The art of antiseptic and aseptic surgery has advanced with the science of bacteriology. Surgical technique has changed as our knowledge of germ life has advanced. While some observers before Lister seemed to have had a vague idea of the relation between wound infection and microörganisms, to him belongs the credit of putting first the knowledge, scanty as it was, into a distinct shape and to practice antiseptic surgery. He acted on the knowledge at that time and his failures were in a great measure due to the lack of that information we now possess. He supposed the chief source of infection was from the air. Tyndall's observation seemed to prove this, consequently he bent his energies to devise a means of purifying the atmosphere.
Only a few years ago, when operating rooms were small and the air was laden with carbolic spray, the operator and patients were deluged with