CHAPTER VII. 



EVIDENCES OF EVOLUTION. 

 Systems of Classification. 



BEFORE discussing the evidences of Evolution, 

 or examining the arguments advanced in its 

 support, it is advisable to have some idea of the 

 different systems of classification which have ob- 

 tained in various periods of the history of science, 

 and to learn on what such systems were based. 

 Have naturalists in all ages employed essentially the 

 same systems of classification, or have their systems 

 been widely different, if not contradictory? Are 

 scientific classifications expressions of natural ar- 

 rangements existing in animated nature, or are they 

 but artificial devices for coordinating our knowledge 

 of nature and facilitating our investigations ? Have 

 species, genera, families, orders, classes and branches, 

 a real or an ideal existence? Are they manifestly 

 disclosed in the plan of creation or are they but 

 arbitrary categories hit upon by naturalists as con- 

 venient aids in arrangement and research ? These 

 are a few of the many questions which present 

 themselves for an answer as we approach the subject 

 of organic Evolution. Others there are also which 

 might be discussed but we have not space for them 

 now. 



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