30 NATIONAL TRENDS IN BIOLOGY 



diate success in their varied efforts. Then, too, it was not 

 abolished because humanitarianism abhorred it, but be- 

 cause another type of civilization was brought about by 

 the invention of the steam engine, which made it pos- 

 sible to sustain civilization without slavery. So, too, mod- 

 ern democracy did not evolve from any interest in the 

 brotherhood of man, but because discovery and explora- 

 tion opened up entirely new channels into which men's 

 lives could flow and lead an independent and self-reliant 

 existence. 



Now let us examine the biological literature and the 

 letters received to see what the biological world considers 

 important. One is struck immediately by the practical 

 agreement of the biologists of all nations as to what is 

 important and what has been done, during the past 

 quarter of a century, that is of lasting value. 



One finds that after almost a half century of experi- 

 mentation with just one idea in mind — that of finding 

 new angles by which to demonstrate evolution — a sigh 

 of relief went up that other fields had finally been opened. 

 Yet, paradoxical as it may seem, the finding of the very 

 factors which opened new fields had its rise in the dis- 

 covery, or rather rediscovery, of a piece of work which, 

 in turn, was the cause of producing another theory of 

 evolution; namely, De Vries' theory of mutation. The 

 rediscovery and verification came about, simultaneously, 

 by De Vries in Holland, Correns in Germany, and Tscher- 

 mak in Austria, and consisted in making known the out- 

 standing work, by patient experiments, of Johan Gregor 



