64 HEBEDITY 



mission of a " good milking strain " by a bull, which 

 cannot produce one drop of milk in a lifetime ? 

 Yet these and many other cases, not to mention the 

 cases where heredity "skips a generation," can be 

 explained on Mendelian principles. It is only 

 necessary to postulate an intertangling of the 

 characters in the germ-cells. Thus, the character 

 that will develop itself as colour-blindness may be 

 conceived as intertangled with the character that 

 makes for maleness of sex. They are segregated 

 together. In the female, the character making for 

 maleness of sex is temporarily suppressed, and with 

 it the intertangled character of colour-blindness. In 

 her male children the two reappear together. The 

 characters that appear in any individual are called 

 dominant, those that remain latent, to become 

 dominant in some future individual, are called 

 recessive. 



CHAPTER VIII 



KEVERSION 



At least three terms suggested themselves for the 

 title of this chapter — reversion, regression, and 

 atavism, each of which hints at a return, through 

 inheritance, to a type supposed to have occurred in 

 the ancestry of the individual under discussion ; 

 or the reappearance in him of latent ancestral 

 characters. 



The word atavism we may definitely abandon — 

 especially since we have more accurate terms to take 

 its place. As Chalmers Mitchell points out, a great 



