Mr. Lister’s first paper on the subject, published in the _Lancet_ for 1867, struck a chord which the editor of that journal emphasised as follows on August 24 of that year (p. 234): “If Professor Lister’s conclusions with regard to the power of carbolic acid in compound fractures should be confirmed by further experiment and observation, it will be difficult to overrate the importance of what we may really call his discovery. For although he bases his surgical use of carbolic acid upon the researches of M. Pasteur, the application of these researches to the case of compound fractures, opened abscesses, and other recent wounds, is all his own.” The risk of blood-poisoning after operations in themselves slight, was declared to be the one great opprobrium of surgery. There was no limit to the operative skill of surgeons, but a miserable and serious risk of fatal after-consequences against which the surgeon had no defence. Mr. (now Sir James) Paget had in 1862 given forth an idea of which we can now more clearly see the bearing, when he said that the best results he had seen in cases of pyæmia were with patients kept night and day in a current of wind. We now see that this in fact amounted to continually passing over the patient air less charged with germs than that of the room or ward in which he was placed. Mr. Lister contemplated the destruction of these germs at the seat of the wound, and the prevention of the access of fresh germs. An example will perhaps illustrate the matter better than a theoretical account. An experiment was performed on the 31st December 1868 on a young calf a few days old, under chloroform, namely, the tying of the carotid artery on the antiseptic system, with threads composed of animal tissue. The threads employed had all been soaked for four hours in a saturated watery solution of carbolic acid, which swelled and softened them. The hair near the wound was cut short, and a solution of carbolic acid in linseed oil rubbed well into the skin to destroy any putrefactive organisms lying amongst the roots of the hair. The sponges employed in the operation were wrung out of a watery solution of the acid, and all the instruments introduced into the wound, together with the fingers of the operator’s left hand and the copper wire used for sutures, were treated with the same lotion, some of which was poured into the wound after the introduction of the last stitch, at one of the intervals left for the escape of discharge, to provide against the chance of any fresh blood which might have oozed out during the process of stitching having passed back and taken fresh germs in with it. The external dressing was a towel saturated with the oily solution of carbolic acid, folded as broad as the length of the neck, wrapped so as to extend freely beyond the wound, and prevented by several contrivances from slipping. A sheet of gutta-percha tissue was applied outside to prevent contamination of the antiseptic towel from without. A few