(Ἀρχάγαθος), a Peloponnesian the son of Lysanias, who settled at Rome as a practitioner of medicine, B. C. 219, and, according to Cassius Hemina (as quoted by Pliny, Plin. Nat. 29.6), was the first person who made it a distinct profession in that city. He was received in the first instance with great respect, the "Jus Quiritium" was given him, and a shop was bought for him at the public expense ; but his practice was observed to be so severe, that he soon excited the dislike of the people at large, and produced a complete disgust to the profession generally. The practice of Archagathus seems to have been almost exclusively surgical, and to have consisted, in a great measure, in the use of the knife and powerful caustic applications. (Bostock, Hist. of Med.)