I’ve written before about the failed Soviet-era attempts to hybridize humans and chimpanzees “King Kong humanzee trivia”. I’ve been updating my knowledge in this area of history, and am reading the very useful 2002 article by Kirill Rossiianov that recounts Ivanov’s work and the development of his interest in cross-breeding humans and anthropoid apes
Changes in social and financial conditions during the Civil War caused many Russian scientists to abandon their former research topics. Ivanov, apparently, also felt the need to find new avenues, new patrons, and possibly new sites for research, which may explain why, in 1922, he asked his young research associate Mikhail Nesturkh to start making abstracts for him from a number of sources on anthropogenesis and primate biology. In several letters written to the American biologist Raymond Pearl during that year he indicated that he was thinking about experiments on apes and, in particular, about hybridization between man and chimpanzee.