The sound of the foetal heart is usually heard at about the middle point between the scrobiculus cordis and symphysis pubis, usually to one side, and that, generally speaking, the left. The extent of surface over which the sound may be heard varies a good deal, and depends, in great measure, on the distance which intervenes between the foetus and stethoscope; hence, when the uterus is distended with a large quantity of liquor amnii, or when the uterine and abdominal parietes are very thick, it is heard over a much larger space, although with diminished intensity; on the other hand, when there is but little liquor amnii in the uterus, it is audible over a small portion only, but is remarkably distinct: this is peculiarly the case during labour after rupture of the membranes. The rapidity and strength of the foetal pulsations appear to be entirely independent of the mother's circulation; violent exercise, spirituous liquors, &c., which will raise her pulse to a considerable degree, have no influence whatever on the foetal pulse. In cases of fever, where the mother's pulse has ranged between 110° and 120°, and even higher, not the slightest change was observable in the sound of the foetal heart; even in acute inflammatory affections, in pneumonia, pleurisy, where there was severe dyspnoea, and also in tubercular phthisis; in cases where the patient has been bled; in cases of menstruation during pregnancy; and even in severe flooding, and when the mother's pulse has been greatly reduced, no perceptible change has been observed in that of the foetus. (Naegelé, _op. cit._ p. 39.) Dr. Kennedy has observed some remarkable cases where the foetal pulse appeared to vary in accordance with that of the mother (_op. cit._ p. 91;) but when we bear in mind the frequent changes in point of rapidity, &c., to which the foetal heart is subject, independent of any thing of the kind in the mother's pulse, and that similar changes are constantly observed in the child shortly after birth; and, moreover, that very considerable acceleration of the maternal pulse has decidedly no effect upon that of the foetus in many well-marked instances, we cannot agree with him in supposing that a connexion of the sort to which he has alluded exists. The double pulsations of the foetal heart can only be heard at one point of the uterus at a time, provided there be but one child; but if there be twins, then the sound is heard in two places at once. It has been supposed by some authors (_Dubois_) that the heart of the second child could not be distinctly heard until labour, when the membranes of the first child had ruptured. Generally speaking, both sounds can be heard pretty distinctly during the last weeks of pregnancy, one of them being low down on one side, and the other high up in an opposite direction. Although in some twin cases there is an evident difference of rhythm between the two foetal hearts, still in many others they are so