336 MEMOIR OF GEORGE WILSON. CHAP. VIII. 



a grass plot ; or writing a letter in brilliant red ink, thinking 

 it was rather a bright black. The examples of such strange 

 confusion, related by Dr. Wilson, are very numerous, and ren- 

 der the book as amusing as it is interesting. 



" As art can do little towards palliating, and nothing towards 

 curing colour-blindness, Dr. Wilson points out the propriety of 

 excluding from certain professions and callings those who have 

 this defect. The professions for which it most seriously disqua- 

 lifies are those of the sailor and railway servant, who have daily 

 to peril life and property on the indication which a coloured flag 

 or a lamp seems to give. Though an imperfect apprehension of 

 colour must prevent a man becoming a painter, it does not 

 exclude his excelling as an engraver, for the colour-blind have 

 a keen eye for form, outline, light and shade, etc. Such callings 

 as the weaver, house-painter, dyer, etc., are manifestly ill adapted 

 for them ; and even the pursuits of the analytical chemist, to 

 whom a knowledge of colour is important, scarcely falls within 

 their list. 



" On what does colour-blindness depend ? A variety of opi- 

 nions exist on this point ; but we shall conclude the subject by 

 quoting that formed by Dr. Wilson : ' We seem to be fully 

 entitled to affirm that the cerebro-retinal apparatus of vision in 

 the colour-blind is, either through congenital defect or subse- 

 quent morbid change, unendowed with that sensitiveness to 

 calorific impressions which it possesses in those whose vision is 

 normal. It is probably the retina that is the chief seat of this 

 diminished sensibility to colour, and the simpler form of colour- 

 blindness might fitly enough be called colour amaurosis! " l 



From 1846 onwards to 1852, a series of researches on Fluorine 

 was carried on, involving much patient investigation and labo- 

 rious inquiry. Its presence was discovered in waters, in mine- 

 rals, fossil remains, plants, and animal secretions. In the 



1 ' Researches on Colour-Blindness/ p. 111. 



In the ' Cosmos' for January 6, 1860, M. l'Abb6 Moigno expresses surprise that 

 no notice is taken in these ' Researches' of labours of his in the same field, pub- 

 lished in the ' Repertoire d'Optique Modeme,' and consisting of a practical and theo- 

 retical resumt on Daltonism or Colour-Blindness. Had this paper come under Dr. 

 Wilson's observation there can be no doubt he would have mentioned any obliga- 

 tion under which it might have placed him. 



