1 86 Heredity. 



domain of physiology, to mental maladies, to animal and human 

 psychology and history facts of various kinds, and adapted for 

 showing all the varieties of hereditary transmission. We next 

 endeavoured to disengage what is constant in the production of 

 these phenomena, and proposed heredity as a biological law, the 

 exceptions being, as we shall see, only the results of disturbing 

 causes; and we examined the various forms of this law. We 

 believe that this theory may be verified, that it has a scientific 

 value. 



The facts which have served to establish the law will serve also 

 to verify it, for it is nothing more than a simple generalization. 

 Of course it were puerile to suppose that, in the present state of 

 physiology, and yet more of psychology, any theory of heredity 

 could be final. Nevertheless, we persist in the conviction that the 

 laws already recited, being only the expression of facts, are no 

 merely subjective view : and this is the important point. 



But it may be possible to go even beyond this, and to submit 

 the laws of heredity to a quantitative test. In a recent work, 

 entitled Hereditary Genius, the statistical method has been applied 

 to this subject. Before giving our -opinion on the question, we 

 will briefly state the results obtained by this author. 



ii. 



Mr. Galton's book possesses merits and defects somewhat common 

 in English works : many figures, a sufficiency of facts, very little 

 generalization. His method is purely statistical. His investigations 

 have for their object not heredity in general, nor even psychological 

 heredity, but simply this question : Is genius hereditary, and to what 

 extent ? Given an illustrious or eminent man, 1 what are the chances 

 of his having had an illustrious or eminent father, grandfather, son, 

 grandson, brother, etc. ? To answer this question, the author has 



1 'There are,' says he, 'in the British Isles, two millions of male persons 

 above the age of fifty. Among these I find 850 that are illustrious, and 500 

 eminent. In one million men, therefore, there will be 425 illustrious and 250 

 eminent.'' The author declares that he has got these same figures by various 

 methods, viz. by consulting the Dictionary of Contemporaries, the necrological 

 notices in the Times, etc. This will give an idea of Mr. Galton's method, and 

 of his taste for exact research. 



