Andromachus, physician to the emperor Nero, invented the most celebrated of these preparations; it was known as the _Theriaca Andromachi_, and was very similar to that of Mithridates, king of Pontus, the recipe for which was said to have been found amongst his papers after his death by Pompey. This was known to the Roman physicians under the name of _Antidotum Mithridatium_. The composition of this medicine was varied greatly in the hands of its different preparers, and it underwent considerable alterations from age to age. Celsus first described it, with its thirty-six ingredients; then Andromachus added to it the flesh of vipers, and increased the number of ingredients to seventy-five. He described the whole process of manufacture in a Greek poem, which has been handed down to us by Galen. Damocrates varied some of the proportions of the compound, and wrote another poem upon it, also preserved by Galen. The medicines prescribed by the Greek and Roman physicians were all prepared by themselves. At that time materia medica consisted chiefly of herbs; some of these plants were used not only for medicinal, but also for culinary purposes, and were collected by other than practitioners of medicine. Many plants were used also for cosmetic purposes and in the baths, so that there must have been numerous collectors and dealers in herbs. Just as in our time dispensing chemists and others have acquired a certain knowledge of the medicinal virtues of the things they sell, so the _pigmentarii_, _seplasiarii_, _pharmacopolæ_, and _medicamentarii_ possessed themselves of medical secrets, and thus invaded the territory of the doctors. Beckmann says[477] that the _pigmentarii_ dealt in medicines, and sometimes sold poison by mistake. The _seplasiarii_ sold veterinary medicines and compounded drugs for physicians.[478] The _pharmacopolæ_, according to Beckmann, were an ignorant and boasting class of drug-sellers. The _medicamentarii_ seem to have been a still more worthless class, for in the Theodosian code poisoners are called medicamentarii. A great number of the medical plants mentioned by Pliny, Dioscorides, and other writers on materia medica were used for quite other purposes than those for which we employ them now. Some drugs, however, were apparently given on what we must admit to be correct scientific principles. Thus Melampus of Argos, one of the oldest Greek physicians of whom we have any knowledge, is said to have cured Iphiclus of sterility by administering rust of iron in wine for ten days. He gave black hellebore as a purgative to the daughters of Proetus when they were afflicted with melancholy. Preparations of the poppy were known to have a narcotic influence, and the uses of prussic acid—in the form of cherry laurel water—stramonium, and lettuce-opium were well understood. Squill was employed as a diuretic in dropsy by the Egyptians.