The Fermentation Tube 217 



Among the more important bacteria which have been tested 

 in the fermentation tube and which fail to set free any gas 

 may be mentioned the following : 



Staphylocci. 



Streptococci. 



Septicaemia hiBjnorrhagica (rabbit septicaemia, swine plague, 

 fowl cholera, Wildseuche, etc.) 



B. typhi abdominalis. 



The various comma bacilli (^Spirillum chol. Asiat. ; Sp. 

 Deneke, Finkler and Prior, Smith.) 



B. anthracis. 



Many aerobic spore-bearing bacilli. 



B. mallei. 



Concerning that strictly aerobic species, B. subtilis, Vande- 

 velde^° finds, contrary to earlier determinations of Prazmowski", 

 COj and H given off in varying quantities. Obviously the 

 former worked with impure cultures. The absence of gas 

 production in cultures of B anthracis was pointed out by Ar- 

 loing* in 1886. 



SOME GENERAL OBSERVATIONS ON THE PRODUCTION OF GAS 

 BY BACTERIA AND ITS RELATION TO THE FORMATION OF 

 ACIDS IN THE CULTURE FLUID. 



A consideration of the results obtained with the fermenta- 

 tion tube develops a number of interesting phases of bacterial 

 life. Perhaps the most important fact to be gathered is the 

 fundamental character of gas production not only in distin- 

 guishing species but groups of species. The phenomenon of 

 fermentation as expressed by gas production may in fact be 

 called a group reaction. It is, for example a common charac- 

 ter of a large group of motile bacteria which we may desig- 

 nate the B. coli group. While it is absent in other equally 

 large and important groups such as Septicemia ha;morrhagica 

 and the comma bacilli. I regard, therefore, the production 

 of gas not as one of the large number of minor differential 

 characters by which we are in the habit of fixing a species 

 but as one of fundamental importance, associated with groups 

 of bacteria having perhaps a common phylogenetic origin. 



