49 
( d ) How would you make plates containing 1/1,000,000 and 
1/10,000,000 cc. of milk. 
( e ) Why not use 0.1 cc. in preference to 1.0 cc. for the inoculation 
of the plates? 
(/*) What sometimes causes colonies to be in a mass in the center 
of a dish or in a mass near one side? 
( g ) Where does the moisture come from that condenses on the 
covers of the dishes? 
( h ) How does the total number of bacteria in milk compare with 
the number in soil? 
(i) Why is it not desirable to average the counts of all the plates 
in getting the final results? 
0) What are spreading colonies? In what way do they affect 
plate counts? 
