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CHAPTER III. 



DEVELOPMENT AND ITS RESULTS. 



WE now proceed to enquire whether the 

 abstract conclusions of the last chapter are 

 confirmed by the results of practical ex- 

 perience. 



Evidence of this description, to be of value, 

 must not be based on a few cases of doubtful 

 authenticity, or on phenomena whose signif- 

 icance is imperfectly understood, but on 

 results so clear, general, and uniform as to 

 justify the conclusion that they are the ex- 

 pression of all-pervading natural laws. 



The weight and quality of such evidence 

 are fully recognised by Mr Herbert Spencer 

 in his ' Principles of Biology,' where (No. X. 

 p. 242) he says : 



" Excluding those inductions that have 

 been so fully verified as to rank with exact 

 science, there are no inductions so trust- 

 worthy as those which have undergone the 

 mercantile test. When we have thousands 



