ALS, one page, 5 x 8, Down Bromley letterhead, February 25, 1868. Letter to zoologist Henry Lee. In full: “I am very much obliged for your kindness in sending me the results about the sexes of trout. I am anxious to ascertain approximately the proportional number of the sexes in any animals; but there are so many causes of error that I fear I shall not succeed. With my best thanks for your information.” In fine condition, with central horizontal and vertical folds, with vertical fold passing through a single letter of signature. Accompanied by the original mailing envelope addressed in Darwin’s hand.
Busy at work on his second book on evolutionary theory, The Descent of Man, and Selection in Relation to Sex, Darwin was wrestling with the issue of how to explain the near equal proportion of sexes in conjunction with natural selection. Outlining the basic principles of sexual selection in the second section of the book, Darwin provided a detailed review of many different taxa, including a specific chapter on cold-blooded vertebrates, in which his research on trout came to use. He offered a brief description of frequency-dependent selection in the book’s first edition, released in 1871—the logic that the probability of an individual being able to breed is dependent on the frequency of the opposite sex in relation to its own—but with lingering questions, removed it from the second edition. An excellent note touching on a subject that Darwin eventually left for future generations to investigate. Pre-certified John Reznikoff/PSA/DNA and RR Auction COA.
Terms and abbreviations used in our descriptions.