INTRODUCTION 



common sense they may seem to be. Our doubts are 

 dulled to a quiescence which would, otherwise, be 

 active if we kept clearly in mind that science is based 

 on the same sort of evidence as are all other methods 

 of human knowledge and that men of science are, as 

 Newton pictured them, wanderers on the shore of a 

 vast sea of unknown phenomena, picking up here and 

 there a bright coloured pebble or shell. 



Whatever facts and laws, connected with living 

 organisms, biologists may discover, the positive evi- 

 dence of evolution, that existing species of fauna and 

 flora are the continuously modified forms of pre- 

 viously existing types, must rest on the preservation, 

 and on our discovery, of earlier extinct forms. If we 

 had not found fossils which were different from ex- 

 isting species, our argument for evolution would be 

 academic, to say the least. 



There is probably nothing more fascinating and 

 more stimulating to the person of a contemplative 

 mind than to view in a great museum the collections of 

 past life recovered from the buried rocks and soils of 

 the earth. In these show-cases, there are the fossil 

 shells and plants of the most primitive eras ; in others, 

 there are strange and grotesque monsters reconstruct- 

 ed in plaster from a few insignificant bones, or the 

 most improbable plants built up from a fallen leaf 

 or a petrified splinter; in still others, there are spread 

 out the even more appalling remains of primitive 

 man-like creatures placed in what are supposed to be 



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