Certain forms of disease of the heart, as ossification of the mitral valves, with contraction of the orifice, or in hypertrophy of the left ventricle, with disease of the aortic valves, are frequently attended with hæmoptysis. In either case, the obstruction to the free circulation through the left side of the heart, must induce an over distension of the pulmonary veins, which, upon some unusual exertion, may readily result in extravasation through the bronchial mucous membrane, causing the bloody expectoration which takes place during life, or into the pulmonary connective tissue, giving origin thus to what is known as =Pulmonary Apoplexy=. The post-mortem appearances in these cases, are as follows:—The portion of the lung involved, fails to collapse on opening the chest. It is firm, and of a dark red color; and when cut into, thick blood issues from the cut surfaces. The portion involved may include from one to four cubic inches. It will be found circumscribed with healthy lung tissue, and looks not unlike a clot of venous blood; these circumstances serving to distinguish it from hepatization, which terminates more or less gradually in sound lung. While these hæmorrhagic effusions may, in many cases, cause early death by their size and number, in others, the clot may soften, the lung around become inflamed, or even gangrenous, resulting in the formation of an irregular cavity filled with dark, offensive, semi-fluid contents. In still other cases, where the clot is small, and in part within the air cells, it may soften and become absorbed or coughed up, and the air again enter the cells, or these may contract into a fibrous indurated mass. =Emphysema.= Emphysema of the lungs, is usually described as of two forms—_vesicular_ and _interlobular_. _Vesicular emphysema_, consists essentially in a dilatation or over-distension of a greater or less number of air cells, resulting in giving the portion involved greater buoyancy in water, from diminished specific gravity, lessening the crepitation on pressure, preventing collapse on the opening of the chest, and rendering the affected portion more or less dry and bloodless. From the loss of elasticity, there will be during life, a difficulty in the lungs emptying themselves of air as they should, hence the patient will be subject to severe attacks of oppression upon the slightest aggravating cause. If one lung only is affected, the corresponding side becomes enlarged and less movable than the other; the adjoining viscera, as the heart or abdominal organs, are more or less displaced, the intercostal spaces swell out, and the ribs becoming more horizontal, give a barrel-shape to the chest, which is quite characteristic of emphysema.