One year ago I presented in this hall a paper on anesthesia, in which nitrous oxid in a general way was principally discussed. I now wish more particularly to bring to notice the possibilities of this and its modifications in prolonged surgical operations. We may consider nitrous oxid, nitrous oxid and carbon dioxid, nitrous oxid and oxygen.
In the early days of nitrous oxid administration, the effects produced by the gas were unsatisfactory, due to impurities, besides a large admixture of air, which produced excitement giving rise to the term "laughing gas." Apparatus with more perfect valve arrangement, by which air was excluded, then came into use, and more perfect anesthesia is attainable. Nitrous oxid has been used in isolated cases, in long operations, but from what we are told in many instances the narcosis was anything but satisfactory, the patient often crying and squirming throughout the entire procedure, though