Every doctor is confronted during the practice of his profession by the problem whether a young woman known to suffer from heart disease is justified in entering upon marriage and in exposing herself to the dangers entailed on her diseased heart by copulation, pregnancy, parturition, and the puerperium. The solution of this problem is as important as it is difficult. On the one hand, it determines the whole future course of a human life which is still ascending the upward path of its vital career, and a negative decision often annuls in a moment the young woman’s ideals and hopes; on the other hand, an affirmative decision involves the responsibility for the consequences of marriage, often grave in these cases. The consequences are in fact apt to be very serious indeed. The normal act of intercourse, in a young and sensitive woman, has already an exciting influence on the nerve apparatus by which the movements of the heart are controlled. The frequency of the heart’s action is greatly increased, the cardiac impulse becomes much stronger, there is marked pulsation of the peripheral arteries, the conjunctiva is injected, the respiration more frequent. These manifestations, which normally are quite transient, attain a greater intensity and exhibit a longer duration in persons affected with heart disease. In some instances, violent tachycardial paroxysms occur, with considerable dyspnœa, pains in the cardiac region, headache, and even syncopal attacks. Pregnancy, in consequence of the extensive changes undergone not only by the reproductive apparatus but also by the general system, and further in consequence of the vital needs of the developing embryo, involves extensive claims upon the cardiac activity. It is easy to understand that the diseased heart must be taxed more severely than the healthy heart by the extension of existing vascular areas, the addition of new vascular areas, and the increase in the quantity of the blood, during pregnancy; and it is not surprising if the overtaxed organ threatens sometimes to give way under the strain. Thus, during pregnancy in women affected with morbus cordis, we observe numerous troubles in the way of disturbances of cardiac activity and passive congestion of various organs, culminating at times in abortion. Parturition and the puerperium, moreover, bring several factors into play which tend to affect unfavorably even a heart that is quite normal; and in cases in which there is disease either of the heart or of the great vessels, these factors may lead to the occurrence of most alarming symptoms. In this connection we may refer to endocarditis, to fatty degeneration of the myocardium, and to the rupture of atheromatous arteries.