84 PASTEUR : THE HISTORY OF A MIND 



will be produced once more the gases, which this time 

 will have an odor, because in this reducing medium, 

 hydrogen is mixed with sulphuretted and phosphoretted 

 hydrogen, which are not formed in contact with air, 

 or, if formed, are oxidized immediately: we shall have, 

 therefore, a putrid odor. But the gases will have the 

 same origin as in the fermentation of lactate of lime. 

 Fermentation and putrefaction are synonymous terms, 

 and there is no reason for maintaining the old distinction, 

 which had not yet disappeared from the conclusions of 

 Helmholtz. In these two phenomena the liberation of 

 gases has the same origin, and it is due to organisms 

 living in the absence of air. It is opportune to ask 

 if there is not a close relation between the phenomena 

 of fermentation and of anaerobic life. Here we have a 

 great question which Pasteur put to himself immediately, 

 but which he did not solve until some years after. 



I have thought best to present without detailed exami- 

 nation all these deductions, because in reality thej^ were 

 the work of some weeks of labor and meditation, and 

 also because we have in them an example of Pasteur's 

 insight, of his ability to discover and state a problem, 

 of the patience with which he gathered together the 

 elements of the solution. During the best years of his 

 life, this man lived in advance of his time, a pioneer lost 

 in the solitude, absorbed in the contemplation of the 

 vistas which he was discovering, and which his eye alone 

 was to scrutinize and survey. What less astonishing 

 than his apparent indifference to things of daily life! 

 He lived in his thoughts without being a dreamer, for a 

 dream which goes somewhere and which bears fruit is no 

 longer a dream. 



