PREFACE. 



There is no little difficulty in obtaining correct 

 and reliable life histories of most of the greatest 

 naturalists. Many of the men to whom natural 

 history science owes so much, lived extremely 

 retired and uneventful lives ; but a few, and as 

 might have been anticipated, the reformers and 

 epoch makers of their respective sciences, have 

 had their most interesting biographies well written. 

 Abstracts of these biographies form a large por- 

 tion of this book ; and the author desires to 

 acknowledge the very copious extracts he has 

 made, from sources which he has recognized in the 

 proper places. 



