The subject is one which, at first thought, would seem to be narrow in its scope, and yet the proper apprehension of it involves the examination of many disconnected reports of cases of extrauterine gestation, some of which devote no attention at all to the consideration of the physical condition of the fetus, while in others the details are aggravatingly meager. The deformities which are alluded to are in almost all cases, if not in all, consequences of the latter months of fetal development, since in those fetuses which are removed during the first half of gestation I have observed no record of deformity, and in those which I have examined personally, the upper and lower extremities have appeared to be normal. The subject derives importance from the fact that the number of fetuses developed outside the uterus and born alive by extraction through an abdominal incision, is not inconsiderable,