CHAPTER VIL 



„. • 'i^j 



The Ultimate Sex-Elements {General and Historical). 



In our analysis of sex-characters we have followed the general 

 course of biological history. We first passed from the form 

 and habit of a male or female organism to the structure and 

 functions of the sexual organs. In discussing hermaphroditism, 

 we had occasion to refer to a third step of biological analysis, 

 that which involves an investigation of the properties of the 



Mammalian ovum, showing nucleolus (ii), nucleus (/'), yolk (c), 

 external porous zone or zona pellucida (^/), and follicular 

 cells ((')• — From Hertwig, after Waldeyer. 



tissues. Now it is necessary to penetrate deeper, namely, to the 

 sex-cells. After these have been considered, not only in them- 

 selves, but finally and fundamentally in terms of the changes in 

 the p7-otoplasni that make them what they are, then we shall be 

 in a better position to re-ascend to some of the problems of 

 reproduction. ^ <^C*^ 



