I will give the description of auricular aneu rism in Mr. Thurnam's words : " The dis ease would appear,from the preparations I have inspected, and the cases which have been re corded, to have been nearly uniformly of the diffused kind, and to have generally involved the entire sinus of the auricle. The dilated walls of the cavity are often thickened and the seat of fibro-cellular degeneration. The lining membrane is opaque, rough, and otherwise diseased, and in some cases even ossified, and is lined with fibrinous layers, very similar to those met with in arterial aneurisms. In all these cases, the lining membrane appears to have been continued into the interior of the dilated portion, which consequently merits the name true aneurism. Occasionally the dilatation is confined to the auricular appendage, which becomes extensively distended with lamellated concretions." The false aneurism, or that resulting from rupture, must be spoken of merely as a pos sible and probable occurrence. I know of no unequivocal example of it; but inasmuch as we must admit that partial rupture of the heart's wall may take place, we cannot deny the possibility of the production of cardiac aneurism in a manner similar to that in which arterial false aneurism is produced.
Dr. I Tope describes cases, which Mr. Thur nam very aptly compares to " the dissecting aneurism." In those cases, Dr. hope says, " steatomatous degeneration had caused the formation of a canal from the aorta underneath one of the sigmoid valves and the internal membrane of the left ventricle." But Mr. Thurnam's explanation seems to me much more likely to be the true one. Ile supposes that the aneurisms had been originally formed in the ventricle, and had subsequently commu nicated with the aorta, as a consequence of the co-existent disease of the valves of that vessel.
The possibility of the formation of an aneu rism resembling the varicose aneurism, has been likewise suggested by Mr. Thurnam, from the occurrence of aneurismal pouches in the sep tum ventriculorum. If such an aneurism were to burst, it would establish a communication with the right ventricle, a portion of the ve nous system—thus producing " a lesion alto gether analogous to that which results from the wound of an artery and its accompanying vein, and to which the name of spontaneous varicose aneurism if the heart is perfectly applicable." Mr. Thurnam mentions a fourth form of aneurism which is not without its analogue in the arterial system, namely, that in which the aneurismal sac is formed by the endocardium and pericardium. This may be compared with a variety of external aneurism in which the lining membrane of the vessel protrudes through a rupture in the middle tunic, constituting a lesion which has been sometimes designated " aneurisma herniosum," and sometimes " internal mixed aneurism." This form of arterial aneurism has been described by IlaIler, Dubois, Dupuytren, and Breschet.
In a large number of these cases of aneu rism of the heart, the pericardium has been at some period or other of the disease more or less extensively inflamed, and adhesions are consequently found : the endocardium like wise frequently exhihits marks of inflammatory action, opacities, white spots, &e. and this
sometimes extends to the valves. In some the muscular substance in the neighbourhood of the sac is degenerated, and assumes the eellulo fibrous form.* Atrophy of the heart.—The heart, or a por tion of it, may be said to be in the state of atrophy, when its muscular fibres are pale, soft, easily torn, inelastic, attenuated, so that the thickness of the parietes is greatly di minished, and the pericardium covering the heart or the atrophied part of it, is shrivelled and wrinkled. When atrophy affects the whole heart, that organ becomes much diminished in size, the capacity of its several cavities being proportionally diminished ; and in some in stances the diminution of the general size ap pears to be more at the expense of the dimen sions of the cavities than of the thickness of the walls.
Morbid deposit of fat on the heart (fatty degeneration of some authors). There is an alteration met with not uncommonly in the muscles of animal life, which is very often de scribed as the fatty degeneration of muscle, but which is in truth an atrophy of the mus cular tissue, and not at all a transformation into fat. This condition, which resembles fat only in its yellow colour, and may be easily distinguished from it by its fibrous form, has never, I believe, been met with in the heart ; a perfect cessation from active contraction must be essential to its production; and as such a state of quiescence cannot occur in the heart during life, this form of degenerate muscular tissue is not found in that organ. We do, how ever, meet with cases frequently, in which fat seems to take the place of the muscular fibres of the heart : in proportion as they appear to waste away the fat is deposited under the serous membrane, until the muscular parietes of the heart are reduced to a very thin lamina, of a pale colour and easily torn, between which and the pericardium a thick stratum of fat is deposited, so that a superficial examination might lead one to suppose that the walls of the heart were wholly converted into this tissue. The ventricles are generally, if not uniformly, the seat of this deposit, which must be re garded as an increase in the deposit which is found naturally along the course of the coro nary arteries. It occurs chiefly in old persons, and it is difficult to say whether the muscular atrophy which is always present is a con sequence of the fatty deposit, or precedes it. So enfeebled has the muscular tissue become that persons labouring under this disease very commonly die of a rupture, or rather a giving way, of the wall of one of the ventricles. it occurs in persons of debilitated habits, who either are incapable of active exertion or from circumstances never attempt it, and, what is remarkable, the subjects of this disease are frequently very emaciated : thus M. Bizot* found this condition in fourteen out of twenty nine emaciated females. The disease is like wise more common in women than in men ; and sometimes free oil is present in the blood in inordinate quantity.