1886.] 



Family Likeness in Eye-colour. 



403 



appears to be much less various in its origin. If then it can be 

 shown, as I shall be able to do, that notwithstanding this two-fold 

 difference between the qualities of stature and eye-colour, the shares 

 of hereditary contribution from the various ancestors are in each case 

 alike, we may with some confidence expect that the law by which 

 those hereditary contributions are governed will be widely, and 

 perhaps even universally, applicable. 



Data. — My data for hereditary eye-colour are drawn from the same 

 collection of "Records of Family Faculties" ("R.F.F.") as those 

 upon which the above-mentioned inquiries into hereditary stature were 

 principally based. I then analysed the general value of these data in 

 respect to stature, and showed that they were fairly trustworthy. I 

 think they are somewhat more accurate in respect to eye-colour, for 

 which family portraits have often furnished direct information, while 

 indirect information has been in other cases obtained from locks of 

 hair that were preserved in the family as mementos. I have also 

 been able to collate some of my results with those lately published by 

 M. Alphonse de Candolle,* who instituted an inquiry that has in many 

 particulars, though not in the main object of the present memoir, 

 covered the same ground as my own, and which was of course founded 

 on an entirely different collection of data. My conclusions in respect 

 to those particulars, of which only a few find place here, are generally 

 corroborated by his. 



Persistence of Eye-colour in the Population. — The first subject of our 

 inquiry must be into the existence of any slow change in the statistics 

 of eye- colour in the population that might have to be taken into 

 account before drawing hereditary conclusions. For this purpose I 

 sorted the data, not according to the year of birth, but according to 

 generations, as that method of procedure best accorded with the 

 particular form in which all my R.F.F. data are compiled. Those 

 persons who ranked in the Family Records as the " children " of the 

 pedigree, were counted as generation I ; their parents, uncles and 

 aunts, as generation II ; their grandparents, great uncles, and great 

 aunts, as generation III ; their great grandparents, and so forth, as 

 generation IV. No account was taken of the year of birth of the 

 "children," except to learn their age; consequently there is much 

 overlapping of dates in successive generations. We may, however, 

 safely say, that the persons in generation I are quite different from 

 those in generation III, and the persons in II from those in IV. I 

 had intended to exclude all children under the age of eight years, but 

 in this particular branch of the inquiry, I fear that some cases of 

 young children have been accidentally included. I would willingly 



* Heredite de la couleur des yeux dans l'espece himiaine," par M. Alphonse de 

 Candolle. " Arch. Sc. Phys. et Nat. Geneve," Aug. 1884, 3rd period, vol. xii, 

 p. 97. 



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