I3O WILLIAM M. GOLDSMITH. 



compact chromatin nucleolus of the early growth period takes 

 up particles of achromatic material, and as the chromatic 

 material assumes a less compact form, more achromatin (linin) 

 is added, seemingly to act as a support to the chromatin aggre- 

 gations. This growth continues until the sex-chromosomes 

 are well differentiated and the true nucleolar body reaches its 

 maximum size. This behavior, as well as the method of breaking 

 down of the achromatic material, indicates that the plasmosome has 

 the same function that has been ascribed to the linin, namely, to 

 support the chromatin material. 



B. GRANULES AND NUCLEAR MEMBRANE FORMATION. 



In addition to the origin and early development of the nucleo- 

 lus, the first thirteen drawings are intended to show the apparent 

 relation that exists between certain granules and the formation 

 of the nuclear membrane. The facts involved in this additional 

 observation are not directly related to the problem in hand, but 

 since they are presented in the same series of illustrations, a 

 discussion of them does not seem out of place. 



As was suggested in the preceding discussion, the chromatin 

 fibers of the synaptic stage (Figs. I and 2) are thick and stain 

 intensely. These threads, though in a contracted condition, 

 possess a number of granular, knob-like enlargements, which 

 stain more intensely than do the remaining parts of the thread. 

 After the threads remain in this condition for some time, they 

 elongate and decrease in thickness (Figs. 3, 4 and 6). 



By virtue of this elongation, the chromatin mass becomes less 

 compact and thus increases in size. At the stage represented in 

 Fig. 4, the bead-like enlargements on the threads, though smaller 

 and more compact, have become more defined, still retaining the 

 stain. Thus they become somewhat individualized, while the 

 part of the thread intervening between the beads takes the 

 chromatin stain less intensely. This gives the thread the ap- 

 pearance of a number of granules (perhaps chromomeres) held 

 in place by some substance quite dense in consistency. In fact, 

 many chromatin fibers were found in this and subsequent stages, 

 in which the contrast was so great between the deeply staining 

 granular enlargements and the intervening spaces, that the 



