124 THE EVOLUTION OF LIFE 
investigations 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.! 
M. Pasteur, in fact, entered upon a controversy 
concerning one of the most important questions in 
the whole range of biological science; and yet he 
assumed the attitude of a man who is so convinced 
beforehand of the error of those who are of an 
opposite opinion that he would not abide by ordinary 
rules; he would not entertain the possibility of 
the truth of the opinions opposed to his own. 
Ambiguous evidence was explained as though it 
were not ambiguous; conclusions based upon good 
evidence were attempted to be set aside in favour of 
evidence which was comparatively worthless ; and 
upon the strength of such illogical methods Pasteur 
proclaimed that he had “mathematically demon- 
strated” the truth of his own views. Still M. 
Pasteur’s reputation as an exact and _ brilliant 
experimenter—true enough in many other most 
important researches—has been all-powerful, and 
the majority of readers have been only too willing 
to accept his conclusions on the _ origin-of-life 
question—conclusions which he had always so 
dogmatically proclaimed. 
When Pasteur found that neutral or slightly 
alkaline fluids were so often fertile under conditions 
which left slightly acid fluids barren, before ignoring 
1 See p. 59 for what the writer in the Contemporary Review had to 
say concerning this mode of reasoning. 

