58 HEREDITY AND EUGENICS 



for all future studies on this subject. It gives not 

 only an elaborately illustrated description of the ex- 

 ternal features and the histolog}^ of the skin and e^'^e 

 pigmentation in albinotic individuals, but also deals 

 with the histor}^ of the subject. Pure albinism is a 

 recessive character* : but the condition exists in vary- 

 ing degrees, and its inheritance, like that of so many 

 human qualities, frequently shows complications. 

 Complete albinism occurs in both white and coloured 

 races of man. Pearson divides albinotics into six 

 classes. Several cases of white spotting in negroes, 

 similar to the classical types seen in paintings of the 

 eighteenth century, have been described in modern 

 times. The evidence certainl}^, as Pearson (191 3) 

 contends, favours the hypothesis that spotting arises 

 de novo where a white-black cross or mixed race is 

 crossed back with a pure white or black. In other 

 words, spotting ma}^ be considered to arise in certain 

 cases as a somatic segregation, repulsion, or dilution 

 effect, and not to be clue to an inherited invisible 

 spotting factor. Striping in various flowers is 

 generall}^ believed to have originated in the same wa}^ 

 A similar case occurs in certain (Enothera hybrids 

 (Gates, 191 5). When (E. ruhricalyx having dark red 

 buds is crossed with CE. grandiflora having green buds, 

 the F;^ is paler red. If this F^ generation is crossed 

 back with Qi. grandiflora, the colour is further diluted, 

 becoming very pale; and in some families the pattern 

 breaks up into spots, a condition which is inherited. 



Once this spotted condition has arisen, it appears 

 then to be fairly stable. Cases of human albinotic 

 spotting are on record which have been transmitted for 

 two to five generations (Stannus, 191 3). The con- 

 dition of spotting has, in some way, become stabilised 

 in the germ plasm, and should, therefore, probably 



* A recent case in which two complete albino " white " 

 parents had an albino son is illustrated by Davenport (19 16). 



