3 64 COLOR-BLINDNESS IN ITS RELATION TO 



the difficulty in distinguisbiug colors experienced by certain individuals 

 may be corrected by exercise. And if this is not possible, it is natural 

 to conclude that more regard is due to the men than to a particuUir kind 

 of signals, since the latter is not absolutely essential, and consecjueutly 

 may be changed if not adapted to the employes. 



1.— INSTRUCTION AND EXERCISE OF THE PERSONNEL IN RECOGNIZ- 

 ING COLORS. 



The importance of the habitual exercise of our senses generally should 

 not be underrated. As we are born with naturally sound organs of loco- 

 motion, and yet require to be taught to walk, so it is necessary to learu 

 to use our organs of sense ; and when experience shows us that many 

 original defects of our organs of locomotion can be remedied as well as 

 those of our visual organs, we readily conceive the idea that this is also 

 possible with color-blindness. If it were the case, this would be, without 

 doubt, the most radical means possible for protecting railway lines, with- 

 out the necessity of displacing a single employ^. 



To avoid all misunderstanding, we must dwell upon the difference that 

 we have mentioned between the genuine perception of the colorblind 

 and the najue he gives to the color of the objects. We have already seen 

 that a true name may often be united to a false perception, but it is evi- 

 dent, also, that just as the perception is anomalous, or merely uncertain, 

 the name must also be uncertain, as it is simply a conjecture. We do 

 not here allude to that acquired color-blindness which, casually occur- 

 ring, might also disappear, but to congenital color-blindness, let it be 

 understood. 



We will endeavor to give some account here of what experience has 

 furnished on this subject, and first of all we will try to discover upon 

 what grounds it is claimed that color-blindness can be cured. 



An effort has been made to derive one indication of this from the fact 

 that amongst the numerous instances of color-blindness that have been 

 discovered and mentioned by different writers since Huddart, tliere are 

 many more amongst men than women. It is concluded from this, in the 

 first place, that color-blindness is much more common amongst men than 

 women, and from this statistical fact, added to the undoubted experience 

 that women have more to do with colors from their very infancy than 

 men, from the nature of their clothing, etc., another inference is reached, 

 namely, that exercise assists in diminishing and counteracting color- 

 blindness. All this may be true, but the argument fails in more than 

 one particular. In the first place, it has not been at all proved, we think, 

 that color-blindness is less common among women than men. The 

 majority of the cases of color-blindness described by writers have been 

 accidentally discovered, that is to say, without any special examination. 

 If we observe, first of all, that these are probably the most marked cases 

 of color-blindness, and also that they are usually not persons who have 

 much to do with colors (as these easily conceal their defect), it will be 



