The Experimental Production of Stones in the Bladder

Abstract

Davalos investigated in rabbits the effects of the infectious and traumatic factors in the production of bladder stones. A culture of Proteus vulgaris isolated from the urine of a patient suffering with urinary lithiasis was used. It was selected because it has the ability to split urea of the urine, with the liberation of ammonia, and produces sudden changes of the urinary pH which help to precipitate phosphates and carbonates. Preliminary expts. showed that this organism precipitates crystalloids in the urine from patients with lithiasis. After 12 hrs.'' incubation at 37[degree] C. the dissolved phosphates were diminished by approx. 25%. 3 groups of rabbits were treated: One group received instillations of both salicylic acid and the culture of P. vulgaris; the 2d group was given bacteria only and the 3d group salicylic acid only. Instillation of 2-5 ml. of a 1:1,000 alcoholic soln. of salicylic acid instilled daily for 4 days produced chemical cystitis. Among 50 rabbits thus treated 10 developed bladder stones, all of which received instillations of both salicylic acid and microbes. In none of the rabbits given salicylic acid or bacterial culture exclusively were stones found. Evidently both a chemical and a microbial factor are necessary for the production of bladder stones.