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Darwin Correspondence Project

To John Bush   2 April [1868]1

Down. | Bromley. | Kent. S.E.

Ap 2

Dear Sir

I am much obliged to you for your kindness in giving me all the information in your power. Should you ever find the memorandum to which you refer I shd be particularly obliged for fuller details.2

I have heard of analogous cases to that which you relate about crossing rats.3 I have indeed seen it positively stated that if white & grey mice are crossed, the offspring is of either of these colours & never pie-bald.

With my best thanks | I remain dear Sir | yours very faithfully | Ch. Darwin


The year is established by the relationship between this letter and the letter from John Bush, 30 March 1868.
In his letter of 30 March 1868, Bush indicated that he had lost some notes on the exact proportions of the sexes in litters of rats; CD had asked for the information in his letter to Bush of 29 February [1868].


Thanks JB for his information. Has heard of analogous cases to JB’s observations on [colours of] crossed rats; the offspring of white and grey mice are stated to be either white or grey and never piebald.

Letter details

Letter no.
Charles Robert Darwin
John Bush
Sent from
Source of text
Private collection
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 6084,” accessed on 22 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 16