188 Life and Letters of Francis Galton
42, RUTLAND GATE. Nov. 8/75.
MY DEAR DARWIN, Alas! Alas!-and I had taken such pains to express myself clearly, and I see what I mean, so clearly!
I was most obliged for the Brown-Sequard reference in the Lancet, and will certainly alter the paragraph. His non-publication of the papers, even in abstract, read by him at the British Association in 1870, had given me additional fear that there was something wrong.
All the other points you refer to in your letter, I will do what I can about : i.e., make clearer, answer, or amend; but it is too late to make more than small alterations in the proof.
Thank you for reference and offer to send Panum, but I have a description of his results, so far as I want them, in C. Dareste (Ann. SS. Naturelles [Zoologie, T. xvii], 1862, 'Sur les ceufs a double germe,' p. 34).
In my 'Fraser' article there is a most unlucky and absurd collocation of words, which I heartily hope no critic will seize upon, for which I simply can't account except in the supposition of badly scratching out in the ms., and variously altering some passage. It is about `double yolked eggs' and 'simple germs'. I ought never to have passed it in proof; but there it is.
The twins born in one chorion,-never mind whether 2 amnions or not,-is Kleinwachter's dictum which he fortifies by numerous modern German authorities; Kiwisch being the only one who, it appears, still talks of fusion of membranes. I also noted the remark in the Catalogue of the Museum Coll. Surgeons "Teratology" that twins in one chorion are probably (I think that was the word) derived from 2 germinal spots on one ovum.
If you care to see Kleinwachter, I could send it you.
Very sincerely yours, FRANCIS GALTON.
42, RUTLAND GATE, S.W. Nov. 10/75.
MY DEAR GEORGE, I got my back Statistical Society publications last night and have read your cousin-paper with very great interest'. You certainly have exploded most effectually a popular scare. Would it be profitable to make any "probable error" sort of estimate of your results,;which should eventuate in some such form as this: "The injurious effects of first cousin marriages, measured in such and such ways, cannot exceed so and so, and probably do not exceed so and so"l
You ought to found a fortune upon your discovery,-Thus: there are, say, 200,000 annual marriages in the kingdom, of which 2,000 and more are between first cousins. You have only to print in proportion, and in various appropriate scales of cheapness or luxury:
"WORDS of Scientific COMFORT
To COUSINS who are LOVERS"
then each lover and each of the two sets of parents would be sure to buy a copy; i.e. an annual sale of 8,000 copies! ! (Cousins who fall in love and don't marry would also buy copies, as well as those who think that they might fall in love.)
I read my "Theory of Heredity" at the Anthropological last night, when up got a mad spiritualist who orated, and then offered to address the meeting on the subject as a medium; the spirit speaking through his lips. (This was not accepted.)
Ever sincerely yours, FRANCIS GALTON.
GEORGE DARWIN, Esq.
Nov. 10th. Night.  DOWN, BECEENHAM, KENT. RAILWAY STATION. ORPINGTON. S.E.R.
MY DEAR GALTON, I have this minute finished your article in Fraser and I do not think I have read anything more curious in my life. It is enough to make one a Fatalist, I am in a passion with the Spectator who always muddles if it is possible to muddle. But after all he does not write so odiously as I did in my letter, which you received so beautifully. I should be glad
' Journal of the Royal Statistical Society, Vol. xxxvtn, pp. 153-82. I may perhaps be permitted to add the word of warning that the danger of cousin marriage is not a popular scare. Any patent or latent defect is certain to be emphasised by cousin marriage as of course any good characteristic.