Gall Stones in Solipeds. 519 



be effected through the blood of the portal vein or hepatic artery, 

 or in the new-born, through the umbilical vein from an infected 

 navel. As other modes of access may be named, a gradual ad- 

 vance from the duodenum through the common bile duct, or 

 more speedily on or in the bodies of parasites (ascaris, strongylus, 

 stephanurus, taenia, echinococcus, distoma, fasciola, coccidia), 

 etc. 



Changes in the chemical composition of the bile have been invoked 

 as a cause of gall-stones, and Naunyn has found that the inflamed 

 biliary epithelium secretes an excess of cholesterine and salts of 

 lime. Thomas has also observed a great increase of cholesterine 

 in connection with a catarrhal angiochohtis in the dog. 



Among other alleged causes of biliary calculi are advanced age 

 (Rigot, Hering), acidity of the bile (Zundel), constipation, and 

 any organic disease of the liver and bile ducts which interferes with 

 excretioti of bile. 



Age is supposed to act by inactivity, lessened secretion, 

 hepatic torpor, and the greater presumption of liver disease, 

 acidity by the precipitation of cholesterine and the dissolving of 

 lime present in the tissues, and constipation through hepatic 

 inactivity, obstruction of the flow of bile, and the tendency to 

 infection through intestinal fermentations. 



It may be added that any diminution of glycocholate or tauro- 

 cholate of .soda or potash, decreases the solubility of cholesterine 

 and bile acids and favors their precipitation. 



GAI,L STONES IN SOI.IPEDS. 



Characters. The biliary calculi of .solipeds are of all sizes and 

 shapes. When numerous they are mcstly the size of a pin's head 

 (lyucet). Birnbaum found in one animal 400 like peas. 

 Dieckerhoff has repeatedly found four or five of the size of a 

 hazelnut. Verheyen found one as large as an apple and says one 

 exists at the Berlin Veterinary College which weighs several 

 pounds. Rigot found 90 in the biliary ducts of an old horse, 

 and Zundel records the death of a stallion of twenty-six year,s 

 from multiple gall stones. 



