My dear Sir

I well remember your very interesting observations, and I have since collected many analogous facts, but when I shall have time and strength to publish I do not at all know. I thank you for your obliging offer, but I cannot at present think of any particular facts in relation to Nicaragua.² I include, however, some queries on a subject, which greatly interests me; and if you could interest yourself I should be especially obliged for any answer in regard to Negroes or American Indians.³ You would have to read the queries several times over, and you will find it curiously difficult to observe; for any emotion excites some sympathy in observer’s mind and this at the moment makes the point to be forgotten. I should be grateful for a letter with even a single question answered. I have had many answers but hardly any about negroes—the less civilised the better.⁴ I sincerely hope that you will enjoy fairly good health, and be successful in your Expedition,⁵ and I remain

My dear Sir | yours very faithfully | Charles Darwin.