BACTERIOLOGICAL TECHNIQUE. 235 



perforated by glass tubes drawn to a point are filled to 

 such a height that when the fluid is heated to 80 C. 

 it will just fill them. They are inoculated when the 

 bouillon is at about 60 C., heated to 80 C., and then 

 sealed by closing the tube's point by means of a flame. 

 After inoculating and heating, instead of sealing the 

 glass tube a sterile rubber cork can be inserted. If 

 much fermentation is expected, the cork should be 

 clamped or tied to the bottle, so that it will not blow 

 out. One advantage of this method is that any con- 

 taminating organisms which have no spores will be 

 killed. When sealed the bottles should be cooled and 

 then placed in the incubator. 



