This substitution of the senses is but; an example of the great law of compensation which we find throughout nature.
Jonston quotes a case in the seventeenth century of a blind man who, it is said, could tell black from white by touch alone; several other instances are mentioned in a chapter entitled "De compensatione naturae monstris facta." It must, however, be held impossible that blind people can thus distinguish colors in any proper sense of the words.

Different colored yarns, for example, may have other differences of texture, etc., that would be manifest to the sense of touch.

We know of one case in which the different colors were accurately distinguished by a blind girl, but only when located in customary and definite positions.

Le Cat speaks of a blind organist, a native of Holland, who still played the organ as well as ever.

He could distinguish money by touch, and it is also said that he made himself familiar with colors.