Xll 
HAROLD’S DISCUSSIONS. 
PLANT AND ANIMAL LIFE. 
CHAPTER 
XXII. 
The Universe of Little Things (Germ Life) . 
PAGE 
205 
XXIII. 
Varietiy and Types in Nature. 
. 
221 
XXIV. 
Heredity. 
226 
XXV. 
Variation by Food 
235 
XXVI. 
Variation by Environment 
239 
XXVII. 
Variation by Use and Disuse . 
250 
XXVIII. 
Natural Selection 
263 
XXIX. 
Biological Evolution . 
, 
278 
XXX. 
The Progression of Life . 
. 
281 
XXXI. 
The Beginnings .... 
. 
287 
