Inheritance of Physical and Mental Trails 



275 



of a prevailing brown head of liair. This spotted condition 

 is due to a positive factor, just like spottedness in mice. 

 From a spotted parent at least half the offspring are spotted; 



? 



[t] [t] [n] [j] ^ [t] (r^ 



IB [T](T)[^[tl^[t](^(t) [^ [T] [N](N) 



K (^® (I)(T) 



Fig. 82. — Pedigree of a family with tyloses (T). Xote that 11 affected per- 

 sons have at least one parent affected. — Unna. 



Dt' 



Ot* *rO ^p irO iirO i ^tD 



OfS Dt^ n'4 ilo d 4 * 6|n 6 iii 



i55 6& *oft i¥ir¥TiW6^66 



Fig. S3. — Pedigree of faulty enamel of teeth. This peculiarity ap[)ears only 

 in the oiispring of an aft'ccted parent, consequently it is a positive trait. — Tukxer. 



but a person with uniform coat belonging to the spotted 

 strain will have no children with the white patch. 



Probably the same law is followed in the case of families 

 without teeth and also in famihes with faulty enamel of the 

 teeth (Fig. 83). Apparently there is a determiner that 



