I have received both your letters, and they tell me all that I wanted to know in the clearest possible way, as, indeed, all your letters have ever done. I thank you cordially. I will give the case of the murderer ('Expression of the Emotions,' page 294. The arrest of a murderer, as witnessed by Dr. Ogle in a hospital.) in my hobby-horse essay on expression. I fear that the Eustachian tube question must have cost you a deal of labour; it is quite a complete little essay. It is pretty clear that the mouth is not opened under surprise merely to improve the hearing. Yet why do deaf men generally keep their mouths open? The other day a man here was mimicking a deaf friend, leaning his head forward and sideways to the speaker, with his mouth well open; it was a lifelike representation of a deaf man. Shakespeare somewhere says: "Hold your breath, listen" or "hark," I forget which. Surprise hurries the breath, and it seems to me one can breathe, at least hurriedly, much quieter through the open mouth than through the nose. I saw the other day you doubted this. As objection is your province at present, I think breathing through the nose ought to come within it likewise, so do pray consider this point, and let me hear your judgment. Consider the nose to be a flower to be fertilised, and then you will make out all about it. (Dr. Ogle had corresponded with my father on his own observations on the fertilisation of flowers.) I have had to allude to your paper on 'Sense of Smell' (Medico-chirurg. Trans. liii.); is the paging right, namely, 1, 2, 3? If not, I protest by all the gods against the plan followed by some, of having presentation copies falsely paged; and so does Rolleston, as he wrote to me the other day. In haste. Yours very sincerely, C. DARWIN. CHARLES DARWIN TO W. OGLE. Down, March 25 [1871]. My dear Dr. Ogle,