The antiseptic method, as it has since been known, was naturally at first crude, although its scientific basis has never been shaken; and that it has been since, in large measure, modified, and that surgeons now resort to little, if any, of the paraphernalia which first made it such a formal proceeding, in no regard shake the scientific nature of its foundation, but rather have tended ever to corroborate it and establish it more and more firmly. Lister began with the supposition that the air contains the germs which are most active and pernicious in producing disease. It has been since learned that air-contact is, perhaps, least of all to{324} be dreaded. We, however, recognize the germs as always the efficient agents, though we have since learned that other sources of contamination are much more to be dreaded than air. It had been the custom, up to Lister's time, to observe usually the ordinary forms of cleanliness, but, not appreciating the multitude of germs which lurk in and about the skin, it had not been customary to scour and prepare it as we have learned to do since Lister's day. The ligatures and instruments which were used and the dressings which were applied, as well as the sponges used during the operation, usually went through the ordinary forms of cleansing; and yet Lister's investigations showed the utter inadequacy of such preparation. His most important object-lesson, however, was that everything that came in contact with fresh or bleeding tissues might carry infectious material (i.e., germs), unless it had itself been thoroughly freed from their presence. Accordingly, the system taught the accurate preparation of everything.--from the skin of the patient, which was to be carefully cleansed and shaven, to the hands of the operator, which were to be scrupulously scrubbed, as well as those of every assistant who might handle or touch any of the instruments or dressing materials. It included, also, the careful preparation of sponges, sutures, and ligature materials, all of which were kept protected from air-contact and in antiseptic solutions until the moment of their use. The dressing materials were impregnated with substances like carbolic acid, which had been proven to be germicidal; and impermeable material, like oiled silk, was used to cover the surgical dressing, in order that fluids which might leak through should not come in contact with the air, which might permit of their putrefaction, while, at the same time, air from without could have no access to the deeper parts thus protected.