A person totally color blind would see in the solar spectrum a band of gray in various tones, and hence if a red and a green should seem to be of the same tone of gray he would call both either red or green, and after much experience would come to give color names to various tones of gray.
Such cases, however, are exceedingly rare, if in fact they exist. Other scientists and physiologists have doubted the truth of the claims made by both Holmgren and Helmholtz, and some have made extended experiments regarding color blindness which seem to oppose the Holmgren theory. In view of these conditions it does not seem necessary for a teacher in the elementary grades to attempt to grasp the situation very fully, and much less to aid in the solution of the problem. Very fortunately this is unnecessary, because in all the scientific tests proposed for adults nothing is accomplished which any primary school teacher will not be easily able to determine during the first two or three years of ordinary school work, if the modern system of color instruction is pursued.
There is no better material than colored papers for testing the color perceptions, and the exercises of selecting, matching and arranging the spectrum colors by means of the small color tablets generally in use in the first years of school are the very best that can be devised without regard to any of the abstract theories concerning either the cause or the possible classification of color blindness.
For some reason the most common form of color blindness occasions a confusion between red and green, as for example, we are told, by some people, that in picking wild strawberries in a field the fruit can be distinguished from the leaves and grass only by the shape, and the green fruit from the ripe by the touch or taste.
If a teacher discovers that a child is unable to readily give the name of a color it may not indicate want of color vision, but merely inability to remember names, and therefore various tests which will naturally suggest themselves can be made to aid in reaching a decision on this point. Should the results of the tests seem to indicate some defect in color vision, the nature of the trouble should be sought and memoranda made from time to time for future reference, and if the final result shows a radical lack of color perception the parents should be informed of the fact and a physician consulted.
It is probable that the number of color blind women is very much less than that of men, and much time has been spent in debating the matter, but some doubt remains as to whether this opinion does not obtain because the girls are brought so much more intimately into relation with colored materials in selecting their articles of dress, and consequently come to know the names of colors much better, and in fact enjoy a much better color education than the men. A more correct decision regarding this question can better be reached when both the boys and girls receive a systematic color education and their color sense is more equally cultivated.
Outline of a Course in Color Instruction.
