To Charles Lyell 8 October 
My dear Lyell
I have long been purpoting to write to you, but have not done so, from having seen hardly anyone & done little, & therefore having hardly anything to say.— I cannot think of any other questions about negro-crosses: but I may mention (however unlikely you may be to take up so disgusting a subject) that it has been asserted that on the negros born in N. America, the lice are larger & of a blacker colour, than the common species; & that the Europæan lice will not live on negroes. From some analogous statements made to me with respect to the men of the Sandwich islands, I am inclined to believe there may be some truth in these statements.1 Mr Denny (to whom I communicated specimens & this information)2 wd be most grateful for specimens, if you cd get them in spirits, through some medical man, who cd get them through some nurse to some Hospital &c &c I suggest this as a feasible means, without disgusting yourself much.—
I see Long in his Hist. of Jamaica says he has never known two mulattos have offspring!!!!!—3 Can you obtain any comparative information on the crosses between Indian & Europæans & Negros & Europæans?—4
I have lately been taking a little tour to see a Farm, I have purchased in Lincolnshire: & thence to York, where I visited the Dean of Manchester,5 the great maker of Hybrids, who gave me much curious information.— I also visited Waterton at Walton Hall & was extremely amused at my visit there.6 He is an amusing strange fellow; at our early dinner, our party consisted of two Catholic priests & two Mulattresses! He is past 60 years old & the day before run down & caught, a Leveret in a turnip field. It is a fine old House & the Lake swarms with water-fowl. I then saw Chatsworth, & was in transports with the great Hot-house:7 it is a perfect fragment of a Tropical forest & the sight made me thrill with delight at old recollections. My little ten-day tour made me feel wonderfully strong at the time; but the good effects did not last.— My wife, I am sorry to say does not get very strong; & the children are the hopes of the family, for they are all happy life & spirits.—
I have been much interested with Sedgwick Review;8 though I find it is far from popular with non-scientific readers. I think some few passages savour of the dogmatism of the pulpit, rather than of the philosphy of the Professor chair; & some of the wit strikes me as only worthy of Broderip in the Quarterly. Nevertheless it a grand piece of argument against mutability of species; & I read it with fear & trembling, but was well pleased to find, that I had not overlooked any of the arguments, though I had put them to myself as feebly as milk & water.— Have you read Cosmos yet: the English Translation is wretched,9 & the semi-metaphsico-poetico-descriptions in the first part are barely intelligible; but I think the volcanic discussion well worth your attention; it has astonished me by its vigour & information.— I grieve to find Humboldt an adorer of Von Buch, with his classification of volcanos, craters of Elevation &c &c & carbonic-acid gas atmosphere. He is, indeed a wonderful man.—
I hope to get home in a fortnight & stick to my wearyfull S. America, till I finish it.— I shall be very anxious to hear how you get on from the Horners, but you must not think of wasting your time by writing to me. We shall miss, indeed your visits to Down & I shall feel a lost man in London, without my morning “House of Call” at Hart St.—
Emma desires to be most kindly remembered to you both & Believe me, my dear Lyell | Ever yours | C. Darwin
Discusses American Negroes and their parasitic lice. Henry Denny’s need for lice specimens.
Discusses effects of racial crosses in man.
Describes his trip to Yorkshire.
Comments on Sedgwick’s review [of Vestiges of creation].
Mentions Humboldt’s Kosmos. Criticises Humboldt’s geology.
Please cite as
Darwin Correspondence Project, “Letter no. 919,” accessed on 21 January 2017, http://www.darwinproject.ac.uk/DCP-LETT-919