x PREFACE 
the evolution theory may, at no distant date, be re- 
printed in the original, as they are not bulky and 
could be comprised in a single volume. 
This life is offered with much diffidence, though 
the pleasure of collecting the materials and of put- 
ting them together has been very great. 
BROWN UNIVERSITY, PROVIDENCE, R. [., 
October, 1gor, 
