(Ἀμμώνιος) LITHO'TOMUS, an eminent surgeon of Alexandria, mentioned by Celsus (De Med. vii. Praef. p. 137), whose exact date is not known, but who probably lived in the reign of Ptolemy Philadelphus, B. C. 283-247, as his name occurs in Celsus together with those of several other surgeons who lived at that time. He is chiefly celebrated for having been the tist person who thought of breaking a stone within the bladder when too large for extraction entire; on which account he received the cognomen of λιθοτόμος. An account of his mode of operation, as described by Celsus (De Med. 7.26, p. 161), is given in the p. 220. Some medical preparations used by a physician of the same name occur also in Aetius and Paulus Aegineta, but whether they all belong to the same person is uncertain.