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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    but more particularly when seen with her affected eye; the author diagnoses the case as unilateral green-blindness, but there appears to have been some weakness of the vision for red also, and, so far as it goes, it brings a measure of support to the view that vision for red and green are relatively unstable. The second case of unilateral colour-blindness, described by von Hippel 1 , is of much greater value, as it was typical with regard to this anomaly and was very fully examined by the author, and later by Holmgren 3 , to whom von Hippel intro duced the case, primarily with a view' to discovering what were the fundamental colour sensations of the colour-blind; after a long series of tests and experiments the agreed conclusions of the investigators were that the patient’s left eye was normal and his right eye was red-green-blind; for his affected eye the two fundamental tones were pronounced to be yellow and blue, the yellow stretching over that part of the spectrum usually seen as red, orange, yellow and green, and terminating in the blue-green, where there is a narrow neutral belt, and the blue stretching over the remainder of the spectrum; interesting tests with after-images were carried out on this case and were found to be normal with the left eye, but with the affected eye all after-images from red, orange, yellow and green were given as blue, after-images from blue and violet were given as yellow. Other cases of unilateral colour-blindness or colour anomaly have been described, and whilst no case has been found to conflict with the conclusion of von Hippel, many of the cases are incompletely described or are atypical in some respect, or are pathological in origin, and so are not individually of much value for purposes of the determination of the fundamental colours of the colour-blind, but they do collectively bring much support to the contention that the sensations of red and green are rela tively unstable, and that these are the perceptions which most readily depart from the normal. Perhaps the most definite support to von Hippel’s conclusions is to be found in the case of unilateral protanopia described by Hayes 3 ; the patient was fully tested and on being asked to look through a spectroscope with her colour-blind eye, and arrange coloured papers in a series corresponding to what she saw, she matched the spectrum by (i) three varying shades of grey; (ii) yellow; (iii) greenish yellow; (iv) greenish blue; (v) blue; (vi) violet. This case had a colour-blind maternal grand father, which supports the probability that the case was of congenital origin, and belonged to the usual type of congenital red-green blindness. Of cases which have a unilateral anomaly of colour vision which appears to affect primarily the perception of red and green, that described by von Kries 4 is perhaps the most interesting. Yon Kries describes his case as one of congenital unilateral green weakness, and amongst other tests he gives the patient definite wave lengths through the spectroscope, and notes what he sees with his normal and with his anomalous eye respectively; the results as quoted below suggest a definite weakness in the response to the red stimulus as well as to the green on the part of the affected eye. 1 Bibl. Nos. 141, 155 3 Bibl. No. 347. 25—2 2 Bibl. No. 157. 4 Bibl. No. 386.