344 PLANT-BREEDING 



multiplying itself most rapidly where the conditions proved 

 to be most suitable ? 



So it is in many cases. The present life-conditions 

 allow the occurrence of a species whenever they have 

 no relation at all to its special characters, or whenever 

 these characters are fitted for them. If not, a plant 

 may be accidentally introduced and perhaps thrive for 

 some years, but in the long run it will always be extermi- 

 nated. 



The same principle may be appHed to the origin of a new 

 form. If its new character is harmless or more or less 

 suited, the type will thrive as well as the parent form from 

 which it derived its origin. If, however, it proves to be 

 injurious, it goes without saying that the form will be con- 

 demned to extermination after a longer or shorter struggle 

 for existence. Its only chance of escaping this judgment 

 Ues in migration, by which, perhaps, it may find elsewhere 

 more suitable life-conditions. 



Returning to our general discussion we may state that 

 the study of the relations of Hving organisms to their present 

 environment must be revised and rebuilt upon quite new 

 principles. The qualities of the plants are not the problem 

 to be solved. The question is how the given quahties 

 of the species are suited to the environment, and how they 

 enable the organism to hold out against its present enemies, 

 and against the dangers of cUmate and winter. The question 

 has often been discussed whether we are right in speaking 

 of the use of some character or in saying that a quahty 

 serves a distinct purpose. No doubt, much abuse has been 

 made of these terms, and the common assumption that all 

 quahties must serve some special purpose is evidently 

 exaggerated. The only point which is open for inquiry is 

 the question on which marks of an organism depends its 

 possibihty of hving and multiplying itself on the spot where 



