Did Poincaré say ``Set theory is a disease''? (Q752679)

The author has carefully researched the alleged quotation in the title of the paper, finding that it began with a footnote on the last page of \textit{O. Hölder}'s 1924 book Die mathematische Methode, from which it was picked up by James Pierpoint and reported to the AMS at a meeting in Nashville in 1928. From that point on it became a ``fact'' widely quoted in both popular and scholarly histories of mathematics. In fact no written record of Poincaré's having made such a remark at the 1908 International Congress (where he is alleged to have done so) exists, and neither Hölder nor Pierpoint was at the Congress.