Sir

I notice in several parts of your work on the Variation of Animals &c you speak of instances of Colour Blindness in women.¹

I wrote a paper on this subject in the Phil. Trans (1860 I think)² and had read all I could find at that time, & conferred with everybody who had gone into it carefully—and my impression was that, no case had been authenticated of a woman being really colour blind—

Possibly cases may have since been found: Could you oblige me by giving me a reference to any good & trustworthy records of any such cases?³

I must apologise for asking you this, as a perfect stranger; but it is in the desire to clear up a curious point in science,

Very sinly yours | W^m. Pole | F.R.S.

Cha^s Darwin Esqr | MA FRS

Athenæum.