DETERMINATION OF SEX 477 



been noticed that males and females were produced in regular 

 alternation following the order of laying : what determines this ? 

 The unfertilised eggs of a queen-bee always develop into drones, 

 the fertilised eggs develop into workers (usually sterile females) 

 and queens (fertile females) : what does this mean ? Through- 

 out the summer the green-flies or aphides produce partheno- 

 genetic eggs which all become females, but at the end of the 

 season males are produced (also, of course, from partheno- 

 genetic eggs), and then the normal bisexual reproduction occurs : 

 what does this mean ? 



Can we discover when the sex of the offspring is determined, 

 and how it is determined ? It must be confessed that in many 

 cases we have no secure data as to the earliest moment at which 

 it is possible to say of a developing embryo that it is going to be 

 a male or a female. More precise information on this point would 

 probably eliminate at once a number of the factors alleged to 

 have a determining influence. 



Various Kinds of Answers. — To the question , What determines 

 whether an organism shall develop into a male or into a female, 

 many and varied answers have been given. Some of these 

 answers are bound up with theories as to the nature of sex, 

 which are legion. In fact, the number of speculations as to 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 long ago added Blumen- 

 bach's theory of " Bildungstrieb " or formative impulse to the list. 



" 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 was natural to refer to ' inherent properties of male- 



