I have obtained a description of two very important instruments from the works of Hero of Alexandria (285-222 B. C., ed. 1575). There are a few interesting references to instruments in the works of the early Christian fathers. Tertullian is the only one of these I can claim to have systematically searched, but in one of his sermons he refers to no less than four surgical instruments, one of which is not described by any other author. It were a work of supererogation to recount the names of the other Greek and Roman writers whose works I have run through in a profitless search for references to instruments. Some of these, such as Dioscorides, are of great importance in themselves though valueless for our purpose. Others, such as many of the minor Greek writers contained in the collection by Ideler entitled _Physici et Medici Graeci Minores_ (Berlin, 1841), and the minor Latin writers contained in the collection of _Medici Antiqui Omnes_ (Aldus, 1547), are of little value of any kind. Before the capture of Alexandria by Omar in 651, many Greek medical writings had been translated into Syrian. At a later date such of these as had escaped destruction were turned into Arabic by the scholars of Bagdad (Honain and his School), in the ninth century. These, introduced into Spain in the Middle Ages by the Moors, were again translated into Latin and supplied for many a day the greater part of the medical knowledge of Europe, until the study of the few Greek texts which had escaped destruction showed the true origin of Arabian medicine. It will thus be seen that there is some information, in fact a great deal, to be had from the study of the works of the Arabs, but the barbarous style of the Latin and the roundabout way in which the works have been preserved, having passed through translations of three different languages, preclude any very exact deductions being drawn from them. Some of these works are profusely illustrated with figures of instruments, but I have been careful not to fall back on any of the Arabs except to support deductions drawn from more direct sources. The chief Arab writers of interest to us are:--Serapion (800), Rhases (882), and Ali Abbas (after 950), all of Honain's School at Bagdad. The huge work of Avicenna (born 980), _The Canon_, was much used by the Arabs. It was published at Cordova, which became the Bagdad of the West after the Arabs crossed to Spain in 811. The work of Albucasis (ob. 1106) was also published at Cordova, and contains much surgical information and has many illustrations of surgical instruments, but these must be used with due caution. I have used the edition published at Strasburg in 1532.