388 Report of the Committee on Colour -Vision. 



heap towards it, and thus gradually form a little bridge, but 

 which for correctness they will not vouch for. No such half- 

 nieasures must, however, be allowed. 



44 Deciding whether the Examined are fitted for their Duty. 



44 The method of scrutiny here described is able to detect, as 

 we have seen, not only complete or incomplete colour-blindness, 

 but a feeble chromatic sense. Moreover, it has been proved that 

 there is a perfect gradation, from complete colour-blindness on 

 the one side to the normal chromatic perception on the other. 

 The question then naturally arises, from our practical point of 

 view, whether it is possible to draw a dividing line between the 

 kinds and degrees of defective colour- vision which would except 

 those who could not cause any inconvenience to the railway 

 service, and, in case of an affirmative answer, where such limit is 

 to be found. 



" It must first be remembered that, in the existing state of 

 things, these questions neither can nor ought to be settled in 

 the same manner in every case, since the examination is intended 

 for individuals of two different classes — 1st, the aspirants for 

 railway employment ; and, 2nd, the employes, or those already in 

 service. 



" It will be readily understood how great is the difference of 

 the cases, in deciding what may be the result of the examination. 

 We have already given our views on this point. Justice here 

 calls for an essential distinction, supposing that the test has 

 been always made with sufficient aceurac}'. Hence we must pay 

 especial attention to both of the above classes when deciding 

 whether an employe is fitted for his duty. 



" (A) Those who are Applicants for Railroad Service. 



" We must bear in mind that in Sweden, according to the 

 regulation in force there for the management of state railways 

 (followed also, as far as we know, on the private lines), it is 

 required that, in order to be admitted, each applicant must ' prove 

 by a certificate from a physician that he is exempt from any kind 

 of infirmity, disease, or defect of conformation that could be 

 prejudicial to the exercise of his functions ; ' and also, that 

 among these defects of conformation, in connection with signals, 

 are reckoned the defects of the chromatic sense, to which the 

 managers have especially directed the attention of the medical 

 men attached to the lines. 



k ' According to the principles laid down, the greatest severity 

 should be observed ; or, in other words, the least defect in the 

 sense of colours should be a sufficient ground for rejection. 



44 We must seek, therefore, to adapt the method of testing to this 

 law. The object of a test is to prevent any one from working 

 as a railroad employe who does not have a perfectly normal 

 colour-perception. We have already sufficiently explained the 

 evils arising from contrary action in case of admission to 



