LAWS CONTROLLING HUMAN SOCIAL HEREDITY 313 



sharp contrasts between human and animal evolu- 

 tion has been in the influence of individuals upon 

 the race. Among animals, the individual counts 

 for little or nothing. When a single Daphnia may 

 have millions of offspring during the few weeks of 

 summer, it matters not in the evolution of the race 

 whether any particular individual survive or perish. 

 Even among more slowly multiplying animals the 

 same thing is true. The only way that an elephant 

 can influence his race is through the organic heritage 

 which he gives his offspring, and if he dies and 

 leaves no offspring he has had no part in the prog- 

 ress of evolution. It has sometimes been questioned 

 whether among animals the individual counts at all ; 

 for strong reasons have been advanced for suppos- 

 ing that the process of evolution has been by aver- 

 ages and means rather than by the appearance of 

 isolated individuals in advance of the rest. Evolu- 

 tion has been described sometimes as an advance of 

 the race en masse rather than by any particular 

 advance along special individual lines. In more 

 recent years a somewhat different conception has 

 become popular. It seems that in many cases 

 among animals and plants sudden new departures 

 from the original type appear amid the offspring of 

 normal parents. Such new departures have been 

 called mutations, and evidence has been accumulat- 

 ing rapidly in recent years that these mutations may 

 become permanent, thus constituting a noticeable 

 advance in the race at a single step. So far as this 

 may occur, of course, an individual may count em- 

 phatically in the process of evolution. But if such 

 an individual does count, it is a result for which he 

 is wholly irresponsible, since it depends entirely 



