His thanks for the extracts sent by SB.
Down | Bromley | Kent
My dear Sir
I write merely to say that I have received the extracts, which you have so kindly made for me, & which I am extremely glad to see, as showing how many varieties existed or exist in China.— In the midst of your many & important studies it is very kind of you to give up so much of your time to help me.
Believe me | Yours truly obliged | Charles Darwin
- f1 1851a.f1The year is suggested by the relationship to the letters to Samuel Birch, 6 February  and [12 March 1856] (Correspondence vol. 6).
- f2 1851a.f2CD visited Birch, the assistant keeper in the department of antiquities of the British Museum, on14 March 1856. CD cited Birch's translations of passages from an ancient Chinese encyclopedia describing breeds of domesticated fowl in Variation 1: 238, 246--7.