NATURE OF DARWIN's THEORY. 27 



of the Doctrine of Descent, no longer as the ingeniously 

 desig-ned work of a Creator building up according to a 

 definite purpose, but as the necessary consequence of active 

 causes, which are inherent in the chemical combination of 

 matter itself, and in its physical properties. 



In fact, we can most positively assert, and I shall justify 

 this assertion in the course of these pages, that by the Doc- 

 trine of Filiation, or Descent, we are enabled for the first time 

 to reduce all organic phenomena to a single law, and to dis- 

 cover a single active cause for the infinitely intricate 

 mechanism of the whole of this rich world of phenomena. 

 In this respect, Darwin's theory stands quite on a level with 

 Newton's Theory of Gravitation ; indeed, it even rises higher 

 than Newton's theory ! 



The grounds of explanation are equally simple in the two 

 theories. In explaining this most intricate world of phe- 

 nomena, Darwin does not make use of new or hitherto 

 unknown properties of matter, nor does he, as one might 

 suppose, make use of discoveries of new combinations 

 of matter or of new forces of organization ; but it is 

 simply by extremely ingenious combination, by the syn- 

 thetic comprehension, and by the thoughtful compa- 

 rison of a number of well-knoAvn facts, that Darwin has 

 solved the "holy mystery " of the living world of forms. The 

 consideration of the interchanging relations which exist 

 between two general properties of organisms, viz. Inherit- 

 ance and Adaptation, is what has here been of the first 

 importance. Merely by considering the relations between 

 these two vital actions or physiological functions of organ- 

 isms, also further by considering the reciprocal inter-action 

 which all animals and plants, living in one and the same 



