]70 LUTHER BURBAXK 



further test. The following year it was planted 

 in the same careful manner. But although a few 

 of the seeds germinated and sent up cotyledons, 

 not one had the power of developing beyond 

 that stage. 



All of these seeds in the twentieth year seemed 

 to have lost the capacity to produce a central 

 bud from which the plant stem could develop. 



Of course it may have been only an accident 

 that a few seeds were able to take on mature 

 growth after nineteen years, whereas not one 

 could do so after twenty years. But I am in- 

 clined to think that the seeds had reached just 

 about their limit of suspended vitality. The fact 

 that germination began, but that it did not con- 

 tinue because of lack of a central bud, suggests 

 that degeneration of part of the substance of the 

 seed had taken place. Seemingly it was only the 

 most resistant seeds that were able to stand this 

 degenerative process, and retain unimpaired 

 vitality to the end of the nineteenth year. The 

 heredity of those that grew was preserved in- 

 tact : the seeds producing exactly such plants and 

 fruit as if they had been planted nineteen years 



before. 



The Vitality of Seeds 



The interesting question arises as to whether 

 the degeneration of germinal matter was con- 



