CYTOPLASMIC INCLUSIONS OF THE GERM-CELLS. 595 
(1) The mitochondria in the egg are often diagnostic before 
the Nebenkern rods alter. 
(2) The Nebenkern varies more in individual spermatogonia 
than between Demolhs spermatocyte and oocyte examples. 
(3) The whole train of events leading to the appearance of 
undoubted Nebenkern and of mitochondria is so liable to 
variation that it would be impracticable to look to such struc- 
tures as sex determiners. 
(4) The Nebenkern may be late in appearance, even after 
the cell is undoubtedly male. 
(5) Bouquet stages are not rightly to be considered as 
definite milestones, parallel in the sex development of either 
sperm or egg cells, for the bouquet stage may appear in the 
male at a time when it is known that the sex 1 has been deter- 
mined cell generations ago. I refer in this to the secondary 
spermatogonia which go on dividing and which sporadically 
enter growth stage. 
(6) The amount of Nebenkern material in the bouquet 
stages of the male alone varies from “ none demonstrable ” 
to a large amount. 
It will be seen, therefore, that lack of proper examination 
and of sufficient knowledge of the Nebenkern has led Demoll 
to suggest a theory unsupported by evidence of any descrip- 
tion. 
What would certainly be more logical would be to say that 
the alteration in the Nebenkern was the result of and not the 
reason for the appearance of a definite sex. As far as 
diagnosis goes the mitochondria are better objects for building 
up theories, but for many reasons the last paragraph about 
the Nebenkern also applies to the mitochondria. As for the 
suggestion that the sex-chromosome guides the Nebenkern in 
its “choice of sex 33 I have no evidence either for or against. 
Demoll's idea that up to the appearance of the Nebenkern 
the cell may be considered indifferent is disproven by every 
species of evidence. 
The only other likely suggestion as to the function of the 
Nebenkern is one which has been freely supported by certain 
