52 EVOLUTION AXD DOGMA. 



fields of the earth ; the investigations of micro- 

 scopists in the boundless domain of microbian life; 

 the dredging of the ocean depths in various parts of 

 the globe by a constantly increasing corps of trained 

 votaries of science, show that we are yet very far 

 from having anything approaching a complete cen- 

 sus of the rich and varied fauna and flora which 

 adorn our planet. 



But great as is the number of species actually 

 existing, it is but a small fraction of those which are 

 known to have lived and died since the dawn of life 

 on the globe. A hundred million species or more, 

 it has been computed, have appeared and died out 

 since the time the Eozoon Canadense began its hum- 

 ble existence. And as our knowledge of the past 

 history of the earth becomes more thorough, there 

 is every reason to believe that we shall find this esti- 

 mate, extravagant as it may appear to some, below, 

 rather than above, the reality. 



Synchronously with this advance in the knowl- 

 edge of nature, the impression which had all along 

 been entertained by a greater or lesser number of 

 philosophers and students of nature has become 

 stronger that all the changes and developments 

 which the earth has witnessed ; all the prodigality 

 of form and size and color, which a bounteous 

 nature has lavished upon a fauna and flora whose 

 species are past numbering, is the result not of so 

 many separate creative acts, but rather of a single 

 creation and of a subsequent uniform process of 

 Evolution, according to certain definite and immu- 

 table laws. 



