CYTOLOGy 



6-8 



When a yeast cell buds the chromosomes in the nuclear vacuole 

 and the centrosome divide together. The first step is the 

 formation of a long slender tube leading from the vacuole to the 

 periphery of the cell. This phenonenon is best observed in cells 

 containing enough glycogen so that the iodine stain delimits the 

 vacuole and its tube as a clear space in the surrounding reddish 

 brown cytoplasm. Observation is facilitated by the use of a Wrat- 

 ten 45 filter which converts the reddish brown color of the cyto- 



Fig. 6-3 A Copy of Renaud's Drawing of the Division of the 

 Centrosome in the Yeast Cell Showing the Existence, especially in 

 Figs. 3 and 6, of tiie Centriole. This Division is Concurrent with 

 the Division of the Chromosomes but, for the Peasons Stated in the 

 Text, I Have Concluded that what Benaud Has Shown is the Distri- 

 bution of Heterochromat in Between Mother and Daughter Cell rather 

 than a Nuclear Division. 



plasm to blue -black and reduces the chromatic aberration of the 

 lens system. The canal from the vacuole may begin any place on 

 the surface of the vacuole, but usually appears at a point on the 

 vacuole near the centrosome. The bud is produced where the pro- 

 cess from the vacuole meets the cell wall; when the canal emerges 

 at the side of the vacuole, distal to the centrosome, the long, slen- 

 der process extends all the way from the most distant part of the 

 cell through the cytoplasm and finally produces the bud near the 



