602 GEORGE T. HARGITT 



sionally there may be more than one (fig. 7). The first indica- 

 tions of change in the nucleus of the growing oocyte are merely 

 the occurrence of rather illy-defined spots and blotches in the 

 nucleoplasm, as though the chromatin of the nucleolus was 

 being distributed over the rest of the nucleus. Figure 7 illus- 

 trates these early changes; it also shows that both nucleolus 

 and nucleus have increased in size along with the increase in 

 size of the cell itself. The nucleolus is somewhat lighter in 

 color, as though it were losing some of its chromatin. That 

 such is indeed the case is clearly shown in oocytes slightly older, 

 for the nucleolus becomes noticeably less dense, may show vacu- 

 oles, and a distinct nuclear reticulum begins to form during the 

 progress of these changes. In the further progress of these 

 changes the reticulum becomes distinct, develops spots of denser 

 appearance here and there (fig. 8) which become the nodes of 

 the network. The meshes of the net become wider, the chro- 

 matin grains coarser and at the same time the nucleolus loses 

 so much of its chromatin as to stain very faintly (fig. 9) , and the 

 entire nucleus now has a clear appearance, sharply differentiated 

 from the cytoplasm. 



It is about this time that signs are first evident of nuclear 

 material in the cytoplasm. In the early period this is not very 

 abundant but it is clear, as shown in figure 9; such emission of 

 nuclear substances continues and becomes more abundant as 

 the germinal vesicle approaches the time of the maturation 

 mitoses (fig. 12). The substances passed into the cytoplasm 

 first show as sharply defined grains or masses, but they soon 

 disappear, probably by solution. If this material plays any 

 specific part in the metabolism of the cell there is no marked 

 indication of it, except for the formation of vacuoles about the 

 dissolving material. A somewhat similar process was observed 

 in Campanularia, but here the result was to produce yolk. 



From the stage represented in figure 9 through that of figures 

 10 and 11 the nuclear reticulum becomes increasingly coarser, 

 the chromatin grains in the reticulum larger and denser, and the 

 nucleolus also larger, but much paler, till it scarcely stains. This 

 is the condition found in oocytes which are well along in their 



