36 THE POPULAR SCIENCE MONTHLY 



persons suffering from chronic intestinal putrefaction have shown no 

 diminution in the putrefactive products excreted in the urine where 

 the patients have added a soured milk to their usual diet. It is, of 

 course, clear that in cases of this sort the failure of the putrefactive 

 process to decline may be attributable to the introduction of more than 

 the habitual amount of protein material. The observation is, however, 

 of interest in that it emphasizes the fact that the ingestion of lactic 

 acid, even if probably associated with lactic acid fermentation within the 

 intestine, may not suffice to exert any beneficial influence in reducing 

 putrefaction. 



I do not wish to be understood as maintaining that the presence 

 of lactic acid in soured milk is of no value in checking intestinal putre- 

 faction. I wish merely to point out that the administration of lactic 

 acid per se can not be regarded as a significant anti-putrefactive pro- 

 cedure. It seems to me probable, on the other hand, that the presence 

 of lactic acid in the large intestine would at least in a degree tend to 

 restrict putrefactive decomposition. But I must own that positive evi- 

 dence on this point seems to be at the present time entirely wanting. 

 In my judgment only very carefully planned studies would suffice to 

 enable us to form a final opinion on the value of lactic acid as an anti- 

 putrefactive agent. "We are not justified in developing an enthusiastic 

 attitude toward lactic acid as an agent in the inhibition of intestinal 

 putrefaction on the basis of our present knowledge. 



Let us now consider the effects derivable from the bacteria used in 

 lactic fermentation. As an example of a strong lactic acid producer 

 we may take B. bulgaricus, used in the production of lacto-bacilline. 

 This organism is a powerful lactic acid ferment, forming large amounts 

 of lactic acid from milk sugar while forming very little alcohol. The 

 organism grows well in milk and on some media containing an 

 abundance of soluble carbohydrates, as, for instance, in malt extracts. 

 We may take the behavior of B. bulgaricus in the digestive tract as 

 being typical of efficient lactic acid bacilli in general. There are two 

 questions which we must put to ourselves regarding the therapeutic 

 effects of such bacteria. First, to what extent do the lactic acid bacilli 

 replace obligate normal types of bacteria or the undesirable saprophytic 

 forms present in disease ? Secondly, to what extent is it desirable that 

 there should be a replacement of the intestinal flora by lactic acid 

 bacilli ? 



It is one of the fundamental assumptions of the sour milk treat- 

 ment of intestinal diseases that the lactic acid producing microorgan- 

 isms establish themselves throughout the digestive tract and through 

 their more or less aggressive growth directly or indirectly inhibit the 

 development of putrefactive or other undesirable forms of bacteria. 

 In some of the statements put before the public in regard to the action 



