To William Ogle   9 November 1870

My dear D^r. Ogle,

I have read your paper with the greatest possible interest.¹ It will be extremely curious if your views are confirmed and you are able to explain (not to mention more important points) so many odd little details about the colouring of animals. I have no distinct evidence of the white pigs, sheep, etc. eating the poisonous herbs; but if you will look to the facts given in Vol. 2 p. 337 of my Var. of Dom. animals, you will see that the white parts alone are affected, and this does not seem to agree with your view.² By the way, you speak as if the Himalayan rabbit had to provide for its own food when adult, though no doubt you know that it is an artificial Var:³ I read many years ago D^r Stark’s paper, and often wondered over the subject, and this has enhanced my interest in your paper.⁴ I hope you will continue your investigation. Would it not be possible to hear of an Albino dog (or some animal at the Zoological Gardens) and it would not be difficult to test a dog’s power of smell.

And now I want to beg a little favour of you: I have received conflicting statements about the platysma myoides being brought into strong action in persons suffering from severe dyspnœa;⁵ would you kindly observe this point for me? I believe that the contraction of this muscle is easily perceived by the transverse wrinkles on the neck and by the skin near the corners of the mouth being drawn down. I can reconcile the discrepancies between good authorities on this point only by supposing that this muscle acts only during certain forms of dyspnœa.⁶

I have had no communication with you since hearing, about a year and a half ago, that you had been most dangerously ill;⁷ and I rejoiced sincerely at your recovery. Since then I have read one or two capital papers by you on the Fertility of flowers.⁸ Yours very Sincerely. | Charles Darwin.

P.S. The contraction of the Platysma interests me in relation to expression, which is a hobby-horse of mine,— this muscle is said to contract under great terror. I cannot even positively ascertain whether this is true.— One Doctor declared he had seen it violently contracted in a man with injured brain, who was unconscious and screamed incessantly.⁹ In fact this muscle is the bane of existence!