380 Report of the Committee on Colour- Vision. 



be made with discrimination. The first test often shows blue to 

 be a ' confusion colour.' This may, in certain cases, be the 

 sign of violet-blindness, but not always. We have not thought 

 it advisable to recognise defects of this kind ; and only the 

 marked cases, that other tests establish as violet colour-blind- 

 ness, should be reckoned in the statistics." 



Dr. Joy Jeffries, in his book on colour-blindness, gives a 

 translation of Holmgren's special directions for conducting* the 

 examinations : — 



" Special Directions for Conducting the Test. 



" The method, as we have said, plays an important part in an 

 examination of this kind, not only irom the principles upon which 

 it rests, but also from the manner in which it is used. The best 

 plan for directing how to proceed is by oral instructions and 

 de visit ; but here we are obliged to accomplish this by description. 

 Now, this is always defective in some respects, especially if we 

 wish to be brief. What has been said would evidently suffice 

 for an intelligent and experienced physician; but it may not be 

 superfluous to enter still further into detail to provide against 

 any possible difficulties and loss of time. The object of tl.e 

 examination is to discover the nature of a person's chromat c 

 sense. Now, as the fate of the one to be examined and that of 

 others depend upon the correctness of the judgment pronounced 

 by the examiner, and that this judgment should be based upcn 

 the manner in which the one examined stands the trial, it is of 

 importance that this trial should be truly what it ought to be, — 

 a trial of the nature of the chromatic sense, and nothing else, — 

 an end that will be gained if our directions are strictly followed. 

 It is not only necessary that the examiner should carefully observe 

 them — which does not seem to us difficult — but that he also should 

 take care that the individual examined does thoroughly what is 

 required of him. This is not always as easy as one might 

 suppose. If it were only required to examine intelligent people, 

 familiar with practical occupations and especialty with colours, 

 and with no other interest connected with the issue of the 

 examination than to know whether they are colour-blind or not, 

 the examination would be uniform and mechanical; but it is 

 required to examine people of various degrees of culture, all of 

 whom, besides, have a personal interest in the issue of the 

 examination. Different people act very differently during the 

 examination for many reasons. Some submit to it without the 

 least suspicion of their defect; others are convinced that they 

 possess a normal sense. A few only have a consciousness, or at 

 least some suspicion, of their defect. These last can often be 

 recognised before examination. They will keep behind the 

 others, and attentively follow the progress of the trial ; and, if 

 allowed, will willingly remain to the last. Some are quick; others, 

 slow. The former approach unconcernedly and boldly ; the 

 latter, with over-anxiety and a certain dread. Some have been 



