18 Life and Letters of Francis Galton 



determine it quantitatively. Actually for his data we have the following 

 correlations*: 



Father Mother 



Son -396+ -024 -302 ±-027 



Daughter -360 ±-026 -284+ -028 



There was thus really quite a well-marked prepotency of the father in 

 the case of stature. Later results on ampler and better material have 

 failed to confirm this prepotency f; I think it may well have been due to 

 amateur measuring of stature in women, when high heels and superincum- 

 bent chignons were in vogue ; it will be noted that the intensity of heredity 

 decreases as more female measurements are introduced. Daughters would be 

 more ready to take off their boots and lower their hair knots, than grave 

 Victorian matrons. As we have not since succeeded in demonstrating any 

 sex prepotency in parentage, Galton's assumption that such did not exist 

 justifies his theory. But this assumption was not justified by his actual data 

 and affects seriously the values of the constants he reached, which are all too 

 low in the light of more recent research. I think we should be inclined to 

 say now that the regression of the offspring deviate J is on the average 

 nearer to f than to Galton's § of the midparental deviate. Galton, however, 

 recognised very fully that his numerical values were only first approxima- 

 tions. He writes: 



"With respect to my numerical estimates, I wish emphatically to say that I offer them 

 only as being serviceably approximate, though they are mutually consistent, and with the 

 desire that they may be reinvestigated by the help of more abundant and much more accurate 

 measurements than those I have at command. There are many simple and interesting relations 

 to which I am still unable to assign numerical values for lack of adequate material, such as 

 that to which I referred some time back, of the relative influence of the father and the mother 

 on the stature of their sons and daughters. 



"I do not now pursue the numerous branches that spring from the data I have given, as from 

 a root. I do not speak of the continued domination of one type over others, nor of the persistency 

 of unimportant characteristics, nor of the inheritance of disease, which is complicated in many 

 cases by the requisite concurrence of two separate heritages, the one of a susceptible constitution, 

 the other of the genus of the disease. Still less do I enter upon the subject of fraternal devia- 

 tion and collateral descent§." 



Galton's reasons for making a special study of stature are dealt with at 

 considerable length and summarised as follows: 



" The advantages of stature as a subject in which the simple laws of heredity may be 

 studied will now be understood. It is a nearly constant value that is frequently measured and 

 recorded, and its discussion is little entangled with consideration of nurture, of the survival 

 of the fittest, or of marriage selection. We have only to consider the midparentage and not to 



* Phil. Trans. Vol. 187 A, p. 270, 1896. 



t See Biomelrika, Vol. II, p. 378, 1902. 



| Galton in this paper introduces the term "deviate ": "I shall call any particular deviation 

 a 'deviate,'" Journ. Anthrop. Inslit. Vol. xv, p. 252. The term was perhaps unnecessary con- 

 sidering the existence of " deviation," but it has come into general use, and is perhaps more 

 justifiable in Galton's sense than " variate," which is now so often used, not for a particular 

 variation, but for the " variable " itself. 



§ Journ. Anthrop. Instit. Vol. xv, p. 258. 



