260 THE ZOOLOGIST. 



protect me to a certain extent from being held to be merely a 

 theorist, one might claim to find some support from the words 

 of Vigors,* who, criticising the other extremist, writes : — 



"It is upon the labours of man that he dwells, and not on 

 the works of Creation. He dwindles, as it were, into a mere 

 compositor of the volume of Nature, artificially putting together 

 the symbolic words that should stand for ideas, while the ideas 

 themselves in their true spirit and meaning escape him. And 

 thus the exertions, which, properly directed, might have tended 

 to explain the laws and elucidate the operations of Nature, which 

 might have been devoted to a study purely intellectual, are lost 

 in a pursuit which is strictly and exclusively mechanical." 



I have personally not been able to get beyond the Unknown 

 Power, be it natural or supernatural, in the evolution of species 

 any more than in the evolution of worlds. The chief matters 

 that seem to be definite and not pure supposition are the 

 interesting facts concerning the microscopic discoveries that 

 have been made in the composition of the germ cell as regards 

 its nucleus and chronosmomes, and it is perhaps to further 

 discovery in this direction that one might expect more facts 

 to come to light bearing on the problem of the Eelationship of 

 Species. 



Summary. 



1. That there are practically two evolutions : — 



(a) Visible and Corporeal. 



(b) Invisible and Essential. 



And while they are both never out of harmony, we are by no 

 means always able to estimate from the visible aspect of the 

 former (a) the degree of evolutionary progress attained by the 

 latter (b). 



2. That the blood and germ affinity may change without loss 

 of structural resemblance (a). 



3. That the form of animals may change without loss of 

 relationship (b) [blood and germ affinity] . 



4. That where these two evolutions cause apparent anomalies, 

 or point to opposite conclusions, habits which are congenerous 



::: Quotation from ' Cassell's Natural History.' 



