Darwin's awesome thoughts on "Mesmerism": Posts towards a course on Society, Culture and Biology

Writing to William Darwin Fox, "one of his earliest correspondents (4)," Charles Darwin commented in December 1844:

With respect to mesmerism, the whole country resounds with wonderful facts or tales... I have just heard of a child, three or four years old (whose parents and self I well knew) mesmerised by his father, which is the first fact which has staggered me. I shall not believe fully till I see or hear from good evidence of animals (as has been stated is possible) not drugged, being put to stupor; of course the impossibility would not prove mesmerism false; but it is the only clear exerimentum crucis, and I am astonished it has not be systematically tried. If mesmerism was investigated, like a science, this could not have been left till the present day to be done satisfactorily, as it has been I believe left. Keep some cats yourself, and do get some mesmeriser to attempt it. One man told me he had succeeded, but his experiments were most vague, as was likely from a man who said cats were more easily done than other animals, because they were so electrical!

Francis Darwin ed. The Life and Letters of Charles Darwin, Including an Autobiographical Chapter, 2 volumes. (New York: Basic Books, Inc, 1959): i; p. 341