THE HEREDITY OF SEX 63 



are male and female yet they give rise to males and 

 females in equal numbers. If one sex were a dominant 

 this would be in accordance with Mendelian theory. 

 In accordance with the view that the dominant is 

 something present which is absent in the recessive, 

 the Mendelian theory of sex assumes that femalencss 

 is dominant, and that maleness is the absence of 

 femaleness, the absence of something which makes 

 the individual female. If we represent the character 

 of femaleness by F and maleness or the recessive by 

 /, we have the ordinary sexual union represented by 



the gametes will then be 



F+! and /+/, 

 and the fertilisations 



Ff and //, 

 or males and females in equal numbers, as they are, 

 at least approximately, in fact. 



The close agreement of this theory with what 

 actually happens is certainly important and suggests 

 that it contains some truth. But it cannot be said 

 to be a satisfactory explanation. It ignores the 

 question of the nature of sex. According to the 

 theory the female character is entirely wanting in 

 the male. But what is sex but the difference 

 between ovum and spermatozoon, between mega- 

 gamete and microgamete ? The theory then asserts 

 that an individual developed from a cell formed by 

 the union of male and female gametes is entirely 

 incapable of producing female gametes again. Every 

 zygote after conjugation or fertilisation may be said 

 to be bisexual or hermaphrodite. How comes 

 it then that the female quality entirely disappears ? 

 Whether the gametocytes are distinguishable at 



