LITTLE is known about itching. Editors know that "itching" is a
much safer noun to use than "pruritus," a word misspelled by
about half the medical profession and their amanuenses in the
conviction that the ultimate syllable contains an inflammatory
"i." People in general know that mosquito bites cause itching.
So do, say the experimenters, histamine, kinins, certain
proteolytic enzymes and cowage ("A tropical woody vine `mucuna
pruriens' having crooked pods covered with barbed brittle hairs
which cause intolerable itching. Also, these hairs, mixed with
honey or other vehicle, used as vermifuge"). Although substances
have been identified that do cause itching, the neurochemistry
of the common spontaneous itch remains obscure. Similarly
uncertain is the modality of the sensation. The conventional
view, summarized as long ago as 1941, is that an itch is a
nonpainful pain. In other words, itching is the result of weak
stimulation of pain receptors. According to