The termination of carditis in Suppuration, which is much less frequent, gives rise to Abscess of the Heart.

In accordance with what has been already stated, abscess of the heart is almost entirely confined to the wall of the left ventricle, where one or more accumulations of pus may be present.

They are generally of inconsiderable size, being about equal in circumference to a pea, a bean, or a hazel-nut. A more considerable size, if it does not consist in an extension of surface, is indeed incompatible with the continued existence of a recent abscess, since it wouldspeedily be associated with a rupture of the walls.

These abscesses are usually of an irregular form, exhibiting various sinuosities, running in different directions.

The muscular substance of the heart immediately adjoining them, is in a condition of purulent infiltration and disintegration; at a somewhat greater distance, it is pale, permeated by a serous or sero-purulent exudation, soft, and admits of being easily torn; while still further from the abscess it is livid, and not unfrequently interspersed with varicose vessels; it is also relaxed. Occasionally, the contiguous muscular substance, in consequence of being infiltrated with a solidified fibrinous exudation, presents a lardaceous or lardaceo-callous appearance.

Under the last-named conditions, the abscess may be encysted, in which case it may exist for a longer period, while its contents may moreover become either in part absorbed, or in part condensed and cretified, and the abscess may in consequence be obliterated. Its usual termination, however, where paralysis of the heart does not supervene, will be its opening either internally or externally, and, in consequence, or independently of these causes, there will be complete perforation of the wall of the heart from laceration of the strata of the muscular substance, which are incapable of further resistance. It frequently happens in internal openings, that the endocardium not only suppurates, but is torn to an extent corresponding with the size of the abscess. Such an opening is followed by a discharge of pus into the cavity of the heart and its absorption into the blood; and very commonly, even before the symptoms of pyaemia have been fully developed, by a swelling of the muscular substance of the heart, owing to the penetration of blood into the cavity of the abscess, and by laceration of the remaining external layers of muscle, that is to say, by perforation.

Some very rare instances of superficial abscesses opening internally may be unattended by perforation, in which case the cavity of the abscess will constitute an acute form of aneurism of the heart, till the pyaemia induced by the discharge of pus into the cavity of the heart ultimately proves fatal. We are not acquainted with any well-attested case in which the discharge of pus has been restrained by the mass of the blood flowing into the opened cavity of the abscess, and by the deposition of fibrinous coagula, or where aneurism of the heart had, in this manner, become established for any length of time.

In the preceding remarks on endocarditis and carditis, and the sequelae of these processes, we have frequently alluded to Aneurism of the Heart. The importance of this secondary heart-disease demands, however, that we should treat the subject specially; and we, therefore, purpose devoting the following section to its consideration.

Aneurism of the Heart, known also as partial [Aneurisme du coer faux), or, according to Breschet, as consecutive aneurism, is a circumscribed dilatation of one of the cavities of the heart, depending specially on a diseased condition of the texture of the endocardium and of the muscular substance of the heart. We retain the designation of aneurism, with its inappropriate accompaniments of "partial," and "false," because the terms have been universally adopted, and because this condition exhibits in its pathological relations a certain resemblance to that which we designate Aneurism of the Arteries. We would, however, at once definitively explain, that we do not consider that there exists any close affinity between these two conditions. In fact, according to our views, this resemblance depends mainly on the circumstance that both conditions are based on an alteration of texture; we will, however, leave it to our readers to compare the two, and to analyze for themselves the special similarities and differences they may be found to present. We are utterly unable to concur in Thurnam's views on aneurism of the heart: nor can we adopt, as the sequel will show, the classification by which he divides aneurism of the heart into numerous species, corresponding to the different forms of aneurism of the arteries.

At the present day we are acquainted with only two essentially differing species of aneurism of the heart, one of which represents an acute, and the other a chronic form; the former corresponding generally to false and the latter to true aneurism of the arteries. We are led, from the numerous observations we have ourselves made, either wholly to discard all other forms, or at any rate to regard those as doubtful which are based on the unsatisfactory researches of other inquirers.

1. One, and certainly a rarer form of aneurism of the heart, is a proximate result of a recent inflammatory process of the endocardium, and probably, also, in great measure of the contiguous muscular substance of the heart, and depends on a laceration of the diseased tissue, which is itself the immediate consequence of its inflammatory relaxation. The blood rushes violently through the rent, which is either limited to the endocardium, or involves with it a portion of the adjacent layers of the muscular substance, and thus disturbs the still uninjured muscular tissue of the heart to various depths. A cavity is thus formed, whose walls consist of the upheaved, lacerated muscular substance, and which is surrounded at its mouth by a torn and fringed margin of endocardium. The blood poured into this cavity deposits its fibrin in the form of soft coagula, infiltrating the lacerated muscular substance, and occurring on the fringed membranous margin in the different forms of vegetations observed in the valves. This aneurism is developed in an acute manner, as may be seen from what has been already stated, and is accompanied by the appearances of recent endocarditis. We have never seen a case in which the walls of an aneurism of this nature had become consolidated into a fibroid, callous tissue; for, in all the cases we have examined, the aneurismal formation was only of recent date, having existed only for a very inconsiderable period after the endocarditis, during the continuance of which it had originated. None of the cases in which an aneurism with solid, callous walls, existed for any length of time after the endocarditis, afford the slightest evidence that it had originated in this acute manner from laceration. The investigations of foreign observers have so far influenced pathologists, that they have begun their inquiries regarding aneurism of the heart with callous walls with the preconceived opinion that a loesio continui occurs in the endocardium, as in the so-called mixed aneurism (A. spurium of Scarpa) of the arteries; and the difficulties attending the investigation of this form of aneurism of the heart, have greatly contributed to the maintenance of this error, notwithstanding the numerous proofs we have advanced to the contrary.