FACTS OF INHERITANCE 141 



pometric laboratory, and by observations on 

 sweet-peas, and to some extent on moths. 



Most trustworthy, however, were the data pro- 

 cured in regard to stature, which, as Galton points 

 out, is a quality with many advantages as a subject 

 of investigation. It is nearly constant during 

 mature life, it is readily and frequently measured 

 with accuracy, and it does not seem to be of appre- 

 ciable moment in sexual selection. Its variability, 

 though small, is normal ; that is to say, it is ex- 

 pressible in the normal curve of the frequency of 

 error. 



As the subject is by no means easy to those 

 unaccustomed to statistical inquiry, and as we 

 cannot, within our limits, explain the methods, 

 it may be most profitable to give a few illustrative 

 quotations from Galton's " Natural Inheritance " 

 (1889). 



" If the word ' peculiarity ' be used to signify 

 the difference between the amount of any faculty 

 possessed by a man and the average of that 

 possessed by the population at large, then the law 

 of regression may be described as follows. Each 

 peculiarity in a man is shared by his kinsmen, 

 but on the average in a less degree. It is reduced 

 to a definite fraction of its amount, quite inde- 

 pendently of what its amount might be. The 

 fraction differs in different orders of kinship, 

 becoming smaller as they are more remote " 

 (p. 194). 



" However paradoxical it may appear at first 

 sight, it is theoretically a necessary fact, and one 

 that is clearly confirmed by observation, that the 

 stature of the adult offspring must on the whole be 

 more mediocre than the stature of their parents ; 



