CHAPTER II 



EXPERIMENTS IN CHEMISTRY AND 

 CRYSTALLIZATION 



Pasteur's scientific career upon which we now find 

 him fully embarked presents a remarkably con- 

 sistent and logical development. As we follow it 

 in the succeeding chapters we shall see how each 

 step almost inevitably leads to the one which fol- 

 lows. Many scientists work in varied fields, but 

 for the most part their versatility is the product 

 of a variety of interests with no organic inter- 

 relationship. With Pasteur a single thread may 

 be discerned running through all his research. 

 From the study of crystals he is led to attack the 

 subject of fermentation, and then successively the 

 problem of spontaneous generation, the maladies 

 of wine and beer, the diseases of silk worms, the 

 germ theory of disease of animals and men, and 

 the production of vaccines for the prevention and 

 cure of infectious diseases. Between the early 

 studies of the crystalline form of the tartrates of 

 potash and ammonia and his final great achieve- 

 ment in the conquest of hydrophobia occur a series 



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