90 PASTEUR: THE HISTORY OF A AIIXD 



courtesy. If your infusions remain sterile it is because 

 you heat too much. You alter thus the air in the flasks, 

 or else you destroy the vegetative force of your liquids. 

 The first of these objections was acceptable, although it 

 lacked force and precision in an epoch when the composi- 

 tion of the air was still unknown. But what was to be 

 said of the second? The vegetative force of the hquid, 

 does not that recall invincibly the dormative property of 

 opium, ridiculed a hundred years before by Mohere? 

 This strange conception, nevertheless, met with favor, 

 and, if I recall it, it is because the idea served as a banner. 

 If, in the discussions on spontaneous generations, there 

 have always been savants, who, like Spallanzani, have 

 endeavored never to go beyond experiment, there also 

 have been always those who, like Needham, have not 

 hesitated, in a time of great need, to have recourse to 

 the vegetative force, to the creative power of infusions, or to 

 other conceptions not less vague and chimerical. There, 

 as everywhere, has been the tribe of those who love to 

 deceive themselves with words. 



Be that as it may, the celebrated debate raised be- 

 tween Needham and Spallanzani was left without any 

 definite conclusion, each of the adversaries showing 

 clearly that the other was wrong on some points, but not 

 proving that he himself was right on all. However, 

 science in its onward march validated or invalidated 

 their arguments. We have said that Gay-Lussac, by 

 studying the conserves of Appert, which were nothing 

 more than the application to domestic economy of the 

 results of Spallanzani, found that the air in the tins no 

 longer contained oxygen: this seemed to justify the first 

 objection of Needham given above. But in 1836, it 

 occurred to Schultze to replace with ordinary air the air 

 in the flasks of Spallanzani. After having determined 

 that they are sterile, he shows that they remain sterile 



