of every root and the uses to which can be put mere slim threads of vegetation, and turning to healthful purposes that which the very beasts refuse to touch as food.

II. This subject was less popular with our countrymenRoman writers on the subject. than it should have been considering their vast appetite for all things useful and good; the first student of it, and for a long time the only one, being that same Marcus Cato, the master of all excellent crafts, who merely touched briefly the subject, without neglecting even veterinary medicine. After him one only of our distinguished men has tried his hand at the subject, Gaius Valgius, an author of approved scholarship, who left unfinished a work dedicated to the late emperor Augustus, beginning also his preface with a devout prayer that his Imperial Highness should always, and above all others, be the healer of every human ill.

III. Before Valgius the only Roman who had written on this subject, as far as I can discover, was Pompeius Lenaeus, a freedman of Pompeius Magnus, in whose day, I find, scientific treatment of it first found a home among Roman students. For it was Mithridates, the greatest king of his time, whomMithridates. Pompeius vanquished, that was, we know by evidence as well as by report, a more attentive investigator of life’s problems^a than any of those born before him. By his unaided efforts he thought out the plan of drinking poison daily, after first taking remedies, in order that sheer custom might render it harmless; he was the first^b to discover the various antidotes, one of which is even known by his name; he also discovered the mixing with antidotes of the blood of Pontic ducks, because