At the beginning of the pain a few drops of chloroform are poured on the cloth and the patient instructed to breathe vigorously. The cloth is removed as soon as the pain ceases and when the next contraction comes on, the process is repeated. As the head passes the perineum, the chloroform should be pushed to complete anæsthesia, both to save suffering and to give the doctor full control of the perineum. When the nurse gives the anæsthetic, she should watch the doctor for his signal to increase the vapor or remove the mask. _Summary._—Cover the eyes with a wet towel and anoint the face with cream or oil before using chloroform. Remove false teeth, if present. Obstetric degree—a few drops on mask at beginning of each pain. Surgical degree—complete anæsthesia. Watch pulse and respiration. A nurse should never leave a patient who has had an anæsthetic until she is conscious. Vomiting is especially dangerous. =Normal Labor.=—Labor is the process by which a fœtus of viable age is expelled from the uterus. By normal labor is meant a case where the fœtus presents by the vertex and terminates naturally without artificial aid, or complications. It varies greatly in severity, duration and danger to mother and child. A first labor is more prolonged and difficult than later confinements. A woman in her first delivery is called a primipara, in subsequent cases, a multipara. The _date_ at which labor comes on is difficult to determine accurately. The average duration of pregnancy is from 275 to 280 days, forty weeks, or ten lunar months, but conception does not occur necessarily at the time of coitus, nor is it possible to know with any certainty when it does occur. Labor may occur two weeks earlier than calculated, with benefit to the mother, and no harm to the child; but if the woman goes over time, the child becomes much larger and the labor harder and more dangerous to both. =Causes of Labor.=—Why labor should occur at all is not known. Many theories have been advanced, none of which is entirely satisfactory. Some of the best known are the growing irritability of the uterus accompanied by an increase in the frequency and strength of the intermittent uterine contractions or increasing distention of the uterus. Thus it is believed that when the uterus is distended up to a certain point, it will try to relieve itself like the bladder, or a baby’s stomach. It may be that any one of the following factors, or all of them acting together, are influential. Dilatation of the cervix by the presenting part. Increasing distention of the lower half of the uterus with pressure on neighboring nerve structures. The circulation of fœtal products of metabolism (toxins) acting on the nerve centers. The menstrual periodicity. Heredity and habit. Physical and emotional causes.