Vlll INTRODUCTION. 



ferent branches of this science. Erroneous impres- 

 sions which are not corrected by any ulterior teaching 

 must necessarily become thoroughly confirmed. And 

 yet to judge of zoology by the collections of stories 

 which amused our childish years, is very much the 

 same thing as if we were to form a judgment of phy- 

 sical science from the tricks of a juggler, or of astro- 

 nomy from what we learn by pointing a telescope 

 in the open air at Saturn's ring or the mountains in 

 the moon. 



I have thought that the best means of bringing 

 the educated classes to adopt more correct ideas was 

 to leave zoology to defend itself by showing the 

 great truths which it has discovered and the nume- 

 rous facts which it comprises, and by indicating the 

 problems of general physiology which it has solved 

 and the profound questions of natural philosophy 

 which no other science can so well enter upon. By 

 this course I hoped to bring over to the ranks of its 

 defenders a band of intellectual supporters, and I 

 think I may venture to assert that experience has 

 shown that my hopes were not unfounded. 



Many utilitarians, while they admit the interest 

 which is awakened by this order of facts and ideas, 

 inquire, Cui bono ? — This discouraging question, 

 which was formerly addressed to all sciences, is now 

 limited to zoology. It is admitted that mathematics 

 are of some use ; physics and chemistry have long 

 since given proof of their utility by the deduction 



