VITALITY OF PUTREFACTIVE ORGANISMS. 



139 



it,^ as shown at a, fig. 12. Two-thirds of the cylinder 

 were occupied by the infusion. After the introduction 

 of the latter, the neck of the bulb was plugged with 

 cotton-wool, and hermetically sealed above the plug, 

 as at B, fig. 1 2. The bulbs were afterwards plunged in 

 water deep enough to cover their necks. The water was 



Fig. 12. 



gradually raised to the boiling-point, and maintained 

 at the boiling temperature for ten minutes. They 



* I have called them * pipette-bulbs ' because they are formed 

 by hermetically sealing one shank of a pipette, close to the bulb, 

 leaving the other shank open for the introduction of the infusions. 

 German pipettes, on account of their cheapness, were at first com- 

 monly used ; but in cases of long-continued boiling, explosions 

 were so frequent that bulbs of English glass of specially resistant 

 quality were resorted to. 



