278 



Prof. Karl Pearson. 



or to selective death-rate, or to secular evolution diminishes with 

 age. 



(4) The following are the coefficients of correlation (r) and the 

 coefficients of regression (B) for parents and sons : 



Table II. Inheritance of Stature by Sons. 



Father and elder sons 



Father and younger sons .... 



Mother and elder sons 



Mother and younger sons . . . 



r. 



0-4120 0-0264 

 0-4170 0-0262 

 0'4094 0-0265 

 0-4111 0-0264 



R. 



-4281 

 0-4427 

 -4374 

 -4488 



If we measure, as seems reasonable, the hereditary influence of 

 parentage by the magnitude of the coefficient of correlation between 

 parent and offspring, then several important conclusions may be 

 drawn from this table. 



(i) There is no sensible difference between the influences of the 

 father on younger and on elder sons, and no sensible difference 

 between the influences of the mother on younger and on elder sons. 



If we pay attention to such slight differences as exist, there would 

 appear, not to be an increase of paternal and a decrease of maternal 

 influence on younger children, but an extremely slight increase of 

 both. In other words, so far as stature in sons is concerned, judged 

 by correlation : No steady telegonic influence exists. 



(ii) There is a very slight prepotency of the father over the 

 mother in the case of both younger and elder sons ; a prepotency 

 which will be slightly magnified when account is taken of the abso- 

 lute stature of the two parents. 



But the great prepotency of paternal inheritance noticed in the 

 former memoir is not confirmed. The co-efficients of maternal in- 

 heritance have been increased by more than 30 per cent, (from O293 

 to 0'410), while those of paternal inheritance (0'396 as compared 

 with 0*414) have remained almost stationary. This result seems to 

 show the want of constancy of the Galton's functions for heredity 

 within the same race. An explanation on the ground that the 

 present statistics embrace a wider range of the community than the 

 earlier, and possibly a more closely correlated class,* fails, at any 

 rate in part, owing to the sensible constancy of the paternal correla- 

 tion. The main difference of course between the present and the 

 former statistics is the exclusion of the influence of reproductive 



* I have pointed out (loc. cit., p. 284) that working and lower middle class 

 families appear to be more closely correlated than those of the upper middle class. 



