" Trois espbces d'hyperemie du foie doivent care admises, relativement aux conditions de l'economie dans lesquelles elles surviennent.
" tine premiere espece d'hyperemie est celle qui resulte d'un travail d'irritation dont le foie est devenu le siege. Cette irritation est tantot idiopathique, et tantrit elle est la suite dune irritation primitivement fixee sur le tube di gestif.
" Une seconde esikee d'hyperetnie, dont le foie me parait susceptible, est celle dans la quelle le sang s'accumule d'uue manibre route passive au sein du parenchyma hepatique, comme it s'accumule dans les gencives des scorbutiques.
" Enfin le troisime esphce d'hyperemie du foie est purement mecanique ; elle s'observe dans les cas grit un obstacle quelconque s'oppose a la Libre entree du sang dans les cavites droites du cceur ; le sang stagne alors dans les veines sus-hepatiques, et engorge le foie." Now the researches of Kiernan have proved that " in consequence of its double circulation, the liver is naturally in a state of sanguineous congestion" after death, and that author has also pointed out the various forms of conges tion which are observed in the organ. " San guineous congestion of the liver, he observes, " is either general or partial." a. General congestion affects the whole of the substance of the liver, which presents a gene rally diffused red colour; the central portions of the lobules having usually a deeper hue than the marginal portions.
Partial congestion is of two kinds, Hepatic venous congestion.
Portal venous congestion.
b. _Hepatic venous congestion may exist in two stages. " In the first and most common stage (fig. 42) the hepatic veins, their intra lobular branches, and the central portions of the lobular venous plexuses are congested. The congested substance is in small isolated patches of a red colour, and occupying the centres of the lobules is medullary ; the non-congested substance is of a yellowish white, yellow, or greenish colour, according to the quantity and quality of the bile it contains ; it is conti nuous throughout the liver, and forming the marginal portions of the lobules is cortical." "This is the usual and natural state of the organ after death," and arises from arrest in the circulation of the hepatic veins, while the cur rent of blood in the minute branches of the portal vein is still in motion.
" In the second stage (fig. 43) the congestion extends through the lobular venous plexuses to those branches of the portal vein situated in the interlobular fissures, but not to those in the spaces, which being larger there and giving origin to those in the fissures, are the last to be congested ; when these vessels contain blood the congestion is general, and the whole liver is red. In this second stage the non-congested
substance appears in isolated circular and ra mous patches, in the centres of which the spaces and fissures are seen. This form of congestion "very commonly attends disease of the heart and acute disease of the lungs or pleurae; the liver is larger than usual in consequence of the quantity of blood it contains, and is frequently at the same time in a state of biliary conges tion, which probably arises from the sangui neous congestion. Although in the first stage the central portions of the plexuses, and in the second the greater portion of each plexus, and those branches of the portal vein occupying the fissures are congested, and although the plexuses are formed by the portal vein, yet as th& form of congestion commences in the hepatic veins and extends towards the portal vein, and as it is necessary to distinguish this form from that commencing.in the portal vein, the term of he patic-venous congestion will not probably be deemed inapplicable to it." The second stage of hepatic venous congestion, generally com bined with biliary congestion, gives rise to those various appearances which are called drain drinkers' or nutmeg liver.
c. " Portal venous congestion is of very rare occurrence ; I have seen it in children only. In this form, the congested substance never as sumes the deep red colour which characterises hepatic-venous congestion ; the interlobular fis sures and spaces and the marginal portions of the lobules are of a deeper colour than usual ; the congested substance is continuous and cor tical, the non-congested substance being Inc dullary and occupying the centres of the lo bules." The causes of congestion are all such as tend to interfere with the circulation in the liver or with the general circulation ; for in stance, impediment to the circulation of the blood through the capillaries of the lungs, diseases of the valves of the heart, aneurism, &c. A slighter degree of obstacle produces congestion of the hepatic veins only, the venous turgescence being limited by the lobular ve nous plexus. If the obstruction be greater, the lobular venous plexus itself is congested ; if the cause continue, the congestion extends through the interlobular fissures into the neigh bouring lobules, and in a more advanced de gree the congestion spreads itself throughout the whole of the lobules, and becomes general. From the liver the congestion extends to the alimentary canal, and gives rise to intestinal limmorrhages, haemorrhoids, ascites, &c.