_Probably the most common of mistakes is crowding the anesthetic._ The anesthetist becomes aware of faint, high pitched notes in the breathing—the beginning of obstructed respiration. He examines the lid and corneal reflex and these convince him that the patient is in the state of _superficial_ anesthesia. Naturally, he gives more of the anesthetic. To his great chagrin the breathing becomes progressively more stertorous. The cyanosis which was at first slight, deepens. The noisy breathing attracts the surgeon’s attention. The perspiring anesthetist is enjoined to push the jaw forward; but the spasm of the muscles is too great. The teeth are pried apart, barbarous instruments are brought into play to pull the tongue forward. The patient has not received sufficient air all this time—his face is slate-colored. The nasal or pharyngeal tube, tongue traction, oxygen, artificial respiration with rhythmic chest compression, stretching of the sphincter ani, all follow in an illogical onslaught, until finally a long deep breath is induced and the victim is resuscitated. The condition was one of _respiratory-collapse_. The cause was crowding of the anesthetic. WHEN SHALL THE PATIENT BE DECLARED READY FOR OPERATION? As soon as the first, unimpeded, snoring respirations are heard, the cleansing of the field of operation may begin. If the cleansing manipulations do not disturb the rhythm of the snoring respiration, the rate of the pulse does not increase and the patient makes no defensive movements, he is very likely already in the proper plane of anesthesia. Note is at once made of the state of the pupil and lid corresponding to this plane. [Sidenote: Initial Incision] When the surgeon makes the initial incision observation is again made as to whether the rhythm of the respiration and the rate of the pulse remain undisturbed and whether the patient continues to be passive; if this is the case, the patient is considered to be in the correct plane of anesthesia—the plane in which he must be kept throughout the operation. [Sidenote: Awakening Stimuli] Of course, it is clear that the depth of the narcosis must, in a measure, be proportionate to the magnitude of the awakening impulses set up by the surgeon’s manipulations. In abdominal work these impulses are more intense near the solar plexus of nerves, that is, in the upper part of the abdomen. Traction on the mesentery or the introduction of long gauze tampons into the abdominal cavity for “walling off” sets up powerful awakening stimuli. MAINTENANCE OF THE SURGICAL PLANE OF ANESTHESIA. In order to conduct a narcosis scientifically one must know the signs of sufficient anesthesia and the signs of awakening. [Sidenote: Respiration]