Avicenna’s description is evidently copied from our author. He also mentions that some surgeons open the lower part of the cornea, and extract by it. However, he does not approve much of this procedure. Canamusali briefly mentions that cataract must sometimes be removed by a surgical operation. When convulsions come on after the operation he directs us to apply castor to the nose. Rhases describes accurately the operations of couching, extracting, and sucking out the cataract. He is the only ancient author, except Celsus, who recommends the cataract to be torn in pieces when it cannot be got properly depressed. He mentions that the famous surgeon Antyllus practised extraction by opening the lower part of the cornea. He also speaks of a certain surgeon who sucked it out through a glass tube. Haly Abbas describes distinctly the operation of couching, but evidently copies from Paulus. He makes no mention, however, of extraction, as far as we can discover, in any part of his works. The operation of couching the cataract is minutely described by Jesu Haly, but he makes no mention of extraction. He was the son of Haly Abbas. Sprengel, in his ‘History of Medicine,’ refers to Haly Abbas as one of the ancient authorities who make mention of the operation of extracting the cataract; but if this be the case the edition from which they quote (Venetiis, 1492) must be considerably different from the one with which we are acquainted. (Lyon, 1523.) Haly forbids examinations of the eye after the operation, to ascertain whether or not the patient has recovered his sight. We will give the description of Vegetius in his own language: “Jumentum igitur pridie temperabis a cibo vel potu maximè prohibebis, in loco molli elides caputque ejus et cervicem aptè collocabis: ita patentem oculum facies ut claudere non possit: deinde ab ipsâ fronte paracenterium inter tunicas oculares subjicito, ne pupillam tangas, aut aliquid lædas interius. sed ipsum album de superiori parte ubi hypochysis posita est, capitello paracenterii deorsum deprimis ad palpebram inferiorem subtiliter. Quod si depositum fuerit, non prius paracenterium eximas, nisi clausum oculum penicello calido diutissime vaporaveris. solet enim resilire. Quod si evenerit, reprimito, donec ita componatur ut resilire non possit. Cum itaque intellexeris claritatem pupillæ sine illo obstaculo hypochysis, tunc eximes ferrum, et invenies animal videre.” Sprengel affirms, but not quite correctly, as will be perceived from the account of the ancient opinions given above, that it was towards the beginning of the 18th century that it was first discovered that the crystalline lens is the seat of the cataract. Otherwise he gives an admirable history of the operation, in which he does ample justice to the ingenuity and inventive genius of the ancients. (Hist. de la Méd. xviii. 2.)