44O J. MCA. KATER. 



vacuole, small or entirely absent in very young cultures, but 

 attaining a relatively great size after several days. In some 

 cases it almost entirely fills the cell (Fig. 2). This vacuole is 

 generally round, with a very regular outline. The cytoplasm 

 is distinctly alveolar and contains numerous metachromatic 

 granules. Occasionally cells are found with none of these 

 granules, especially in very young cultures (Fig. 5) and some- 

 times there are only a few present, in which case they are located 

 near the nucleus (Fig. 4). In old cells with a large vacuole there 

 is frequently such a great mass of metachromatic material 

 surrounding the nucleus that the latter body is obscured (Figs. 2 

 and 3), and the granular nature of the metachromatin is not 

 discernible. Lines of fine granules can be seen leading from this 

 mass to large granules in other parts of the cell, thus converting 

 the metachromatic material into a connected unified system. 

 These granular strands are especially evident where they go 

 around the vacuole, and constitute the nuclear reticulum of 

 Wager. Guilliermond figures basophilic granules within the 

 vacuole. It is these granules above and below the vacuole which 

 he sees and there are really no granules within the large vacuole. 

 When material is fixed in Bouin's solution and stained in iron- 

 alum-hsematoxylin without washing out the picric acid the 

 metachromatic granules do not stain. When this procedure is 

 properly carried out, the well stained nucleus embedded in the 

 alveolar cytoplasm is quite evident and easily studied. (Figs. 

 6 to 8.) 



The nucleus of Saccharomyces is quite similar to that of higher 

 plants, particularly Phaseolus (Kater, 1926). The nuclear mem- 

 brane is equally as evident as in higher plants. Centrally 

 located is a large basophilic nulceolus or karyosome from which 

 radiate slender slightly basophilic linin strands. These strands 

 run from the nucleolus to the nuclear membrane in identically 

 the same manner as in Phaseolus. There are generally about 

 six such strands visible. Just inside the nuclear membrane are 

 located a number of chromatin granules. The larger ones are 

 found at the points where the linin strands come in contact with 

 the nuclear membrane. Except for the minute size of the 

 nucleus (i to 3 micra in diameter) it is hardly distinguishable 



