THE FORMATION OF A DEAF VAIMKTY OF THE HLIMAN RACE. 



199 



If we add together the tottil luiinber ol' inakvs mikI t'einales l■{^[)()l■t(Hl to liavc inanicd and tho 

 total iiHinber of doaf chihlreii stated to liave been born to tlieni, we ol)tain the tullowinj;- fi.i;ure« : 

 810 individuals iiiarried, and 82 deaf offspring. We cannot eonchide from this that the records 

 indicate that 82 deaf children were born to the 816 pupils referred to, for many of the male pupils 

 mentioned had uudoubtediy married female deaf mutes educate<l in the same institution with 

 themselves. In such cases the deaf ofitsj)ring were [)rol)ably recorded twice — once under the name 

 of the father and once under the name of the mother. If we desire to obtain, not the actual 

 number of deaf children recorded to have been born to the pui)ils, but the proportional e number, 

 we may safely add together the children recorded to have been born to the male and female ptijjils; 

 for, if 810 families have 82 deaf children, the proportionate number of deaf children (10 tor every 

 100 families) is a mean between the results obtained from the marriages of the males and females 

 considered separately, and is more reliable than either from being based on larger numbers. 

 In the following tables this plan of addition lias been adopted, and it must be remembered that 

 the number of families noted and the number of deaf children born, as deduced from the reports 

 of the American Asylum and Illinois Institution, must not be taken to indicate the actual number 

 of families formed by the pupils of these institutions, nor the actual number of deaf chihiren born 

 to them. They simply indicate a proportion, which is expressed in the third column by a percentage. 



If none of the males married females recorded in the same reports, then the figures in the 

 following tables would indicate actual as well as proportionate numbers; but this is not the case. 



Table XXVII. — Proportion of deaf offspring resulting from the marriages of deaf-mutes. 

 [Ueduced from tbe reports of the Americau Asylum and Illinois Institutiou.] 



The following tables enable us to compare the above results with tliose obtained fiom each 

 institution, considered separately: 



Table XXVIII. — Proportion of deaf offspring as deduced from reports of Illinois Institution and 



American Asylum. 



ILLINOIS INSTITUTION. 



AMERICAN ASYLUM. 



Both parties deaf-mutes 



One party a deaf-mute 



One or both parties deaf-mutes.. 



502 

 140 



642 



411 

 15 



(;4 



9.8 



to. 1 



1(1.(1 



