To F. C. Donders   21 June 1870

My dear Sir

I have received from D^r Moore the translation of your paper, & have read it with the greatest interest. After making some extracts I am asked by D^r M. to send it to D^r Beale for publication in the October number of his Journal.¹ Your information has proved incomparably fuller & more decisive than I had ventured to hope. You cannot imagine what an advantage it is to my little essay to have on this head a firm foundation. Now that I see how laborious y^r. investigation has been,—I sh^d have regretted to have incidentally led you to employ so much of your time, did I not feel convinced that physiologists will think the results, independendly of the particular point in question, worth much labour. Several of y^r. incidental remarks have also interested me much. I had intended publishing my essay on expression as part of a larger work nearly completed;² but I believe that it will be too large, & that I must keep back for a short time, my essay³

I do not know whether it is worth mentioning, but I think that the closing of the eyelids serves in part to prevent the eyes suffering from vibrations, I observe that dogs & cats when crushing a bone, close their eyelids. Various kinds of monkeys which do not close their eyelids when screaming close them when sneezing.⁴

With the most cordial thanks for your extreme kindness, believe me my dear Sir | yours very sincerely | Ch. Darwin.