To William Ogle 17 November 1
Down. | Beckenham | Kent. S.E.
My dear Dr Ogle
I am very much obliged about the platysma; & hope that you will keep the subject a little before your mind, more especially as I see that you are quite au fait about expression. It is new to me that this muscle can ever be brought into voluntary action.2 I have been coming to the same conclusion as you have, viz that this muscle has nothing to do with expression.3 Dr C-Brown tells me that it does not contract with insane patients under extreme terror.4 Yet I was unwilling to think that the belief was quite a delusion, owing to Duchenne’s striking photographs & some older statements to the same effect.5 (possibly the source of whole belief) If Gratiolet’s statement cd be trusted that this muscle contracts under dyspnoea, it is conceivable that it might act under terror from association with panting breath.6 One of my sons in sounding certain notes on the flute draws the corners of his mouth much backwards & downwards, & then I can see radiating longitudinal furrows on each side of his neck.7 A clever surgeon, who has attended to these subjects, tells me that this is produced by another muscle (name forgotten) which is attached below to the clavicles.8 You will know all about this, & at some future time I shd be grateful to hear whether there is such a muscle, the contraction of which wd produce the longitudinal furrows.
I cannot yet give up the ghost about white colour & vegetable poisons. If you cd prove that white animals were deficient in the power of smell I shd be more staggered.9 I cannot as yet think that so many observers have been deceived. I wd suggest, (if you are willing, as I hope, to continue the subject,) that you shd send yr paper to Prof. Wyman of Boston, U. States, with a letter asking him if he cd get it observed in Florida, by some careful man whether if the paint-root is given to black & white pigs, both will eat it.10
With many thanks for yr very interesting letter yours very sincerely | Ch. Darwin
I wonder whether white pigs find truffles & pig-nuts as well as black pigs.
Thanks WO for information on platysma, which he did not know could be brought into voluntary action. Is coming to believe it has nothing to do with expression.
On the relation between white colouring and susceptibility to poisonous plants, CD suggests WO send his paper to J. Wyman and propose he investigate whether white as well as black pigs will eat paint-root.
Please cite as
Darwin Correspondence Project, “Letter no. 7373,” accessed on 30 March 2017, http://www.darwinproject.ac.uk/DCP-LETT-7373