The oldest Egyptian king, Menes, and Attalus Phylometer, the last king of Pergamus, were both learned in the knowledge of the properties of plants. The latter monarch also knew something of their medicinal uses, and was acquainted with henbane, aconite, hemlock, hellebore, etc. Other Egyptian rulers cultivated the art of medicine, and there is little doubt that, probably through the priests, who were the chief practitioners of the art of healing, they gathered a considerable knowledge of the properties of many poisonous and other herbs. Prussic acid was known to the Egyptians, and prepared by them in a diluted form, from the peach and other plants. It is highly probable, indeed, that the priests had some rudimentary knowledge of the process of distillation, and prepared this deadly liquid from peach leaves or stones, by that method. The "penalty of the peach" is alluded to in a papyrus now preserved in the Louvre, which points to the liquid being used as a death draught. The ancient Greeks, like the Chinese of to-day, looked upon suicide, under certain conditions, as a noble act, for which poison was the usual medium. Their "death cup" was mainly composed of the juice or extract of a species of hemlock, called by them cicuta. The Chinese, from remote times, are supposed to have used gold as a poison, especially for suicidal purposes, and at the present day, when a high official or other individual puts an end to his life, it is always officially announced, "He has taken gold leaf"; a curious phrase, which probably has its origin in antiquity. Nicander, of Colophon, a Greek physician, who lived 204-138 B.C., in his work on "Poisons and their Antidotes," the earliest on the subject known, describes the effects of snake venom and the properties of opium, henbane, colchicum, cantharides, hemlock, aconite, toxicum (probably the venom of the toad), buprestis, the salamander, the sea-hare, the leech, yew (decomposed), bull's blood, milk, and certain fungi, which he terms "evil fermentations of the earth"; and as antidotes for the same he mentions lukewarm oil, warm water, and mallow or linseed tea to excite vomiting. The same writer also made a rough classification of the poisons known in his time, twenty-two in all, and divided them into two classes--viz., "those which killed quickly," and "those which killed slowly." Of the minerals, arsenic, antimony, mercury, gold, silver, copper, and lead were used by the Greeks; the antidote recommended in case of poisoning being hot oil, and other methods to induce vomiting and prevent the poison being absorbed into the system. Bull's blood is classed as a poison by various ancient writers, and it is recorded that Æson, Midas King of Phrygia, Plutarch, and Themistocles, killed themselves by drinking bull's blood. It is probable that some strong poisonous vegetable substance, such as cicuta, was mixed with the blood.