The Anomalies Of The Vascular Trunks most commonly associated with absence of the ventricular septum, are a more or less striking narrowness and obstruction, or even the complete closure of one or other of the arterial trunks, more especially the pulmonary artery, so that the aorta springing from both ventricles supplies the circulating system generally, and the lesser circulation especially, by means of anomalous pulmonary branches. The aorta here shows itself inadequate to the discharge of the blood from both ventricles, and the cyanosis must, therefore, undoubtedly arise from the obstruction opposed to the entrance of blood from the venous system, for we find in numerous cases of deficiency of the septum, where the vascular trunks are normal as well as where they are displaced, that cyanosis is either wholly absent, or that it occurs only on certain occasions, as, for instance, in pulmonary disease; that is to say, it arises in consequence of the retention of the blood in the venous system, by which the passage of the blood from the right side of the heart to the lungs is impeded; there can, however, be no doubt that an admixture of the venous and arterial blood is constantly taking place.

In like manner, where the entire ventricle is not properly developed, it and the vascular trunks to which it gives rise are rendered insufficient for the discharge of the mass of the blood.

The heart, in all these cases, exhibits dilatation and hypertrophy, which either affect both ventricles uniformly, or one more than the other, especially the right one, so that the heart retains its foetal character, more especially in reference to the mutual relation of the ventricles.

Cyanosis is either continuous, although commonly remittent, or results from certain definite causes, among which we may reckon all those which influence the free passage of the blood through the lungs and heart, - as mental emotions, violent bodily exercise, etc. Pulmonary diseases may, perhaps, be regarded as the most powerful of any; and among these, the pulmonary catarrh which affects children and young persons is more especially influential in giving rise to symptoms of cyanosis; the more so, perhaps, because habitual bronchial catarrh is very commonly found to be associated with the above-named malformations, in consequence of the insufficient emptying of the pulmonary vessels into the heart. Cyanosis occasionally appears in childhood and puberty, when it is undoubtedly to be ascribed to a want of relation originating at this period of life, between one or other of the arterial trunks and the heart.

The appearances presented after death correspond with the character of the cyanosis, whether it be constant or transitory, and whether it have arisen from different known and obvious causes, or be owing to influences either unknown or unexplained; and we thus find that some persons suffering from cyanosis manifest retarded development, deficient nutrition and animal heat, and general debility, and die prematurely, while others exhibit merely a very slight depression of the functions of organic life. In some cases, in which the heart presented conditions admitting of the admixture of venous and arterial blood, all the functions were fully performed; - a circumstance that it has been attempted • to explain by the assumption that no admixture of the two kinds of blood occurs, in consequence of the equal development of both sides of the heart.

A morbid form of growth frequently associated with cardiac cyanosis, is the drumstick-like or club-shaped form of the ends of the fingers, with a corresponding convexity of the nails. This phenomenon has not been explained, and if, as has been asserted by different observers, a similar malformation is acquired in pulmonary phthisis, it may serve, from its association with pulmonary cyanosis, to confirm our view of the mode of origin of cardiac cyanosis.

An important observation militating against the ordinary view of the mode of origin of cyanosis has been made by Breschet, who found, in one case, that the subclavian artery of the left side sprung from the pulmonary artery, while the extremities presented no anomalous color. We find, however, that there exists a species of local cyanosis in those cases in which the return of the venous blood has been obstructed by the afflux of arterial blood into a vein, as in varicose aneurism. Finally, in the foetus there is no cyanotic color, although there is a constant admixture of the arterial and venous blood (Fouquier).

Capillary Haemorrhages

Capillary Haemorrhages of the most various organs constitute phenomena in every way important in cardiac cyanosis. They most commonly occur as bleedings from the lungs, and are undoubtedly occasioned by the rupture of the overcharged capillaries. They afford as strong a confirmation of our views as a case which fell under our notice of a cyanotic boy, aged 8 years, who died from laceration of the trunk of an insufficient aorta beyond its arch, and in whom there was an opening in the ventricular septum, closure of the pulmonary artery, and an origin of the aorta from both ventricles.