THERAPEUTIC ACTION OF FERMENTED MILK 37 



of the lactic acid bacilli it is claimed that they drive out other forms 

 of bacteria from the large intestine^ the chief seat of intestinal putre- 

 faction. It is desirable that we should soberly consider the known 

 facts relating to this question. I think it safe to say that the ability 

 of lactic acid forms to replace or dominate other types of bacteria in 

 the large intestine is much exaggerated. I have devoted some study 

 to this question, especially in the case of the B. hulgaricus employed 

 in the production of lacto-bacilline. This organism, owing to its 

 large size, morphology and cultural peculiarities is easily recognized 

 and is cultivable, from the intestinal contents. When given to human 

 beings in the large numbers present in lacto-bacilline it can after a few 

 days' administration be cultivated without difficulty from the move- 

 ments. Even when large quantities of the fermented milk have been 

 taken I have not found that it becomes the dominant organism, although 

 it may be present in moderate numbers. On stopping the administra- 

 tion of the lacto-bacilline, the B. dulgaricus generally disappears in the 

 course of a few days, showing that it has not permanently established 

 itself within the intestinal tract. There may be exceptions to this 

 statement, but I have not yet met with any. These clinical results are 

 quite in accord with those obtained by Dr. Kendall and myself in 

 experiments upon a monkey fed for two weeks on lacto-bacilline ex- 

 clusively. At the end of this period, when the movements were show- 

 ing the regular presence of B. hulgaricus in relatively moderate 

 numbers, the animal was killed and the digestive tract examined with 

 care at all its levels. The lactic acid organisms were found in greatest 

 abundance in the small intestine. In the lowest portion of the small 

 intestine a notable falling off was observed and other types of bacteria 

 were prominent. In the large intestine the numbers were only 

 moderate as compared with other varieties of bacteria, thus clearly- 

 showing that in this instance, at least, the B. hulgaricus was very far 

 from dominating other associated types of bacteria. I consider this 

 fact noteworthy, as the experiment was carried out under conditions 

 highly favorable to the establishment of the lactic acid bacilli in the 

 digestive tract. The large number of microorganisms given and the 

 relatively short extent of the digestive tract in the monkey should, it 

 would seem, provide conditions for the adaptation of the organisms 

 throughout the alimentary canal. 



It is probable that the experience Just recounted with regard to 

 lactic acid bacilli is not at all exceptional, or in other words that 

 foreign bacteria in general find it difficult to gain a permanent footing 

 in the digestive tract. The literature of experimental bacteriology 

 shows this to be the case. Personal experiments made with a highly 

 fermentative putrefactive organism — B. cerogenes capsulatus (B. 

 welchii or B. perfringens of the French writers) — in feeding expert- 



