620 POPULAR SCIENCE MONTHLY. 



ance, and there is ample evidence that the value in breeding of a 

 given parental characteristic does depend upon its origin, and that 

 one due to nurture has a very different value from one which is 

 itself inherited. 



Of the 2,459 deaf pupils of the American Asylum, nearly six 

 hundred have married and have become the parents of over eight 

 hundred children, of whom 104, or more than twelve per cent, 

 were born deaf a ratio which is great enough to prove that in- 

 heritance has some influence. Analysis of the records shows 

 clearly, however, that these deaf children are not uniformly dis- 

 tributed among the married pupils of the asylum, but that the 

 result is influenced by the character of the parental deafness. 

 From 283 of the 590 marriages no children are reported, while 

 from three other families no report is made except that all the 

 children hear, so that the 811 child en which are reported are from 

 only 304 families, and in many of them only one parent was deaf. 

 Of the 101 children of forty of these marriages none are reported 

 as deaf, and all but eleven are reported as hearing, and the 710 

 children are from the remaining 264 marriages. In fifty-two of 

 the marriages both father and mother were congenitally deaf, and 

 these are the parents of forty-eight out of the 104 congeuitally deaf 

 children, but they are the parents of only 151 of the total number 

 of 811 children, and nearly thirty-two per cent of all the children 

 of these congenitally deaf parents are congenitally deaf. 



In two of the groups in which the marriages may be classified 

 the number of marriages and the number of children are about 

 equal, but there is a most remarkable difference in the number of 

 deaf children. 



In fifty-five marriages, with 139 children, both parents are re- 

 ported as adventitiously deaf, while in fifty-two marriages, with 

 151 children, both were congenitally deaf. In the latter group 

 fifty-two children, or 3T78 per cent, are congenitally deaf, only 

 eighty-eight are stated to hear, and no facts are given about the 

 hearing of fifteen of them. In the first group only four of the 139 

 children, or 3'87 per cent, are reported as congenitally deaf, 129 

 are reported as hearing, and six are not reported. 



I have divided all the marriages into four groups : In one all 

 the children hear; in the second from five to six per cent are 

 deaf ; in the third from twelve to eighteen per cent are deaf ; and 

 in the fourth 31'78 per cent are deaf. In the first group, in which 

 all the children hear, five of the marriages, with eighteen chil- 

 dren, are between a hearing husband and a wife who is adventi- 

 tiously deaf ; one marriage with four children between a hearing 

 man and a woman the source of whose deafness is unknown ; six 

 marriages, with thirteen children, where the wife hears and the 

 husband is adventitiously deaf; twenty- three marriages, with 



