PREFACE TO THE SECOND EDITION. 



xv 



those who possess the Principles of Biology^ which many 

 references are made to passages in First Principles, would 

 be inconvenienced by the want of correspondence between 

 the numbers of the sections in the original edition and in the 

 new edition, were they without any means of identifying the 

 sections as now numbered. The annexed list, showing which 

 section answers to which in the two editions, will meet the 

 requirement : 



The original stereotype plates have been used wherever 

 it was possible ; and hence the exact correspondence between 

 the two editions in many places, even where adjacent pages 

 are altered. 



London, November, 1867. 



