[28] _Aspirators_.--The various electric aspirators so universally used in throat operations should be utilized to withdraw secretions in the tubes fitted with drainage canals. They, however, have the disadvantages of not being easily transported, and of occasionally being out of order. The hand aspirator shown in Fig. 11 is, therefore, a necessary part of the instrumental equipment. It never fails to work, is portable, and affords both positive and negative pressures. The positive pressure is sometimes useful in clearing the drainage canal of any particles of food, tissue, clots, or secretion which may obstruct it; and it also serves to fill the stomach or esophagus with air when the ballooning procedure is used. The mechanical aspirator (Fig. 12) is highly efficient and is the one used in the Bronchoscopic Clinic. The positive pressure will quickly clear obstructed drainage canals, and may be used while the esophagoscope is in situ, by simply detaching the minus pressure tube and attaching the plus pressure. In the lungs, however, high plus pressures are so dangerous that the pressure valve must be lowered. [Fig. 11--Portable aspirator for endoscopy with additional tube connected with the plus pressure side for use in case of occlusion of the drainage canal. This aspirator has the advantage of great power with portability. Where portability is not required the electrically operated aspirator is better.] [FIG. 12.--Robinson mechanical aspirator adapted for bronchoscopic and esophagoscopic aspiration by the author. The positive pressure is used for clearing obstructed drainage canals and tubes.] [FIG. 13.--Apparatus for insufflation of ether or chloroform during bronchoscopy, for those who may desire to use general anesthesia. The mechanical methods of intratracheal insufflation anesthesia subsequently developed by Meltzer and Auer, Elsberg, Geo. P. Muller and others have rightly superseded this apparatus for all general surgical purposes.]