CHAPTER V 



CONTROVERSIES OVER SPONTANEOUS 



GENERATION 



Pasteur's studies on fermentation inevitably 

 brought him face to face with the problem of the 

 origin of those minute forms of life through whose 

 activity the process of fermentation is caused. The 

 minute organisms found in decaying substances 

 were regarded by many scientists as arising, by a 

 process of spontaneous generation, out of organic 

 matter in a state of dissolution. Pasteur , who had 

 traced specific kinds of fermentation to specific 

 organisms, and had shown that these organisms 

 reproduced their own kind true to type, and more- 

 over possessed extraordinary powers of dissemina- 

 tion through the atmosphere, was very skeptical in 

 regard to their alleged origin, de novo, out of or- 

 ganic matter. Realizing the futility of the meta- 

 physical discussions and a priori arguments on the 

 subject, which had been so frequently indulged in, 

 and convinced that it is only by careful and critical 



experimentation that the question could finally be 



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