IX 



TABLE III. (1/ glucose bouillon). 



medium, the errors, arising from such a factor being 

 overlooked, are possibly very many. 



From Tables III, IV, V, VI and VII it is evident, that 

 with an increase in quantity of glucose to 1, 2, 3, 4 and 

 5/othere is a proportional decrease in the power of B.coli 

 to change the colour from magenta to yellow. Therefore 

 under these circumstances, the neutral red reaction cannot 

 be applied to differentiate B. typhosus and B. coli. 



As Rothberger and Scheffler prefer to work with 

 neutral red agar, we have also ascertained what effect 

 the kind and quantity of sugar, degree of acidity and 

 alkalinity etc. had upon the results in this medium. 



From Table VIII, in which a shake culture, as proposed 

 by Rothberger, Scheffler and Hunter, has been used, it is 

 to be observed, that it is only in the column neutral, that 

 B. coli has been able to change the colour from red 

 to yellow within 24 hours. In colums 1.5, 1 and 0.5 



13 



