THE BACTERIA OF THE ALIMENTARY TRACT. 165 



As more or less constant inhabitants of various portions of 

 the intestinal tract have also been described certain spirilli 

 and blastomyces (yeasts) as also moulds and streptobacilli. 

 The majority of these are harmless saprophytes. It must 

 also be mentioned in this connection that it is probable that 

 the faeces contain bacteria which it has not as yet been pos- 

 sible to cultivate on artificial media. 



5. The following may be said regarding the distribution 

 of the bacteria in the alimentary tract. The mouth has an 

 exceedingly plentiful bacterial flora which through the 

 agency of the food and swallowed saliva is carried down 

 the ossophagus. In the stomach the bacteria become greatly 

 reduced in number. This is dependent upon the fact that 

 the secretions of the gastric mucosa destroy or at least 

 inhibit the growth of micro-organisms in this organ. Which 

 constituent of the gastric juice it is that brings about this 

 sterilization in the stomach is not entirely decided, but it 

 seems to be the hydrochloric acid. The pepsin by itself 

 has no apparent action upon the bacteria and simple hydro- 

 chloric-acid solutions of the concentration found in the 

 stomach are sufficient to bring about the same degree of 

 bacterial destruction as is brought about by the gastric juice. 



The bactericidal effect of the gastric juice is of no mean 

 ( linical importance, for, as has been shown by OPPLER, SEI- 

 FERT, HESTER, and others, gastric and intestinal fermentation 

 is much greater in cases of anacidity of the stomach than 

 under normal circumstances. OPPLER believes that many 

 chronic diarrhoeas are primarily dependent upon a lack of 

 acid in the stomach, and MESTER has found that while in- 

 testinal putrefaction is not increased when putrid meat 

 is fed to healthy dogs, this is the case when anacidity is 

 present. To the decreased amount or total lack of hydro- 

 chloric acid is also attributable the presence of butyric and 

 other fatty acids in the stomach contents of patients suffer- 

 ing from gastric carcinoma and other diseases of the stomach. 

 These acids are produced in part through the decomposi- 



