BACTERIAL METABOLISM WITHIN THE BODY 701 



nant microbes by beneficent bacilli, and encouraging the latter to colonize 

 in the large intestines as a safeguard against future endogenous poisoning, 

 is the essence of the Metchnikoff hypothesis. 



The method of administration of the Bulgarian sour milk bacillus was 

 through milk which first was to be sterilized, then inoculated with a 

 pure culture of the organism, and set aside to ferment to a high degree 

 of acidity. Milk thus soured and populated with enormous numbers of 

 Bulgarian bacilli was to be drunk in large amounts daily. It will be seen 

 that the objective to be attained was to introduce naturally preserved milk 

 [soured milk] containing preformed lactic acid, into the alimentary canal, 

 in the expectation that it would not undergo putrefaction there. Also, 

 that the Bulgarian bacillus would become resident, and supplant the na- 4 

 tive putrefactive microbes. 



The results have, on the whole, been disappointing from the clinical 

 point of view, although sour milk has unquestionably become a popular 

 beverage. It is unfortunate that the emphasis was laid upon the accli- 

 matization of the bacilli of Bulgarian kephir granules in the alimentary 

 tract of man. Available evidence through the work of Herter and Ken- 

 dall, and Rahe, indicates they do not grow in the alimentary tract in com- 

 petition with the normal intestinal flora. From a priori considerations 

 there is little justification for the belief that they would grow there. Ob- 

 servations upon the alimentary flora of normal or niilk-fed nurslings have 

 never revealed the presence of Bulgarian bacilli. It might confidently 

 be expected that lactic acid producing bacteria, parasitic in milk, would 

 grow if they could endure the intestinal environment. On the contrary, 

 the human intestinal lactic acid bacilli which thrive on a milk diet are 

 Bacillus bifidus in the normal nursling, and Bacillus acidophilus in arti- 

 ficially fed babies. 



One of the important details of the Metchnikoff sour milk therapy 

 procedure is a restriction of the protein in the diet of the patient. It is 

 quite clear that rigorous attention to this factor is of unqualified benefit. 

 To make up the requisite caloric [energy] content of the food, some sort 

 of carbohydrate is recommended. It was surmised that the carbohydrate 

 might also help establish the Bulgarian bacillus as an intestinal inhabit- 

 ant. 



It may be stated that the chief value of the sour milk therapy as out- 

 lined above was to introduce considerable amounts of preformed lactic 

 acid. There appears to be little doubt that this lactic acid of exogenous 

 origin is an important restrictor of certain types of intestinal fermenta- 

 tion, especially that in which the "gas bacillus' 7 is either a causative factor 

 or at least an indicator through its unusual luxuriance of growth (Kendall 

 and Smith, Hewes and Kendall, and Simonds). 



There is no very definite proof that anaerobic bacteria are important 

 factors in intestinal putrefaction. Indeed, the evidence points to Bacillus 



