MENTAL INHERITANCE 461 



sumption warranted? We can not say until we have examined the 

 present status of the prohlem of inheritance; but whether or not we 

 are pessimistic as regards the future of the race, we must agree that 

 the sudden and increasing burden which culture places upon the hu- 

 man mind raises this problem to the first rank of importance. 



Suppose that we look, then, at the grounds of belief in the heredi- 

 tary transmission of mind. The belief itself stands among the fixed 

 convictions of common sense. In our every-day thinking we take it 

 for granted. The child, we maintain, inherits its father's bad temper 

 just as it inherits its mother's good looks. We consider twice before 

 we adopt the foundling, which may be of dull or vicious parentage. 

 We shake our heads over the wayward son, remembering that his 

 father " sowed his wild oats," and we observe " like father like son," 

 or " blood will tell." We expect to find talent in the children of the 

 gifted, thrift or dwarfed intellect or high purpose, according as these 

 qualities are " bred in the bone." The folk-tale of paupered prince or 

 stolen princess who never, though reared as swineherd or scullion, loses 

 regal bearing and courtly demeanor, the wide respect for royal blood, 

 and the easy belief in the " born criminal," alike testify to the common 

 and venerable persuasion that minds, and even morals, are subject to 

 hereditary transmission. 



It is only when we stop to inquire precisely what is inherited in all 

 these instances, and how it is conceivable that mind should pass from 

 parent to offspring, that we leave the highway of common sense and 

 enter the more difficult path of critical observation and induction. It 

 is obvious that a clear statement of the problem and a forecast of 

 method are of the first importance. 



Inasmuch as the notion of " inheritance " involves both the process 

 and the products of transmission, the inheriting and the thing in- 

 herited, a choice of methods is at once suggested. Shall we — that is 

 to say — seek to describe the mechanism of inheritance, or to discover 

 the like qualities that have actually appeared in successive generations 

 of blood-relatives? It is quite impossible to state the alternatives 

 without adverting to the fact that biology has, for a half-century, been 

 absorbed in the parallel investigation of physical inheritance. ISTor are 

 we likely to forget, in the midst of our commemoration of Darwin's 

 birth and of " The Origin of Species," that the whole doctrine of or- 

 ganic evolution rests upon the facts of heredity. Whatever the factors 

 that determine racial descent — fluctuating variation, or the sudden 

 change of type, use and disuse, natural, artificial, sexual or organic 

 selection — both continuity in the process of bionomic change and main- 

 tenance of the change once produced, demand the conception of a 

 hereditary likeness. Without inheritance the establishment of a stock 

 would be impossible, and without a stock, variations and mutations 



