In this paper I will give a somewhat brief report of the high lights of the history of anaesthesia, followed by a generalized description of the various general inhalation anesthetics, their action on the human organism, and the administration of these, with the factors governing their use. The subject which I have chosen is a wide one, on which volumes have been written. It is also a very interesting subject, and if I can but give the reader a general idea of the history, theory, and administration, of anesthetics, man's most remarkable discovery in his fight against pain, my aim will have been accomplished.