FERMENTED MILKS 395 



Herter and Kendall established an acid reaction throughout 

 the intestinal tract of a monkey by feeding an exclusive diet of 

 sour milk prepared with Bacillus bulgaricus, but failed to establish 

 the organism in the ileocecal region, and even in the large intestine 

 the bacilli were found only in small numbers. "Thus in the re- 

 gion characterized by the most active putrefaction the lactic acid 

 bacilli failed to establish themselves in relatively large numbers." 

 Even more conclusive are the experiments of Rahe, who failed 

 utterly in acclimatizing Bulgarian bacilli in the lower human in- 

 testine. 



Heinemann and Hefferan succeeded in isolating lactobacilli 

 from human feces and in demonstrating their presence through- 

 out the digestive tube, including the mouth, the 'stomach, and 

 the intestines. 



Wegele, after using Metchnikoff's sour milk, came to the con- 

 clusion that the production of lactic acid in statu nascendi in the 

 digestive tube was of greater benefit than the ingestion of lactic 

 acid in sour milk, and Wejnert thought he had markedly reduced 

 the number of bacteria in feces by using lactobacilline milk, which 

 contains Bacillus bulgaricus, Streptococcus lacticus, and a yeast. 



The difficulty in securing reliable proof of such observations 

 as have been mentioned leaves us in doubt as to the validity of 

 the conclusions arrived at by investigators. It is hardly prob- 

 able that the introduction of lactic acid bacteria, no matter in 

 what form, in the digestive tube would be accompanied by the 

 formation of a sufficient degree of acidity to really inhibit the 

 growth of anaerobes. If, however, this should occur, there would 

 be also a decided inhibition of digestion, since the digestive fluids 

 of the intestinal tract are of an alkaline reaction and require 

 an alkaline reaction for normal work. The reaction would be 

 changed to an acid reaction by the acid produced by the bacteria. 



Metchnikoff states in his very interesting book that during 

 his travels in Bulgaria he found exceedingly large numbers of 

 centenarians, and ascribes their long lives to the extensive use 

 of sour milk. The fermented milk foods of the Bulgarians and 

 neighboring peoples, however, differ somewhat from the milk 

 recommended by Metchnikoff. While the fermented milks of 

 the natives of southeastern Europe contain a small amount of 

 alcohol due to the presence of yeasts, Metchnikoff condemns this 

 method of producing fermented milks and claims superiority of 

 milks prepared by the use of lactic acid bacteria without yeasts. 

 Perhaps the habits of the Bulgarians have some effect on prolong- 

 ing life, as they are a hardy race, habituated to a simple diet, 

 and they spend much of their time in the open air. 



It has been claimed that ingestion of lactic acid bacteria is 



