'Here many have used the scalpel. Meges (since it is rather weak and may cut down upon some projecting part, and while the tissues overlying that are divided it may not divide those where there is a hollow underneath, but may leave a portion which requires to be divided afterwards) made an instrument straight, with a projecting lip at the heel and rounded and cutting at the tip. This, held between the two fingers, index and middle, the thumb being placed on the top, he pushed down so as to divide not only tissues but any projecting portion of the calculus, and as a consequence at one stroke he made a sufficient opening.' Etangs in his edition of Celsus gives as his idea of the instrument described an instrument of the shape indicated in the accompanying diagram (Pl. VIII, fig. 6). Thus he makes the cutting edge a concave semicircle, and therefore we may dismiss his conjecture, for a cutting edge on this principle would never cut its way into the bladder in the manner described by Celsus. Daremberg (_Gaz. Med. de Paris_, 1847, p. 163, &c.) conjectures an instrument which seems to me to be nearer the true interpretation (Pl. VIII, fig. 4). This instrument, with some modification, I would accept. The lunated handle figured by Daremberg is not strictly speaking what is meant by _labrosum_, and _summa parte_ I take to refer to the back part of the blade, and not to the back part of the instrument as a whole. _Rectum_ I take to indicate that the instrument was straight and not a curved bistoury. I conceive that the lithotomy knife of Meges was only a modification of the one in general use, and that in order to enable it to be held more firmly in the manner described by Celsus, Meges raised a lip on the handle at the heel of the blade, and in order to allow it to cut its way into the stone itself to some extent (which was his avowed object) he rounded the end of the blade, so that it might be rocked upon the stone without chipping as a pointed blade would do. I think the above explanation provides an instrument corresponding to a legitimate interpretation of the text and at the same time suited for the operation indicated (Pl. VIII, fig. 5). _Perforator for the foetal cranium._ Greek, ἐμβρυοτόμον. A special instrument for perforating the foetal cranium is mentioned by Soranus (II. viii. p. 366): Εἰ δὲ μείζονος τοῦ κεφαλίου ὑπάρχοντος ἡ σφήνωσις ἀποτελοῖτο, διὰ τοῦ ἐμβρυοτόμου ἢ τοῦ πολυπικοῦ σπαθίου κρυπτομένου μεταξὺ λιχανοῦ καὶ τοῦ μακροῦ δακτύλου κατὰ τὴν ἔνθεσιν. 'If the head be too big, the obstruction may be removed by the embryotome, or the polypus knife, concealed between the index finger and the thumb during its introduction.'