HIS ZOOLOGICAL RELATIONS. 59 



thanjndependent creation of new ones, seems to have 

 been the method of nature in the production of the 

 newer and higher forms. And further, that this 

 principle of adaptive modification, ioferred from the 

 study of existing life-forms, receives ample confirma- 

 tion from the science of extinct forms, in which the 

 ascent from lower to higher is marked, not by the 

 superaddition of new parts, but simply by the change 

 or further specialisation of those pre-existing. The 

 whole scheme of vitality, from the earliest known 

 formations up to the present day, being clearly a de- 

 velopment of the same tjrpical ideas, shall we regard 

 the newer forms as created stage after stage, in accord- 

 ance with this aboriginal plan, or shall we regard 

 their introduction as provided for and brought about, 

 like other phenomena, by the operation of law and 

 secondary causation 1 This is the whole question at 

 issue. Need we indicate which view is most in 

 accordance with the known operations of nature, or 

 which recommends itself most forcibly to the accept- 

 ance of the educated intellect 1 



