The first appellation the Grecians gave to those who exercised the art of healing was _iatros_. Originally it merely signified a man possessed of the power of relieving accidents, either by manual exertions, or the hidden virtues of some amulet or charm. Sextus tells us that in ancient times it applied to an extractor of arrows, _sagittarum extractor_. No doubt, this operation constituted the chief business of the surgeon in the infancy of the art; and warriors and heroes themselves performed it on the field of battle, as fully exemplified in Homer. The primitive title of _iatros_ gradually descended to surgical practitioners. We find that Nebrus and Heraclides were the chief _iaters_ of Cos, the birthplace of Hippocrates. To this day the same name is given to medical men in Greece, where, until lately, they were in the habit of perambulating the streets, and seeking occupation by crying out at certain distances, _Callos iatros!_ (The good doctor!) Balsamo, a celebrated mountebank, being at Cairo, where he died, one of his disciples repaired to Europe, and, anxious to bear a singular name, assumed this cry, and called himself _Calloiatro_, or, according to the corrupt pronunciation, _Cagliostro_: his history is well known, and he certainly excelled in impudence and industry all his predecessors. These Greek _iaters_, when going over to Italy to practise, called themselves _medici_, which Cato wanted to change into _mendici_, for, said he, "These creatures, (_Illi Graeculi_,) quit their native country, where they were starving, to seek their fortune in Rome (_ut fortunam sibi mendicent_)." Under this austere censor few of these emigrants dared to settle in the Roman territories, but after his demise they inundated the country to such an extent, that it was said that Rome had more physicians than patients who needed their attendance. This influx of practitioners occasioned constant competition, and each _iater_ endeavoured to obtain fame and emolument by underrating his opponents, and endeavouring to introduce novel doctrines, seeking a livelihood, as Pliny observed, _inter mortes et mendacia_. It was on these adventurers that the following epigram was written: Fingunt se cuncti medicos,--idiota, sacerdos, Judaeus, monachus, histrio, rasor, anus. The quackery of these candidates for popularity became the subject of bitter satire; and Martial thus speaks of the _Iatre_ Symmachus: Languebam, sed tu comitatus protinus ad me Venisti centum, Symmache, discipulis; Centum me tetigere manus, aquilone gelatae, Non habui febrem, Symmache; nunc habeo.[7] This Symmachus, it appears, invariably moved abroad surrounded by hundreds of his disciples, whose cold investigating hands produced upon their patients the effects to which Martial alludes. LUNAR INFLUENCE ON HUMAN LIFE AND DISEASES.