sented, to that we see on quickly separating two slabs of marble, between which a layer of butter was interposed. This plastic material gradually becomes organized, and we find minute red vessels projecting

A heart covered with plastic exudation, investing both the parietal and visceral layer of the pericardium, which has been cut open and reverted. An incision has been made through the false membrane over the left ventricle, to turn it back and show the subjacent muscular tissue. The lymph fringes the right auricle and coats the root of the aorta.

into it; and as this process proceeds the two surfaces become intimately adherent to one another; the lymph loses its fluid constituents; it is converted into firm bands, connecting more or less loosely the visceral and parietal pericardium, which, according to their density and tenacity, indicate the period of their formation. If adhesion does not result, absorption may remove these appearances, and nothing but a general opacity or thickening of the pericardium remains; or again, the active condition may be arrested after the formation of villi, and without the supervention of adhesion they may continue in a passive state, and present the appearance termed the hairy heart, the cor villosum. It is customary to quote as an instance of this a classical name; the great enemy of Sparta, Aristomenes, was captured and killed on his third entry into Lacedæmon, and his heart is stated by Pausanias to have been found covered with hair. In a less sthenic constitution the effusion resulting from pericarditis will be of a more serious character; and we then find the pericardium more or less distended with a straw-colored fluid, in which flakes of lymph are discovered, while traces of lymphatic exudation are seen attached to the membrane with thin free ends waving in the fluid. We have seen the pericardium mount up from this cause to the second rib, and the quantity of serum varies from half an ounce to two quarts. In this case, as in the former, absorption may take place, leaving but comparatively slight traces of the previous disease, and the pericardium itself appears to adjust itself to the reduced quantity of its

contents.

is of a more atypic nature than the last. It is the least frequent, and is always associated with a large amount of serous effusion. It is chiefly met with in protracted cases, though Dr. Hope avers that even in the first stage a degree of milky opacity is observable in the serum, which may be attributed to an admixture of real pus. Hope is of opinion that even pus may, if not exceedingly copious, be sometimes partially absorbed, leaving only its solid parts to undergo ulterior changes.

The serous effusion just spoken of must not be confounded with the dropsical accumulation of fluid, to which we should restrict the term hydropericardium, and which is a frequent accompaniment of general dropsy. In many cases of wasting disease we find a few ounces of serum in the pericardium, which we must refer to mere want of tone in the vessels, and which appears to be eliminated shortly before death. It is not associated with symptoms of inflammatory action; and the fluid itself is a clear, amber-colored serum. In long-continued dropsy of the pericardium the heart is generally found contracted, and the muscular tissue anemic and of light-brown hue. Occasionally, an atrophic condition of the sarcolemma results, which is characterized under the microscope by an absence of the striation seen in healthy muscle.

In the exudation resulting from acute inflammation we occasionally meet with a small quantity of blood. Hemorrhage, independently of this cause of mechanical injury, or of rupture of the muscular tissue of the heart, is not met with in this locality as it is in the sac of the arachnoid. As regards the extent of the phlogistic process in the pericardium, it generally involves the entire surface of the membrane in acute cases; the chronic form, except as a sequel of the former, has a tendency to limitation, and its residuary effects are seen in the form of circumscribed white patches, either on the visceral or parietal portion, or of partial adhesions or isolated bands of false membrane.

Pericarditis is not often an idiopathic disease. Dr. Latham, who was the first to notice its frequent complication with the rheumatic diathesis, has rarely met with it except in this connection. Andral gives six cases of pericarditis not connected with rheumatism, of which three were uncomplicated with any other morbid affection; while Corvisart only met with five independent of rheumatism, which were all, excepting one, complicated with disease of other parts. The rheumatic complication is one found at all periods of life. Messrs. Rilliet and Barthez and Dr. West look upon it as essential in young children; and all writers on the subject concur with regard to its frequency in adults, though the statistical results arrived at are not perfectly uniform. A further powerful predisposing cause is to be found in renal disease, and more especially in that form known as Bright's disease of the kidney. Dr. Taylor gives the following results of the analysis of the causes of thirty-eight cases of acute pericarditis:

There was rheumatism in

Bright's disease in

Bright's disease doubtful, or other form of renal disease, in
Cyanosis

Extension of inflammation from adjoining tissues in

It follows that in examining the dead subject, we should, in all cases of pericardial disease, be particularly careful not to omit looking to the condition of the kidneys, even if the symptoms during life were not such as to draw the physician's attention to these organs. Considering the degenerative character of Bright's disease, and its chronic course, we are justified in regarding it as a powerfully predisposing cause to inflammation of serous membranes, and particularly of the pericardium. The fact of the relation of the two diseases being established, will also assist us during life in discovering one by the indications of the other, as has already been the case in regard to rheumatic pericarditis; for the subjective symptoms of the latter are occasionally so slight, that but for our knowledge of the predisposing influence of rheumatism, we might not be induced to look for the evidence of heart disease. This remark applies with almost greater force to affections of the endocardium, which, as we shall have occasion to see, offers a yet greater proclivity to the morbid influence of the rheumatic diathesis than the external investment of the heart.

