SPONTANEOUS GENERATION 



303 



isms developed from "germs" present in the air falling into 

 the liquids and not spontaneously. 



While Tyndall's experiments were of great value as indi- 

 cated, they probably were harmful in another way. These 

 ** germs in the air" were considered by bacteriologists as 



Fig. 175. — Tyndall's box. One side is removed to show the construction. 

 The bent tubes at the top are to permit a free circulation of air into the in- 

 terior. The window at the back has one corresponding in the front (removed) . 

 Through these the beam of light sent through from the lamp at the side was 

 observed. The three tubes received the infusion and were then boiled in 

 an oil bath. The pipette was for filling the tubes. (Popular Science Monthly, 

 April, 1877). 



well as laymen to include necessarily many disease germs 

 and to indicate the very general, if not universal, presence 

 of these latter m the air. This idea led to many erroneous 

 practices in sanitation and disinfection which even to this 

 day are not eliminated. 



