I have endeavored in the following pages to pre sent a brief résumé of our present knowledge con cerning chloroform and its effects. The subject is so important that it cannot need apology; the apol ogy must be for the Author. My medical education commenced at a [time when the vastness of the boon conferred by the discovery of the anaesthetic was just beginning to assert itself, and I was associated frequently with the late Dr. Snow, whose name is everywhere known in connec tion with the subject. For a considerable time also I was in the habit of administering chloroform at King's College Hospital, as well as in the practice of Mr. Fergusson and other friends (to whom I am anxious to express my obligations). Hence I have felt a real and practical interest in the matter of which this book treats.