Volume 5

Treasury of human inheritance / edited by Karl Pearson, R.A. Fisher, L.S. Penrose.

Date:
1909-
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Treasury of human inheritance / edited by Karl Pearson, R.A. Fisher, L.S. Penrose. Source: Wellcome Collection.

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    is likely that III. 18 had no severe defect, for his wife, III. 17, who had a colour-blind son, IV. 33, appears to have made no note of the defect in her husband; she marked her father, II. 18, as having had normal colour vision. The origin of the defect in IV. 21 is not quite clear; his mother is likely to have been a carrier, for her only married sister, III. 13, had a colour-blind son, IV. 27, one son with normal colour vision, and her only married daughter, IV. 29, had three sons, of whom two, V. 38 and 39, were colour-blind. III. 12 lived near his nephew, IV. 21, and was believed to have normal colour vision. II. 14, maternal grand father of IV. 21, was a lawyer, he died in 1848; his daughter, III. 9, referred to the colour-blindness of her son in a number of her letters, but never mentioned the defect as being present in her father; a great- grandson of one of the brothers of II. 14 thinks that he remembers some stories suggesting colour-blind ness told about one of his great-grandfather’s brothers, but no definite information was obtained; a sister of II. 14 married the son of her mother’s sister, and four generations of her descendants have been traced with normal colour vision. II. 15 had a twin sister who was married and appears to have had normal descendants for four generations. The father of II. 15 and 16 was an officer in the Continental Army who, when offered the position of adjutant-general, at first declined it, partially 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; he wore spectacles and was dependent upon them. III. 7, father of IV. 21, had two sisters, III. 5 and 6, who married two colour-blind brothers, III. 3 and 4. III. 4 and 6 had two sons and two daughters with normal colour vision; one of the daughters married and appears to have normal children and grandchildren. III. 3 and 5 had one son and five daughters; two of the three married daughters transmitted the defect; thus IV. 6 had two sons, of whom one was colour-blind; IV. 8 had three sons, all of whom were colour-blind, and three daughters, two of whom, V. 11 and 13, were married; V. 11 had four normal sons; V. 13 had two normal sons. III. 3 and 4 had another brother, III. 2, about whose colour vision no information could be obtained. The mother of the sibship III. 2—4 was colour-blind; she had one sister, II. 3, unmarried, who also was colour blind, one sister was known to have normal colour vision and nothing was known of the colour vision of two brothers, II. 1 and 2, and three sisters, II. 7—9; all the brothers and sisters of II. 4 appear to have died without issue; no information could be obtained concerning the colour vision of the parents of these colour-blind females, thus we are not in a position to say whether the father was colour-blind or not, nor whether the mother was a carrier, nor can we affirm that all the sons of II. 4 were colour-blind. Consan guinity. (See Bibl. No. 405.) Fig. 581. Bell's Case. Colour-blindness in two distinguished men of science. IV. 5 was first discovered to be colour-blind when, as a little boy, he was sent to look for a stick of scarlet sealing-wax which had been dropped on the lawn and which he failed to find; his daughter, V. 7, writes that he could only see bright blue and yellow, violet or purple he called blue if there was sufficient blue in them, but if red pre ponderated he became confused and called them brown; stories are told of how he was let down by his tailor who made him a pair of rather bright green trousers with red spots which he thought were two shades of brown, and on another occasion a pair of bright apple green gloves were sold to him instead of pale lavender ones. He could draw very well; his sepia sketches were charming, and he seemed to think they matched what he saw. Two of his daughters were artists and considered that they could not have a more delightful companion than their father in a picture gallery, and that he had an unerring instinct for the “good” in art. He was greatly interested in the subject of colour-blindness and did not know of any other case having occurred in the generations preceding him; his parents were second cousins and there had been many intermarriages between the two families at an earlier date; his mother’s family belonged to an old firm of manufacturers of dye-stuffs (dry salters) and if any member of the firm had been colour-blind it would almost certainly have been detected; some of his father’s family had also been in partnership in the firm; his mother’s brothers, III. 1—4, were good painters in water-colour and one of them was a caricaturist of some repute; his father, III. 7, was a man of scientific tastes and great ability, he was a manufacturing chemist. Thus we have no positive information that there was no colour-blindness in generations I, II and III of this pedigree, but it is improbable that able men carrying on work as manu facturing chemists, or the manufacture of dye-stuffs, could be affected without being aware of the fact. IV. 5 had one son and four daughters, who believe themselves to have a very good colour-sense; the subject has been much discussed amongst them since their earliest childhood. The two brothers and the sister of IV. 5 were believed to have normal colour vision, but IV. 4 was a sugar manufacturer in Demarara and had been much abroad; IV. 2 had one son, however, who appears to have had some less severe degree of colour-blindness. The widow of V. 1 believed that he was not colour-blind, she writes that he took a great interest in the subject and often asked his students and friends for their judgment of colour; she says that his sight was abnormally clear, that when he sketched his greens were very green and that he hardly ever saw blue in distances unless very great; we are told, however, by a colleague who worked in close con nection with him for some years, that he could never see yellow in the spectrum; there is no doubt what ever about the accuracy of this observation, for he was a man of great scientific distinction and the point must have frequently arisen, and been a source of some difficulty in his work. V. 7, first cousin to V. 1,