IN-AND-IN BREEDING. 1Y9 



boys ; none of them of deaf and dumb parents. The 

 gentleman who superintends the manufactories, and 

 who, consequently, has the best opportunity of tracing 

 the subsequent history of his scholars, informs me 

 that some of them are married and have children, all 

 of whom are perfect in their organs of hearing. One 

 instance has occurred, in which both parents were 

 born deaf, yet their children hear." 



" At the school for the deaf and dumb in Man- 

 chester (England), in 1837, * there were forty-eight 

 children taken from seventeen families .... an 

 average of nearly three such cases in each family. 

 Out of these instances there appears but one in which 

 the defect was known to exist in either parent." 



The following cases are likewise quoted from Mr. 

 Sedgwick's valuable article on " Hereditary Diseases : " 

 " Mr. Wilde, whose observations included the whole 

 of the deaf and dumb population of Ireland, states, 

 that c ninety - eight deaf and dumb persons sixty 

 males, and thirty-eight females were married. In 

 eighty-six instances fifty-four males, and thirty-two 

 females only one parent was deaf and dumb : from 

 the marriage of these, two hundred and three children 

 resulted, among whom there was but one instance of 

 mutism, a male, in the county of Limerick. Six in- 

 stances have been recorded of the intermarriage of 

 deaf and dumb persons : their offspring amounted to 

 thirteen, of whom only one, a female, in the city of 

 Dublin, was deaf and dumb.' " 



"Lastly, in the thirty-fifth annual report of the 



1 "Notes and Reflections," by Sir Henry Holland, as quoted by 

 Sedgwick, loc. tit., p. 142. 



