VARIOUS THEORIES. 229 



ness which attends the latter part of the natural life of a man. 

 And all trees also which have been propagated from such a seed- 

 ling by means of buds or grafts, or, in other words, all trees of 

 the same variety, are to be considered as merely extensions of 

 that seedling, and will have a cotemporary vigor and decline 

 and decease with it. The period of vigor or decline may be 

 much extended by circumstances favorable to the general health 

 of any particular tree, and by unfavorable influences it may be 

 shortened : but however well situated, sooner or later it will man- 

 ifest feebleness by the change in the quality of its fruit, the small 

 quantity it is able to bear, by the decay of branches, and espe- 

 cially by its liability to be attacked by disease, such as the canker, 

 which rapidly destroy its remaining vitality. These diseases 

 may be guarded against, and may often be cured ; but the longer 

 the period since the origin of the variety from a seed, the greater 

 the liability and the more difficult the cure.* 



This theory is entirely discredited by other distinguished bota- 

 nists and horticulturists, among whom are Dr. Lindley in Eng- 

 land, Decandolle on the Continent, and Mr. Downing and H. W. 

 Beecher in America. 



These consider that there is no such similarity between the 

 life of a tree and the life of an animal, and that a bud and a seed 

 contain equally the germ of new life ; that they are, in fact, the 

 same thing, except that they are prepared to be developed under 

 different circumstances. That each bud, twig, and branch, has a 

 life of its own, and the trunk is but an association of roots, or of 

 connections between each bud and its roots. It may be separated 



* Professor Turner, of Illinois College, advocates the view that every time a seedling 

 tree is divided, whether in root or top, its natural longevity and proportionate vital force 

 are proportionally divided, abstracted and shortened ; and believes that some of the 

 worst forms of hereditary, and also of annual diseases, flow from a succession of such 

 mutilations through a series of generations, or are produced by an effort of nature to 

 resist and repair this interference with her natural process. 



