IN 1923 Paul Kammerer summarised research which he claimed demonstrated the inheritance of acquired characteristics. Since the success of Mendelian genetics had already made Kammerer's work suspect a report of his lecture1 was followed by a long and acrimonious debate. The Kammerer case thereby became a cause celebre in the biology of that decade. The controversy has recently been resurrected in a popular book by Koestler2 and has gained additional prominence from an internationally televised BBC documentary based on the book. This paper reports a failure to duplicate one of Kammerer's key experiments.