Lobotomy
In the early 20th century, when methods of treating mental illnesses were scarce, an invasive procedure called lobotomy was invented. Despite the lack of evidence that this procedure, during which the nerve pathways in the lobes of the brain are severed, has any positive effects in treating illnesses, lobotomy became widely used. Active campaigning for the effectiveness of lobotomy and the spread of misinformation in the media led many to believe that lobotomy was a miracle cure. Only years later was the procedure recognized as one of the most shameful and tragic events in medical history.
#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?)