192 



sweetj fuU and harmonious ; but never reaches a close : 

 no cadence is heard with which the intellectual ear can 

 feel satisfied*." 



As regards that most obscure of questions, what the 

 limits of species really are, observation alone can decide 

 the point. It frequently happens indeed that even 

 observation itself is insufficient to render the lines of 

 demarcation intelligible, — therefore, how much more 

 mere dialectics ! To attempt to argue such a subject 

 on abstract principles, would be simply absurd ; for, as 

 Lord Bacon has remarked, " the subtilty of Nature far 

 exceeds the subtilty of reasoning : " but if, by a careful 

 coUation of facts, and the sifting of minute particulars 

 gathered from without, the problem be fairly and deli- 

 berately surveyed, the various disturbing elements which 

 the creatures have been severally exposed to having been 

 duly taken into account, the boundaries will not often be 

 difficult to define. Albeit, we must except those races 

 of animals and plants which, through a long course of 

 centuries, have become modified by man, — the starting- 

 points of which win perhaps continue to the last shrouded 

 in mystery and doubt. It would be scarcely consistent 

 indeed to weigh tribes which have been thus unnaturally 

 tampered with by the same standard of evidence as we 

 require for those which have remained for ever un- 

 touched and free, — especially so, since (as we have already 

 observed) it does absolutely appear, that those species, the 

 external aspects of which have been thus artificially con- 

 * Indications of the Creator (London, 1846), p. 163. 



