The Fer7neniatio7i Tube 223 



The bacillus of Friedlander produces gas in glucose and sac- 

 charose with equal rapidity. Very slight action on lactose. 



Proteus vulgaris produces gas in glucose and saccharose 

 with equal rapiditj'. No action on lactose. 



Bacillus cloaccc produces gas in glucose and saccharose with 

 equal rapidity. Action on lactose slow. 



The probability of the direct breaking up of the molocule 

 of saccharose and lactose' without inversion, has been affirmed 

 by nearly all recent authorities and seems plausible when gas 

 accumulates very rapidly as in cultures of B. cloacae. It is 

 evident that the observations made with the fermentation tube 

 open some very interesting problems, the solution of which 

 must be left to others. 



In connection with the selective action on sugars manifest- 

 ed by different species seemingly related to each other the 

 thought has occurred to me that a clue to the habitat of bac- 

 teria might be obtained by an investigation of their predilec- 

 tions. Inasmuch as there are certain products such as lactose 

 peculiar to animals, and certain others, such as saccharose 

 peculiar to plants an adaptation to one or the other carbo- 

 hydrate would indicate a saprophytic existence on animal or 

 vegetable products. This hypothesis however needs a larger 

 array of facts than I am able to put together, to prove or dis- 

 prove its correctness. 



The production of CO, and H together with other gases 

 during the decomposition of proteid substances has been af- 

 firmed by Kerry" and Bovet'*. The former used carefully 

 prepared serum-albumin, the other serum-albumin and yolk 

 of eggs. In the accurate determination of the source of gas 

 production in putrefactive processes, it is evident that carbo- 

 hydrates must be carefully eliminated since the fermentation 

 of these substances with evolution of CO2 and H seems to be 

 such a wide spread function among bacteria. 



There is one other phase of the subject of fermentation 

 which has an important bearing upon bacteriology. I refer 

 to the formation of acids * which seems to be clearly traceable 



* Thus in milk cultures o^ B. coli, Baginsky'^ found formic, acetic, 

 aud lactic acids. The same were found by Scruel. Pere' detected ace- 

 tic and lactic acid. Franklaud, Stanley and Frew" determined, in cul- 



