Many physicians consider it professional to keep their remedies secret, and boast of private formulas, which they will not share with their rivals. In Tiberius’s day there was a Paccius Antiochus who prepared a marvellous powder, a kind of panacea for many ills. He compounded it behind locked doors and mystified even his assistants as to its nature; but on his death he had the decency to bequeath his formula to the Emperor who had it deposited for inspection in all the public libraries; and Hadrian has just done the same with some formulas left by the great Marcellus of Side. =142. Absurd Medicines. Theriac.=--Some of these remedies are of an extraordinary nature and so intelligent a man as Symmachus can have no confidence in them. Still plenty of good doctors will tell you that a piece of hyena-skin is an excellent remedy for mad-dog bites, and that certain very filthy substances make good poultices for swellings. The imperial government actually employs several slaves to catch adders, whence are derived several important medicaments; and it is claimed that medicines to cure gall-stones must be pounded with a pestle that contains no iron. There is no need to dwell on the absurd articles foisted on the gullible by the quacks; pills made from dried bugs and centipedes are among the very least obnoxious. There is supposed to be a specific medicine for every disease, and Symmachus’s office is crammed with little chests bearing such labels as “_Drug from Berytus for watery eyes. Instantaneous_”; “_Ointment for gout. Made for Proculus, imperial freedman. Safe Cure_”; “_Remedy for scab. Tested successfully by Pamphilius during the great scab epidemic_,” or “_Eye-salve tried by Florus on Antonia, wife of Prince Drusus, after other doctors had nearly blinded her_.”[82] There is also a large box of a famous compound to be used whenever diagnosis is uncertain. _Theriac_ is a mixture of sixty-one different elements including dried adders. Whoever takes it is sure to find at least _one_ substance that will assist his disease; and it is prescribed by almost every physician at the opening stages of a malady, before he can attempt diagnosis. =143. Fear of Poisoning. Popularity of Antidotes.=--A large part of the doctor’s drug collection is, however, made up of _antidotes_ for poisons. Everybody dreads being poisoned. Many peculiar deaths which ought to be diagnosed as caused by natural illness are charged up to venomous drugs[83] and indeed a deadly dose rather than a deadly dagger seems a favorite means for murder. People still whisper stories of that awful poison-vender, the woman Locusta, who probably supplied Nero’s mother Agrippina with the fatal powder she sprinkled on her husband Claudius’s dish of mushrooms, and then another dose to Nero himself to kill his stepbrother, Britannicus, with a highly spiced goblet.