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J. BRONTE GATENBY. 
but the nucleus, which induces differentiation along a special 
path. The natural outcome of this suggestion is the word 
“ sex-chromosome/’ Curiously enough, after examining many 
hundreds of sections I have never seen mitosis in the germinal 
epithelium. When I consider that I only found very few 
cases of divisions of the primary spermatogonia, I am re- 
luctant to make a statement which might be injudicious, but 
I cannot overlook the fact that there appears to be abundant 
evidence that the germinal cells divide amitotically, and no 
evidence for mitosis. It was my desire to examine the cyto- 
plasm of a germinal epithelial cell in mitosis, if it could be 
found, for at this stage many bodies become revealed. 
Any evidence that one might have for believing that all 
nuclei in the germinal epithelium of the ovotestis are endowed 
with the same potentialities — that is, for maleness, femaleness, 
or for becoming a nurse-cell — and that this power is directed 
in any one of the three channels by purely external or 
environmental conditions, is somewhat hypothetical. The 
favourite view, that abundant yolk cells (nutriment) affects 
the decision, seems negatived by the fact that male pro- 
germinative cells can, and do, appear in areas choked with 
yolk. A number of cells stuck upon the germinal epithelium 
seemed too big to be male cells, and their cytoplasm recalled 
that of the spermatocyte. I was much puzzled by these, and 
it has occurred to me that they might be intermediates 
between spermatocytes and oocytes. They contained distinct 
Nebenkern batonettes of the semi-lunar type, and mito- 
chondria of a fine nature, but not flocculent. The cells were 
much larger than a full-grown spermatocyte, and were located 
in a yolkless area of the epithelium. Could it be possible that 
the indifferent cell is affected by stimuli sent forth by the 
presence of yolk cells, by crowded spermatogonia, and by the 
general condition of that area in which it lies ? It seems 
certain that the matter is complicated, and cannot be reduced 
to the bald statement that oocytes appear because of abundant 
nutrition. 
I think that there are a variety of conditions which act on 
