140 



The Journal of Heredity 



of his grandson IV. 1. IV. I's mother 

 mentions his color-blindness in a num- 

 ber of her letters, and had her father 

 been color-blind it would seem not im- 

 probable that she would have men- 

 tioned the fact and hence that IV. 1 

 would have known whence the defect 

 came. The only hint I have found is 

 that a great-grandson of one of the 

 brothers of II. 1 thinks that he remem- 

 bers some stories suggesting color- 

 blindness told about one of his great- 

 grandfather's brothers, and attaches 

 them in his mind to II. 1, but this is too 

 vague to build on. 



Hoping to find the defect among the 

 descendants of II. I's brothers I have 

 entered into correspondence with a 

 number of people, without success. 

 II. 1 had six brothers and two sisters; 

 four brothers and one sister died 

 without issue; of the other two brothers 

 neither had daughters who left child- 

 ren, and the remaining sister married 

 her first cousin (her mother's sister's 

 son) by whom she had two sons and a 

 daughter; one son died at the age of 

 four and the other, who has left three 

 generations of descendants with normal 

 vision, was not color-blind. Without 

 going into further details, suffice it to 

 say that I have gone back another 

 generation, to the mother of II. 1 and 

 her brothers and sisters, as well as 

 ascertaining that her uncles and aunts 

 all died without issue. 



Having failed to find the defect in 

 the family of II. 1 I turned my atten- 

 tion to that of his wife, II. 2. She 

 was one of a pair of twins, only 

 daughters; and I hoped to find the 

 defect among the descendants of her 

 sister II. 3. II. 3 has a single child, a 

 daughter, III. 4, who married and had 

 seven daughters and three sons, of 

 whom two have normal vision, and the 

 third had marked talent as a painter, 

 so could hardly have been color-blind ; 

 in short, there has been no color-blind- 

 ness among three generations of de- 

 scendants of III. 4. 



Whether or not III. 4 was a carrier, 

 her mother II. 3, may have been. She 

 and her twin sister II. 2 were the only 

 daughters of I. 1, an officer in the Con- 



tinental Army, who when offered the 

 positon of adjutant-general at first de- 

 clined it partly on the ground that his 

 defective eyesight did not allow him to 

 "survey distinctly a wide or distant 

 area. He had experienced this defect 

 from early life." (Quoted from his 

 Biography.) The mere fact of color- 

 blindness was not recognized until about 

 the period of the Revolution so it is not 

 surprising that his defect, if it was 

 color-blindness, was spoken of as 

 "near-sightedness." This officer, I. 1, 

 wore spectacles, at that time a rarity, 

 and was dependent upon them, an argu- 

 ment against color-blindness being the 

 sole cause of his disability. About his 

 wife's (I. 2) family I know little. 



To summarize: Family 1 shows red- 

 green color-blindness occurring in the 

 males of three generations and follow- 

 ing the well-known rule of transmission. 



Family 2 is of greater interest than 

 Family 1 in that we find two cases of 

 female color-blindness. II. 4, 5 and 6 

 were sisters, II. 4 and 6 married and 

 II. 5 unmarried. Both II. 5 and 6 were 

 color-blind, but II. 4 was not and 

 according to the rule their father, 

 I. 3 must have been color-blind and 

 their mother 1.4 a carrier, but I have 

 not indicated 1.3 as color-blind on the 

 chart because his was not a known case. 

 I have been unable to get any informa- 

 tion about other descendants because, 

 so far as I can find out, the two 

 brothers and five sisters of II. 6 

 died without issue, nor do I know 

 whether any of them, besides II. 5 and 



6 were color-blind; but according to 

 the rule half the sisters and half the 

 brothers would be color-blind, and the 

 sisters who escaped would be car- 

 riers, supposing that I. 3 were color- 

 blind and 1.4 a carrier. 



1 1 . 6 had three sons and no daughters. 

 We know that two sons, III. 6 and 

 8 were color-blind, and no doubt HI. 



7 was also, for the offspring of a color- 

 blind woman show 100% defectiveness, 

 color-blindness in the males, carriers 

 in the females. III. 7 had an only 

 child, a son, in whom the defect would 

 not be expected to appear; he is child- 

 less. 



