PREFACE. vil 



' I could not waste my time in going back upon 

 things already accomplished.' 



' No ; but my desire is that someone else should 

 consecrate his time to the work. And listen,' added 

 this friend, with audacious frankness ' do you know 

 by whom, in my opinion, this book ought to be 

 written ? By a man who, without having been in 

 any way trained to follow in your footsteps, is ani- 

 mated by the most lively desire to understand the 

 course which you have pursued ; who, while living at 

 your side, has been each day impregnated with your 

 method and your ideas ; who, having had the happi- 

 ness of comprehending your life and its achievements, 

 does not wish to confine the pleasure thus derived to 

 himself alone.' 



' Where, then,' interrupted Pasteur with a kindly 

 smile, not without a tinge of irony, ' is this man, at 

 once so happy, and so impatient to share his happi- 

 ness with others ? ' 



' He is now pleading his cause before you. Yes, 

 I would gladly attempt such a work. I have seen 

 your efforts and observed your success. The experi- 

 ments which I have not witnessed you have always 

 freely explained to me, with that gift of clearness 

 which Vauvenargues called the " polish " of masters. 1 

 Initiated by affection, I would make myself initiator 

 by admiration. It would be the history of a learned 



1 'Verms des maitres.' 



