442 J. MCA. KATER. 



After the bud has attained almost normal size and the distri- 

 bution of metachromatic granules is completed the nucleus gives 

 evidence of impending division. The chromatin accumulates on 

 the linin strands, making them very evident and extremely 

 basophilic. At the same time the disperse chromatin granules 

 enlarge and the whole nucleus becomes a perfect miniature of 

 an early prophase in Phaseolus vulgaris (Kater, 1926, Figs. 15 

 and 1 6). Meanwhile the nucleus remains stationary (Fig. 16). 

 The steps in the transformation of such a nucleus into chromo- 

 somes cannot be followed with any degree of certainty, but 

 many stages such as the one represented in Fig. 17 were seen. 

 A knot of chromosomes probably occupying the old location of 

 the nucleolus is here observed at the periphery of which individual 

 chromosomes are becoming disentangled from the rest. 



So far neither a dividing centrosome or spindle can be identified. 

 However, as the chromosomes become arranged on the metaphase 

 plate a spindle becomes visible (Fig. 18) and in some cases the 

 ends are lodged in a granule perfectly comparable to the centriole 

 in metazoa. No astral radiations are visible (Fig. 19). Such a 

 centrosome has previously been reported in yeast (Swellengrebel, 

 I 95; Guilliermond, 1917). In Fig. 18, the chromosomes are 

 quite clearly separating in the same way as they do in higher 

 plants and animals. Except for the difference in size the early 

 anaphase represented in Fig. 19 could easily be mistaken for a 

 metazoan mitotic figure. No careful attempt was made to 

 count the chromosomes of Saccharomyces as their size makes it 

 impractical. However, it seems certain that there are more than 

 the four reported by Swellengrebel (1905) and Fuhrmann (1906). 

 Probably at least twice that number. 



The migration of the chromosomes through the isthmus into 

 the bud is not at all clear. In some figures the orderly arrange- 

 ment of the anaphase plates seems to be maintained (Fig. 22) 

 while in others the chromosomes appear to enter the bud one 

 at a time. In such cells the spindle disappears and only the 

 irregularly arranged chromosomes can be seen (Fig. 21). In 

 overstained slides specimens similar to the one illustrated in 

 Fig. 22 very greatly resemble amitosis, and are probably re- 

 sponsible for the confusion on this point. 



