PHYSICAL CHARACTERS IN MAN 6i 



family in which " for maii}^ generations some members 

 had a single lock differently coloured from the rest 

 of the hair," and an Irish family in which a small 

 white lock occurred in son, mother, and grandmother. 



Cockayne (1914) states that piebalds are very un- 

 commion both in black and white races. He describes 

 a piebald English family of six generations with nine- 

 teen affected mem_bers, belonging to a farming stock 

 near Bury St. Edmunds, Suffolk. Some members 

 of the famil}^ are fair and some dark, but both inherit 

 the peculiarity, which consists of a blaze in the fore- 

 head. Three members of this family have hetero- 

 chromidia iridis, and some have additional white 

 patches of skin on the body. In the last four genera- 

 tions of affected families the total num.bers are seven- 

 teen having the flare to twelve* normal. This is near 

 enough to the equality which would be expected 

 if the flare were a heteroz^^gous dominant condition, 

 and is in general accord with Pearson's case, but the 

 excess is on the other side and is, perhaps, not signi- 

 ficant in either case. We ma}-, then, conclude that 

 the flare behaves as a simple dominant, at least in 

 these three independent families, and in the two de- 

 scribed in the following paragraphs. 



A family with a white forelock occurring in four 

 generations has been described by Holmes and Scho- 

 field (191 7). This lock occurs in the centre of the 

 fore part of the scalp, the region affected being quite 

 small (size of a florin). Heterozygous females do not 

 show the mark. It would appear that the character 

 behaves as a dominant in males and as a recessive in 

 females (see Fig. 11), like the inheritance of horns 

 in crosses of a breed of sheep in which onh' the males 

 have horns with one in which both sexes are hornless. 

 In a white forelock family, described by Pearson, 

 Nettleship, and Usher in the monograph on albinism 



* One of these is doubtful. 



