OB JE C TIONS A GA INS T E VOL U TION. 201 



which still remains to be accomplished, but some- 

 thing which can scarcely be realized before many 

 years shall have elapsed, and until much serious 

 labor shall have been expended on the vast, and as 

 yet but partially explored, domain of animated na- 

 ture. 1 Such a theory, when fully worked out, will 

 do for biology what the heliocentric theory has 

 achieved for astronomy. It will place in the clear 

 light of day what is now veiled in darkness, and 

 render certain what at present can but vaguely be 

 surmised. The lack of this perfected theory, how- 

 ever, does not imply that we have not already an 

 adequate basis for a rational assent to the theory of 

 organic Evolution. By no means. The arguments 

 adduced in behalf of Evolution in the preceding 

 chapter, are of sufficient weight to give the theory 

 a degree of probability which permits of little doubt 

 as to its truth. 



Whatever, then, may be said of Lamarckism, 

 Darwinism and other theories of Evolution, the 

 fact of Evolution, as the evidence now stands, is 

 scarcely any longer a matter for controversy. Hence, 

 it is the factors which have been operative during 

 the long course of organic development, and a 

 theory that can be brought into harmony with these 

 factors, and which is at the same time in consonance 

 with the phenomena observed, that men of science 



1 In the American Naturalist for May, 1895, Professor 

 Osborn, in concluding an interesting article on the " Search for 

 the Unknown Factors of Evolution," pertinently observes : "My 

 last word is that we are entering the threshold of the Evolution 

 problem instead of standing within its portals. The hardest 

 tasks lie before us, not behind us, and their solution will carry 

 us well into the twentieth century." 



