REPRODUCTION 1 57 



phenomena of sex. Their most fundamental idea, that of polarity, was often 

 inseparable from the idea of the contrast between the sexes. Even Schopen- 

 hauer devoted a special chapter to observations on the metaphysics of sex- 

 ual love. Led by the poets, arid by Goethe — the man of the world, — these 

 philosophers were able to appreciate the fateful power of the differences 

 between the sexes. Since Darwin's time, however, biologists have not con- 

 sidered the subject of any paramount importance. It is true that Darwin 

 based his theory of sexual selection on the differences between the male 

 and female of the same species. This theory, however, lacks most of the 

 beauty which characterizes living nature. He only saw in these differ- 

 ences secondary adaptations to the external conditions of life. Since then 

 this subject has lost much of its significance. Blind to the processes of actual 

 life, and carried away by their observations of microscopic structure, 

 biologists have tended to look upon the problem of sex, under which, 

 according to some philosophers, all the problems of the world lie hidden, 

 as merely a problem of chemistry and of cell structure. From the fact 

 that the spermatozoon and the ovum are both cells, it was inferred that 

 there is no essential difference between them. By considering the sexual 

 cells from which they originate, instead of the adult individuals, in all 

 the fullness of their hfe and struggle, they concluded that there is no es- 

 sential difference between man and woman; the differences which actually 

 exist between them are, according to these theorists, merely special adapta- 

 tions for the purpose of facilitating the union of the spermatozoon with 

 the ovum. 



All the contrivances connected with sex are variations upon one and the same 

 theme; firstly, they enable the sex cells to come together, and secondly, they in- 

 sure that the egg shall be nourished and kept in safety. We call the one set of con- 

 trivances "male," and the other "female." All these relationships are of a second- 

 ary nature, and have nothing to do with the real essence of fertilization; this is 

 the union of two cells, and is therefore purely a cell phenomenon. In these views 

 we agree with Weismann, Rich, Hertwig, Strasburger, and A4allpas, who have 

 expressed similar opinions (O. Hertwig, Allgemeine Biologic, 1902). 



On this view one question alone remains: what is the meaning of the 

 process of fertilization itself? In the simplest forms of life, as, for instance, 

 the bacteria, there were originally no sexual differences. These developed 

 gradually, and began in the fusion of two otherwise similar cells. To facil- 

 itate conjugation one cell gradually assumed a passive role, and the task 

 of accumulating food; the other became more active, hence smaller, and 

 sought out the former. Thus began the differentiation between ovum 

 and spermatozoon. When, later, multicellular organisms developed, the 

 process of reproduction was taken over by a few cells, and for the purpose 

 of facilitating conjugation the two sexes became differentiated in various 

 directions. 



This is the way in which Strasburger, Maupas, and Weismann ac- 



