Just got back from a short trip to upstate NY where I picked up a copy of a book called This Noble Harvest by Anne Ophelia Dowden (1979). It calls Datura stramonium "thorn apple" (I had forgotten about that one) and says the following:
"Belladonna, thorn apple, and henbane are such plants - all extremely poisonous, and all belonging to the same family as tomato, potato, and tobacco. Their leaves roots, and seeds contain the narcotic alkaloids atropine and hyoscyamine, which work on the central nervous system....In modern medicine, henbane is an ingredient in the drug that produces 'twilight sleep' in childbirth; and most wartime brain-washing involved hyoscyamine, plus scopalomine (from another plant of the same family*) and morphine or a barbiturate. The scientific name Hysocyamus means "hog-bean" because swine are supposed to eat it safely. It stupefies other animals, and its seeds, with those of thorn apple, were sometimes mixed with the fodder of horses and cows in the hope that placid animals would gain weight more quickly. Thorn apple boiled in hog's grease, was widely used for burns and inflammations, and Parkinson approves it as a drink for 'one that is to have a legge or an arme cut off.' It is often called jimsonweed in the United States because it was first introduced near Jamestown, Virginia. Though this plant came to us from Europe, a similar species is native to South America, where Incas used it as an anesthetic, and a Colombian tribe gave it to wives and slaves before burying them alive with dead warriors."
* the asterisk is mine - I don't know why she doesn't say scopalomine can come from datura, but it can.
Hope you all find this as interesting as I did!