=Cæsarean Section= is the operation by means of which the child is delivered through an incision in the abdominal and uterine walls. It is believed by some that the operation was named for Julius Cæsar, who was presumably delivered by this method, but this seems scarcely probable. The operation was frequently fatal in those days and, moreover, as the uterine wall was not sutured after the child was extracted, a woman was not likely to have other children afterward even if she did live, and Cæsar’s mother had several children after he was born. Another explanation for the name is that during Cæsar’s reign a law was passed which required that the abdomen be opened and the child extracted in every case in which a woman died late in pregnancy, as one means of increasing the population. Thus it will be seen that the operation itself is very ancient, but as performed to-day it embodies the most modern and scientific knowledge and methods. The usual indications for it are cases of contracted or deformed pelves; cases of tumors which block the birth canal or when very speedy delivery is imperative as in some cases of eclampsia. The anatomical indications for Cæsarean section are dependent upon the degree and character of the pelvic contractions and upon the size and mouldability of the child’s head in relation to the pelvis. This explains why in two women with pelves of the same size and shape, one will have a spontaneous delivery and one will require a section. The former has a relatively small child which can pass through her pelvis; while the second woman’s baby is too large, or the head not sufficiently mouldable, to pass through hers. This is one exemplification of the great importance of pelvimetry and of constant watching during pregnancy, for the best results from Cæsarean section are obtained when it is recognized that spontaneous delivery is unlikely or impossible; the operation accordingly is performed at a time which is deliberately selected by the obstetrician. The elected time is often about two weeks before the expected date of confinement in order that the baby may have the longest possible intra-uterine life and that the operation may be performed before the patient goes into labor. In these cases in which it is known that a section is to be performed vaginal examinations are omitted after the pelvic measurements are taken, in order to minimize the possibilities of infection, this being one of the great risks of the operation.