336 



The Journal of Heredity 



ALBINISM IN MAN. 



Seventeen spotted and 16 normal ne- 

 groes are the aggregate descen- 

 dants of Mrs. S.* A.*, a spotted 

 mutation who foimded a new race. 

 This photograph represents her 

 • grandson, Jim D*., whose father 

 was a wholly normal Negro. The 

 white factor nmning in this family 

 acts, in heredity, like the white 

 factor for belting in swine, and is 

 dominant. The width of the black 

 stripe varies among the individuals, 

 but all ari- white in front. Photo- 

 graph first used by Simpson and 

 Castle in the Amcricin Naturalist. 

 (Fig. 5.) 



Idc found on the other side. In several 

 hundred observations of black switch on 

 tails of Jersey cattle, no instance was 

 found where the tongue was not also 

 black; there are nearly as many Jerseys 

 found with white switch, but these all 

 have white tongue. An interesting 

 subject was a heifer with a gray switch, 

 (white hairs and black hairs being 

 mingled in equal ntimbers), and the 

 tongue was neither white nor black but 

 a blended blue. This works also with 

 the black-end Hampshire swine, where 

 a few have undesired white on end of 

 tail: nearly universally will it be found 

 that the nose, sometimes only the 

 center of the rooter, will be found of 

 white skin. The pairing of white spots 

 or black spots with near equality in size 

 is found to some extent on nearly all 

 domestic animals bearing spots on the 

 coat: and only rarely, when the spot is 

 quite small, will a mate not be found at 

 the opposite side. This seems to prove 

 causation. 



The conception that size of color-area 

 is dependent on the age at which 

 differentiation occurs simplifies the 

 ]jhcnomcnon of pattern, whether the 

 entire coat be a unit, or each individual 

 feather of a fowl be the unit as with 

 Barred Ph'mouth Rocks. With feather- 

 barring, Oscar Riddle found that the 

 white bars and the black bars were each 

 all laid down on all the feathers belong- 

 ing to the one bird as they were growing 

 from the follicles at fixed minimum and 

 maximum periods of the bird's body- 

 tenii)erature and blood-])ressure : simu- 

 lating the congestive coldness and stib- 

 sequent fever-reaction of third-day 

 malarial ague. 



HETEROZYGOUS P.\TTERN. 



When the pattern of individuals 

 depends on the hybridity (heterozy- 

 gosity) of ])aired chromosomes, it can 

 not be heritably fixed: and concrete 

 illustration is found with the roan- 

 shorthorn. Blue Andalusian fowl, and 

 at least two lines of sjDotted horses in 

 America. With these horses (though not 

 with the s])otted Shetland i)ony, which 

 is jjattemed by dilTereiit factors from 

 these), this spotting is the result of two 



