opinion at least, after this 

 reinvestigation be considered as a failure. To me this conclusion is no more sur- 

 prising than the first one. It must be stated, however, that in later years the theory 

 of the nuclear origin of the chondriosomes has again been taken up by Alexeieff , 

 Walton, and K. E. Schreiner. 



As far as I know, Alexeieff has published a number of notes on the subject, all 

 dealing with protozoa (1916). He finds in these organisms bodies which he calls 

 "mitochondries," and which he believes to be of nuclear origin; hence he proposes 

 calling them chromidia. I must say that nowhere can I find any argument in favor 

 of this author's conclusions. 



Walton (1916) thinks he has demonstrated that the chondriosomes of the 

 seminal cells in A scan's cam's Werner are formed at the expense of nuclear material 

 in the spermatocytes, and he draws therefrom far-reaching conclusions. As chon- 

 driosomes do, however, exist in the spermatogonia of Ascaris (Duesberg 1912, 

 p. 638, and Faure-Fremiet, 1913), Walton's premises are incorrect, and any further 

 discussion is unnecessary. The explanation of his failure is very simple: he fixed 

 with strong Flemming's and Carnoy's fluids, neither of which can be trusted for 

 the preservation of the chondriosomes. 



More serious appears Schreiner's attempt. So far he has, to my knowledge, 

 published observations only on the fat-cells of the subcutaneous tissue of Myxine. 

 He promises to deal in subsequent papers with pigment-cells, blood-cells, and cells 

 of the connective tissue, with glandular and seminal cells, the study of which brings 

 him to the same conclusion as the study of the fat-cells. In these he finds a num- 

 ber of rods, "Plasmastabchen," stainable with acid fuchsin (after Altmann's or 

 Altmann-KulFs method), or with iron-hematoxylin, "welche zur Bildung der 

 Fettvakuolen Anlass geben." Schreiner's view on the formation of fat is 

 a confirmation of those already expressed by a number of authors, among them 

 Metzner, Dubreuil, and Hoven. He differs from them, however, inasmuch as, 

 according to him, the "Plasmastabchen" are formed from nuclear substance, not 

 from chromatin, as in Goldschmidt's chromidial theory, but from nucleolar sub- 

 stance. He concludes that his observations formally contradict what he calls 

 "die Meves-Duesbergsche Lehre." 



