Inheritance of Physical and Mental Traits 



281 



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in 



,9|6 »p i 6 (J) (^ 



learn to write or to draw, to meet difiicult situations by 

 intelligent adjustment, to control the appetites and passions, 

 to appreciate moral 

 ideas. Many persons 

 who are not regarded 

 as feeble-minded have 

 some of these or simi- 

 lar defects; the typi- 

 cally feeble-minded 

 are defective in several 

 or many such mental 

 traits. In what follows I shall use feeble-mindedness in 

 the latter sense. 



From the studies of Dr. Goddard and others, it appears 

 that when both parents are feeble-minded all of the children 

 will be so likewise ; this conclusion has been tested again and 

 again (Fig. 91). But if one of the parents be normal and of 



Fig. 89. — Pedigree of retinilis pigmentosa 

 (black symbols) in a family described by 

 Mooren. — Nettleship. 



Dt(§^' 



OtD 



m n' n' n^ ©'tD ©tE Ht®t[e" 





7 \e I. 



D D 



^ u' Et®' [n]t(d) n" [nIt®" (d)' (d)' (d)' 



N^" 



N' 



N 



D 



Fig. 90. — Pedigree of a family with deaf mutes (D) in a large proportion of the 

 later generations. 



normal ancestry, all of the children may be normal (Fig. 

 92); whereas, if the normal person have defective germ 



