CYTOLOGICAL PHENOMENA 47 



tant modifications. The cytoplasm is hollowed out by a certain 

 number of little vacuoles which are distinct from the vacuole con- 

 taining the metachromatic corpuscles. The cytoplasm, then, takes 

 an alveolar structure. The nucleus always takes its place at the 

 center; it seems to swell and take on an ameboid shape. One ob- 

 serves at this time in all of the cytoplasm, and especially about the 

 nucleus and along the walls, a large number of basophile granules 

 of irregular form, some angular and others filamentous. 



After 48 hours fermentation, the glycogenic vacuoles fuse into a 

 large vacuole which takes up almost all of the cell and absorbs the 

 nucleus cytoplasm and the vacuole with the metachromatic cor- 

 puscles. The cell is then transformed into a sort of glycogenic sac. 

 At this moment the glycogen seems to be retained by the cell, for 

 it is not consumed. The income is greater than the expenditure. 

 The basophile granules decrease in number and adhere to the wall 

 of the cell. At this time, there appear in the glycogenic vacuole a 

 considerable number of small granules which differ from the basophile 

 grains by their smaller dimensions and lesser pigmentation and whose 

 functions are unknown. At this stage the nucleus undergoes a 

 variation in pigmentation which is very close; it stains intensely 

 and takes on a homogeneous aspect. At the end of the fermentation, 

 the cells assume the structure which they had at the beginning. 



These are the modifications through which yeasts pass in the 

 course of fermentation: change in the structure of the cytoplasm, 

 appearance of grains of secretion, variation in pigmentation of the 

 nucleus are the well-known phenomena in secreting cells. For the 

 most part the yeasts fit this scheme with a few differences in detail. 



Cytological Phenomena during Vegetative Multiplication 



A. Budding: We have already described budding and it will 

 not be necessary to recapitulate at this time. Let it .suffice simply 

 to indicate the cytological phenomena which take place during this 

 change. By its appearance, the bud is made up of a very dense 

 cytoplasm containing a few basophile grams which have emigrated 

 from the mother cell. When it has acquired a certain dimension, 

 a little vacuole appears in the midst of the cytoplasm which is filled 

 with metachromatic corpuscles. This vacuole results often from the 

 entrance of a little of the vacuole from the mother cell. 



During this phenomenon, the nucleus occupies its usual position 

 even if it is at the opposite end from the bud, and undergoes no 

 modification until this has acquired its definitive dimension. At 



