EVOLUTION 171 



After this succession of facts, there came a revelation 

 which convinced more men that evolution is a fact 

 than any evidence which had preceded. The geologists 

 had begun to uncover that wonderful succession of 

 plants and animals from the earliest geological periods 

 to the present time. They saw in the oldest periods 

 forms unlike any now existing; they saw gradual changes 

 with each succeeding horizon; they saw a steady ap- 

 proach to forms like those of to-day, until by insensible 

 gradations the present flora and fauna were ushered in. 

 This geological record, becoming continuously more 

 detailed in its interpretation, set men to thinking 

 seriously. 



Finally, after all this evidence was in, men began to 

 look around them and to realize what they had been 

 doing for centuries in domesticating animals and plants. 

 They had been bringing them from the wild state and 

 changing them so much by the methods of culture that 

 in many cases the wild originals could not be recognized. 

 Most of our cultivated plants, if found in nature as- 

 sociating with their wild originals, would be regarded! 

 as extremely distinct species. 



In the presence of such an array of facts, is it to be 

 wondered at that certain men began the serious, scienti- 

 fic study of evolution ? As a result, the second period 

 in the history of evolution was ushered in, and evolution 

 became a science. 



2. OBSERVATION AND INFERENCE. In time this 

 period extends from 1790 to 1900. It is characterized 

 by the appearance of a succession of explanations of 

 evolution. It is important to remember that the men 



