Cholelithiasis. — Biliary Calculi. — Gall Stones. 539 



angular crystals. The very fact that a precipitate assumes a 

 spherical form suggests the presence of colloids as an active factor 

 in the precipitation. Heat appears to intensify this action, though 

 probably the normal body temperature operates mainly through 

 the more active proliferation of bacteria. 



Bacteridian infection. In connection with the action of colloids 

 it has been observed that when such bodies are in a condition of 

 fermentation they are much more potent as precipitants than if in- 

 active and sterile. But as all fermentations are the work of 

 microorganisms we are at once brought to the conclusion that 

 bacterial infection is one of the most potent causes of calculous 

 formations. The invading microbes operate upon the dissolved 

 solids, causing changes in their condition which reduce their 

 solubility, and thus determine the separation of calculi and con- 

 cretions in a manner allied to the precipitation of nitrates in the 

 soils. 



But the same microbes operate in producing the colloids which 

 cooperate so effectively in the formation of calculi. The catarrh- 

 al biliary ducts, or bladder shed their epithelium, and transude 

 white and red globules, and form pus and an excess of mucus, all 

 tending to the separation of the biliary solids or forming nuclei 

 on which these solids may condense. The calculi and concretions 

 tend in their turn to maintain and advance the inflammation. 



The access of the microbes to the biliary duct or bladder may 

 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, toccidia), 

 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 angiocholitis 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 

 excretion of bile. 



