The eye-agates were sometimes used to form the eyes of idols. At a later period some of these “agate-eyes” were removed from the statues and cut with a glyptic subject on the lower side. Some of the most interesting antique gems are of this kind. In Aleppo (and elsewhere in the East) there is a certain type of sore known as the “Aleppo button” or “Aleppo boil.” The boil frequently does not appear for a long period after infection has taken place. It often appears as a swelling surrounded by a white ring, and there is a belief among the natives that there are “Aleppo stones,” these being the so-called “eye-agates” frequently produced by cutting a three-layer, naturally pale yellow or pale gray agate, with intervening white zones in such a way that it looks like an eye or a double-eye, and such stones are used in alleviation of the Aleppo sore. What beneficial influence they may have is due to the fact that the agate is cold and furnishes a little relief for the time. This “Aleppo boil” or “Oriental sore” so prevalent in many parts of western Asia, is produced, according to the best authorities, by a pathogenic organism _Leishmania tropica_ (Wright) 1903. As to the means by which this organism is introduced into the human subject nothing very definite is known, but mosquitoes or _Phlebotomus_ have been suggested as possible transmitting agencies.[216] The eye of some invisible monster, the eye of the dragon, the eye of the serpent, were all regarded as possessed of malign power. It is well known that in the East Indies a peacock’s feather is thought to bring ill-luck, the eye in the feather being the baleful point. Even in our own time, and among those for whom this primitive superstition has no terrors, the humorous use of the idea—as shown, for instance, in the “Dick Dead-Eye” of Gilbert and Sullivan’s “Pinafore”—proves that the Evil Eye is familiar to our thoughts. For this reason, stones such as those which have been named the cat’s-eye, the tiger’s-eye, or the oculus Beli, always possess a certain strange interest. One of the earliest descriptions of the opal in English is that written in the reign of Queen Elizabeth by Dr. Stephen Batman (d. 1584). While the passage is essentially a translation from the “De proprietatibus rerum,” of Bartolomæus Anglicus, the English version is interesting in itself as showing what was accepted by English readers of the time regarding the virtues of the opal. There is, of course, no trace of the foolish modern superstition touching the ominous quality of this beautiful gem. Batman writes:[217]