Inheritance of Physical and Mental Traits 281 



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

 intelligent adjustment, to control the appetites and passions, 

 to appreciate moral 

 ideas. Many persons 



who are not regarded - I I 



as feeble-minded have n Q& JPJ9 Q Q 



some of these or simi- , , HL, J_^ 

 lar defects; the typi- = C 1 



Cally feeble-minded ' FK J Sg.-Pedigree of reLifo pigmentosa 



are defective in Several (black symbols) in a family described by 



or many such mental Mooren.-NETTLEsmP. 



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



the latter sense. 



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

 that when both parents are f eeble-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 



D 



n I"3 I j JL f , . J^f . . . . JL c JL.7 I a l 



i N N N (D) T | | (D)T[DJ ln]T()TLnJ D D 



/Vfc drof-mvf't'n tn I I ^* ^ I 



t*./drrn <>/ yr*ntl- 



Cf,:/^f I 



V D 0T' 0T^ N * 0T^ ' ' 



Y is? N? N 



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 



