This idea is given corroboration by some facts of color blindness.
It must not be assumed that every one has the same sense of color, otherwise there would be no color blindness.
Color blindness, or at least certain kinds of color blindness, appear to follow the same scheme.
There is a very important defect in vision which should be detected as early in life as possible, and that is color blindness.
Until the year 1853, very little was known about color blindness, and much less written about it.
An interesting example is the common type of color blindness known as Daltonism.
The subject of color blindness has received much attention because of its practical importance in the affairs of our daily lives.
He seems to have initiated the theory of color blindness that was later developed by Helmholtz.
Color blindness seems to be an instance of the conspicuous absence of such a unit characteristic.