The ancient apologists for the human vivisections of Herophilus and Erasistratus used to say that these anatomists were thus “enabled to behold, during life, those parts which nature had concealed, and to contemplate their situation, colour, figure, size, order, hardness or softness, roughness or smoothness, etc. They added that it is not possible, when a person has any internal illness, to know what is the cause of it, unless one is exactly acquainted with the situation of all the viscera; nor can one heal any part without understanding its nature: that when the intestines protrude through a wound, a person who does not know what is their colour when in a healthy state cannot distinguish the sound from the diseased parts, nor therefore apply proper remedies; while, on the contrary, he who is acquainted with the natural state of the diseased parts will undertake the cure with confidence and certainty; and that, in short, it is not to be called an act of cruelty, as some persons suppose it, to seek for the remedies of an immense number of _innocent_ persons in the sufferings of a few _criminals_.”[418] AMMONIUS OF ALEXANDRIA, surnamed LITHOTOMUS, probably lived in the reign of Ptolemy Philadelphus (B.C. 283-247). He is celebrated as having been the first surgeon who thought of crushing a stone within the bladder when too large for extraction entire; for this reason he was called λιθοτόμος. Celsus describes his method.[419] Of the Herophilists we may mention DEMETRIUS OF APAMÆA (B.C. 276), who named and described diabetes, and was distinguished as an obstetrician. MANTIAS, who, B.C. 250, first collected the preparations of medicines into a special book. DEMOSTHENES PHILALETHES, who, under Nero, was the most celebrated oculist of his time, wrote a work on diseases of the eye, which was the standard authority until about A.D. 1000. The work has perished, but Ætius and Paulus Ægineta have preserved some fragments of it. He wrote also on the pulse. HEGETON was a surgeon of Alexandria who was mentioned by Galen as having lived there as a contemporary of several physicians who were known to have resided in that city at the end of the second or the beginning of the first century B.C. He was a follower of Herophilus, and wrote a book on the causes of diseases entitled Περὶ Αἰτιῶν, which has perished. Of the school of Erasistratus we may mention XENOPHON OF COS, who wrote a work on the names of the parts of the human body, and on botany and the diseases of women. NICIAS OF MILETUS, a friend of the poet Theocritus; PHILOXENOS, who, according to Celsus, wrote several valuable books on surgery; and MARTIALIS the Anatomist, who visited Rome about A.D. 165. He knew Galen, and wrote works on anatomy which were in great repute long after his death.