_Oxygen Tank and Tracheotomy Instruments_.--Respiratory arrest may occur from shifting of a foreign body, pressure of the esophagoscope, tumor, or diverticulum full of food. Rare as these contingencies are, it is essential that means for resuscitation be at hand. No endoscopic procedure should be undertaken without a set of tracheotomy instruments on the sterile table within instant reach. In respiratory arrest from the above mentioned causes, respiratory efforts are not apt to return unless oxygen and amyl nitrite are blown into the trachea either through a tracheotomy opening or better still by means of a bronchoscope introduced through the larynx. The limpness of the patient renders bronchoscopy so easy that the well-drilled bronchoscopist should have no difficulty in inserting a bronchoscope in 10 or 15 seconds, if proper preparedness has been observed. It is perhaps relatively rarely that such accidents occur, yet if preparations are made for such a contingency, a life may be saved which would otherwise be inevitably lost. The oxygen tank covered with a sterile muslin cover should stand to the left of the operating table. _Asepsis_.--Strict aseptic technic must be observed in all endoscopic procedures. The operator, first assistant, and instrument nurse must use the same precautions as to hand sterilization and sterile gowns as would be exercised in any surgical operation. The operator and first assistant should wear masks and sterile gloves. The patient is instructed to cleanse the mouth thoroughly with the tooth brush and a 20 per cent alcohol mouth wash. Any dental defects should, if time permit, as in a course of repeated treatments, be remedied by the dental surgeon. When placed on the table with neck bare and the shoulders unhampered by clothing, the patient is covered with a sterile sheet and the head is enfolded in a sterile towel. The face is wiped with 70 per cent alcohol. It is to be remembered that while the patient is relatively immune to the bacteria he himself harbors, the implantation of different strains of perhaps the same type of organisms may prove virulent to him. Furthermore the transference of lues, tuberculosis, diphtheria, pneumonia, erysipelas and other infective diseases would be inevitable if sterile precautions were not taken. All of the tubes and forceps are sterilized by boiling. The light-carriers and lamps may be sterilized by immersion in 95 per cent alcohol or by prolonged exposure to formaldehyde gas. Continuous sterilization by keeping them put away in a metal box with formalin pastilles or other source of formaldehyde gas is an ideal method. Knives and scissors are immersed in 95 per cent alcohol, and the rubber covered conducting cords are wiped with the same solution.