4S2 
SUMMARY OP CURRENT RESEARCHES RELATING TO 
The counting is done as follows. An average number of colonies is 
found in one of the sector circles, in a definite working area, and the 
number is multiplied by the ratio of the area of the sector circle to the 
Fig. 92. 
Diameter one-half actual size. 
Fig. 93. 
’Diameter one-third actual size. 
