62 PASTEUR 



are not so when they are rigorously sheltered 

 from the air." 



Pasteur began his experiments at the end of 

 1859, and he pursued them in the midst of the 

 din of battle, for his adversaries disputed his 

 conclusions in advance. The contest lasted for 

 more than four years, with attacks, counter- 

 attacks and violent battles, but finally the vic- 

 tory remained with Pasteur, without even his 

 most bitter enemies venturing to dispute him 

 further. 



Assailing his problem at its foundation, he 

 proved the actual existence of germs and spores 

 in the atmosphere ; then he conceived of a dis- 

 tribution of glass globes which would enable 

 him to demonstrate by experiment what he had 

 already maintained against the supporters of 

 spontaneous generation. Pasteur declared that 

 germs are unevenly distributed in the at- 

 mosphere, and that the air of high mountain 

 tops contains either few or none at all ; Pouchet 

 and Joly, on the contrary, contended that air, 

 by its own nature, could cause spontaneous 



