THE DETERMINATION OF SEX 475 



hornless females, which may be either pure or impure, homozygous 

 or heterozygous. 



2. The Determination of Sex 



The Determination of Sex is one of the great unsolved problems 

 of Biology. It seems to be peculiarly elusive, but perhaps that 

 simply means that it is near the central secret of life itself. Over 

 and over again the solution has slipped through the fingers of 

 Science just when they seemed to be closing upon it. Perhaps 

 this means that we have not yet learned how to ask the question 

 rightly. Perhaps the problem is very complex, with different 

 answers in different cases ; perhaps the solution is, after all, very 

 simple. 



A Multitude of Theories. From ancient times a keen interest 

 has been taken in the question of the determination of the sex of 

 the offspring, and of the answers that have been proposed it 

 may well be said that " their name is legion." For many of the 

 answers are bound up with " theories of sex," which are also 

 legion. It is quaint to notice that the number of speculations 

 connected with the nature of sex has been well-nigh doubled 

 since Drelincourt, in the eighteenth century, brought together 

 two hundred and sixty- two " groundless hypotheses," and since 

 Blumenbach caustically remarked that nothing was more "certain 

 than that Drelincourt's own theory formed the two hundred and 

 sixty-third. Subsequent investigators have at least tried to add 

 Blumenbach's theory of a fundamental " Bildungstrieb " or 

 formative impulse to the scrap-heap. 



The numerous answers offered to the question : What settles 

 the sex of the offspring ? might be arranged on an inclined 

 plane so as to illustrate the progress of natural knowledge. " As 

 in so many other cases, the problem of the determination of sex 

 has been looked at in three different ways. For the theologian, 

 it was enough to say that ' God made male and female.' In 

 the period of academic metaphysics, still so far from ended, it 



