Some observers thought there were two kinds of itch, one caused by the acarus, the other independent of it. Bolder theorists held that the insect was the product of the disease. The dispute continued until 1834, in which year Francois Renucci, a native of Corsica, and at the time assistant to the eminent surgeon d’Alibert at the Hôpital St. Louis, Paris, undertook to extract the acarus in any genuine case of itch. As a boy he had seen the poor women extract it in Corsica, as Bonomo and Cestoni had seen others do it at Leghorn, though his learned master at the hospital remained sceptical for some years. It was near the middle of the nineteenth century before the parasitic character of itch was universally acknowledged. XI MASTERS IN PHARMACY We are guilty, we hope, of no irreverence towards those great nations to which the human race owes art, science, taste, civil and intellectual freedom, when we say that the stock bequeathed by them to us has been so carefully improved that the accumulated interest now exceeds the principal. MACAULAY: “Essay on Lord Bacon” (1837). DIOSCORIDES. It has been a subject of lively dispute whether Dioscorides lived before or after Pliny. It seems certain that one of these authors copied from the other on particular matters, and in neither case is credit given. Pliny was born A.D. 23 and died A.D. 79, and would therefore have lived under the Emperors Tiberius, Caligula, Claudius, Nero, Galba, Otho, Vitellius, and Vespasian. Suidas, the historian, who probably wrote in the tenth century, dates Dioscorides as contemporary with Antony and Cleopatra, about B.C. 40, and some Arab authorities say he wrote at the time of Ptolemy VII, which would be still a hundred years earlier. But Dioscorides dedicates his great work on materia medica to Areus Asclepiades, who is otherwise unknown, but mentions as a friend of his patron the consul Licinius Bassus. There was a consul Lecanius Bassus in the reign of Nero, and it is therefore generally supposed that Dioscorides was in his prime at that period, and would consequently be a contemporary of Pliny’s. It is possible that both authors drew from another common source.