THE FORMATION OF A DEAF VARIETY OF THE HUMAN RACE. 



249 



Table N. — Avali/.sin of2'2,iT2 vanes of deaf-mutes from the cenxiis returns, showing the numtnr of 

 these (kof mutes living June 1, 1880, icho became deaf each year since the yeor' 1770. 



Table O. — Analysis 0/ 22,472 cases of deaf-mutes from, the census returns. 



[This table shows tbat tlie decliue in tbe nuiiiber of" these deaf-iiuites returned who became deaf 

 since 1873 aflects tbe congenital, as well as the non-cougenitally deaf.] 



S. Mis. 110- 



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