i 4 HEREDITY AND SOCIETY 



bred " blues," while two quarters will be produced by 

 the union of two cells, one " brown " and one " blue," 

 and be cross-bred with regard to eye-colour like their 

 parents. And like them, since brown is dominant, 

 their eyes will contain brown pigment, like those of 

 their pure-bred " brown " brothers and sisters. 



If we denote an individual with the dominant 

 character as D and one with the recessive character as 

 R we get the scheme : 



A " dominant " marries a " recessive " D x R 



and has offspring 



all cross-bred but outwardly resembling the dominant D R x D R 

 One of these cross-breeds marries a similar cross-breed 



and has offspring 

 equally divided between (i) pure-bred 



" dominants," (2) mixed-bred " domi- DD DR RD RR 

 nants recessives," (3) mixed -bred 



" recessive-dominants," (4) pure-bred (i) (2) (3) (4) 

 recessives. (2) and (3) are identical. 



Now, as long as the pure dominants at one end and 

 the pure recessives at the other find mates similar to 

 themselves with respect to the character considered, 

 they breed true, notwithstanding their mixed parent- 

 age. The individuals called DR or RD, however, 

 contain the recessive character concealed in their germ 

 cells, whence it may reappear in their offspring. 



There is thus an essential difference in the inherit- 

 ance of a character, according as it is dominant or reces- 

 sive. A dominant character, whether good or evil, will 

 show if it be present. If an abnormality be dominant, 

 normal people will never reproduce it, even though 

 born of an abnormal family, for, as they do not show 

 the character, they are free from it. Certain physical 

 deformities have been shown to be dominant characters. 



