Themison, who lived at Rome in the reign of Augustus Cæsar, and who is said to have been the first physician to have distinguished rheumatism from gout, is noted in pharmacy as the author of the formulæ for Diagredium and Diacodium. He praised the plantain as a universal remedy, and is also the earliest medical writer to mention the use of leeches in the treatment of illness. Several of the writers on medical subjects of this period adopted the method of prescribing their formulas and the instructions for compounding them in verse. The most famous instance is that of Andromachus, physician to Nero, whose elegiac verses describing the composition of his Theriakon are quoted by Galen. The idea was that the formula thus presented was less likely to be tampered with. Theriakon as invented contained 61 ingredients. Its principal improvement on the more ancient Mithridatum was the addition of dried vipers. Andromachus appears to have acquired a large and lucrative practice in Rome at the time when wealth was most lavishly squandered. Among other medical verse writers were Servilius Damocrates, who lived in the reign of the Emperor Tiberius, and who invented a famous tooth powder, a number of malagmata, (emollient poultices), acopa (liniments for pains), electuaries, and plasters; and Herennius Philon, a physician of Tarsus (about A.D. 50), whose fame rests on his philonium, a compound designed to relieve colic pains, which appear to have been specially frequent at that period. This philonium was composed of opium, saffron, pyrethrum, euphorbium, pepper, henbane, spikenard, and honey. Menecrates, physician to Tiberius, and said to have written 155 works, was the inventor of diachylon plaster, but his diachylon was a compound of many juices (as the name implies) along with lead plaster. The Romans were curiously badly off for regular doctors until Julius Cæsar specially tempted some to come from Greece and Egypt by offers of citizenship. Augustus, too, warmly encouraged the settlement in the city of trained medical men. PHARMACY IN THE ROMAN EMPIRE. The separation of the practices of medicine, pharmacy, and surgery, which became general though never universal, was of course a gradual process. Galen expresses the opinion that Hippocrates prepared the medicines he prescribed with his own hands, or at least superintended the production of them. According to Celsus, it was in Alexandria and about the year 300 B.C. that the division of the practice of medicine into distinct branches was first noticeable. The sections he names were Dietetics, Surgery and Pharmaceutics.