500 Animal Life and Intelligence. 



fifty. A week afterwards they are distributed in different 

 forms. Some are selected for a higher form, others have 

 to take a lower place. But though selection has classified 

 the material, it has not altered the position of the mean of 

 ability among the fifty boys. This can only be done by 

 expelling a certain number or excluding them from the 

 school. 



Granted, therefore, that elimination is practically ex- 

 cluded, human selection can at most classify the individuals 

 according to their intellectual faculties. It cannot raise the 

 mean standard of intellectuality. If, therefore, this mean 

 standard has been raised during the last three centuries, 

 there has been a tendency to vary in this particular direction, 

 which may* to say the least of it, be due to the inheritance 

 of individual increment. 



I am, of course, aware that the matter is complicated 

 by the increased and increasing diffusion of knowledge 

 through the printing-press and by the extension and 

 improvement of education. But education, to take that 

 first, though it may raise the level of each generation, can 

 have no cumulative effect. For the effects of education 

 cannot, on Professor Weismann's hypothesis, be inherited. 

 You may educate brain and muscle in the individual, but 

 his heir will inherit no good or ill effects therefrom. Each 

 generation goes back and starts from the old level. There 

 is no summation of effect ; or, if there is, it tells so far 

 against Professor Weismann. 



And with regard to the diffusion of knowledge, this, 

 though it brings more grist to the intellectual mill, can 

 have no effect in raising the mean standard of excellence in 

 the mill itself. There is more to grind ; but this does not 

 improve the grinding apparatus ; or, if it does, it tells so 

 far against Professor Weismann's hypothesis. To vary the 

 analogy, the diffusion of knowledge increases the store of 

 available food ; but it does not bring with it any additional 

 power of digesting the food; or, if it does, it may be 

 through inherited increments of mean digestive power. 



* It may also, in part, be due to " organic combination." 



