April 22, 1898.] 



SCIENCE. 



553 



middle classes.* We thus conclude that They do uofc, however, exceed the limits of 



these results confirm Gallon's law in so far en-ors of observation. la the case of 



as they tend to show that the strength of mothers and sons the divergence is very 



inheritance is not a character of race or organ, slightly above the probable error ; the ob- 



Inhebitance or Cephalic Index— Table of Values. 



Cephalic index is clearly not more 

 strongly inherited than stature. Its varia- 

 bility is also very much that of stature. 

 It is accordingly difficult to see why it 

 should be considered as peculiarly a racial 

 character. 



(6) The divergencies between the ob- 

 served values for the coefficients of inherit- 

 ance for the cephalic index and the theo- 

 retical values obtained on the basis of 

 Galtou's law of ancestral heredity are 

 greater than the divergencies between the 

 former and the coefficients for stature.:]; 



* Phil. Trans., Vol. 187, A, pp. 270-281. 



t S. D. = standard-deviation or ' error of mean 

 square. ' 



Jit is to be noted that, putting paternity aside, 

 the order of relative magnitude of the coefncients of 

 heredity is precisely the same for both cephalic index 

 and stature. 



served and theoretical values are identical 

 in the case of mothers and daughters ; 

 they are less than the probable error for 

 brothers and brothers and only slightly 

 larger than it for brothers and sisters ; 

 for sisters and sisters the divergence is 

 about one and a-half times the probable 

 error. The mean weighted values of the 

 coefficients for direct and collateral kinship 

 are 0..3366 and 0.4004, the former dillering 

 by less than half its probable error from 

 the theoretical value 0..3000, and the latter 

 sensibly identical with its theoretical value, 

 0.4000. 



We conclude, therefore, that Galton's 

 law of ancestral heredity gives values for 

 the inheritance within the limits of tlie 

 probable errors of observation. But, 



(c) As in the case of stature there is, on 



