No. 2.] COMPARATIVE CYTOLOGICAL STUDIES. 463 



appear not to stain at all, and of a few delicate fibers, which 

 stain a lilac color (Figs. 267-269). As the germinal vesicle 

 increases in size these chromatin fibers gradually become 

 thicker and more numerous, commence to stain more deeply 

 with haematoxylin, and gradually connect together to build 

 a chromatin reticulum ; the minute, unstained microsomes 

 still occur between these fibers. Finally, in the largest nuclei 

 at my command, and ones which had been fixed with the fluid of 

 Flemming and stained by the triple stain of this cytologist, we 

 find, in addition to the abundant unstained microsomes, short, 

 rod-like masses of chromatin, which stain deeply with gentian 

 violet, and each appears to be formed of a row of granules or 

 thickened discs (Fig. 280). Whether the minute microsomes 

 are true chromatin or are lanthanin (oedematin) granules is 

 open to question ; the latter assumption might be the correct 

 one. We notice two remarkable phenomena in the chromatin 

 changes just depicted : (i) the grouping of the chromatin in 

 the center of the nucleus, around the nucleolus, at the comple- 

 tion of the mitotic stages ; and (2) immediately subsequent to 

 the preceding, the lilac stain of the chromatin after haematoxy- 

 lin. Now, concomitant with the former of these two phenomena, 

 the yolk makes its first appearance in the cytoplasm, and as we 

 have shown above, usually in the close vicinity of the nucleus. 

 It would be quite erroneous to conclude that the yolk globules 

 are in any way produced by the chromatin, as e.g., by a migra- 

 tion of chromatin particles out of the nucleus ; for in this stage 

 all the chromatin is removed from the periphery of the nucleus. 

 On the other hand, however, I would suggest the hypothesis 

 that the reason for the chromatin being removed from the 

 periphery of the nucleus is because at this period the peripheral 

 portion of the latter is chiefly concerned in the assimilation of 

 yolk substance from the cytoplasm. In support of this assump- 

 tion the fact may be recalled that in the following stage the 

 chromatin fibers are stained a lilac color, as if they were stained 

 with eosin, as well as haematoxylin, and not as before, simply 

 with the former stain ; this would show that during this period 

 there is an addition of a cytoplasmic substance to the chromatin 

 fibers, perhaps allied to the substance of the yolk globules, and 



