266 J. E. S. MOORE. 



the apices of the spindle figure. It will, however, be well 

 to advance the description of the mitosis a little before dis- 

 cussing this point. The first nuclear difi'erentiation appears 

 at one side of the nucleus as a colourless spot (fig. 2), which 

 grows, driving the chromatic network before it to one side 

 (fig. 3). The individual chromatin bands become shorter and 

 thicker in proportion to this displacement, and nearly all the 

 fine strands of " linin'' disappear from this area, or, in other 

 words, the spheroids fuse one with another, the fusion being 

 produced by the substance of the clear globules breaking 

 through the walls of intervening fluid one into another. In 

 fact, this fusion spreads just as in soap froth the larger bubbles 

 grow at the expense of the smaller, and the continuance of 

 such a process results in the chromatin being thrown to one 

 side in the form of a crescent (fig. 3), its threads are naturally 

 thickened in proportion to their displacement, and the curious 

 initial figure, which so much struck Hermann in the sperma- 

 tocytes of the salamander, appears to be a necessary conse- 

 quence of an intra-nuclear fusion in Branchipus.^ 



As the intra-globular fiuid (with its staining granules) is 

 between the adjacent spheroids, or in any single instance is 

 peripherally disposed towards them, it follows that if the fusion 

 continues until the whole nucleus consists of one or of a small 

 number of spheroids, the intervening staining chromatin will 

 be, as it practically is, all on the periphery. 



Secondly, the fewer the globules, the larger and fewer the 

 angular spaces between them (figs. 4, 5), and consequently the 

 more deeply staining intervening matter appears as a limited 

 number of chromosomes connected by fine striae (linin) ; their 

 actual number will naturally depend on the size of the 

 spheroids compared with that of the nucleus.^ 



A great deal of importance has been attached directly 



^ 'Arch, fiir mikroskop. Auat.,' Bd. xxxvii, pp. 569 — 582. 



* I do not mean to maintain that there are no other controlling factors in 

 the formation of a definite number of chromosomes; this cannot be the case 

 on account of the wide difference in the size of the nuclei of tissues of the 

 same animal. At the same time we have no knowledge of the reticulum as 

 related to different cellular dimensions. 



