462 THE MULTIPLICATION OF EFFECTS. 



less irritability, perhaps sympathy for some suffering which 

 the irritability indicates, perhaps anxiety about an unknown 

 misfortune which she thinks has produced it. Nor are we 

 without evidence that among adults, the like differences of 

 development are accompanied by like differences in the 

 number of emotions that are aroused, in combination or 

 rapid succession the lower natures being characterized 

 by that impulsiveness which results from the uncontrolled 

 action of a few feelings ; and the higher natures being char- 

 acterized by the simultaneous action of many secondary feel- 

 ings, modifying those first awakened. 



Possibly it will be objected that the illustrations here 

 given, are drawn from the functional changes of the nerv- 

 ous system, not from its structural changes; and that what 

 is proved among the first, does not necessarily hold among 

 the last. This must be admitted. Those, however, who rec- 

 ognize the truth that the structural changes are the slowly 

 accumulated results of the functional changes, will readily 

 draw the corollary, that a part-cause of the evolution of the 

 nervous system, as of other evolution, is this multiplication 

 of effects which becomes ever greater as the development 

 becomes higher. 



161. If the advance of Man towards greater hetero- 

 geneity in both body and mind, is in part traceable to the 

 production of many effects by one cause, still more clearly 

 may the advance of Society towards greater heterogeneity 

 be so explained. Consider the growth of an industrial or- 

 ganization. When, as must occasionally happen, some in- 

 dividual of a tribe displays unusual aptitude for making an 

 article of general use (a weapon, for instance) which was 

 before made by each man for himself, there arises a tend- 

 ency towards the differentiation of that individual into a 

 maker of weapons. His companions (warriors and hunters 

 all of them) severally wish to have the best weapons that 

 can be made; and are therefore certain to offer strong in- 



