The means of procuring the vigour necessary for sexual delights has also been sought for in certain preparations celebrated by the alchymists. Struck by the splendour of gold, its incorruptibility, and other rare qualities, some physicians imagined that this metal might introduce into the animal economy an inexhaustible source of strength and vitality; while empirics, abusing the credulity of the wealthy and the voluptuous made them pay exorbitantly for aphrodisiacal preparations in which they assured their dupes that gold, under different forms, was an ingredient. Among innumerable other instances, is that of a French lady who, to procure herself an heir, strove to reanimate an exhausted constitution by taking daily in soup what she was made to believe was potable gold, to the value of 50 francs, a fraud to expose which it suffices to say that the largest dose of perchloride of gold that can be safely administered is 1/6th of a grain. The tincture of gold known by the name of _Mademoiselle Grimaldi's potable gold_ enjoyed a wonderful reputation towards the close of the 18th century as an efficacious restorative and stimulant; and numerous instances of its all but miraculous powers were confidently adduced. Dr. Samuel Johnson, indeed, in a note upon a well-known passage in Shakespeare,[164] denies the possibility of making gold potable: "There has long," he observes, "prevailed an opinion that a solution of gold has great medicinal virtues, and that the incorruptibility of gold might be communicated to the body impregnated with it. Some have pretended to make gold _potable_ among other frauds practised upon credulity." So far back, however, as the 17th century the Abbé Guence shewed that it was feasible, and even described the process minutely; and it is now known to every chemist that gold is susceptible of entering into immediate combination with chlorine by the agency of heat, that it may even be dissolved in water charged with chlorine, and that various methods exist of obtaining chlorate of gold, a combination which is often successfully employed in the treatment of syphilitic cases. Ether, naptha, and essential oils take gold from its solvent, and form liquors which have been called _potable_ gold.