112 PHYSIOLOGY OF BACTERIA 



relative values. Figure 11 shows that this is actually 

 the case until very high values are reached. It seems 

 that from 12% alcohol upwards, there is a very slow 

 yet noticeable rate of fermentation which is almost as 

 high with 12% as with 14.5% alcohol. 



Fig. 11. — Rate of alcoholic fermentation in the presence of alcohol. 



Several series of experiments on the lactic fermentation 

 by Rahn (1911) and by Baker, Brew and Conn (1919) 

 can also be used for a test of the general principle. 

 Here again, the computed values are not absolutely 

 constant, but are sufficiently close to support the principle 

 involved. Rahn (1929b) repeated the experiment shown 

 in Table 16 and Fig. 11 with Lactoh. acidophilus and 

 lactic acid. The results in Table 17 show the rate, 

 i.e., the percentages of acid formed by 420,000,000 cells 

 per c.c. If plotted against the amount of acid added, a 

 straight line is obtained, as in Fig. 11. Even the 



