364 LUTHER BURBANK 



formed into new species under the influence of 

 natural selection. 



But whoever considers this matter attentively 

 will come presently to realize that in any such 

 analysis of the operation of natural selection in 

 the evolution of species as that just suggested 

 there is an underlying assumption to the effect 

 that the various modifications of the individual 

 are transmitted to the offspring of the individual. 



Unless such is the case, it is clear that there 

 could be no such thing as the evolution of new 

 species. It would avail nothing for the progeny 

 of an individual that this individual was well 

 adapted to its surroundings, unless the said 

 progeny inherit the characteristics that made 

 such adaptation possible. 



There is no logical escape from that conclu- 

 sion. Whatever our conception of the mecha- 

 nism of heredity, or of the exact manner in 

 which the transmission of variation occurs, no 

 one can be an evolutionist who does not believe 

 that acquired characters are transmitted through 

 heredity. 



There was a school of biologists who gained 

 great prominence a few years ago, who denied 

 the possibility of the transmission of acquired 

 traits. Throwing logic to the winds, they based 

 their denials on a metaphysical interpretation of 



