In various parts of the book the author has very rightly laid great emphasis upon the influence which the work of the surgeon has upon that of the anæsthetist. The latter may learn much from an occasional glance at the field of operation. He should not interest himself in the details of operative procedure to the distraction of his mind from his own responsibilities; but he can, in abdominal surgery, see for himself whether the muscles are properly relaxed, and observe the state of operation, so that he can when necessary deepen the anæsthesia in good time, while not maintaining deep anæsthesia when a light one would suffice. Finally, he can check his other sources of information as to the condition of the circulation by noticing the force with which cut arteries spout, the colour of the blood and the size of uncut veins. Like other branches of medicine, adequate study as well as practical experience is required in order to master the art of administering anæsthetics, and that a reliable manual of instruction is essential, goes without saying; I feel on perfectly safe ground in recommending this book as such both to the student and the practitioner. ALEXIS THOMSON. PREFACE. This little book is an attempt to present to the student and practitioner a condensed account of modern anæsthetic views and practice. In choosing a general scheme I have tried to lay emphasis upon the relation of anæsthesia to general medical science rather than upon elaborate descriptions of anæsthetic apparatus and methods which a few years hence may be superseded. I have therefore devoted the first four chapters to an account of the various forces which modify the physiology of the patient during an operation under a general anæsthetic, in so far as we at present understand them. I trust that they will prove not only a sound basis for the information given in the rest of the book but also a help towards forming a judgment upon new methods and appliances as and when they meet the attention of the reader. In making a selection of drugs and appliances for description, I have eliminated those which do not appear to me to have any real sphere of usefulness. The account of nitrous oxide and oxygen has been given in some detail. Both the profession and the lay public have arrived, through the experiences of the war, at a more just appreciation of the possibilities of this combination than was at all general before the year 1914. At the present day, no one who proposes to engage in anæsthetic work can afford to remain unpractised in its administration. I have an apology to make to my women readers. Throughout the book, when speaking of the anæsthetist, I have presumed the male sex. Such phrases as “his or her” and “he or she” are tedious and inelegant, and their omission must not be taken as forgetfulness on the author’s part that women frequently make very good anæsthetists.