Certain facts in the history of the Romans prove that there was a profession of medicine in Rome even in very early times. Plutarch, in his _Life of Cato the Censor_, speaks of a Roman ambassador who was sent to the king of Bithynia, and who had his skull trepanned. By the Lex Aquilia a doctor who neglected a slave after an operation was responsible if he died in consequence, and in the Twelve Tables of Numa mention is made of dental operations. A college of Æsculapius and of Health was established in Rome 154 B.C. An inscription has been discovered in the excavations of the Palatine which has preserved the memorial of its foundation.[437] The medical profession of ancient Rome was quite free, and such instruction as its followers considered it necessary to acquire could be obtained how and where they chose. There was no uniform system of education; the training was private in early times, and was imparted by such physicians as cared to take pupils for a certain specified honorarium. It was not till later times that the Archiatri in their colleges, which were somewhat on the model of the mediæval guilds, took pupils for instruction in medicine and surgery. Pure medical schools did not exist amongst the Romans.[438] Pliny complained[439] “that people believed in any one who gave himself out for a doctor, even if the falsehood directly entailed the greatest danger.” “Unfortunately there is no law which punishes doctors for ignorance, and no one takes revenge on a doctor if, through his fault, some one dies. It is permitted him by our danger to learn for the future, at our death to make experiments, and, without having to fear punishment, to set at naught the life of a human being.”