BIOMETRIC IDEAS AND METHODS 65 



intensity l of inheritance between these individuals. 

 But the validity of this assumption has never 

 been demonstrated, and presumably never can 

 be, because the assumption itself is contrary to 

 demonstrated biological facts, which can at any 

 time be experimentally verified. The facts to 

 which I allude are those upon which rest the 

 demonstration of the existence of the genotype as 

 contrasted with the phcenotype in inheritance. 2 



These facts in general show that the somatic 

 and the germinal conditions or states with ref- 

 erence to a particular character may be quite 

 different in the same individual. It results, then, 

 that the somatic condition of such a character in 

 the progeny has no direct or necessary relation 

 to the somatic condition of the same character 

 in the parent. 



Nothing is brought out more clearly by all 

 recent experimental studies of inheritance than 

 that the somatic condition of a character in a 

 particular organism is a very unreliable criterion 



1 This term "intensity of inheritance" has been very generally 

 used by biometricians. One ventures to wonder, in the light of 

 present knowledge, whether the expression itself does not involve an 

 unsound assumption. As a matter of fact, is inheritance ever a 

 graded phenomenon, as implied in this expression ? The whole body 

 of evidence available makes this seem to me extremely doubtful. 

 However, I have no desire at this time to press, or even to argue, the 

 point. I merely offer the suggestion that the critical reader think 

 it over for himself. 



2 Cf. Johannsen, W. "Elemente der exakten Erblichkeitslehre," 

 3d edit., 1913. 



F 



