THE EFFICIENCY OF DISINFECTANTS IK) 



following periods of time : i minute, 5 minutes, 10 minutes, 

 and 30 minutes. In making these inoculations allow the loop 

 to go to the bottom of the inoculated tube. Label each with 

 the strength of the disinfectant and time of exposure and 

 place it in the incubator. It should be noted that the 

 adding of .25 cc. of culture diluted slightly the strength of 

 the disinfectant. 



Note at the next exercise the condition of each inoculated 

 tube. From them the approximate strength of the disinfectant 

 used and the time necessary to destroy the bacteria can be 

 determined. When this is found the more exact strength and 

 time can be determined by repeating the experiment with 

 weaker dilutions or shorter exposures or both. 



Examine cultures that were heated at the previous exercise. 



