others in the living state, putrefaction might be prevented, however freely the air with its oxygen might enter." He had heard of carbolic acid as having a remarkable deodorizing effect on sewage, and, having obtained a quantity, determined to try it in compound fractures. "Applying it undiluted to the wound, with an arrangement for its occasional renewal, I had the joy of seeing those formidable injuries follow the same safe and tranquil course as simple fractures in which the skin remains unbroken." The earliest antiseptic dressings were very cumbrous. At first an antiseptic crust of blood and pure carbolic acid was formed, and protected by a sheet of block tin; next carbolic acid and oil were used; then a layer of putty made with carbolic acid was applied; after this, a plaster made of shellac and carbolic acid. This was superseded by the typical dressing, or the Lister bandage, in which a layer of waterproof silk, the "protective," was placed over the wound to protect it from the direct action of the irritant substance in the antiseptic dressing materials; over this came some eight or more layers of carbolized gauze or muslin, with a sheet of guttapercha tissue between the outer two of these. The whole was then bound round with carbolized gauze, so as to effect as far as possible an air-tight inclosure of the wound. With this was associated a spraying of carbolic acid when the wound was being treated or the bandages were being applied or changed, in order to prevent the access of microbes in the air. As the structure of the bandage became gradually simpler and more convenient, so the system itself was improved and simplified till, while the principle remains the same, the mode of applying it has become very different from what it was at first. The most important of these improvements seems to have been suggested in 1871 or 1872 by a paper of Dr. Burdon Sanderson's showing that bacteria, unlike the spores of fungi, are deprived of vitality by mere desiccation at an ordinary temperature, so that, while a drop of water from ordinary sources or the contact of a moist surface is sure to lead to bacteric development and putrefaction in an organic substance susceptible of that change, the access of dust from exposure to the atmosphere merely induces the growth of fungi and comparatively insignificant chemical alteration. "If this were true," Lister said, in a communication to the Royal Society of Edinburgh made in April, 1873, "it would be needless to provide an antiseptic atmosphere in carrying out the antiseptic system of treatment; and all that would be requisite in the performance of a surgical operation would be to have the skin of the part about to be operated upon treated once for all with an efficient antiseptic, while the hands of the surgeon and his assistants and also his instruments were similarly purified; a dressing being afterward used to guard
