Peter of Spain, a native of Lisbon, was a physician who became Pope
under the title of John XXI. He died in 1277. He wrote a treatise on
medicine, or rather made a collection of formulas, including most of
the absurd ones then current and adding a few of his own. One was to
carry about a parchment on which were written the names of Gaspard,
Balthasar, and Melchior, the three wise men of the East, as a sure
preservative from epilepsy. Another was a method of curing a diarrhœa
by filling a human bone with the excrements of a patient, and throwing
it into a river. The diarrhœa would cease when the bone was emptied of
its contents.