Hyperaemia of the liver appears in three forms: as active hyperaemia, resulting from idiopathic or consensual irritation; as passive hyperaemia, dependent upon torpor in the portal vascular system; and lastly, as mechanical hyperaemia, chiefly induced by obstacles in the circulation through the heart and lungs; the last form is one of very frequent occurrence, and is marked by the intensity and extent to which it affects the entire viscera. In rare cases an anomalous anastomosis of the epigastric cutaneous veins with the umbilical veins which have remained permanently open, gives rise to persistent hyperaemia of the liver. (Vide Veins).

The anatomical signs are congestive turgor of the viscus, increase of size, especially in the vertical diameter, but without any further change of form, dark-red color, and obliteration of the yellow substance, softening of the parenchyma, and a large supply of blood. In habitual, and particularly in permanent mechanical hyperaemia, the vessels in the liver, as well as the trunk of the vena portae, and the branches from which it arises, are found dilated and varicose.

Habitual hyperaemia of the liver is apt to be followed by hypertrophy; and as a consequence of an increased production of portal blood, and an exaggeration of its peculiar qualities, the nutmeg-liver may result, which again, may give rise to granular degeneration of the organ.

Apoplexy of the liver is a very rare occurrence; it results from congestion which has rapidly attained a very high degree, and undoubtedly commences as capillary hemorrhage; an apoplectic spot is thus caused, which may enlarge and induce a rupture of larger vessels. According to the seat of the hemorrhage we find two varieties, viz., peripheral or deep-seated hemorrhage; both may however occur simultaneously. In the former, the hepatic peritoneum, especially that investing the convex surface of the right lobe, is detached in a varying extent, and underneath it is found fluid or coagulated blood to a larger or smaller amount. These hemorrhages occur chiefly in infants, as a consequence of impeded respiration and pulmonary circulation, from suffocative catarrh. The hepatic peritoneum may become ruptured, and thus cause an effusion of blood into the abdominal cavity. The liver is in a state of permanent congestive tumefaction, and being overcharged with blood, presents a dark-red color, and looseness of texture. We are reminded by these effusions of the analogous bleedings at the cranium, accompanied by a detachment of either the pericranium or the dura mater, which constitute the so-called thrombus or cephalhaematoma.

In the second variety, apoplectic spots of various forms and sizes are found in the parenchyma; there are generally several of them dispersed through the organ. This variety is found more frequently in adults than the former, but the two may take place at the same time. If a cure follows, a cellulo-fibrous callous cicatrix remains.

Anaemia of the liver is the result of hemorrhages, exhaustion, or a reduction of the mass of blood by extensive exudative processes, and is accompanied by a diminution of the consistency of the liver. It is also constantly associated with many hepatite diseases, such as the fatty, the lardaceous, and waxy liver, to which we have already adverted.