522 GALL-BLADDER. 



tion will extend through the lobular venous plexuses "into those 

 branches of the portal vein situated in the interlobular fissures, but 

 not to those in the spaces, which, being larger, and giving origin to 

 those in the fissures, are the last to be congested." In this second 

 stage the liver has a mottled appearance, the non-congested sub- 

 stance is arranged in isolated, circular, and ramose patches, in the 

 centres of which the spaces and part of the fissures are seen. This 

 is an extended degree of hepatic-venous congestion ; it is " active 

 congestion" of the liver, and very commonly attends diseases of the 

 heart and lungs. 



There is another form of partial venous congestion which com- 

 mences in the portal vein; this is, therefore, portal venous congestion. 

 It is of very rare occurrence, and Mr. Kiernan has observed it in 

 children only. " In this form the congested substance never assumes 

 the deep red colour which characterizes hepatic venous conges- 

 tion; the interlobular fissures and spaces, and the marginal portions 

 of the lobules are of a deeper colour than usual; the congested 

 substance is continuous and cortical, the non-congested substance 

 being medullary, and occupying the centres of the lobules. The 

 second stage of hepatic-venous congestion, in which the congested 

 substance appears, but is not cortical, may be easily confounded 

 with portal venous congestion. 



These are instances of partial congestion, but there is sometimes 

 general congestion of the organ. " In general congestion the whole 

 liver is of a red colour, but the central portions of the lobules are 

 usually of a deeper hue than the marginal portions." 



GALL-BLADDER. 



The gall-bladder is the reservoir for the bile ; it is a pyriform sac 

 situated in a fossa, upon the under surface of the right lobe of the 

 liver, and extending from the right extremity of the transverse fis- 

 sure to its free margin. It is divided into a body, fundus, and neck ; 

 the fundus or broad extremity in the natural position of the liver is 

 placed downwards, and frequently projects beyond the free margin 

 of the liver, while the neck, small and constricted, is directed 

 upwards. This sac is composed of three coats, serous, fibrous, and 

 mucous. The serous coat, is partial, is derived from the peritoneum, 

 and covers that side only which is unattached to the liver. The 

 middle or fibrous coat is a thin but strong cellulo-fibrous layer, inter- 

 mingled with tendinous fibres. It is connected on one side to the 

 liver, and on the other to the peritoneum. The internal or mucous 

 coat is but loosely connected with the fibrous layer; it is every 

 where raised into minute rugae which give it a beautifully reticu- 

 lated appearance, and forms at the neck of the sac a spiral valve. 



It is continuous through the hepatic duct with the mucous mem- 

 brane lining all the ducts of the liver, and through the ductus com- 

 munis choledochus, with the mucous membrane of the alimentary 

 canal. 



