My dear Sir

I should be a very ungrateful man if I did not comply to the utmost of my power with any wish of yours.¹ Therefore I will do my best with respect to the expression of patients suffering from general paralysis; and I am glad to hear that you are going to take up in so thorough a manner this important subject. But I really think it will be impossible for me to write even a short essay on the subject. I have had a good deal of experience with photographs showing expression, and am convinced that the utmost that I can do is to give you the impression which each produces on my mind; and I doubt whether any one could safely do more. Though photographs are incomparably better for exhibiting expression than any drawing, yet I believe it is quite necessary to study the previous appearance of the countenance, its changes, however small, and the living eyes, in order to form any safe judgement. I suspect moreover that our judgement is in most cases largely influenced by accessory circumstances. From your being able to study the living patients, and more especially from your various letters to me, I am fully convinced that you could do well that which I could effect only in the most imperfect manner. Nevertheless I shall be very glad to give you the impression which a careful inspection of any photographs which you may send me produces on my mind.

Pray believe me, My dear Sir | Yours very sincerely | Ch. Darwin