I A CHAPTER IN DARWINISM 11 



no opportunity should be lost of calling attention to 

 its real character. Bit by bit, naturalists had suc- 

 ceeded in discovering the order of nature so far that 

 all the great facts of the universe, the constitution 

 and movements of the heavenly bodies, the form of 

 our earth, and all the peculiarities of its crust, had 

 been successfully assigned to one set of causes the 

 properties of matter, which are set forth in what we 

 know by the name of the "laws of physics and 

 chemistry." Whilst geologists, led by Lyell, had 

 shown that the strata of the earth's crust and its 

 mountains, rivers, and seas were due to the long- 

 continued operation of the very same general causes 

 the physico-chemical causes which at this moment 

 are in operation and are continuing their work of 

 change, yet the living matter on the crust of the earth 

 had to be excluded from the grand uniformity which r 

 was elsewhere complete. 



The first hypothesis, then, which was present to 

 Mr. Darwin's mind, as it had been to that of other 

 earlier naturalists, was this : " Have not all the 

 varieties or species of living things (man, of course, 

 included) been produced by the continuous operation 

 of the same set of physico-chemical causes which 

 alone we can discover, and which alone have been 

 proved sufficient to produce everything else ? " " If 

 this be so," Mr. Darwin must have argued (and here 

 it was that he boldly stepped beyond the specula- 

 tions of Lamarck and adopted the method by which 

 Lyell had triumphantly established Geology as a 

 science), " these causes must still be able to produce 



