166 Duration of Races of Plants. 



subject to none of the laws for its continuation in existence, 

 beyond the individual that controls the original parent 7 If, 

 then, this position is sound, does it not clearly follow that a 

 variety of fruit may, from constitutional defect, or other 

 cause, become partially or generally diseased, and run out, 

 without infringing or doing violence to the laws which govern 

 the natural order of vegetation ? Let me be fully understood : 

 although it is unhesitatingly admitted that originally there 

 can be no such thing as a race of plants wearing, or running 

 out, it by no means follows that all the descendants of a 

 race, however operated on by artificial means, remain in per- 

 fect health, but, on the contrary, it is more than probable 

 that every innovation on the original law of generation, is 

 but a step to undermine and impair the constitution of the 

 product. 



If, then, after having produced, by the application of science 

 and art, a variety of fruit deemed worthy of propagation, and 

 having lost, by the application of science and art, the power 

 of propagation or continuing this variety or sort by the natu- 

 ral process, and being able to do so only by engrafting or 

 budding on other trees, or by layering it, what do we more 

 than continue that identical tree in existence, no difference to 

 what part of the world, or how extensively it is spread? 

 And do we not as much spread with it any constitutional 

 disease which it may have inherited, as the color of the fruit 

 it bears? And although, like a family of children who have 

 inherited the consumption, under various treatment and in 

 different climes, a portion may survive for a brief period the 

 rest, the whole and entire variety in all parts of the world, 

 must become subject to the effects of the same inherent cause. 

 I think, then, the plain and irresistible conclusion to which 

 every practical inquirer must come, is, that varieties of fruit 

 may, and do, wear or run out. 



The health and vigor of the stock on which the variety is 

 grafted, undoubtedly has a partial effect as the soil in which 

 it grows, to retard or promote to its final termination the con- 

 stitutional tendency of the variety, but can no more prevent 

 the result than to change the color of the fruit. In fact, the 

 stock has but little to do with what is put on it, more than 



