Darwin, Charles Robert to Francis Galton Letter from Darwin informing Galton that Dr Ogle has twin sisters, and that one of their children has a misplaced biscuped tooth, which may or may not be a case of reversion. Darwin also recommends a book by Puvis, "Sur la dgnration" [M A Puvis, De la dgnration des varits de vgtaux (1837). The letter is signed by Darwin, but written in an unknown hand, possibly that of a secretary. 25 Sep 1875