370 Report of the Committee on Colour-Vision. 



colour-defects than their poor ; but even among them the males 

 exceed the average. 



" There are naturally difficulties attending the examination of 

 the deaf-mutes. But after repeated examinations had made the 

 process perfectly clear to them, it was apparent, from the nature 

 of their mistakes, that there was among them a very high 

 average of colour-defects. Those examined inhabit schools in 

 London, and naturally live in a condition of considerable isolation 

 from the surrounding world. 



"It is worthy of note that, when in any class of persons 

 colour-defects exceed the average in number and intensity, 

 there is often an unduly high proportion of red-blind as com- 

 pared with green-blind. This is especially marked among the 

 Jews, for among them the pronounced cases of red-blindness 

 were 3*6 per cent, of the whole number examined, against 

 1*3 per cent, of green-blindness ; whereas among males generally 

 the red-blind were 2 per cent., and the green-blind 1*5 per cent. 



" A large number of male children (2,859) were examined in 

 Dublin by Mr. Swanzy. Their average is somewhat higher than 

 that found in England, being 4-2 per cent, of pronounced cases. 

 But as the examinations were necessarily made by different 

 hands, and as the boys examined in Dublin were, on the average, 

 of poorer class than those furnishing the corresponding statistics 

 in this country, we must be cautious in inferring a greater average 

 percentage of colour-defects in Ireland than in England. 



" Interesting results are derived from a comparison of the 

 percentages in the different groups examined, especially with 

 regard to their different positions in the social scale, by which is 

 implied presumably a corresponding difference in education. 



" Thus, in England, among the police (4,932 examined), and in 

 schools of about the same social rank (1,729 examined), the 

 pronounced cases form 3*7 per cent. In middle-class schools the 

 same form 3*5 per cent. In the professional class, as represented 

 by medical students and sons of medical men (435 examined), the 

 same form 2*5 per cent. Among the boys at Eton the same form 

 2*46 per cent. 



"And even more striking instances are recorded in Ireland, by 

 Swanzy, who finds the percentage among the sons of artisans 

 and labourers (2,486 examined), to be nearly twice as great as 

 among the sons of the professional and wealthier classes. 



" Nor can any observer fail to be struck by the much greater 

 certainty and rapidity with which the children of the upper 

 classes pick out the various shades of the same colour. And the 

 momentary confusion of blue and green, which is not uncommon 

 among the poorer classes, independently of any defect of colour- 

 vision, is very rarely seen among the others." 



The following report regarding the tests of a Japanese 

 regiment was communicated by Mr. Brudenell Carter : — 



Table of the Results of Investigations on Colour-blindness. 



