82 EISEN. [Vol. XVII. 



VIII. Permanency of the Structures of the Cell. 



The permanency of the various structures of the cell has 

 already been referred to at various times in this paper, but a 

 summary of all the observations may here be of interest. If 

 we begin by considering the largest structures in the cell, the 

 chromosomes, we find that they can in no possible manner be 

 considered as permanent, even if we allow that some slight sub- 

 division is unimportant. Not only do the chromosomes, during 

 the confluent umbrella stage, become so fused together that 

 there hardly remains a trace of their individuality, but we have 

 at that time only one single confluent mass in which we only 

 can perceive very faintly the chromiolic granules, and more 

 distinctly the endochromatic granules ; but of the original chro- 

 mosomes there is at the end of this stage hardly a trace. I 

 say hardly, because we might consider that the points which in 

 some cases project from the umbrella actually represent the 

 original chromosomes. But even this is not quite certain, be- 

 cause we find scattered all through the umbrella-shaped mass 

 the endochromatic granules of the chromoplasts, which un- 

 doubtedly shows that a real and complete fusion has taken place, 

 and that the points in question only represent the line along 

 which this fusion has proceeded. On the other hand, in the 

 resting stage of the polymorphous spermatogonia there are no 

 structures which correspond to the chromosomes. The chro- 

 mioles are, as we have seen, suspended on fine threads of linin, 

 and are so scattered that not even the leaders can be recog- 

 nized. Nor is there any "Anlage" even of chromosomes until 

 the leaders have formed. The chromosomes can therefore 

 not be permanent structures of the cell. 



If we now turn to the chromomeres, we shall find that they 

 also are only ephemeral structures and no more permanent than 

 the chromosomes. Long before the chromosomes have become 

 confluent, the chromomeres have lost their identity as chro- 

 momeres, the chromioles of which they were composed having 

 become arranged in double rows in the chromosome. But 

 while in this stage the chromosomes are of slightly greater 

 permanency than the chromomeres, we find that in the resting 



