The most important of the internal organs of generation is the uterus. Its structure, anatomical character, physiological attributes and pathological changes have received the most attention from the zealous investigation not only of the obstetrician and gynecologist, but of the physiologist; and last, but not least, the pathologist. The peculiar and especial office that places it in the foremost rank of the anatomical structures in the woman is that of reproduction. After copulation, should fecundation take place, it then becomes the nest upon which the fecundated ovum rests, grows, matures, during that period which we term gestation, and at the expiration of this nearly uniform period it expels its contents: labor; and then resumes again its normal size and functions. These changes comprise a normal pregnancy, so familiar to you all. But this evening I will speak of the pathology of pregnancy; that is, of one of the functional derangements