MITRAL INSUFFICIENCY IN THE HORSE. 1 35 



cong^ested, transudation takes place into the splanchnic cavities, and 

 cedema appears about the lower portions of the body. 



In consequence of its position close to the heart, and of the rich- 

 ness and peculiar arrangement of its vascular supply, the liver is the 

 first of the viscera to be affected. Stasis in the posterior vena cava 

 first reacts on the hepatic and intra- lobular veins, then on the capil- 

 laries and interlobular or perilobular vessels. In the first stage the 

 changes are simply congestive ; the liver is very large and engorged 

 with blood, and incisions show a marbled appearance, a crowd of 

 little blackish points being scattered over a lighter ground. All the 

 lobules show the same abnormal appearance ; the central portion, dark 

 in colour, is formed by the enlarged orifice of the intra-lobular vein ; 

 the periphery is whitish or greyish white. To this peculiar modifica- 

 tion of the hepatic tissue, seen in old-standing diseases of the heart, 

 has been given the name of cardiac or nutmeg liver. The microscope 

 shows dilatation of the intra-lobular veins, enlargement of the capil- 

 laries, and more or less pronounced compression of the hepatic 

 trabeculse throughout the entire area of the lobules. At a more 

 advanced stage inflammatory supplement the preceding phenomena. 

 Examined with the naked eye the liver is still large, consistent, and 

 spotted. The microscope reveals diffuse sclerotic lesions, both in the 

 inter- and intra-lobular regions, the walls of the intra-lobular veins are 

 thickened, and appear as though surrounded by a connective-tissue 

 sheath ; the portal spaces are slightly enlarged by trifling hyperplasia 

 of the same character, which in time may extend to the entire peri- 

 phery' of the lobules. Deformed first of all by dilatation of the hepatic 

 capillaries, and then compressed by this double series of new growths 

 within and around the lobules, the hepatic cells undergo fatty degene- 

 ration. Does hepatic congestion of cardiac origin in the horse ever end 

 in rupture of the liver? This has been affirmed, and some cases have 

 been recorded. In the post-iuortcm examinations I have made the 

 liver has always appeared simply congested, or firm, consistent, and 

 more or less cirrhotic. Where rupture has occurred in horses with 

 heart disease it seems possible that special degenerative changes had 

 existed side by side with those due to circulatory disturbance. This 

 point has not yet been carefully studied. 



Although much less pronounced than those of the liver, the changes 

 undergone by the intestine and stomach are not less evident. As 

 soon as the portal circulation is impeded the mucous membrane of 

 these organs becomes passiveh' congested, the muscular tissue loses 

 power and acts less energetically, and gastro-intestinal catarrh may 

 develop. Like the liver, the spleen first shows simple passive con- 



