Abstract
Viable bacteria were introduced into the stomach of a series of non-leaking gastric fistula dogs and cultures made at certain time intervals along with titrations of the free acid and acid-deficit. One agar plate of B. prodigiosus growth was washed off in 100 cc. of sterile saline. All animals were fasted 20 to 24 hours before experiments. When 100 cc. of a heavy B. prodigiosus suspension was placed in a gastric lumen containing free acid secretion, the subsequent specimens removed and cultured upon nutrient agar were sterile. If there was an absence of free acid in the stomach and the same procedure was followed, the nutrient agar plates were so overgrown that dilutions had to be made to estimate the bacterial content. Some experiments were carried out over 3 and 4 hours of time. It was observed that so long as free H-ions were present no viable bacteria could be demonstrated. But if an acid-deficit developed during the course of the experiment, we observed a sudden appearance within the lumen of the stomach of many viable B. prodigiosus and they persisted so long as free acid was absent. Test bacteria were only introduced at the beginning of the experiment, their presence or absence within the lumen of the stomach determined by subculturing on nutrient agar, could be correlated with the acid-base balance existing at the time within the cavity of this organ.
Over 300 experiments have been carried out, B. prodigiosus, B. coli, and B. miirii have been used as test bacteria. The results are the same with each bacteria. The test bacteria have been suspended in saline, milk, phosphate buffered solutions, and meat. Graph 1 illustrates an example where there was an acid-deficit at the beginning of the experiment and it persisted for one hour.
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