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THE AMERICAN NATURALIST [Vol. LV 



other terms which will have greater precision ot meaning. ' 

 Let us accept his timely proposal, which obviously applies 

 espeeiallv to the more technical and precise terminology of genet- 

 i(s With his luu t(tms a^cillable ^\e ma^ safeh lolegate the 

 older ones, aside from historical references, to the more popular 

 language of science. 



Shull uses the older words to illustrate the application of his 

 proposed terminology, but he does not specifically discuss their 

 future delimitation m ease they still retain a certain useiuliiess. 

 Their future, I believe, deserves consideration. Tt seems certain 

 that they will remain familiar words because of their historical 

 value, in relation both to Mendel's work and to its earlier ex- 

 tension. Doubtless they will long be especially useful in the 

 more popular presentation of genetic topics, to obviate burden- 

 some use ot more precise but more formidable expressions. 



Historically, it is plain that the meaning of Mendelian has very 

 largely kept pace with the widening conception of the funda- 

 mental applicability of Mendel's th(>orv. although often, as Shull 

 stat(^. with the addition of (lualilvuio- expi-ossions. \Vhen this 

 widening process reaches the ^ar•1llt'^1 point ot i)i'ac1ical useful- 

 ness, it leads to a broad definition of .1/^ mh lism w h u-h. I believe, 



.lUiohavt I i^mI aloiv i Im. ot <luu u k U i )ii t sm ntialh cone 

 spondmg to th( broadti definition Mdiddians' once en 

 countered frequent denials of the completeness and the gener- 

 ality of segregation, and frequent assertions that new somatic 

 ratios implied other modes of inlieriTance ot equal significance 



