166 



MARRIAGE AND DISEASE. 



passes over one generation, to reappear in the next. 

 He also relates a case of a family of sixteen persons, 

 eight of whom were born deaf and dumb, and one, 

 at least, of the members of ^hich transmitted the 

 affection to his descendants as far as the third genera- 

 tion." * 



, Here is the tree of a family whose history is vouched 

 for by the Lunacy Commissioners of Scotland, which 

 shows the transmission of deaf-mutism through four 

 generations : 



M. 



Mute. 



This is a most interesting and instructive case. 

 Besides showing that deaf-mutism may be transmitted 

 directly from parent to child, in spite of the other 

 parent being normal so far as this particular character 

 of degeneration is concerned, it also shows clearly 

 that in many cases where deaf-mutism appears in the 

 children of parents who can both of them hear and 

 speak, the defect in the children is distinctly heredi- 

 tary. Had we had no family history, it is not to be 



* Sir W. Turner's Address to Anthropological Section, British 

 Association, Newcastle, 1889. 



