QUESTION OF PHYSICAL DEGENERATION 253 



breaking down, now that the experiment, so to call it, of the 

 marriage of deaf-mutes is being tried with ever-increasing 

 frequency. This will become clear if I reproduce one or two 

 tables referring to the subject from Mr Fay's excellent book. 1 



The number of marriages dealt with is sufficient to make the 

 results dependable and the question of transmission is settled 

 beyond a doubt. Mere coincidence cannot explain the facts, 

 since when both partners come from sound families the percent- 

 age of deaf children is a mere fraction. 



The greater percentage of marriages resulting in deaf offspring 

 when only one of the parents is deaf is certainly remarkable. 

 But when investigations are made, it turns out that deaf-mutes, 

 even when they choose a hearing partner, usually marry into a 

 family tainted with deafness, and this fact in a great measure 

 explains the curious phenomenon that the figures present. 

 Besides this, in the table just given, the congenitally and ad- 

 ventitiously deaf are all included without distinction. In the 

 following table the two classes are separated and the figures do 

 not give quite the same verdict. The last heading but one re- 

 mains perplexing, but only ninety-eight marriages are dealt with, 

 and it may be that this number is insufficient to justify inferences, 

 when no information as to family tendencies is available. 



1 Marriages of the Deaf, p. 31. 



