FREQUENCY.--Early interruption of pregnancy is extremely common. Some sociologists declare that it is becoming more and more frequent, and see in it a grave national danger. French statesmen attribute the alarming decline of the birth-rate in their country, in great part, to a rapid increase in the number of pregnancies which end prematurely. Reliable English and German statistics indicate that of the pregnancies which come under the observation of physicians approximately twenty per cent, end in miscarriage. In our own country, though extensive and complete data are not available, it is likely that the incidence is equally high. The actual frequency of miscarriage is generally underestimated. Patients themselves often do not know what has really happened. When the accident occurs a few days after conception, bleeding may be its only evidence, which will almost certainly be misinterpreted as an irregularity of menstruation; and professional advice will not often be thought necessary. Moreover, in other cases in which the true situation is appreciated the patient does not feel sick enough to seek medical assistance. If it were possible to include in the statistics all these cases as well as those which are concealed because intentionally provoked, the frequency with which pregnancy is interrupted during the early months would be found somewhat greater than is usually supposed. If we omit the miscarriages which occur within the first few weeks of pregnancy, and which consequently often escape detection, the majority of cases fall within the second and third months. After the fourth month has passed, the probability of such an accident, though not excluded, is greatly diminished. Some statistics recently published by Taussig make this clear. In a series of several hundred cases of miscarriage, one hundred and fifty-seven instances occurred in the second month, two hundred and twenty-two in the third month, seventy-three in the fourth month, thirty-seven in the fifth month, and five in the sixth month. This order of frequency might be anticipated from the anatomical conditions which prevail during the early months of pregnancy, since the attachment of the embryo to the mother is at first relatively insecure, but gradually grows firmer, and becomes as secure as it ever will be by about the fifth month. It is noteworthy that miscarriage occurs much less commonly in the first than in subsequent pregnancies. Indeed, a somewhat greater liability to the accident with each succeeding pregnancy goes far toward explaining the greater frequency of miscarriage among women who have passed the thirty-fifth year than among those who are younger.