DEAF-MUTISM. 165 



gives other important figures. He says : " In 379 

 instances there were 2 deaf-mutes in the family, in 

 191 families 3, in 53 families 4, in 21 families 5? in 5 

 families 6, and in each of 2 families no fewer than 7 

 deaf-mutes were born to the same parents." 



Now, it is not too much to infer, when a degenerate 

 condition is met with in from 2 to 7 children of a 

 family, that the cause, whatever it may be, comes from 

 the parents, in other words, is hereditary. Here, then, 

 oat of 3297 cases we have 651, or 20 per cent., in 

 which the condition is proved to be due to parental 

 defect, from the fact of its attacking from 2 to 7 of 

 the children of those parents. It will be noticed that 

 these figures closely agree with those of Eibot, who 

 found 2 to 5 children afflicted with deaf-mutism in the 

 families of 22 per cent, of the pupils of the London 

 Deaf and Dumb Institution. 



How any one with all this evidence before him can 

 come to the conclusion that deaf-mutism does not 

 depend upon parental peculiarity, but occurs merely as 

 a "sport" or freak of Nature quite beyond explana- 

 tion, and that its repetition in several of the children 

 of certain parents is but a strange coincidence, it is 

 difficult to imagine. 



We have also evidence of congenital deafness being 

 transmitted unchanged through several generations. 

 "Mr. Burton, who has paid great attention to this 

 subject, refers to several families where the deaf- 

 mutism has been transmitted through three successive 

 generations, though in some instances the affection 



