Colour perception and other visual functions in their practical aspects / by Freeland Fergus.

  • Fergus, A. Freeland (Andrew Freeland), 1858-1932.
Date:
[1910?]
Catalogue details

Licence: In copyright

Credit: Colour perception and other visual functions in their practical aspects / by Freeland Fergus. Source: Wellcome Collection.

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    honours ” in the department of mental philosophy in the University of Edinburgh. There was no lack of intellect, it was simply a case of the visual acuteness not having been developed. It is to be noted tha(t this gentleman had exactly those powers of vision which are associated with the light sense, although, of course, even these were not well developed. He could make out objects, lie could tell differences of illumination, he could even walk with comparative freedom along a road, he had the functions of vision depending upon the light sense, but absolutely no visual acuteness in the restricted and proper sense of the term. The other patient was a young girl who earns her living by teaching music. The same thing occurred in her case. Laborious hours were spent both by myself and the house surgeon in trying to get her to read such print as Nos. 14 and 16 of Jaeger’s types, but all to no purpose. No. 20 she could spell, but that, of course, was entirely a matter of the light sense and not of visual acuteness, yet this girl is able to make her livelihood by teaching the piano, and is able to get into a tramcar down at Dalmuir and come up to the city of Glasgow and find her way to the Glasgow Eye Infirmary without any assistance or trouble. Here, again, the functions of vision are those due to the light sense and not to visual acuteness. It is specially to be noted that in both these patients there was good light sense before they were operated on. The opaqueness of the lenses had not interfered with the develop¬ ment of the light sense, but had interfered, and most markedly so, with the development of visual acuteness. We venture to say, and that without fear of contradiction, that no person has been operated on for congenital cataract after adolescence with restoration of vision in the sense of visual acuteness. So far as we are aware, in the cases recorded any vision that results in such patients is poor, and is merely such as is to be obtained from an ill-developed light sense. The bearing of this on Molyneaux’ problem is, of course, quite obvious. Molyneaux’ question was, Supposing a person was kept totally blind from earliest infancy till manhood, if then the possibility of sight were suddenly restored, would that man see ? The answer, of course, all depends upon what is meant by sight. If it means to see like an ordinary mortal—that is to say, to be able for reading and writing and the other occupations in life which require visual acute¬ ness—then the answer is absolutely in the negative. The person never will; but under ordinary circumstances if the