48 THE FAMILY AND THE NATION 



injury in infancy, by such diseases as scarlet fever, and 

 by other causes. 



As an example, let us take a case studied by Moos, 



A deaf-mute man, represented by the symbol ^, 



married a normal healthy woman, represented by Q- 



They had a deaf-mute son and a normal daughter. 

 The daughter married a normal man, and had two 

 deaf-mute daughters and one normal son. One 

 daughter married a deaf-mute man, and had a deaf- 

 mute son, while the normal son married a normal 

 woman, but his one son was a deaf-mute. 



We can exhibit these relations in tabular form, the 

 character to be traced, in this case deaf-mutism, being 

 indicated by blackening the circle representing the 

 individual possessing it. 



I 



n / 

 in 



IV 



f? 



9=r^ 



'•=ff 'f 'Of 9 

 /4 ^4 



This pedigree shows not only direct inheritance 

 from parent to child, but the reappearance of deaf- 

 mutism in a grandchild (III. 2) born of two normal 

 parents, and in a great-grandchild (IV. 2) where both 

 parents and grandparents were free from the affliction. 



