=Malformations= of the heart, are extremely rare in adults, or even in children that have passed the early days of infancy. They consist frequently in arrest of development of the auricular septum, or, in other words, of a patulous foramen ovale, which, by permitting of a mixture of arterial and venous blood upon the left side of the heart, results in early death. I have in several instances found this foramen imperfectly closed in the adult heart, but the opening has been so small—barely sufficient to permit the passage of a probe—as to offer little or no obstacle to the proper performance to the heart’s function. Malformation of the heart is undoubtedly one of the many causes of death in utero, which might be demonstrated by a post-mortem examination. =Aneurism.= Partial aneurism, or false aneurism of the heart, consists in the formation of a sac or pouch, in some portion of the walls of the organ, communicating with the cavity of the chamber, in the walls of which it has been formed. They may form in any part of the muscular walls of the heart, but are more frequent in the left ventricle. They would seem to result from a separation of some of the muscular fibres, when, by their retraction, a cavity or pouch, of a rounded or oval form results, which, in some instances, has its walls composed of the pericardium alone, there being a complete destruction of the muscular fibres. The interior of these pouches, may be found filled with layers of coagulated fibrinous deposits, as in the case of aneurism of arteries; or, if they communicate with the ventricular cavity by a large opening, they may be filled with a simple soft clot of blood. The size of these aneurismal pouches, vary from that of a cherry, to a pigeon’s egg, or larger, when they change much the usual figure of the heart, by their projection upon the external surface. The following conditions have been supposed to favor the formation of these aneurismal sacs:—1st, softening of the muscular tissue of the heart; 2d, ulceration of the lining membrane; and 3d, rupture of the muscular fibres. =Rupture= of the walls of the heart sometimes happens, producing sudden death. It may result from severe contusions of the chest, in which case, the auricles are more likely to give way. More frequently, rupture will result from softening of the walls in fatty degeneration or ulceration, or from the bursting of an aneurism of the heart, or from stenosis of the aorta. In the latter cases, the left ventricle will be usually the seat of the rupture. 6. Displacements. _Changes of Position_ of the heart, are by no means unfrequent. They may be congenital in their origin, or the result of disease in the surrounding organs. Of congenital displacement, we may mention first: