ON THE ROAD TO FAME 61 



was conclusive, and, although they were re- 

 peated by Gay-Lussac, Schulze and Schwann, 

 their results remained uncertain and often con- 

 tradictory. 



When Pasteur intervened the theory of spon- 

 taneous generation was supported by Pouchet, 

 and it may be said that it was accepted by a 

 considerable number of scientists. It is true, 

 however, that no decisive evidence had been 

 offered either for or against the theory. It was 

 at this moment that Pasteur revealed himself, 

 not only as a man of daring and profound 

 thought, but as the most careful and experi- 

 enced of operators. To those who believed in 

 spontaneous generation he said, "Everything 

 comes from a germ, and even these animalcula, 

 which seem to you to have been born spontane- 

 ously in the infusions in which they develop, 

 come quite simply from germs and spores which 

 are floating in the air. You have conducted 

 your experiments badly ; I will begin them over 

 again, and I will prove to you that the sub- 

 stances which you regard as subject to decay 



