[Letter] 1875 Jan 4 [to an unnamed correspondent] / Francis Galton. [3p. on 1 leaf, holograph signed. Accepts an offer, "having a great curiosity to learn something about Lichens". Informs that Dr Hooker at Kew has been carrying out experiments for him which he hopes will throw light on "reversion" and "variation". Asks if his correspondant knows any twins]