I. 



As every fresh branch of investigation in natural 

 history has a tendency to gather around it a rapidly 

 accumulating literature, some explanation may pro- 

 bably be looked for from an author who offers a new 

 contribution to the public. And when, as in the 

 present instance, the writer's intentions are of an 

 humble kind, it is the more desirable that he should 

 state his views at the outset. Nor can the force of 

 this claim be supposed to be lessened, from the grati- 

 fying fact, that the present writer has already re- 

 ceived a warm welcome from the public. 



But, before entering upon any personal explana- 

 tions, it may not be out of place, in an introduc- 

 tory chapter such as the present, to bring under 

 review some of the objections which have been, and 

 still continue to be urged against this, in common 

 with other departments of study, which are attempted 

 to be made popular. No branch of natural history 

 has been subjected to more disparaging opposition, 

 partly, it must be owned, from the misplaced enthu- 



