Historical study reveals that Darwin rather than Lamarck is the more likely source of Freud's neo-Lamarckianism. Freud's single scientific reference to Lamarck is in his paper "On Coca," in which he cites a 1783 paper by Lamarck on the same subject. Lamarck's evolutionary ideas, in contrast to the invertebrate classification for which he was justly famous, had been ignored or scorned in the

period of Freud's education, until Haeckel sought precursors for Darwin. Freud's interest in Lamarck appears about World War I when he proposed to Ferenczi a joint work on Lamarckianism and psychoanalysis. But nothing came of it.