This poison was much used at Rome about two hundred years before the Christian æra. As several persons of distinction died the same year at that period, and of the like distemper, an inquiry being made into the cause, a maid-servant gave evidence against some ladies of the first families, who, she said, prepared and distributed poison; and above a hundred and fifty of them were convicted and punished[109]. As so many had learnt this destructive art, it could not be suppressed; and we find sufficient proofs in the Roman history that it was continually preserved. Sejanus caused such a secret poison to be administered by an eunuch to Drusus, who gradually declined afterwards, as by a consumptive disorder, and at length died[110]. Agrippina, being desirous of getting rid of Claudius, but not daring to despatch him suddenly, and yet wishing not to leave him sufficient time to make new regulations respecting the succession to the throne, made choice of a poison which should deprive him of his reason, and gradually consume him. This she caused to be prepared by an expert poisoner, named Locusta, who had been condemned to death for her infamous actions, but saved that she might be employed as a state engine. The poison was given to the emperor in a dish of mushrooms; but as, on account of his irregular manner of living, it did not produce the desired effect, it was assisted by some of a stronger nature[111]. This Locusta prepared also the poison with which Nero despatched Britannicus, the son of Agrippina, whom his father Claudius wished to succeed him on the throne. As this poison occasioned only a dysentery, and was too slow in its operation, the emperor compelled Locusta by blows, and by threatening her with death, to prepare in his presence one more powerful. It was first tried on a kid; but as the animal did not die till the end of five hours, she boiled it a little longer, until it instantaneously killed a pig to which it had been given, and this poison despatched Britannicus as soon as he had tasted it[112]. For this service the emperor pardoned Locusta, rewarded her liberally, and gave her pupils whom she was to instruct in her art, in order that it might not be lost. The art of preparing this poison must have been well understood also at Carthage. When M. Attilius Regulus, the Roman general, who had been taken by the Carthaginians, was sent to Rome to propose to the senate that the Carthaginian prisoners might be restored in exchange for him, he prevented this negotiation, because he knew that a poison had been administered to him, by which the state would soon be deprived of his services. He returned, therefore, to Carthage, in compliance with the promise he had made to the enemy, who put him to death with the most exquisite torture[113].