Unless therefore those modern chymists, who assert the perfect innocence of antimony, expect from us that implicit confidence which their predecessors, who held a very different opinion, rigorously exacted, it cannot, on their authority, be admitted that it does not contain arsenic. Wonderful as the works are which they have atchieved, many secrets of nature have escaped their researches, which may hereafter be discovered, and many will, undoubtedly, elude all human investigation.
Nor is more credit due to those who assert that all arsenical particles are volatilised, and carried off by the force of fire; the crocus, regulus and glass of antimony containing such subtil virulent particles as must for ever escape observation, since without losing in any degree their specific gravity, they impart, almost inexhaustibly, an emetic power to wine and other liquors, and the operation of these essences of antimony, as they have been emphatically called, is similar to those of arsenic.[34]
But although, in opposition to the testimony of the best chymical writers, it should be granted that there is no arsenic in antimony, it cannot be affirmed, that it does not contain poison, since by unfolding its texture by the force or fire, it is rendered highly virulent; and by the addition of various substances, in the stomach, it becomes violently emetic[35].
By those who assert the perfect innocence of antimony, and extol its virtues, orpiment is allowed to be a poisonous substance, and giving it as a medicine, is declared a practice too dangerous to be followed[36], yet it is ranked by Hoffman with antimony. It ought to be remarked, says he, that orpiment was known to the ancient philosophers and physicians, and universally deemed a poison, and to this day is sold for arsenic. Yet it does not, when taken internally, give any molestation, either by vomiting or purging, and may be given, in a large quantity, to dogs, without hurting them. But if it is exposed to the fire, then, indeed, it acquires a poisonous quality, as is also the case with antimony, which, though in its natural crude state, it is rather a medicine than a poison, yet when melted by fire it exerts a violent emetic power[37].
Crude white arsenic, the most virulent poison of that tribe, is not always baneful[38]. It is now more than twenty years since it was taken in large quantity by four persons, on whom it had no other effect than, what is usually produced by antimonial preparations, to excite violent vomiting. All of them were lately, and, I believe, are still in perfect health. To this I was an eyewitness, and took large lumps of white arsenic out of the pot in which their victuals were prepared. It happened at Kelso, in the shire of Roxburgh, and is well known in that country.
I was a few years afterwards, desired to visit a gentleman in Northumberland, who had taken white arsenic: it operated in the same manner, and for several years after this accident he continued in his usual health.
Thus far does arsenic resemble antimony, but their affinity is still more strongly asserted by Hoffman. While, says he, the sulphureous part of antimony is intimately combined with the arsenical or reguline[39]; it cannot exert its violence. For mineral poisons cannot act or become noxious, till the poisonous parts are freed from their union with those which correct their virulence.
But that mineral sulphur has a power of correcting poison, is clearly proved by that experiment which shews, that arsenic, the greatest poison, being melted on a slow fire, with an equal portion of mineral sulphur, is converted into a mass, almost void of virulence; and if regulus of antimony is fused with an equal portion of the same sulphur, it immediately loses its drastic power[40].
This theory probably introduced an arsenical medicine into practice at Berlin, where Hoffman, who was physician to the king of Prussia, resided. Newman, professor of chymistry and director of the Royal Elaboratory and Dispensatory in that city, observes, that chymistry is capable of converting sundry poisons into remedies; thus the virulent antimonial regulus is changed, by that art, into the mild diaphoretic antimony; and some have been hence induced to imagine, that arsenic might also be corrected and rendered safe, and have even ventured to put so dangerous a speculation in practice. A preparation of arsenic with nitre has been actually sold at Berlin, and in other places, under the title of a specific febrifuge[41].