IX 



the stronger solution used by former investigators, 

 appeared to cause greater uncertainty in the results. 



Experiments were also made to see, whether the 

 results were influenced by the addition of the neutral 

 red, before or after sterilisation of the media. Variations 

 on this account being so very slight, the first method 

 was adopted as preferable from a technical point of 

 view, the chance of infection being excluded. The media 

 used were titrated with Vio normal NaOH, phenolph- 

 talein as indicator, and when specified as neutral in the 

 tables, neutral to phenolphtalein is meant. The amount 

 of Vi normal NaOH necessary to neutralise 100 Cc. of 

 the different bouillons was ca. 1.2 to 1.4 Cc. By a nor- 

 mal bouillon is meant, a bouillon proved by the fermen- 



TABLE I. (Normal bouillon). 



