Dear Sir

I am grateful for the extremely kind manner in which you offer me further assistance, and for the very valuable aid already given.¹ And this is all the more kind, as I am well aware how much your time must be occupied with your arduous duties. The information about the hair standing on end is now quite ample.² I am also glad to hear that you have seen the “grief muscles” in action, for these cannot often be observed.³ But I may add that I have just had a letter from Egypt from a trustworthy observer that he has seen this expression in a negro.⁴ I shall be particularly anxious to hear at some future time about the platysma which has been my bête noire for a year or two.⁵ It is indeed wonderful what aid you have already given me, and I think will give me. I may remark with respect to what you say about the neck of one of your patients (though to you the remark will probably be superfluous) that there is a muscle, the name of which I have just now forgotten, running from near the clavicle to the corners of the mouth; I see this muscle in strong action, producing prominent diverging lines on the neck of one of my sons, when he draws strongly backwards the corners of his mouth in producing certain notes on the flute.⁶ I am very much obliged for your present of the photographs of the cretin; they are dreadful to look at.⁷ Can the throwing back of the head be an extreme exaggeration of the attitude assumed during laughter? I have noticed the head thrown a little backwards when a person out of complaisance pretends to laugh and be amused. Sometime ago I went into several shops in London to try to buy photographs of the insane, but failed;⁸ so you may believe with how much interest I have carefully looked at your excellent ones, and made some notes. I do not, however, think that your kind offer of copies would be of any special use to me. They shall be returned together with Duchenne by rail; and are sent off to-day.⁹

I have arranged the plates of D. with the text, as I think this is the most convenient plan; but you can take them out and arrange them as you like. If you have the inclination and time, I should be delighted if you would write any remarks on the plates or separately,—such as whether you thought any decidedly good or bad etc. Some French authors sneer at Duchenne, but I am inclined to think highly of this work, and Huxley tells me that he has made out much about the muscles of the hand by the aid of galvanism.¹⁰ I shall not want the book returned for a couple of months and I enclose the best address for its return. On the 10th I and my family start for North Wales to stay there for about 7 weeks, as my health which is always very poor has lately been worse. My address there is C. Darwin, Caerdeon, Barmouth, N. Wales.

Pray believe me, my dear Sir with cordial thanks | Yours sincerely | Charles Darwin

June 8th, 1869