[98] I took the trouble to search for this passage in Jac. Hollerii lib. de morbis internis, Parisiis 1711, 4to, but I could not find it, though the beginning of the book treats expressly of head-aches. [99] Magia Naturalis, lib. vii. [100] Kircheri Magnes, sive De Arte Magnetica, lib. iii. c. i. [101] P. Borrelli, Hist. et Observ. Medico-physic. cent. 4. obs. 75. [102] Observations sur l’usage de l’aimant en médecine, par MM. Audry et Thouret. SECRET POISON. Under this name are generally understood all poisons which can be administered imperceptibly, and which gradually shorten the life of man, like a lingering disease. They were not first discovered in the 17th century in France and Italy as many believe, but were known to the ancient Greeks and Romans, by whom they were used. I must however allow, that they were never prepared with more art at any period, or in any country, or employed oftener and with more success, than they were in these countries, and at that time. If it be true that they can be prepared in such a manner as to occasion death at a certain period previously determined, or that the person to whom they are given will die within a certain time limited, it must be confessed that the ancient poisoners have been far exceeded by the modern. But this advantage will be considered as scarcely possible, when one reflects upon the many variable circumstances which have an influence on the operation of medicines and poisons; and it has often happened that a company have swallowed the same poison, at the same time, and in the same quantity, some of whom have died sooner and some later, while some have survived. Thus died Pope Alexander VI. in the year 1503, and Cæsar Borgia recovered without any loss of health, though, by the bottles being changed through mistake, he drank of the poison that had been prepared for the other guests alone. At any rate, I am of opinion that the celebrated Tophania, when she engaged to free wives from disagreeable husbands within stated weeks and days, must have had certain and very accurate information respecting their constitution and manner of living, or, as the physicians say, their idiosyncrasy.