382 THE BEGINNINGS OF LIFE. 



\ set it aside, except upon evidence equally direct and 

 equally positive, though more extensive than that upon 

 which the rule had been originally founded. Certainly, 

 no one should have attempted to set it aside on the 

 strength of indirect evidence, which, though equally 

 capable of explanation in accordance with either one of 

 the two opposing views, was tacitly represented to be 

 explicable only in accordance with one of them. Such, 

 however, was the course pursued by M. Pasteur. It will, 

 perhaps, scarcely be credited by many that the investiga- 

 tions of M. Pasteur, which have had so much influence, 

 and which have been looked upon by many as models of 

 scientific method, should really contain such fallacies. 

 On other important occasions, however, his reasoning 

 has been similarly defective, though he himself claimed 

 and was believed by many to have ' mathematically de- 

 monstrated ' what he had so plausibly appeared to prove. 

 In the present case, after his experiments with milk 

 in Schwann's apparatus, M. Pasteur ascertained that in 

 other alkaline or neutral fluids, even when they had 

 been subjected to all the conditions above mentioned, 

 inferior organisms might be found more or less quickly. 

 But he also discovered that even such solutions no 

 longer yielded organisms, if instead of being subjected 

 to a heat of 2i2F they were exposed for a few 

 minutes to a temperature of 23OF. And it was on the 

 strength of two or three other links of such evidence 

 as this that M. Pasteur sought to upset the rule with re- 

 gard to the inability of inferior organisms to resist the 



