216 Report of the Department of Bacteriology of the 



some further tests are given in Table VI in which the use of 0.05 

 per ct. of dextrose has had no appreciable influence. This latter 

 table contains thirteen comparative counts between the formula 

 given in Table I (with 0.1 per ct. dextrose and 0.1 per ct. asparagi- 

 nate) and a modified formula in which the asparaginate content is 



Table VI. — Tests to Determine the Effect of Using Only .05 Per Ct. 



Dextrose in Asparaginate Agar. 



* This medium contained 0.2 per ct. asparaginate. 



f Counts on the asparaginate agar with 0.05 per ct. dextrose that are higher than 

 the corresponding counts upon the medium with 0.1 per ct. dextrose are printed in 

 bold-faced type. 



Jin this case there was such irregularity between the number of colonies upon the 

 parallel plates that a satisfactory average could not be taken. 



doubled but only half the usual amount of dextrose is used. The 

 count has proved higher on the modified formula than on the 

 ordinary asparaginate agar in all but four cases, and equal to it in 

 one of those four; but the counts on the two media are always so 

 nearly the same that no weight can be attached to the differences 

 between them. It is plain that, if reducing the amount of dextrose 

 has had any influence upon the count, that influence has been 

 neutralized by increasing the amount of asparaginate, a result 

 which is not to be expected in view of the data given in Table IV, 



