Text-books on obstetrics have a series of rules, based on pelvic measurements, concerning the indications for cesarean or other methods of delivery in cases of contracted pelvis, but the problems are not so simple and uniform as to be always accurately solved by the data derived from measurements. One woman with a contracted pelvis may require cesarean delivery; another woman with the same measurements may have a normal parturition because the child happens to be small or its skull compressible. The best pelvic measurement is made with the fetal head. A difficult decision as to whether a cesarean delivery is necessary or not comes up in the majority of cases in primiparae; in multiparae the physician has the experience from former births to guide him. In over 90 per cent. of primiparae the fetal head normally is found engaged in the pelvis in the last week of gestation, and can be felt by a vaginal examination. In multiparae the head usually is not engaged until labor begins. If the fetal head does not engage in a primipara, this fact at once suggests an absolutely or relatively narrow pelvis. When labor has begun, if the fetal head cannot be pushed into the true pelvis of a primipara, especially after anesthesia, the necessity for cesarean delivery may be clearly evident. In the cases where there is doubt that the child can get through the pelvis, but good reason to think that it can, many obstetrical experts try the effect of labor for two hours or a little more, and if there is no real progress they deliver through laparotomy. There is considerable objection now to version or the application of high forceps, but many skilful men prefer these methods at times. When version has been done and it fails there is no chance to save the child's life. In the trial of labor, the expectant treatment, extraordinary watchfulness is required and a full knowledge of the special procedure that may be necessary.