Bacterial Multiplication 153 



oxygen demands, etc., vary tremendously among species of bac- 

 teria. However, the standard agar-plating technic is as good a 

 method as is available for routine use in determining viable bac- 

 teria counts. As long as each step in the process is standardized, 

 and the two main sources of error are minimized— namely, dilution 

 error and colony distribution error, the method has merit if correct 

 interpretation of the results are attempted. Technicians should be 

 able to check each other on a given sample within 5 to 10%, and 

 for all practical purposes, this is accurate enough. 



