THE BEGINNINGS OF LIFE. 397 



21 2 F. And whilst these differences tend strongly to 

 confirm the truth of the mode of explanation which 

 I have suggested of the discrepancies observed by 

 M. Pasteur when he repeated Schwann's experiments 

 with acid and alkaline organic infusions respectively, 

 they may also be considered to strengthen the pro- 

 babilities in favour of my assumption that an acid 

 fluid is less prone to undergo those molecular changes 

 which lead to the evolution of living things, than 

 a fluid, otherwise similar, whose reaction is neutral 

 or faintly alkaline. And yet, this explanation was 

 utterly ignored by M. Pasteur ; he leads his readers to 

 believe that the before-mentioned discrepancies were 

 explicable only in one way; and he moreover illogically 

 attempted to set aside a rule, concerning the limits of 

 c vital resistance ' to different degrees of heat, to which 

 he had previously assented, on the strength of evidence 

 which was most ambiguous and inconclusive. 



One finds M. Pasteur, as a chemist, engaging him- 

 self in a controversy concerning one of the most im- 

 portant questions in the whole range of biological 

 science; and yet he assumes the attitude of a man 

 who is so convinced beforehand of the error of those 

 who are of the opposite opinion, that he will not abide 

 by ordinary rules of fairness ; he will not even, at first, 

 assume the possibility of the truth of the opinions which 

 are opposed to his own. Ambiguous evidence is ex- 

 plained as though it were not ambiguous ; conclusions 

 based upon good evidence are attempted to be set aside 



