[Although not very agreeable to the reader to learn that he swallows above six pounds of mill-stone powder in the course of the year, it may perhaps ease his mind to know that the learned author is entirely mistaken in regarding it as a poison. The inhabitants of the northern countries of Europe frequently mix quartz powder with their heavy food to assist in its digestion; and we are informed by Professor Ehrenberg, that in times of scarcity, the inhabitants of Lapland mix the siliceous shells of some species of fossil Infusoria with the ground bark of trees for food. It is probably from this circumstance that the infusorial deposit derives its name of _Berg-mehl_, or _Mountain-meal_.] [134] For the following important information I am indebted to Professor Baldinger:--“There is no doubt that the slow poison of the French and Italians, commonly called succession powder (_poudre de la succession_), owes its origin to sugar of lead. I know a chemist who superintends the laboratory of a certain prince on the confines of Bohemia, and who by the orders (perhaps not very laudable) of his patron, has spent much time and labour in strengthening and moderating poisons. He has often declared, that of sugar of lead, with the addition of some more volatile corrosive, a very slow poison could be prepared; which, if swallowed by a dog or other animal, would insensibly destroy it, without any violent symptoms, in the course of some weeks or months.” [135] Garelli, the emperor’s principal physician, lately wrote to me something remarkable in the following words:--“Your elegant dissertation on the errors respecting poisons brought to my recollection a certain slow poison, which that infamous poisoner, still alive in prison at Naples, employed to the destruction of upwards of six hundred persons. It was nothing else than crystallised arsenic, dissolved in a large quantity of water by decoction, with the addition, but for what purpose I know not, of the herb cymbalaria. This was communicated to me by his imperial majesty himself, to whom the judicial procedure, confirmed by the confession of the criminal, was transmitted. This water, in the Neapolitan dialect, is called _aqua del Toffnina_. It is certain death, and many have fallen a sacrifice to it.”--Hoffmanni Med. Rationalis System., p. ii. c. 2. § 19. [136] Ueber die Arsenikvergiftung. Leips. 1786, 8vo, p. 35.