DEAF-MUTISM. 163 



sidered, transmitted in a majority of cases unchanged 

 from parent to child. The family defect which shows 

 in the child as congenital deafness may be met with 

 in the ancestors or collateral relatives as idiocy, 

 insanity, blindness, epilepsy, scrofula, physical de- 

 formity, or the like, for these are but the various out- 

 ward signs of that general tendency to degeneration 

 which mark such families. It is not necessary to 

 trace deaf-mutism as deaf-mutism through several gene- 

 rations of the family line to prove its dependence on 

 hereditary taint. It is but the sign by which the 

 innate degeneracy makes itself known to the outer 

 world, and this sign will vary in successive generations, 

 and even in different members of the same generation. 

 Thus in the family of the deaf-mute, inquiry will 

 frequently discover idiotic, epileptic, blind, or scrofulous 

 brothers and sisters ; dipsomania, insanity, epilepsy, 

 phthisis or imbecility in the parents or earlier ances- 

 tors, and like conditions in collateral branches of the 

 family. It is only in exceptional cases that we can 

 expect -a reappearance of the identical phenomena of 

 degeneration in each new generation, and that of deaf- 

 mutism is not one of these. 



It must not, however, be thought that it is at all 

 uncommon to find this particular outward sign of 

 family decay transmitted unchanged from parent to 

 child, or appearing in several members of the same 

 family. Occasionally a whole family is found deaf 

 and dumb. Bibot, who argues strongly in favour of 

 the hereditary character of deaf-mutism, found that 



