106^ HEREDITY IN RELATION TO EUGENICS 



become known until more extensive pedigrees of stuttering 

 families have been obtained. Two pedigrees have been 

 obtained(Figs. 70, 71). 



qf 



DrO'cM 



ho 





:<'-''1 



Fig. 70. — Pedigree of a family that contains stutterers (black symbols); 

 1, stutterer; 2, impediment in speech; 3, impediment, if excited. F. R.; Bar. 4. 



Stuttering is seen to affect both sexes. It can hardly be 

 a dominant trait because it is found so often in children 

 of unaffected parents. It might be due to the absence of ' 



5Eiih 





Fig. 71 



Fig. 72 



Fig. 71. — Pedigree of a part of a family of stutterers (black symbols). 

 Fig. 72. — Pedigree fragment of poltering family. Affected individuals in 

 black. Berkan. 



some factor if consanguineous marriages were common in 

 these pedigrees. 

 The trick of repeating short words and syllables is some- 



