The principal predisposing cause is the stagnation of bile, and this may arise either from its inherent density or from partial obstruction. In the various pre disposing conditions given it will be found on examination that they all act in the same way, viz.: in lessening the pressure of the flow of bile through the common duct. It is not impossible that chemical conditions, such as have been described by Thudicum and the French writers, may underlie the formation of calculi, but certainly the existence of such conditions has never been demon strated.
Typioal ealeuli produced in guinea-pigs and following results obtained: Foreign bodies when introduced into the gall bladder can stay there for an indefinite time, provided they are aseptic, without causing, inflammation or precipitating the solids from the bile. When the foreign bodies are previously impregnated with virulent micro-organisms, however, they cause a more or less intense chole cystitis and preeipitate the solids from the bile. As long as the bacteria retain their virulence they cannot form a cal culus, but only a sediment mixed with pus. This precipitate has no tendency to aliere or to adhere to foreign bodies. Five or six months are required for the formation of a perfect calculus. The kind of bacteria injected seems to be of quite secondary importance. .111ignot (Arch. Ga. de 'Med., Aug.. '93).
Hillary calculi may b e caused by cholesterin, bilirubin calcium precipitated by chang,ed reaction, bacteria of various types, and foreig,n bodies. Gall-stones fire uncommon in childhood, rare under thirty, somewhat common between thirty and sixty. usual after sixty years. Fe males suffer from them in the ratio of 4 to 2. Anything predisposing to stasis is a potent cause. The bacillus eoli coin munis and. bacillus typhomis are the most potent generators of binary calculi.
F. C. Shattuck (Phila. Aled. Jour., Oct. 6, 1900).
Pathology.—FORMATION OF CALCULI. —Cholesterin, the principal constituent of biliary calculi, is constantly found in the bile, being kept in solution by the biliary-acid salts: the glycocholate and taurocholate of soda. It is not found in the blood, nor in the liver, unless there be necrosis of the hepatic cells. It must, therefore, be produced by the epithelial lining of the bile-ducts and gall-bladder. Its precipitation will depend either upon its increased proportion in the bile, or upon the diminished solvent power of the latter fluid. Where both conditions
exist together, the process of concretion is still more favored.
Although the quantity of cholesterin in the normal bile is fairly constant, it may be considerably increased by inflam mation of the mucous membrane of the gall-bladder and passages. The same condition produces a lessened alkalinity of the bile, which diminishes its solvent power. It is thus seen that catarrhal inflammation at once produces the two conditions favorable to the precipitation of cholesterin. The process may be set up by such germs as the colon bacillus, the typhoid bacillus, and the pneumo coccus. The fact that such organisms have been found in the nuclei of calculi confirms the theory of this method of their origin, which was elaborated by Naunyn in his work published in 1S92. The presence of a nucleus of bilirubin calcium or cholesterin is not of itself sufficient to give rise to a calculus. This has been proved by experiments upon dogs. Cholesterin calculi, according to Naunyn, may form in two ways: either with small cholesterin masses as nuclei, or small aggregations of sediment be come the centre of calculi. This sedi ment consists of brownish particles and yellow, gritty- masses in which fat-gran ules and cholesterin crystals are often present.
A comparatively-soft nucleus may be surrounded by a hard layer of choles terin. When a calculus is once formed it increases in size, layer upon layer. The crystallization of the cholesterin takes place within the calculus after its forma tion.
The -portal of entry- of the micro-or ganism is probably the duodenal opening of the common bile-duct. It is also probable that, in the great majority of cases, the germs pass into the gall-blad der and not into the intrahepatic ducts. The possibility of entrance through the blood-vessels must be allowed, but has not been proved.
Naunyn is of opinion that the colon bacillus is the principal agent in the production of calculi. Within the last few years the relationship between ty phoid fever and cholelithiasis has been studied by Osler, of Baltimore; Hunter, of London; and others. The frequency with which the latter disease follows typhoid, and the fact that Eberth's bacillus has so often been found in the gall-bladder of those who die of typhoid fever, are interesting facts in this con nection.