My dear Frank

Do you attend the Hospital? If so, see if you can observe in a shivering fit, as in cold stage of ague, whether the Platysma is contracted.² In young men, the contraction makes divergent longitudinal ridges as on your own neck, when fluting; in old & thin men it makes chiefly fine transverse wrinkles, and folds on sides of chin & lower parts of cheeks.— I fancy touching neck would tell best.—

I fear you cannot aid me about operations: I want much to know whether with patients much frightened, before chloroform is given, whether the Platysma contracts.³

Yours affect | C. Darwin

I write for mere chance of aid.—