234 BIOLOGY: GENERAL AND MEDICAL 



H. That the sex of the offspring is a Mendelian 

 character but still an accident of fertilization. 

 To fully comprehend this theory it is necessary 

 that the reader shall read the theory of Mendel 

 as outlined in the chapter upon "Conformity to 

 Type." 



Castle, Correns, Bateson, Doncaster, and others 

 have written in support of this view, and their 

 theories are ingenious and suggestive. 



Castle believes that both male and female 

 organisms are Mendelian hybrids (male-female 

 hybrids), maleness and femaleness being Mendel- 

 ian characters, with respective male and female 

 dominance. During the maturation of the 

 germinal cells the usual disruption of character 

 takes place, so that male and female ova and 

 male and female spermatozoa are produced. He 

 made the assumption that there were selections 

 and repulsions in fertilization so that spermatozoa 

 and ova bearing the same sex never conjoined. 



Instead of regarding both male and female as 

 such, Correns looked upon the male as the sex 

 hybrid and the female as a pure or homozygous 

 organism. The male character he regarded as 

 dominant. All ova were unisexual, and hence 

 always female, whether fertilized or not. The 

 spermatozoa, on the other hand, carried either 

 male or female characters. 



If the female ovum was fertilized by a sperma- 

 tozoon carrying only female characters, it, of 

 course, remained female; but if it were fertilized 

 by a spermatozoon carrying male characters, the 

 male character always being dominant, it, of 

 necessity, became a male. 



The theory is shown to be false by remember- 

 ing that the unfertilized eggs of bees develop into 

 males. 



The reverse aspect of the case might overcome 



