1921 - 22 .] 
On the Dominance Ratio. 
333 
Fjg. 3 . — dfoc 
dz 
\/l + P cosh‘^ 
k= -1 ; 
genetic selection counterbalanced by mutation. Dominance Ratio, -2000. 
Fig. 4. — df<x. 
dz 
\/e~^ sech'^ i^z + cosh- \z 
k='\- 
genotypic selection, with complete dominance, counterbalanced by mutation. Dominance Ratio, ‘SSSS. This is 
the probable condition of natural species, including man. Note the accumulation of rare recessives. 
