IX 



from red to yellow, therefore the quantity of free acid 

 present here must also be carefully estimated. 



Bouillon is used for all the following experiments, 

 as the comparison of the colours is much easier and 

 their shades are more decided. 



Having followed the effect produced by different 

 quantities of acid, alkali, and glucose, which, to a cer- 

 tain extent can also be reduced by B. typhosus, we 

 found it of interest to ascertain what effect the presence 



TABLE XI. (Vg/o lactose bouillon). 



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