Methamphetamine
Methamphetamine was first synthesized by a Japanese chemist in 1893. Early on, before the adverse effects of the drug were taken into consideration, meth was used to treat a variety of ailments, such as narcolepsy and asthma, and was also used as a weight-loss drug.
#18 The idea is that of sympathetic (imitative) magic : mices have good teeth, so they are good for ailing teeth... the same kind of "reasoning" is always used nowadays in... homeopathy !
#19 Some trepanated prehistoric patients have survived long enough for the bone to grow again around the opening !
#1 Maybe one was supposed to have masturbated with a handful of cornflakes. That certainly would have made it a lot less fun. (Cream on your cornflakes, anyone?)