Dioscorides throws a further light on the poisons of antiquity in his great work on Materia Medica, which for fifteen centuries or more remained the chief authority on that subject. He mentions cantharides, copper, mercury, lead, and arsenic. Among the animal poisons are included toads, salamanders, poisonous snakes, a peculiar kind of honey, and the blood of the ox, probably after it had turned putrid. The sea-hare is frequently alluded to by the ancient Greeks, and was evidently regarded by them as capable of producing a very powerful poison. Domitian is said to have administered it to Titus. It is supposed to have been one of the genus _Aplysia_, among the gasteropods, and is described by the old writers as a dreadful object, which was neither to be touched nor looked upon with safety. Among the poisonous plants enumerated by Dioscorides are the poppy, black and white hellebore, henbane, mandragora, hemlock, elaterin, and the juices of species of euphorbia, and apocyneæ. Medea is said to have been the first to introduce colchicum. The black and white hellebore were known to the Romans, and used by them as an insecticide, and Pliny states that the Gauls used a preparation of veratrum to poison their arrows. Arsenic was employed by the Greeks as a caustic, and for removing hair from the face; while copper, mercury, and lead were used in their medical treatment. The study of poisons was forbidden for a long period, and Galen mentions the fact that only a few philosophers dared treat the subjects in their works. In the East, poisons have been used from remote times, not only for the destruction of human life, but also for destroying animals--arsenic, aconite, and opium being employed by the Asiatics for these purposes. The Hindoos have many strange traditions concerning poisons, some being attributed with the property of causing a lingering death, which can be controlled by the will of the poisoner. But this is doubtless more legendary than correct. One curious and mysterious substance mentioned by Blyth, and known in India as _Mucor phycomyces_, is stated to be a species of fungi. When the spores are administered in warm water they are said to attach themselves to the throat and rapidly develop and grow, with the result that in a few weeks, all the symptoms of consumption develop, and the victim is rapidly carried off by that fatal disease. The early Hebrews were also acquainted with certain poisons, the words, "rosch" and "chema" being used by them as generic terms. Arsenic was known to them as "sam," aconite as "boschka," and ergot probably as "son."