STONES OP HEALING	119
	Medieval medical literature has no more interesting example than the treatise entitled "Thesaurus Pauperum," or the "Poor-man's, Treasury," written by Petrus· His-panus,. who later reigned for a brief period as pope under the name of John XXI (1276-1277). The birthplace of the author was Lisbon in Portugal, and he studied for some time at the University of Paris, where his learning earned him high praise. Prior to his election as pope, he served for a time as first physician to Pope Gregory X (1271-1276). Most of the remedies prescribed in this little treatise are naturally such as had long been popular among the peasantry, and the ingredients of which could easily be secured; vegetable growths, plants, herbs and flowers, and certain parts of the more common animals, served here, as in Pliny's day and earlier still, as those most highly favored. Of the comparatively few mineral substances whose use is recommended may be noted the red variety of chelidonius or "swallow stone," for the cure of epilepsy; the powder of the "iris" (probably an iridescent variety of quartz) was also a cure for epileptics. Then we find, strange to say, a recommendation of such costly remedial agencies as emerald and sapphire, either of which if touched on the eye would heal diseases- of that organ. Cold stones placed on the temples and tightly bound on were said to arrest bleeding from the nose, and coral was a great help in syncope. For stone in the bladder two mineral substances, "humus" and ' ' songie, ' ' are warmly recommended (the former can scarcely be held to signify mere "soil"), as are also "stones found in the gizzards of cocks" (the alectorius) and those from the bladders of hogs. All these were to be reduced to powder, dissolved in liquid, and taken in the form of potions. The use of stones and coral rather as amulets or talismans than as remedies is occasionally mentioned. Thus the loadstone, if worn, is said to remove discord between man and woman;