[In addition to these external uses of the magnet, in which it was supposed to act by a peculiar power over the nervous system, it has been employed on account of its true magnetic properties. Thus Kirkringius, Fabricius Hildanus, and subsequently Morgagni, have used it to remove particles of iron which had accidentally fallen into the eyes. Kircher employed it also to cure hernia. The patient took iron-filings internally; and the loadstone in the state of powder mixed with some vegetable substance, thus forming a magnetic plaster, was applied to the hernia. Even Ambrose Paré states on the authority of a surgeon, that several patients had been thus cured. About the 16th and early in the 17th century, two cases occurred, one near Prague in Bohemia, the other in Prussia, in which a knife was swallowed, but it unfortunately got too far and passed into the stomach. By the application of these magnetic plasters, the point became attracted towards the surface, so that it could be removed by incision[102]. In the 18th century, after the properties of magnets had begun to be scientifically investigated, they were made of various forms and their effects studied in numerous parts of Europe, and many treatises were published on their supposed properties. Perhaps the most important and best authenticated, are those of MM. Audry and Thouret. These experimenters believed that they were effective agents. Since that time, the use of magnets as remedial agents has been almost entirely laid aside and forgotten, it having been found that no constancy was exhibited in the results of their application, and that their occasional supposed efficacy depended upon other circumstances, which were overlooked from the sufferers’ attention being engrossed by the magnet. The application of the magnet to remove small particles of iron or steel which have accidentally fallen into the eyes, has been lately revived. In some manufactories, where these minute particles are constantly thrown off in the grinding of hardware and driven into the eyes, large magnets are kept fixed at a proper height, so that the workmen can resort to them immediately. Such is the case for instance at Fairbairne in Belgium, and we believe the same has been adopted in some of our own manufactories to catch the floating particles, and thus to prevent their being drawn into the lungs during respiration. The reader may form some idea of the effective manner in which magnets can be applied, from the following incident which occurred to Prof. Faraday, whilst experimenting with a powerful (electro-) magnet; an iron candlestick which happened to be standing near its poles on the table at which he was at work flew to them, attracted with such violence as to displace or break everything in its way.