The false membranes remaining after an attack of pericardial inflammation, may, unless absorbed, become the seat of similar changes, as we find them undergoing in other structures throughout the body. They present a metamorphosis into fibrous, cartilaginoid, and osseous tissue. The deposit of the latter occurs in smaller or larger patches; they may be numerous and distinct from one another, or they may unite to form, as in a preparation contained in Guy's Hospital (No. 1,448), a complete ring encircling the base of the heart.

TUBERCLE.

The relation of pericardial inflammation to definite dyscrasiæ is evinced negatively, by the absence of any proclivity of the membrane to be affected in tubercular disease. On theoretical grounds we might have been inclined to assume that the vicinity of the diseased lungs in phthisis, as well as the more immediate relation which would seem to exist between the blood circulating in the pulmonary and cardiac vessels, would have been a frequent source of disease in the latter, and the parts supplied by them. But while the meninges of the brain and the peritoneum are constantly found to be the seat of tubercular deposit, the pericardium is remarkably free from it. Louis' has only found evidence of pericarditis three times in phthisis; and he details one case in which some semi-transparent gray granulations were found under the serous lamina of the pericardium, to which he attributes the pericarditis under which the patient was laboring. Dr. Hope states that tubercles are sometimes developed in the false membranes of pericarditis; but neither does he himself give any positive evidence to that effect, nor have we succeeded in finding proofs of it elsewhere. It does, however, appear that the false membrane may itself become subject to simple inflammation, which, from its known vascularity, is in accordance with the general theory of inflammation.

1 Mémoire sur la Pericardite, &c., 1826.

CARCINOMA.

Carcinoma affects the pericardium more frequently than tuberculous disease; it occurs only in connection with a general cancerous cachexia, and a formation of similar growths in other organs; the only variety met with is medullary carcinoma. According to Rokitansky, this secondary mass spreads itself in the form of an infiltration of the fibrous layer of the pericardium over a large portion of its surface, and presses upon and into the tissue itself, where it becomes developed into roundish, or flattened, or teat-like nodules.

FATTY DEPOSIT.

It is not uncommon to meet with an excessive deposit of fat upon and within the pericardium; it occurs in conjunction with general obesity, as well as in cases where there is little subcutaneous fat; nor is it necessarily associated with true fatty degeneration of the muscular tissue of the heart, though we may at the same time find fat insinuating itself into the heart, so as to separate the muscular fasciculi from one another. It will be observed that accumulation upon the heart is largest in the horizontal sulcus, and that its distribution appears to bear a relation to the arrangement of the blood vessels.

PNEUMO-PERICARDIUM.

A condition of the heart rarely found until after death, and termed by Laennec pneumo-pericardium, consists in an effusion of air into the sac. Laennec states that he was able to diagnose its presence during life from the unusually clear sound yielded by percussion in the region of the heart, and by a sound of fluctuation accompanying the movements of the heart and of respiration. In the majority of cases, it is due to post-mortem decomposition of the pericardial fluid. The vital generation of gas in the sac must be an occurrence of extreme rarity, since Rokitansky does not appear to have met with an instance. M. Bricheteau is quoted by M. Bouillaud' as having met with a case of hydropneumo-pericardium, in which a murmur resembling the noise of a water-wheel was heard during life, evidently connected with the alternate movements of the heart. The pericardium was found to contain a fetid effusion, and, on incision, the contained gas escaped with a lisping noise. During the present year (1852), a case of perforation of the oesophagus, which had formed adhesions to the pericardium, occurred in St. Mary's Hospital. The patient was a young woman under the care of Dr. Chambers, in whom the admission of air into the pericardium occurred shortly before death through the perforation; the pericardium was found much distended from this cause, when the post-mortem examination was

Traité Clinique, &c., vol. ii. p. 472.

made; and it was owing to this circumstance that the fibrinous layer, which had been deposited between the surfaces of the pericardium, had not given rise to any friction sound during life.1

FIBRINOUS CONCRETIONS IN THE PERICARDIUM.

To complete the subject of the morbid contents of the pericardium, we have yet to advert to the presence of free bodies, which Rokitansky has met with in a case of pericarditis. He describes them as fibrinous, soft, yellow concretions, of the size of beans or almonds, and similar to the latter in shape; which, he adds, would no doubt have eventually been converted into elastic, tough bodies of fibroid tissue. None of the authors whom we have been able to consult, record any similar case; we may therefore assume that the actual occurrence of free bodies is a circumstance of extreme rarity, and the above seems rather to be due to an accidental agglomeration of fibrinous flakes than to any other new production of tissue.

The case is detailed in the Report of the Pathol. Soc. for 1852-3.