This changed his disease into leprosy which in its turn was cured by drugs which the god prescribed. [Sidenote: Theriac.] The flesh of vipers was an important ingredient in the famous antidote and remedy called theriac, concerning which Galen wrote two special treatises[790] besides discussing it in his works on simples and antidotes. Mithridates, like King Attalus in Galen’s native land, had tested the effects of various drugs upon condemned criminals, and had thus discovered antidotes against spiders, scorpions, sea-hares, aconite, and other poisons. He then combined the results of his research into one grand compound which should be an antidote against any and every poison. But he did not include the flesh of the viper, which was added with some other changes by Andromachus, chief physician to Nero.[791] The divine Marcus Aurelius used to take a dose of theriac daily and it had since come into general use.[792] Galen gives a long list of ills which it will cure, including the plague and hydrophobia,[793] and adds that it is beneficial in keeping a man in good health.[794] He advises its use when traveling or in wintry weather, and tells Piso that it will prolong his life.[795] He explains more than once[796] how to prepare the viper’s flesh, why the head and tail must be cut off, how it is cleaned and boiled until the flesh falls from the backbone, how it is mixed with pounded bread into pills, how the flesh of the viper is best in early summer. Galen also accepts the legend,[797] quoting six lines of verse from Nicander to that effect, that the viper conceives in the mouth and then bites off the male’s head, and that the young viper avenges its father’s death by gnawing its way out of its mother’s vitals. The _Marsi_ at Rome denied the existence of the _dipsas_ or snake whose bite causes one to die of thirst, but Galen is not quite sure whether to agree with them. [Sidenote: Magical compounds.]