Psychoanalyst Dan Merkur discusses Sigmund Freud’s fascination with the fungi kingdom in his paper “Freud’s Mushroom Hunting” (click for PDF). Of their frequent forays together, Freud’s son Martin said:
“Father would have done some scouting earlier to find a fruitful area; and I think one of the pointers he used was the presence of a gaily coloured toadstool, red with white dots…”
I think we all know which mushroom that was.
Although the family outings were apparently geared toward more tame, edible mushrooms, we do know that Freud was aware of the psychoactive qualities of A. muscaria, since he wrote the preface for the 1912 German translation of a book that devoted two chapters to Amanita and shamanism (Scatalogic Rites of All Nations by John G. Bourke, 1891, a book – judging from its title – which I am loathe to delve into even with the promise of late 19th century speculations on shamanic fungi).