36 KANSAS ACADEMY OF SCIENCE. 



by the heredity of genius, the heredity of crime, and all the phenomena of 

 insanity. Color-blindness is, then, a congenital defect, a defect of involution, 

 and consequently cannot be remedied by education. Several French writers 

 have claimed that by systematic efforts the color sense could be developed in 

 the color-blind, but it is evident from their writings that they have con- 

 founded a weak or impaired sense or knowledge of color with color-blindness. 

 Persons who are slow and uncertain in designating color can be educated in 

 chromatics, but the color-blind never. And here permit me to make an ob-. 

 servation, in digressing from my subject ; it is this : the hardest blow dealt 

 to evolutionists theoretically is, that a qualitative mental function being ab- 

 sent, it cannot be developed by efforts at education ; but if a mental charac- 

 teristic exist, however weak and small, it may always be educated. Hence, 

 it would seem that evolution must always be qualitatively what has first been 

 involuted. 



Let us now consider briefly the relation of color-blindness to railway acci- 

 •dents. It is well known that colored signals are absolutely necessary to the 

 management of railways, particularly at night. It has been proposed to sub- 

 stitute form for light, for signals; but the appreciation of light is so much 

 quicker and easier than that of form, that the change has been found im- 

 practicable. The ability, therefore, to determine the language of colored 

 signal lights is absolutely necessary to train-men; and consequently, the 

 safety of trains is endangered just in proportion to the number of employes 

 who are defective in the color sense. The extent of this visual deformity 

 <;an be tolerably accurately determined by statistics. " Dr. Fontenoy found 

 thirty-one color-blind out of 1,084 railroad employes of Denmark, or 2.87 

 per cent. Prof Donders, of Utrecht, Holland, found, among 2,300 railroad 

 employes, 152 color-blind. Dr. Stetling, of Cassel, Germany, found, out of 

 400 railroad employes, six per cent, color-blind. Dr. Krohm, in Finland, 

 found, among 1,200 railroad employes, sixty, or five per cent , color-blind. 

 Dr. Holmgren found, among the employes on the railroads in Sweden, 4.8 

 per cent, color-blind." (Jeffries' Op. Cit., p. 143.) From the number of rail- 

 road employes tested for the color sense in Europe, and persons examined in 

 this country in the schools, we can assert that there are five per cent, of the 

 male population absolutely color-blind, and about five per cent, in addition 

 who have an imperfect perception of color. It is also known that the ma- 

 jority of persons who have this defect are unaware of it, or do not know the 

 extent of their deformity. It is apparent, therefore, that this imperfection 

 must be a great factor in the production of collisions and other accidents on 

 railways. On most railways, red lights signify " danger," white or yellow 

 light, "track clear," and green light, at way-stations, "stop for orders." No 

 person will deny that a certain number of accidents will happen from care- 

 lessness and inattention, especially where great numbers of persons are en- 

 gaged ; and if this is so, how can accidents fail to occur among a vast number 

 of persons, of whom five per cent, are absolutely incapacitated for discharg- 



