# From Francis Galton   8 April 1870

5 Bertie Terrace | Leamington

April 8 1870

My dear Darwin

The white nose and vertical bar is, I find, of no import.1 Bartlett2 was not accessible the day I found them out but he has since told me they are common varieties & I hear the same from Mr. Royds, the rabbit fancier & judge of poultry shows,3 from whom I bought them.

Before leaving London last week, I succeeded in infusing 2 per cent of the rabbits weight in alien blood   before I had only achieved 1.25 or $\frac{1}{80}$th part which (on the supposition of Huxley that blood constitutes $\frac{1}{10}$th of the whole weight of the body) is only $\frac{1}{8}$th of the blood.4

In other words my transfusion hitherto, has given only 1 great-grandparent of mongrel blood to the otherwise pure silver greys. and this is a very small matter.

I do not like to risk another operation on the other jugular of my rabbits till after the forthcoming 3 litters nor till after I have had some more success in the system of more abundant transfusion

I can do nothing with the blood in its natural state it coagulates so quickly, so I defribrinise it.— If I cannot ever succeed in transfusing as much into the rabbits as is necessary to make a fair experiment, I must go to larger animals & try cross circulation with big dogs.

You are very kind in giving me so much valuable advice & so much encouragement.

Miss Cobbe’s review is very characteristic. She has not however quite caught what I am driving at in religious matters & which—if the book shd be enough read to make it reasonable for me to do so—I shall express more clearly.5

Very sincerely yours | Francis Galton

## Footnotes

Abraham Dee Bartlett was assisting Galton in his experiments transfusing rabbits’ blood.
Ernest Edmund Molyneux Royds.
Thomas Henry Huxley made this statement in T. H. Huxley 1866, p. 74. Fibrin: ‘an insoluble protein precipitated as a network of fibres when blood coagulates’ (Chambers). Galton defibrinised blood by stirring it with a split stick (Galton 1871, p. 396).
Frances Power Cobbe had reviewed Galton’s Hereditary genius (Galton 1869) in the Theological Review (Cobbe 1870). No letter from CD to Galton commenting on the review has been found, but see the annotation to the letter from Francis Galton, 31 March 1870 and n. 8. A second edition of Hereditary genius was published in 1892, but it was essentially a reprint of the first, with corrections.

## Summary

The mark he had thought a variation is not, and he thinks his infusion still too small even when the blood is defibrinised.

## Letter details

Letter no.
DCP-LETT-7161
From
Francis Galton
To
Charles Robert Darwin
Sent from
Leamington
Source of text
DAR 105: A13–14
Physical description
4pp