IMPROVEMENT OF THE HUMAN BREED. 



531 



r 



6 come from V parentages, 10 from U, 10 from T, 5 from S, '^ from K, 

 and none from any class below K; but the numbers of the contributing 

 parentages have also to be taken into account. When this is done, we 

 see that the lower classes make their scores owing to their quantity 

 and not to their quality, for while 35 V-class parents suffice to pro- 

 duce 6 sons of the V class, it takes 2,500 R-class fathers to produce 3 

 of them. Consequently, the richness in produce of V-class parentages 

 is to that of the R class in an inverse ratio, or as 143 to 1. Similarly, 

 the richness in produce of V-class children from parentages of the 

 classes U, T, S, respectively, is as 3, Hi, and 55 to 1. Moreover, 

 nearly one-half of the produce of V-class parentages are V or U taken 

 together, and nearly three-quarters of them are either V, U, or T. If, 

 then, we desire to increase the output of V-class offspring, by far the 

 most protitable parents to work upon would ])e those of the V class, 

 and in a threefold less degree those of the U class. 



When both parents are of the V class the quality of parentages is 

 greatl}' superior to those in which onl}" one parent is a V. In that 

 case the regression of the genetic center goes twice as far back toward 

 mediocrity, and the spread of the distribution among filials becomes 

 nine-tenths of that among the parents, instead of being only three- 

 quarters. The effect is shown in Table II. 



Table II. — Distribution of sons. — (1) One parent of class V, the other unknown; (^) both 

 parents of class V {from Table II, with decimal point and an 0). 



Position of tile filial center of (1)=1.44, of (2)=2.89; when both parents are T it=1.58. 



There is a difference of fully two divisions in the position of the 

 genetic center, that of the single V parentage being only a trifle nearer 

 mediocrity than that of the double T. Hence it would be Ijad economy 

 to spend much effort in furthering marriages with a high class on only 

 one side. 



MARRIAGE OF LIKE TO LIKE. 



In each class of societ}^ there is a strong tendency to intermarriage, 

 which produces a marked effect in the richness of brain power of the 

 more cultured families. It produces a still more marked effect of 

 another kind at the lowest step of the social scale, as will be painfully 

 evident from the following extracts from the work of Mr. C. Booth 

 (i, 38), which refer to his class A, who form, as has been said, the 

 lowermost third of our ' ' y and below." ' ' Their life is the life of savages, 

 with vicissitudes of extreme hardship and occasional excess. From 

 them come the battered figures who slouch through the streets and 



