BY THE SAME AUTHOR 
A Stupy or ANIMATE NaTuRE 
2 volumes 
Tue Sgcrets or ANIMAL LiFe 
Tue Wonpbezr or LIFE 
Tue BioLocy oF THE SEASONS 
DaRWINISM AND HuMAN LIFE 
New Edition 
INTRODUCTION TO SCIENCE 
Volume 21 in the 
Home University Library 
HENRY HOLT AND COMPANY 
PUBLISHERS NEW YORE 
