Besides the anomalies already treated of, it remains for us to notice, among those which exhibit special points of interest:

Blood in a fluid or coagulated condition. It is almost always an arterial extravasation, and has been deposited by the spontaneous rupture of the left ventricle, or by a laceration of the origin of the aorta, occasionally also as the termination of an aneurism. The quantity extravasated seldom amounts, under these circumstances, to more than from 2 to 2½ lbs.

Serum is frequently accumulated in greater excess than the normal quantity, which varies from ½ oz. to 1 oz.; and it then constitutes Hydrops Pericardii. This accumulation becomes serious in proportion to its amount, and possesses greater importance where the other coexisting anomalies, by which dropsy is influenced, are inconsiderable. It is generally combined with dropsy of other serous sacs, anasarca, and oedema of the lungs, and usually has a common origin with them. Occasionally it predominates over these aifections, and is especially the case in pulmonary phthisis. The period of its duration may be estimated by the extent to which the fat has disappeared from the heart, and its place been occupied by a serous infiltration of the cellular tissue, and in proportion to the extent of turbidity and swelling from imbibition, observed in the pericardium, and especially its outer surface, and to the decoloration and paleness of the substance of the heart.

The quantity of the Liquor Pericardii is often strikingly small, amounting to no more than what is barely sufficient to moisten the pericardium and the heart itself. The pericardium may even in some parts appear perfectly dry, of a yellowish color, and resembling parchment. We have remarked this appearance, which is devoid of importance, on the lateral portions of the pericardium, principally on its left side, where it had been brought in contact with the anterior parts of a lung in which emphysema has been developed.

We have never met with an accumulation of Air in the pericardium, Pneumatosis Pericardii. Most of the cases recorded, like the pneumatosis of other serous sacs, leave room for many doubts regarding their existence during life.

Free Bodies are of very rare occurrence in the pericardium. In a very remarkable case of pericarditis we discovered, in the serous effusion, numerous fibrinous, soft, yellow concretions of the size of beans or almonds, and similar to the latter in shape, which would no doubt have eventually been converted into elastic, tough bodies of fibroid tissue.