My dear Sir,

In about a fortnight’s time I shall begin to arrange my notes on Expression: & it would be a great assistance to me if you could spare time to give me some notion of any conclusion at which you may have arrived, on the cause of the contraction of the muscles round the eyes during screaming &c²

Secondly, can you give me any explanations why tears are poured out when these same muscles are spasmodically contracted, as during violent choking vomiting &c without any mental emotion such as grief being felt. I find that the voluntary, prolonged & strong contraction of these muscles, even with children, does not cause tears to flow, or hardly at all. I hope my questions will not cause you much trouble, as I know your time is taken up by valuable researches.

I have lately read in an English Journal with extreme interest an abstract of your experiments on the rate of the travelling of the nervous powers.³

With very sincere respect | pray believe me, my dear Sir, | yours faithfully | Charles Darwin.