During the plague at Marseilles, which Belort attributed to the _larvæ_ of worms _infecting the saliva, food, and chyle_; and which, he says, _were hatched by the stomach, took their passage into the blood, at a certain size, hindering the circulation, affecting the juices_ and solid parts, advised amulets of mercury to be worn in bags suspended at the chest and nostrils, either as a safeguard or as a means of cure; by which method, through the _admissiveness_ of the pores, effluvia specially destructive of all venemous insects, were received into the blood. “An illustrious prince,” continues Belort, “by wearing such an amulet, escaped the small-pox.” An Italian physician (Clognini) ordered two or three drachms of crude mercury to be worn as a defensive against the jaundice; and also as a preservative against the noxious vapours of inclement seasons: “it breaks,” he observes, “and conquers the different figured seeds of pestilential distempers floating in the air; or else, mixing with the air, kills them where hatched.” Other philosophers have ascribed the power of mercury in these cases, to an elective faculty given out by the warmth of the body; which attracts the infectious particles outwards. For, say they, all bodies are continually emitting effluvia more or less around them, and some whether they be external or internal. The Bath waters change the colour of silver in the pockets of those who use them; mercury the same; cantharides applied externally (or taken inwardly) affects the urinary organ; and camphor, in the same manner, is said to be an antiphrodesiac. Quincey informs us, that by only walking in a newly-painted room, a whole company had the smell of turpentine in their urine. Yawning and laughing are infectious; so is fear and shame. The sight of sour things, or even the idea of them, will set the teeth on edge. Small-pox, itch, and other diseases, are infectious; if so, mercurial amulets bid fair to destroy the germ of some complaints when used only as an external application, either by manual attrition or worn as an amulet, or inhaled by the nose. One word for all; amulets, medicated or not, are precarious and uncertain; and, now a-day, are seldom resorted to, much less confided in.