But the internal lining of the heart and arteries gives the most unequivocal evidence of its inflammation when it is found of a deep red colour, with coagulable lymph adhering to its surface. This condition is represented, as it was found in the aorta, in one of the beautiful plates, illustrative of the diseases of arteries, by Mr. Hodgson[3]. And the same condition, in the heart, I have seen in a preparation of Dr. Farre's, where lymph is deposited, upon the circular zone, which forms the aperture of communication between the left auricle and ventricle. These appearances denote the most acute inflammation: they are, I suspect, very rarely met with. In the few instances in which I have heard of them, they have been found where death has taken place after short and severe suffering, and with symptoms which characterize inflammation. But the specimens of disease most frequently met with in the internal lining of the heart, consist in an entire change of its natural structure, and in the formation of new products upon it or within it. Many of these, from the analogy of morbid actions in other parts of the body, must be considered to result from chronic inflammation. In any of those situations which have been stated as especially liable to disease, the membrane will become thick, tough, inelastic, puckered and shrivelled; and cartilage or gristle, and bone, will enter into its structure; excrescences will sprout out from it, resembling warts and fungus; and it will become ruptured and ulcerated. Cartilaginous depositions are often found beneath the membrane where it is single; or between its folds where it is double, in the situation of the valves; and thus they seem rather to belong to some structure contiguous to the membrane than to the membrane itself. Such depositions will proceed to a considerable extent, while the membrane still remains free from disease. From a valve, which has been thick, opaque, and cartilaginous, I have seen the membrane separated on both sides, and transparent; the opaque and cartilaginous matter being left behind. Where, in cartilaginous depositions, the lining of the heart has become puckered and uneven on its surface, and the valves shortened and altered in their shape, the membrane itself participates in the disease, and is generally incapable of being separated from the subjacent structure. But great thickening may take place in the situation of the valves, from deposition of cartilage, without any unevenness of their surface or alteration of their shape; and under these circumstances the membrane itself you may expect to find hitherto exempt from disease[4].