Quote: Dalton's colorblindness

I'm writing up some text on the evolution of trichromatic vision, which I always present in my intro class. As I'm writing I got curious about the history of how scientists discovered the evolutionary story of trichromacy and have been reading some historical references. Very interesting is a book by Sir William de Wiveleslie Abney, who gave a series of lectures about color vision in 1894 Abney:1895. His description of the discovery of colorblindness as a phenotype in the 18th century is fun, including a passage describing how the chemist John Dalton recognized his own colorblindness and proceeded to rigorously quantify it. Here's an excerpt:

Mr. Babbage, in Scientific London (1874), gives an account of Dalton's presentation at Court.
Firstly, he was a Quaker, and would not wear a sword, which is an indispensable appendage to ordinary Court-dress. Secondly, the robe of a Doctor of Civil Laws was known to be objectionable on account of its color - scarlet, being one forbidden by the Quakers. Luckily, it was recollected that Dalton was affected with that peculiar colour blindness which bore his name, and that as cherries and the leaves of a cherry-tree were to him of the same colour, the scarlet gown would present no extraordinary appearance. So perfect evidence was the colour blindness, that the most modest and simple of men, after having received the Doctor's gown at Oxford, actually wore it for several days in happy unconsciousness of the effect he produced in the street.