This accumulation of blood in the lungs has, by some writers, been considered as an appearance belonging to idiopathic hydrothorax. Whether it ever exists in that complaint seems to me uncertain. The pressure of water upon the lungs, may possibly interrupt the free circulation of blood through their vessels, yet probably the same pressure would prevent the entrance of blood into the vessels, unless there be some other cause to overcome it, such as increased action of the heart, which attends only the first stage of hydrothorax. It has beside been proved by the experiments of Bichat, that the collapsion of the lungs does not obstruct the circulation of blood through the pulmonary vessels. It seems probable, therefore, that those who have thought this collection of blood an appearance belonging to idiopathic hydrothorax, have mistaken for it the secondary hydrothorax produced by diseases of the heart.
On pursuing the examination, we found, behind the lungs, about five or six ounces of yellowish serum in each cavity of the pleura, and about one ounce in the cavity of the pericardium. The heart was then seen enlarged to more than double its natural size. Its surface, especially along the course of the branches of the coronary arteries, was whitened by coagulated lymph. In the cavities of the heart, which were all enlarged and thickened, particularly the left, were found portions of coagulum mixed with fluid blood. Near its apex, over the left ventricle, was a small soft spot which, to the finger, seemed like the point of an abscess ready to burst. The tricuspid valves, and the valves of the pulmonary artery, had lost somewhat of their transparency, and were a little thickened, though not materially. It is worthy of remark, that these valves have not exhibited any great appearance of disease in any of these cases, while those of the left side of the heart have scarcely ever been found healthy. So it appeared in this case. The mitral valves were uniformly thickened, and partly cartilaginous; the left portion adhered to the side of the heart. The valves of the aorta had lost their usual form, were entirely cartilaginous, and almost equal in firmness to the aorta, which was cartilaginous under the valves, sound in other parts, and rather small, compared to the size of the heart.