SPONTANEOUS GENERATION 



103 



passed through unaffected. Such air he showed 

 was occasionally able to develop organic life in 

 sterilized infusions, but for reasons quite different 

 from those given by Pouchet. 



Is there any relation between the optical purity 





B 



Fig. g. Apparatus Designed to Free Air from Germs by 

 Drawing It Through Sulphuric Acid Contained in B 



Air sucked through in the direction of the arrows causes it 

 to bubble through the acid, but some of the germs, repre- 

 sented by dots, may escape coming into contact with the 

 fluid and pass into the infusion is the flash A. 



of the air and its power of causing putrefaction? 

 Tyndall attacked this problem with his usual thor- 

 oughness and skill. Like Pasteur he experimented 

 with sealed flasks containing infusions which were 

 opened and closed again in different kinds of air. 

 He also experimented upon the air in his favorite 



