INTRODUCTION 7 
It may be that some reader to whose attention this 
collection of essays may come has some criticism or 
comment to make, and it is requested that if this oc- 
curs copies of the letters directed to the essayists be 
sent to the undersigned in order that he may benefit 
from such correspondence. 
In closing I desire to express appreciation to those 
who have interested themselves in this contest, and 
especially to Dr. Edwin B. Tuteur, of Chicago, who 
very kindly assisted me in determining the disposition 
of the prize money. 
HENRY R. HARROWER. 
The Harrower Laboratory, 
Glendale, California, 
February, Nineteen Twenty-one. 
