108 PASTEUR: THE HISTORY OF A MIND 



ported Balard with delight and the laboratory became 

 animated with his expansive joy as soon as he entered. 



Dumas, more majestic, and at this time a power, came 

 more rarely. He was not desirous of seeing things at 

 such close range. He judged them from his superior 

 height and was no less a very good judge; consequently 

 Pasteur never allowed any of his words to escape him. 

 It was a little in spite of his advice that Pasteur had 

 approached this question of spontaneous generations, 

 and there is no doubt that in giving this advice Dumas 

 was lacking in perspicacity, so much was this study in 

 accord with the mind and the works of Pasteur. But 

 the pupil kept his master in touch with his progress; 

 and he was never more happy than when he recounted to 

 the laboratory some word of approbation from Dumas. 



Pasteur had need of these encouragements, for, de- 

 cidedly, he could not make up his mind to take part 

 in the little war which the partisans of spontaneous 

 generation were pursuing before the Academy and in the 

 journals. But this internal ebullition did not prevent 

 him from being a shrewd manceuverer. Consequently, 

 he allowed the most hazardous affirmations to be made 

 without too much protestation, contenting himself with 

 exposing from time to time the weak points in the ex- 

 periments which were opposed to his own. He did 

 not wish to follow his adversaries into their own field, 

 knowing that this was dangerous, and that thus they 

 could draw him where they wished: he waited patiently 

 to see them approach his territory. Thus when they 

 affirmed, on the day following some experiments made 

 on the Maladetta, that "wherever they collected a 

 litre of air, as soon as they put it in contact with a liquid 

 capable of fermentation, enclosed in a matrass hermeti- 

 cally sealed, the latter invariably became filled with 

 living germs," on that day, Pasteur made haste to seize 



