28 Mutability and Individual Variation. 



mention here is Michaele Gandoger whose Flora Eu- 

 ropae is the most comprehensive work along this line of 

 research. 



The controversy before the time of Darwin had 

 therefore led to two essentially distinct results. These 

 were : 



1. The experimental proof of the existence of nu- 

 merous, constant and mutually independent types within 

 the limits of the Linnean species. 



2. The general conviction that these constant types 

 had arisen naturally from larger groups or species by 

 mutation. ^ 



§ 2. DARWIN'S SELECTION THEORY. 



The theory of Descent aims at the scientific explana- 

 tion of systematic relationship. It is Darwin's immortal 

 service to have obtained general recognition for this 

 generalization. By doing this he revolutionized the 

 whole of biological, systematic, embryological and pale- 

 ontological science, tapping inexhaustible sources for new 

 investigation and discovering everywhere mines where 

 new facts wxre to be had for the picking up. 



The several propositions and hypotheses which Dar- 

 win employed as supports for this theory should be re- 

 garded now only as such, since their interest is mainly 

 historical. They have served their purpose and are 

 thereby fully justified. Whether they contain in part 

 what is unproven or what is incorrect matters not. But 

 they contain, over and above that, a large mass of im- 

 portant facts which can be made use of to build further 



* The terms immutability and so forth have not entirely dropped 

 out of use. E. g., B. J. Costantin, Accomodation dcs plantes aux 

 cliniats froid et chaud, Bull. Scientif., public par Alfred Giard, T. 31, 

 p. 490, 1897, and Bateson, Materials for the Study of Variation, 

 1894, P- 2. 



