IMPROVEMENT OP THE III' MAN BBEED. 



529 



shall I regard the .slight numerical inequality of the sexes, but will 

 simply suppose that each parentage produces one couplet of grown-up 

 tilials, an adult man and an adult woman. 



The result is shown to the nearest whole per thousand in the diagram 

 up to " U and above." It may be read either as applying to fathers and 

 their sons when adult, or to mothers and their daughters when adult, 

 or. again, to parentages and filial couplets. I will not now attempt to 

 explain the details of the calculation to those to whom these methods 

 are new. Those who are familiar with them will easily understand the 



STANDARD SCHEME OF DESCENT 



PARENTAL GRADES 

 NUMBER IN EACH 



tOOO COUPLES 

 BOTH PARENTS Of 

 SAME GRADE AND' 

 ONE ADULT 

 CHILD TO EACH 



REGRESSION Or 



PARENTAL TO 



HLIAL CENTRES 



22 Cmildrxn or (l 



67 



161 



2b0 - 



2S0 •• 



161 



67 



22 



Of t 



or 4 



or 7 



or R 



or S 



or T 



or U 



SUMS 



u 



22 



t 



67 



16! 



T R. S 



250 2S0 161 



T 

 67 



7 17 J3 



4 ; i; | 



t 2i 52 SO", ?2 i 



4 IS 23 !17 7 



2 6 8 6 



20 



66 



\62 2b2 252 162 66 



20 



exact process from what follows. There are three poi nts of reference in 

 a scheme of descent, which may be respectively named ''mid-parental," 

 "genetic," and "filial" centers. In the present case of both parents 

 being alike, the position of the mid-parental center is identical with that 

 of either parent separately. The position of the filial center is that from 

 which the children disperse. The genetic center occupies the same posi- 

 tion in the parental series that the filial center does in the filial series. 

 Natural Inheritance contains abundant proof, both observational and 

 SM1901 34 



