THE FACTOES OF ORGANIC EVOLUTION. 75 



remains to be seen. Few can doubt that, if not the ^vhole cause, it is a very 

 important factor in that operation . . . 



On the evidence of palaeontology, the evolution of many existing forms of 

 animal life from their predecessors is no longer an hypothesis, but an 

 historical fact ; it is only the nature of the physiological factors to which 

 that evolution is due which is still open to discussion.&quot; 



With, these passages I may fitly join a remark made 

 in the admirable address Prof. Huxley delivered before 

 unveiling the statue of Mr. Darwin in the Museum at 

 South Kensington. Deprecating the supposition that an 

 authoritative sanction was given by the ceremony to the 

 current ideas concerning organic evolution, he said that 

 &quot; science commits suicide when it adopts a creed.&quot; 



Along with larger motives, one motive which has joined 

 in prompting the foregoing articles, has been the desire to 

 point out that already among biologists, the beliefs con 

 cerning the origin of species hare assumed too much the 

 character of a creed ; and that while becoming settled they 

 have been narrowed. So far from further broadening 

 that broader view which Mr. Darwin reached as he grew 

 older, his followers appear to have retrograded towards a 

 more restricted view than he ever expressed. Thus there 

 seems occasion for recognizing the warning uttered by 

 Prof. Huxley, as not uncalled for. 



Whatever may be thought of the arguments and conclu 

 sions set forth in this article and the preceding one, they 

 will perhaps serve to show that it is as yet far too soon to 

 close the inquiry concerning the causes of organic evolution. 



NOTE. 



After the above articles were published, I received from 

 Dr. Downes a copy of a paper &quot; On the Influence of Light 

 on Protoplasm,&quot; written by himself and Mr. T. P. Blunt, 

 M.A., which was communicated to the Eoyal Society in 



