viii PREFACE 



a great surprise to us to discover so much mental defect 

 in the families of so many of these children. The re- 

 sults of the study of more than 300 families will soon be 

 published, showing that about 65 per cent of these 

 children have the hereditary taint. 



The present study of the Kallikak family is a genuine 

 story of real people. The name is, of course, fictitious, 

 as are all of the names throughout the story. The 

 results here presented come after two years of constant 

 work, investigating the conditions of this family. 



Some readers may question how it has been possible 

 to get such definite data in regard to people who lived 

 so long ago. 



A word of explanation is hence in order. In the first 

 place, the family itself proved to be a notorious one, so 

 the people, in the community where the present genera- 

 tions are living, know of them ; they knew their parents 

 and grandparents ; and the older members knew them 

 farther back, because of the reputation they had always 

 borne. Secondly, the reputation which the Training 

 School has in the State is such that all have been willing 

 to cooperate as soon as they understood the purpose and 

 plan of the work. This has been of great help. Thirdly, 

 the time devoted to this investigation must not be over- 

 looked. A hasty investigation could never have pro- 



