478 J. DUESBERG 



of the myotome, or shorter filaments disposed in longitudinal 

 rows. After the appearance of the striated mj^ofibrils, which in 

 embryos fixed with Regaud's fluid are, as fig. 8b shows, very 

 difficult to see, nearly all the intermediate chondriosomes have 

 disappeared and only the accumulations at both eiids of the 

 myoblasts persist. 



I do not intend in this paper, to dwell on the topic of the role 

 of chondriosomes in histogenesis. I am preparing an extensive 

 study of it, both in normal development and in regeneration. I 

 can, however, state now, that all I have seen corroborates the 

 conviction I gained from the study of the chick-embryo ('10, 2) ; 

 and such preparations from the fish-embryo as I just described, 

 without being conclusive, are certainly in favor of my opinion. 

 Hence, a discussion of the bibliography more naturally belongs 

 to this next study; I take, however, the liberty of making the 

 following remark about a recent paper by M. R. Lewis ('17)^ 

 M. R. Lewis found, that in tissue-cultures of connective-tissue 

 cells, there appear fibers with the differentiation, of w^hich chon- 

 driosomes have seemingly nothing to do. To draw, however, 

 from such observations any conclusions extending to the nor- 

 mally developing embryonic tissue, in which the nature of the 

 differentiations are beyond doubt, seems to me hardly legiti- 

 mate. The results which Baitsell ('15) obtained, show how care- 

 ful we ought to be in our interpretations. 



I come now to a consideration of the behavior of the chondrio- 

 somes in dividing cells. 



In his first paper on the chondriosomes of the chick-embryo, 

 Meves ('08) came to the conclusion that, in contradistinction 

 with what frequently appears to be the case in the spermato- 

 cytes of invertebrates, 



der Ablauf einer Mitose scheint auf das Verhalten und die Lagerung 

 der Mitochondrien und Chondriokonten giinzlich ohne Einfluss zu 

 sein. Die Mitochondrien erhalten sich wiihrend der Teilung als solche 

 und nehmen keine besondere Anordnung an; ebenso bleiben audi die 

 Chondriokonten unregelmassig durch den Zellleib verteilt (p. 840). 



^ Which I was enabled to read in the proofs, through the courtesy of Mrs. 

 M. R. Lewis. 



