Foreword 
As explained in the opening section, the present study grew 
out of the University’s undertaking to conduct a survey of 
one of the counties selected by the Indiana Committee on 
Mental Defectives. In planning the survey it was found pos- 
sible to greatly extend its original scope so as to include a 
more intensive study of the social relations of defectives and 
also to present a number of family histories. The value of 
this latter feature is enhanced by the fact that in this area 
a few strains have contributed a very large percentage of the 
total defective population. Two other facts also stand out. 
One is that these groups tend to intermarry and thus to accu- 
mulate bad heredity ; the other is that the inferior stocks have, 
in the course of a century, gradually been pushed into the 
poorer localities, a process which sociologists call environ- 
mental selection. 
In her field work Miss Hansford had the active cooperation 
of the University Department of Psychology, particularly in 
testing school children, and of the social agencies of the city 
and county investigated. It is perhaps hardly necessary to 
state that real names either of persons or places within the 
county are in no case used. 
U. G. Weatherly. 
