480 J duesheik; 



was never observed. We find as did Buchner that this charac- 

 teristic arrangement of the mitochondria during division of the 

 cell is by no means a constant occurrence." 



Disregarding the fact that Buchner is no authority whatever 

 on these matters and that in his first paper ('08) Meves does not 

 mention any division of chondriosomes, I want to emphasize the 

 fact that I never have considered the division of chondriosomes 

 as a general process. M. R. and W. H. Lewis, however, were' 

 obviously under that impression, though their very observations 

 on the behavior of the chondriosomes during mitosis in tissue- 

 cultures of the chick-embryo agree very well with mine on fixed 

 preparations of the same material. In fact, I have described all 

 possible processes in the dividing cell, the observations being 

 made on various objects. That the chondriosomes may dispose 

 themselves in a palisade of rods around the spindle, to be sepa- 

 rated into equal parts during the division of the cell, is evident 

 in the spermatocytes of many invertebrates and especially in 

 Blaps (cf. Benda, '99 and Duesberg, '10, 3). In the spermato- 

 gonia of Triton, however, I observed a very different process, 

 inasmuch as some of the chondrioconts were seen to pass undi- 

 vided to one daughter-cell ('10, 3, fig. 46), exactly as I had 

 already figured the phenomenon for the chick-embryo ('10, 2, 

 fig. 8). Finally, in Ciona, still another process takes place, — a 

 constantly unequal repartition of the number of chondriosomes 

 between the daughter-cells.^ 



Summarizing our knowledge of the behavior of the chondrio- 

 somes during mitosis, I come to the conclusion that cells may be 

 divided into two categories: those in which the chondriosomes 



^ Relating her observations on the normally fertilized egg of the sea-urchin 

 (Strongylocentrotus lividus), Danchakoff ('16) writes (p. 583): "The sector of 

 the radiation known as the spindle seems to be formed by the substance of the 

 plastosomes (M. Lewis, Robertson), or archoplasm (McClung) , and consists of 

 uniform thin threads." To this, I take the liberty of objecting on the following 

 grounds: 1) that Lewis and Robertson ('16) do not mistake the chondriosomes 

 for the spindle; 2) that the relationship between the spindle and the chondrio- 

 somes has been established by Benda, as early as 1899; the long chondrioconts 

 he found in Blaps surround the spindle, sometimes very closely, but do not form 

 its substance; 3) that, in the egg of the sea-urchin, the chondriosomes are not 

 filaments, but granules (Meves, '12). 



