A resumé of the state of knowledge as it was in 1956, was presented, in Question and Answer form, in the British Medical Journal, Jul 14, 1956; 2(4984): p.112. [page 2 in the pdf]
“Q.-What is the technique of wart charming?
A.-The process whereby warts, the result of a virus infection, can be affected by psychogenic influences, as occurs in wart charming, is not understood. It would seem that nervous impulses from the cerebrum must affect the skin, in some way producing conditions unsuitable for the growth of warts. Perhaps there is an alteration in the blood supply or in the moisture of the skin. Certainly sweating predisposes to warts. The technique of wart charming is as varied as it is ancient. It is often based on a form of magic, the intention being to transfer the warts to some other person or animal or object. Thus the warts may be touched by a lump of raw beefsteak, which is then buried at midnight at a crossroads in the light of a full moon. The warts disappear, having been transferred to the meat. The moon was thought to have considerable influence on warts. Sir Kenelm Digby in the seventeenth century had an infallible cure. The hands were washed by the light of moonbeams in a polished silver basin in which was no water. Alternatively, warts might be transferred to an animal such as a black slug or a toad. If someone who has no warts kills the toad, then he will get as many warts as the toad has spots.
Sir James Frazer, in The Golden Bough, mentions a fourth-century cure for warts. You touch your warts with as many little stones as you have warts. Then wrap the stones in an ivy leaf and throw them away. Whoever picks them up will get the warts and you will be rid of them. The wart charmer in Ireland would visit a village, make a careful note in his hat of the number of your warts, and take them with him on his departure. The buying of warts by a friend is still, at times, found efficacious. X-radiation in small doses and hypnotism are other techniques now practised in wart charming.”
Note: As far as Improbable is aware, since 1956, no further progress has been made regarding the understanding of how psychogenic influences might affect warts. If you have information to suggest otherwise, please let us know by commenting below.
Coming soon: Charming Warts (part 2)