424 KING. [Vor. XIX. 
ing that would indicate that follicle cells or their products enter 
the egg and produce these structures. As these bodies are not 
extruded nucleoli it is evident that they must be considered 
as secretion products of the cytoplasm itself. Since, as Bernard 
(8), Chittenden (20) and others have maintained, the nucleus 
is undoubtedly to be considered as an organ of constructive 
metabolism which “has controlling power over the metabolic 
processes in the cell, modifying and regulating the nutritive 
changes” (Chittenden), it is not to be supposed that the forma- 
tion of the vitelline bodies in the cytoplasm takes place inde- 
pendently of nuclear activity. Although no substance can be 
seen to leave the nucleus at the time that the number of vitel- 
line bodies is rapidly increasing, it is not improbable that a 
fluid, possibly an enzyme, passes from the nucleus into the 
cytoplasm and there causes the formation of these bodies. The 
same enzyme, acting in the nucleus itself, may be the cause of 
the formation of the plasmosomes; for these bodies are being 
produced in considerable numbers in the nucleus at the time 
that the formation of vitelline bodies is taking place most 
actively in the cytoplasm. On this assumption it is probable 
that the vitelline bodies “bear the same relation to the cyto- 
plasm that the nucleoli do to the germinal vesicle,” as Jordan 
has suggested. Whether the substance out of which the vitel- 
line bodies are made is supplied entirely by the cytoplasm, or 
whether the follicle cells contribute material to the egg for 
their formation, I have not been able to determine. I have 
never found follicle cells inside of the egg, although they very 
frequently enter the cells of Bidder’s organ. The function of 
the follicle cells seems to be to form the egg membranes during 
the early stages of development and, after the egg has left 
the ovary, to aid in the absorption of the follicle sacs (King, 
50). 
Several investigators of amphibian odgenesis, besides Will 
and Leydig, have found rounded bodies in the cytoplasm of 
the ege which are doubtless of the same nature as the vitel- 
line bodies in the egg of Bufo. Hertwig (42) states that the 
small bodies which he finds in the cytoplasm of the egg of 
