The Etiology of Gall Stones. II. Rôle of the Gall Bladder. ∗

In the preceding paper it was shown that the greater content of cholesterol in human bile than in that of animals was associated with the formation of a water soluble complex with bile salts. By this means more cholesterin is held in solution. It is obvious therefore that the maintenance of the cholesterol in solution is dependent on the concentration of bile salts in the bile and that if it falls below a certain level the cholesterol will be precipitated. The following studies of the differential absorption rate of bile acids and cholesterol seem to show that the gall bladder under certain conditions may play the major part in gall stone formation.

It will be seen that under normal conditions the gall bladder mucosa in its action in concentrating the bile is able to absorb water, of course, rapidly, and the bile salts and cholesterol, if they are absorbed at all, are absorbed at the same rate. In other words the cholesterol content of the bile rises no faster if as fast as the bile salt content, so that there is a wide margin of safety, and no danger that there will not be enough bile salts to hold the cholesterol in solution.

When the gall bladder is diseased a diametrically opposite action takes place. In this series, the cystic duct was ligated which, as we have shown, 1 leads at once to the infection of the gall bladder. Such a gall bladder with the added insult of the insertion of a needle and ligature of the needle hole looks grossly thickened and diseased at the end of 24-48 hours. In some of the experiments it was also traumatized by scraping its mucosa. In this series of experiments an entirely opposite differential absorption took place.