i8 WAR & STRUGGLE FOR EXISTENCE 



almost transformed the study of inheritance into an 

 experimental science. The most active investiga- 

 tors in this field received their initial stimulus from 

 the rediscovered and now well-known researches of 

 Mendel, a forgotten contemporary of Darwin. This 

 active and brilliant school urges more and more 

 strongly that most of the minute, continuous varia- 

 tions or fluctuations, on which Wallace and Darwin 

 laid stress, are ephemeral effects of the environment, 

 are not transmitted to the next generation, are not 

 summed up in the course of generations, and so play 

 no part in the origin of species. They believe, on the 

 other hand, that new species and new characters 

 come into existence by the appearance of sudden 

 variations, usually large and discontinuous, and that 

 these are not ephemeral, do not require summation, 

 but may be transmitted in full vigour to the offspring 

 of the individual in which they first appear. They 

 have succeeded in producing and fixing strains of 

 animals and plants marked by definite characters, 

 with a certainty that recalls the operations of a 

 synthetic chemist rather than the empirical efforts 

 of a breeder. It would seem as if they had added to 

 the probability of natural selection by showing the 

 existence of variations larger in magnitude and more 

 certain of inheritance than the minute fluctuating 

 variations of Darwin and Wallace. At the most, 

 however, this Mendelian view does nothing to prove 

 the existence of natural selection, but suggests that, 

 if it does exist, the elaboration of new characters and 

 the separation of new species might be much more 

 rapid. And it is to be noted that many of the most 

 ardent Mendelians have such confidence in their own 



