156 THE MENDEL JOURNAL 



that sex is due to a germinal factor, and there seems 

 to be but little doubt that it is inherited in accord- 

 ance with Mendel's law. 



We have however to recognise the possibility that 

 the females and the males of different organisms in the 

 animal and vegetable kingdoms may be differently 

 constituted. The evidence shows that in Man, 

 canaries, fowls, possibly in rabbits, and in some 

 insects, the female is apparently a Mendelian dominant 

 hybrid, carrying the character of maleness as a 

 recessive, while the male is a Mendelian recessive 

 homozygote, and is therefore pure for maleness. 

 On the other hand, in many insects, and possibly in 

 lobsters and crabs, it is the male which is apparently 

 the Mendelian dominant hybrid, carrying femaleness 

 as a recessive. 



The existence of these two types of sex leads 

 us to suppose that in sex-heredity we have one 

 more case in support of the " presence and absence " 

 theory of Mendelian characters. In this newer 

 scheme by which experimental results are sym- 

 bolically represented, we still retain the original 

 terms of dominant and recessive used by Mendel, 

 but they are applied in a different way. When a 

 pure grey rabbit is crossed with a black one, all the 

 offspring are grey. Mendel would have spoken 

 of the grey colour as being dominant to black which 

 would be regarded as recessive. In other words, 

 he would have looked upon the pair of alternative 

 characters as being grey versus black. But we do 

 not now so regard them. We believe the facts are 



