50 



used bouillon containing fresh rabbit blood, obtained practi- 

 cally no fermentation either in glucose or in a whole series 

 of other carbohydrates. Afterwards he got inconstant results by 

 cultivating in peptone water heated together with blood and 

 then filtered. He obtained the most marked reactions by solidi- 

 fying the last-named medium with agar. But the same strain 

 may give different results on the same medium on repeated 

 trials. 



The acid-producing power is therefore so weak that the 

 alteration in reaction in many cases is limited by the very 

 capacity to produce acid. In media which are poor in buffers 

 and favourable for acid production so much acid however 

 may be formed that the power to tolerate acid is the limiting 

 factor. This follows from 1 the authors' experience that the 

 final Ph- when media poor in buffers and favourable for 

 acid formation are employed, is independent of the initial reac- 

 tion even though it varies from Pj-j- 6.8 to Ph- 8. There 

 was no difference in the final Ph- between the different strains. 



The following table shows the results of the various authors: 



This indicates that the fermentation of the pentose, xylose, 

 and the 3 hexoses, glucose, galactose and laevulose, as well 



* Rivers & Kohn however discovered a meningeal strain which 

 did not ferment any of the 5 carbohydrates. 

 -j-; e= marked acid production. 

 (-{_) = very weak acid production. 



«= no acid production. 

 -\-0 = reaction different in the case of different strains. 



