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.
Down. | Beckenham | Kent. S.E.
My dear Dr Ogle
I am very much obliged about the platysma; & hope that you will keepthe subject a little before your mind, more especially as I see thatyou are quite au fait about expression. It is new to me that thismuscle can ever be brought into voluntary action.f2 I have been comingto the same conclusion as you have, viz that this muscle has nothingto do with expression.f3 Dr C-Brown tells me that it does not contractwith insane patients under extreme terror.f4 Yet I was unwilling to thinkthat the belief was quite a delusion, owing to Duchenne’s strikingphotographs & some older statements to the same effect.f5 (possibly thesource of whole belief) If Gratiolet’s statement cd be trusted thatthis muscle contracts under dyspnoea, it is conceivable that it mightact under terror from association with panting breath.f6 One of my sonsin sounding certain notes on the flute draws the corners of his mouth muchbackwards & downwards, & then I can see radiating longitudinal furrowson each side of his neck.f7 A clever surgeon, who has attended tothese subjects, tells me that this is produced by another muscle(name forgotten) which is attached below to the clavicles.f8 You willknow all about this, & at some future time I shd be grateful tohear whether there is such a muscle, the contraction of which wd producethe longitudinal furrows.
I cannot yet give up the ghost about white colour & vegetable poisons. Ifyou cd prove that white animals were deficient in the power of smell I shdbe more staggered.f9 I cannot as yet think that so many observers have beendeceived. I wd suggest, (if you are willing, as I hope, to continue thesubject,) 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 somecareful man whether if the paint-root is given to black & white pigs, both willeat it.f10
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.