VITALITY OF PUTKEFACTIVE ORaANISMS. 



189 



neck of the bulb, a little warmth was applied to the 

 latter, and during its application the neck was plugged 

 with cotton-wool. The air entering through this plug 

 to supply the place of the small quantity displaced by 



Fig. 18. 



the warmth would, I concluded, reach the interior of the 

 bulb perfectly sifted of its floating matter. The necks 

 of the bulbs were hermetically sealed, and the infusions 



