TWENTY-FIEST ANNUAL MEETING. 



105 



IN REGAKD TO COLOR-BLINDNESS AMONG INDIANS. 



BY L. I. BLAKE AND W. S. FRANKLIN, STATE UNIVERSITY. 



The fact that blindness to certain colors exists among civilized people, is well es- 

 tablished; also, the percentage of cases to be found among males has been determined 

 with considerable probability for the races of Europe and America. There has been 

 much diversity in methods of testing, and the results of many reported determina- 

 tions might well be called into question. Still, it is probably not far from the truth 

 that four out of every hundred males are more or less deficient in color sense. Of 

 females, there have been reported (B. J. Jeffries, M. D., "Color-Blindness," p. 74), as 

 examined in Europe and America, 39,828, and of these only 60 were color-blind, or 2 

 per cent. Of both males and females, 156,732 have been tested, and of these, 6,721, 

 or 4.27 per cent., are color-blind. These statistical facts have naturally excited in- 

 terest and discussion. If so large a number as four out of every hundred are unable 

 to distinguish colors, there arises, of course, a practical question, important to the 

 railroads, marine, etc. 



The gravity of this fact is already recognized more or less in all countries, by the 

 test examinations for color-blindness among employes. But there is in these sta- 

 tistics also much of interest to scientists. 



Most cases of color-blindness are found to be congenital, and are incurable 

 Many have been produced by disease, some by violent concussions in accidents, and 

 some by excessive use of tobacco and alchohol. Temporary blindness to violet may 

 be induced by santonine. From these facts several interesting questions have sug- 

 gested themselves to us. If color-blindness follows the laws of heredity, is it on the 

 increase, or decrease? Further, is it a product of civilization? The first of these 

 queries can be answered only by statistical data extending over long periods of 

 time. The second naturally suggests a comparison: first, of the color-sense of civ- 

 ilized nations among themselves; and second, of civilized with uncivilized peoples. 



Of tests on native tribes, we can find but two recorded — those of Dr. Favre on 

 some tribes in Algiers, and those of Dr. Fox on 150 American Indians, but where we 

 do not know. 



First, for the comparison of civilized tribes among themselves, we have calculated 

 the following percentages from tables reported by Dr. Jefifries: 



COUNTRIES. 



Austria 



Denmark 



Belgium 



Holland 



Finland 



Norway 



Sweden 



Switzerland.... 



Germany 



Russia 



Italy 



England 



United States.. 



Average per cent.. 



No great reliance can be placed upon these results. The numbers examined are 

 too small, the methods of testing not uniform, not equally reliable. However, the 

 probabilities of error are about equally distributed; so that the conclusion is fairly 



