Report of the Committee on Colour- Vision. 301 



he were unable to name the colours in English. It is in evidence 



before us that in navigation it is often requisite that the 



look-out man should, without a moment's delay, pass to the 



officer in charge the name of the colour of a light, and that 



hesitation, whether caused by true colour-ignorance or from 



want of knowledge of English terms, might involve disaster. 



This being the case, the Committee are strongly of opinion that 



for the marine services the examination for colour- vision should 



exclude not only men who are colour-blind within the limits ignorance of 



already indicated, but also those who are colour-ignorant, whether the names of 



from defective education or from want of knowledge of the signal colours 



English names. No man should be accepted as a look-out unless ^ ^ J 1 



he were found capable of naming the signal colours correctly men ^ 



and intelligibly, and without hesitation. 



The tests which the Committee recommend for the detection Tests for 

 of colour-ignorance are very simple. After the tests for colour- colour- 

 blindness have been satisfactorily passed it would suffice to 1 g norance - 

 ask the examinees to name the reds and greens of the wool-tests, 

 and if any hesitation was evinced to test them with a lantern- 

 test, such as that proposed by Mr. Galton. Men rejected for 

 colour-ignorance of either type should not be considered per- 

 manently ineligible, but only until such time as their education 

 in the subject was perfected, for it must be recollected that, 

 unlike colour-blindness, colour-ignorance is curable. 



In the marine service, it appears that on each stage of promotion Ee-testing in 

 an officer is tested as to his colour- vision. On some railways also, the marine 

 on promotion, an employe's eyesight is re-tested. It does not and railway- 

 appear that such tests are undertaken with the idea that colour- servlces * 

 blindness of the congenital type may have become more pro- 

 nounced, or may have induced it by disease, but rather with the 

 view that those who have been previously tested may have been 

 passed improperly. No doubt these re-examinations are a safe- 

 guard; but if the tests already passed had been such as to 

 render detection a certainty, there would be no necessity for 

 repetition except for the detection of such colour-blindness as may 

 be due to disease, injury, or over-use of tobacco. Colour-blindness 

 due to these last causes is at first very seldom appreciated by the 

 sufferer, and is usually only discovered upon his consulting a 

 medical man for impaired form-sense. This raises the question 

 as to whether defective colour-sense other than congenital 

 might not, in some cases, be found in those on whom the lives of 

 passengers and others depend. 



Special tests for colour-blindness induced by disease will very Tests for 

 rarely be necessary if, as should always be the case, every exami- colour- 

 nation for colour- vision is preceded by one for form. These latter blindness 

 tests are so well known, that the Committee do not think it neces- 

 sary to enumerate them. If a candidate is found to have defective 

 form-vision of a pronounced type he certainly should be ineligible 

 for the positions of responsibility from which colour-blind persons 

 should be excluded, and the test for form- vision would as a rule 



