THE UTENSILS OF THE CULTIVATION OF BACTERIA. 65 



4. On third day, five hours at 76 C. 



5. Finish sterilization by fifteen minutes in steam ster- 



ilizer at 100 C. 



Before inoculation add 2 or 3 drops of distilled water to 

 each tube. In preparing this medium careful asepsis must 

 be observed. 



THE UTENSILS OF THE CULTIVATION OF BACTERIA. 



For making and keeping cultures the following instruments, 

 glassware, and utensils are required : 



1. Perfectly clean glass tubes, 5 to 7 inches long and J to 



FIG. 12. 



FIG. 13. 



Glass test-tube. 



Erleniiieyer ilask. 



1J inches in diameter (Fig. 12). These should be plugged 

 with ordinary cotton -batting. 

 2. Erlenmeyer flasks (Fig. 13). 

 5 M. B. 



