200 



MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES, 



Tlie perceiitaucs obtaiaeil indicate, of course, tlie uumber of deaf children for every 100 fam- 

 ilies as recorded in the reports, and not the actual number of deaf children for every 100 families 

 (which is known to be gi-eater). 



Tlie general results obtained from the two institution reports are remarkably concordant. 



In the case of the American Asylum, however, it appears that the pupils who married hearing 

 persons iiad a larger proportion of deaf children than those who married deaf-mutes (!) Such a 

 remarkable result requires explanation. The pupils assumed to have married hearing persons are 

 simply recorded in the report as "married," but from private correspondence with the present 

 principal [ M ■ . Williams) I find that in most, if not in all, cases sp recorded the record is really 

 intended to indicate marriage with a hearing peison. 



Even in the case of the congenitally deaf pupils of the American Asylum it appears that 

 those who married hearing persons had a larger proportion of deaf oft'spring than those who mar- 

 ried deaf-mutes. The following table shows that this result can be deduced not only from the 

 tables in the appendix, but from the table quoted above from Dr. Turner's paper on Hereditary 



Deafness: 



Table XXIX. 



Dr. Turher's results (1868) \ -r, n. , -.o-,-. .. c 



for pupils of the Ameri- ' ^"^"l*^ ^''P™ ^f ' f^P°'"* °^ 



Auiericau Asvlura. 



pupi 

 can Asvlum. 



Mairi.aK<'S of tlio conmiuitallv deaf. 



One pareut congenitally deaf and the 

 other a hearing person 



Both parents deaf-mutes (one congen- 

 itally deaf and the other inciden- 

 tally deaf) 



Both parents deaf-mufes (both con- 

 genitally deaf) 



Both parents deaf-uiutes (one or both 

 congenitally deaf) 



a 



30 

 56 



80 



5! 



o 



If) 



6 

 17 

 23 



50. 



10.7 

 70.9 

 28.7 



a 

 "A 



s 



Qi 



U to 



-2S a 



57 



(?) 



(?) 



239 



14 



24.6 



(?) I (?) 

 (?) j (?) 

 34 14.2 



* Class 4 gives summation of classes 2 and 3. 



I have already stated that iu the majority of the cases that have fallen under my personal 

 observation where a deaf-mute was married to a hearing person that the hearing person belonged 

 to a family containing deaf-mutes, and this is significant in the light of the results deduced above, 

 especially when we remember that the late Dr. Harvey L. Peet found that "the brothers and 

 sisters of a deaf-mute are about as liable to havedeaf mute children as the deaf-mute himself, suppos- 

 ing each to marry into families that have or each into families that have not shown a predisposition 

 toward deaf dumbness." If we examine the cases of the pupils who are presumed to have married 

 hearing persons in the light of this idea, separating the sporadic cases from those who have deaf- 

 mute i-elations, we obtain the following results : 



We find from the tables in the appendix that 162 deaf-mutes were "married," presumably, to 

 hearing persons. Of these deaf-mutes 55 are stated to have had deaf-mute relatives, and they are 

 recorde<l to have had 15 deaf children, or more than 27 deaf children for every 100 families; on 

 the other hand, 107 of these deaf mutes were noted as sporadic cases, and only one deaf child is 

 recorded as tlie otfsi)riug of the marriages ! 



