Where so much complication exists, as that just detailed, one is only surprised that vitality can be at all supported after extra-uterine life has commenced; yet we find that children with hearts so malformed live three, four, or five days, and even as many weeks or months; but where the perforation of the septum is not accompanied with the contracted state of the pulmonary artery, life may be prolonged to a considerable period. Thus, Louis quotes one case of a general officer (age not stated), whose death was occasioned by the active part he took in the American war. Along with ossified valves of the right auriculo-ventricular orifice, there existed a perforation of the septum ven triculorum large enough to admit the extremity of the little finger. In another case, quoted from Richerand, the patient aged 40, the per foration of the septum was half an inch in diameter.
We say that the two sides of the heart com municate indirectly when the ductus arteriosus continues, as in its fetal state, to convey the blood of the right heart into the aorta descen dens, where it becomes intermixed with the blood of the left heart. But it is very rare to find this condition existing alone, and when it does so exist, the canal of communication is generally very narrow. More frequently it is complicated with a contracted state of the pul monary artery, the place of which it seems to supply. In a case related by Mr. Howship,* this vessel constituted, in fact, the trunk of the pulmonary artery. The pulmonary artery proper arose in its usual situation, but was quite impervious at its root, though far beyond, and terminated in a cul-de-sac beside the heart. Similar cases are recorded by Dr. Farre. At other times the ductus arteriosus is employed to supply the place of the aorta descenders; the aorta is perfect only as far as the termination of its arch, where it contracts, and its con tinuation is formed by the ductus arteriosus, through which the descending aorta receives its whole supply of blood.t A cry perfect case of this kind is quoted by Dr. Paget/ from Steidele. The aorta and pulmonary artery arose as usual; the aorta was entirely distributed to the head and upper extremities, while the pulmonary artery, after giving off two branches to the lungs, con tinued as the aorta descenilens without any communication with the aorta ascendens.
Malformations of the volvcs.—A not un important class of defective malformations in the heart consists of imperfections in the num ber or structure of the valves. The aorta may have two valves only, one of which may retain its natural form and size, while the other pre sents the appearance of having been formed by the fusion of two valves; it may therefore present one or more openings in it, so as to appear somewhat cribriform. A similar con dition is met with in the pulmonary artery, when sometimes the three valves seem as it were united to form one membrane, which like a diaphragm stretches across the mouth of the artery, and is perforated in the centre by an opening through which the blood finds its way into the artery. This narrowing of the orifice of the pulmonary artery is the most frequent of the congenital malformations of the valves : we have already described it as a frequent con comitant of imperfect septum of the ventricles. Congenital imperfections of the mitral and tricuspid valves are of very rare occurrence. The perforated or cribriform condition which is frequently seen affecting these valves, the Eustachian and Thcbesian valves, and more rarely the semilunar valves, is probably the result of a morbid atrophy.
Congenital absence of the pericardium.— Connected with the malformations by defect of developement we may mention the con genital absence of the pericardium, which, although very rare, rests on too strong evidence to admit any further doubt of the possibility of its occurrence. Most of the cases related by the older authors were in connexion with displacement of the heart, and from the liabi lity of mistaking universal adhesion of the pericardium for this congenital absence, many anatomists, among whom was Haller, denied that such a defect had ever existed.
Dr. Bailie was the first of modern anato mists who accurately described a case of this kind. " Upon opening," he says, " into
the cavity of the chest, in a man about forty years of age, in order to explain at lecture the situation of the thoracic viscera, I was ex ceedingly surprised to see the naked heart lying on the left side of the chest, and could scarcely at first believe what I saw, but the circumstances were too strong to keep me long in doubt. The heart was as bare and distinct as it commonly appears in opening into the cavity of the pericardium, and every collateral circumstance confirmed the fact. . ... The heart lay loose in the left cavity of the chest, unconnected in any way except by its vessels; was of a large size, elongated in its shape, and had its apex opposite to the eighth rib. The right auricle was obviously in view in the same manner as when the pericardium has been opened, and the vena cava superior and inferior were clearly observed entering into it. The appendage of the left auricle was as clearly in view; and when the heart was inverted, so as to have its apex turned upwards, the extent of its cavity was seen with the two pulmonary veins of the left side entering behind the ap pendage. The right and left ventricles were distinct, with the coronary vessels running upon them ; and the aorta and pulmonary artery were seen clearly emerging from them." There is nothing in Dr. Baillie's description to indicate positively whether the visceral layer of the serous pericardium was absent or not, although we may infer its absence ; what he says bearing upon this subject is as follows : " The heart was involved in the reflection of the pleura, belonging to the left side of the chest, which became its immediate covering, and upon making the slightest incision into the substance of the heart, its muscular structure was laid bare, as in any common heart de prived of its pericardium." Breschet* has put on record a case in which the pericardium was absent, not altogether, but in greatest part. The subject of it was a young man of twenty-eight years of age, who died in the Hotel Dieu of an inflammatory affection of the intestines. The heart lay free under the left lung without any external fibro serous envelope. The mediastinum was formed only by a simple serous lamina belong ing to the right pleura, and upon the left of this lay a rudimentary fibrous capsule, attached above to the origin of the great vessels. The serous membrane was altogether absent, but the heart was immediately inverted by a serous lamella, which was prolonged from the left pleura. In both this case and that of Baillie, the left phrenic nerve was displaced and brought towards the mesial line of the body, and not covered by the serous membrane,—an anato mical character, which, as Breschet suggests, may serve to distinguish congenital absence of the pericardium from the simple adhesion of that membrane to the heart.t II. Malformations of the heart by excess of development.—Plurality of the heart itself may be obviously regarded as coming under this head ; but I am not aware of any instance in which a double heart has been found in a perfect single foetus, nor can the possibility of such an occurrence be deemed admissible. It is in monsters formed by the junction of two that this double form of the heart has been met with. Thus, in one case referred to in Bouil laud's work, all the upper parts of the foetus were double, while the inferior were simple. There were two heads, two necks, quite separate and of the ordinary size. The necks terminated in a single very wide thorax, to the upper part of which and between the insertion of the two necks an arm was attached in the vertical direction, one perfectly formed arm being placed on each side of the thorax. There were four lungs, each having a distinct pleura, but only one diaphragm : there were also two hearts and two pericardia, each of which had two venze cavae and a pulmonary artery, four pulmonary veins and an aorta. The two aortae united at the lower part of the dorsal region of the spine, and formed the artery by which the abdominal viscera and lower extremities were supplied.