Report of the Committee on Colour-Vision. 335 



comes on later. In most cases it gets worse. It is not due to 

 the pupil not dilating-, though a fixed small pupil does cause a 

 slight degree of the symptom. 



There is a group of cases of colour-blindness always associated 

 with defective acuteness of vision, the peculiarity of which is 

 that the affected persons see best by dull light, and cannot see 

 nearly so well in bright light — "day-blindness with colour- 

 blindness." The condition is due to disease occurring very 

 early in life, and is stationary. It generally affects several 

 members of a family, and the females as much as the males. 

 Usually the colour-blindness is complete, and often total. 

 Probably some of these cases have from time to time been taken 

 for examples of ordinary congenital colour-blindness. 



Evidence of Captain Macnab, of the Local Marine Board at 

 Liverpool. 



I. am Chief Examiner and Secretary to the Local Marine Board 

 at Liverpool, established under the Merchant Shipping Act, 

 I supervise the colour-testing, and frequently conduct it myself ; 

 in fact, I examine more than anyone else. We have a dark room 

 in which we take the candidates, and have the usual lanterns 

 supplied by the Board of Trade, with the uniform slides. We place 

 the man 18 ft. away from the light, and ask him the usual 

 questions. We also ask him to name colours ; if he succeeds in 

 passing all these tests we give him a certificate, and, if not, we 

 reject him. 



Question. — What are the usual questions ? — We use the usual 

 shades, and ask the man to name them. They are the same 

 colours as the Board of Trade use. Both officers and men are 

 examined by me. They are examined on first entering, and 

 afterwards. The officers generally come from schools, and are 

 of the apprentice class ; we also get a great number of men from 

 large steamships — common sailors. 



Question. — Are either the officers or men allowed to enter the 

 service of the Companies without passing the prescribed examina- 

 tion for colour-vision ? — Yes, anybody can go to sea without pass- 

 ing the colour examination. The last come because large steam- 

 ships find it wise to have them tested. They come direct from the 

 ships. As a general rule, some official from the docks, who has 

 to look after the gathering of the crews, comes and brings a batch 

 of men — quartermasters and sailors — with him. A quartermaster 

 is simply a man who steers, and keeps the gangway. He wears 

 the Company's uniform. He would often have to take the 

 look-out duty. On an emergency, say, if a large number of the 

 crew were down with fever or dysentery, they might take a lower 

 class of men, who had not been examined for steering and look-out 

 duty. When I was at sea it was customary to take " look-outs " 

 from anywhere. The examination for colour-blindness had not 

 then been instituted. It is usual now to submit men to be tested 



