100 ACQUIRED CHARACTERS sec. 



indeed to every agriculturist. Cultivated plants of the most 

 difterent species are gradually accustomed to new stations, to 

 rich or poor soil, by being transplanted themselves or by the 

 planting of their progeny. The fruit-grower of a district 

 where the climate is severe will import his trees, no matter 

 of what species, not from a warm, but from a similar region, 

 if he wishes to make sure of their success. 



Hundreds of examples supporting Schlibeler's conclusions 

 could be obtained in all directions. 



The objection will be urged that in these artificial experi- 

 ments there is no formation of new species. In the preceding 

 pages I have already recognised the justice of this criticism 

 as a statement of fact. But I do not acknowledge it as a 

 valid basis for the proposition : that the fact that external 

 influences, that artificial cultivation, effect changes in animals 

 and plants which last as long as the influences themselves 

 proves nothing with regard to the action of external con- 

 ditions, to the inheritance of acquired characters, to the 

 modification of species. 



All the results of cultivation which man successfully pro- 

 duces in plants and animals, and for thousands of years has 

 produced, prove rather most incontestably the fact that 

 acquired characters are hereditary. 



Why permanent species have not been produced by such 

 results of cultivation, is a question by itself which I have 

 attempted to answer in the preceding. 



In my opinion, to expect that effects which have been 

 obtained and maintained by artificial conditions continued 

 during a relatively short period should persist after the sudden 

 cessation of those conditions is to expect what is perfectly 

 unnatural and unphysiological. 



Only by gradually bringing the organism slowly, step by 

 step, during a very long period of time, into new conditions 

 — if moreover the new conditions harmonised with the direc- 



