40 



Just as useful types of grain arise as the products of atmospheric and 

 soil conditions, weakened conditions of the cultivated plants may also be 

 produced locally and transmitted through seeds. If these weakened con- 

 ditions are repeated from generation to generation by the persistence of 

 causes and accumulate, they may lead in the end to a complete decline and 

 to premature death. 



Yet this is, however, no degeneration of the species or variety, for all 

 these characteristics may be reproduced under other cultural conditions. We 

 perceive this from the fact that the useful special characteristics introduced 

 by a change of seed, are retained only a few years. Then the imported culti- 

 \ated forms become changed and assume characteristics such as are due to 

 the climatic and soil conditions in the place where they are cultivated. Such 

 is also the experience in practice work which constantly attempts in some 

 way to accustom (acclimate) highly productive species of a different climate, 

 to some one cultural region. 



If it seems desirable to apply the term "degeneration" to the above cases 

 of the accumulation of peculiarities leading to a weakening of production 

 and to premature death, it is possible at most only to speak of local transi- 

 tory degeneration of a number of individuals. It is, however, really only 

 a depression of the direction of development, which can be raised again by 

 external factors, such as cultural methods. A persistent depression in 

 growth as a result of the senility of an originally long-lived variety, is not to 

 be assumed within any definite epoch. The disappearance of cultural varie- 

 ties is explained by a decreased profitableness resulting from a deficient 

 power of adjustment to our agricultural methods, which arc con;-tantly be- 

 coming more intensive. 



