FUNCTION OF COLON BACILLUS. 465 



testines or reach them through accident. This is 

 not the place to consider these questions in detail, 

 and they are on none too definite a basis. It may 

 be stated, however, that the colon bacillus and an- 

 other closely related organism, Bacillus [lactis~\ 

 aerogenes, distinctly antagonize the action of cer- 

 tain proteolytic bacteria which appear to be associ- 

 ated with the putrid decomposition of milk and 

 other proteid-containing foods. Bacteria of the 

 latter type exist in the intestines. Unsterilized 

 milk has a natural resistance to putrid decomposi- 

 tion, and sterilized milk to which the colon bacillus 

 or Bacillus \lactis\ aero genes has been added, has 

 a similar resistance. These two bacteria flourish 

 in the presence of carbohydrates, which they 

 decompose with the liberal formation of acids, and 

 through these acids they "limit intestinal putre- 

 faction and influence (favorably) pathologic proc- 

 esses which are caused or maintained by the 

 existing 'alkaline fermentation' " (Escherich and 

 Pfaundler). That the organisms in question 

 antagonize the action of putrefactive bacteria has 

 been shown in test-tube experiments (Hirschler). 



Since the time that v. Emmerich upheld the 

 colon bacillus (or a colon-like microbe) as the 

 cause of Asiatic cholera (1885), opinion as to the 

 pathogenic powers of the organism has undergone 

 many fluctuations. Following Koch's demonstra- 

 tion of the comma bacillus as the etiologic factor 

 in cholera, the colon bacillus was, so to say, re- 

 pressed as a pathologic agent. Later, and especially 

 in France, great significance was again attached to 

 it. The condition still shows a great deal of chaos, 

 although, on account of more refined technic and 

 the elimination of other organisms, as the dysen- 



