Anesthesia can be induced quickly and maintained for periods of 3 to 20 minutes in obstetric, pediatric, dental, and traumatic cases by administering cyclopropane with helium and oxygen from thumb-sized cylinders. The mixture of 30% oxygen, 30% helium, and 40% cyclopropane is nonexplosive. Administration is accomplished by an easily portable machine here described. This midget type of anesthesia machine has been used to anesthetize more than 8,500 patients in the course of five years. It has also been uses successfully in asministering oxygen in units of 3,400 cc. for resuscitation or for brief periods of oxygen therapy. Because of its simplicity the machine is easily refilled or disassembled for cleaning. Clinical experience and laboratory data have shown it to be safe and effective when properly used.