THE FAILURE OF ORCHARDS, AND ITS REMEDY. 225 



formed in the previous year, begin to expand. Each in- 

 dividual cell thus enlarges, until all the numerous cells of 

 which these leaves are composed are of full size. To fur- 

 ther illustrate this, let us suppose, in a brick wall, that each 

 brick at the same time was gradually to expand to several 

 hundred times its present diameter, and you have just what 

 takes place in the growth of an embryo leaf. Here we have 

 a tree in possession of a full-grown leaf. This leaf did not 

 form itself, but was formed by the tree in the preceding 

 year. To produce and sustain this cellular enlargement, 

 there had been stored, the previous year, a large share of 

 nutriment in the buds and in other parts of the tree. This 

 nutriment must not only be sufficient to feed the embryo 

 leaves, but must also be sufficient to produce the small 

 warty excrescences the rootlets and spongioles. These 

 new leaves and spongioles are a tree's laboratory. And 

 those leaves and spongioles first grown were made, with 

 the exception of moisture, wholly out of the materials that 

 were stored by the tree during the growth of the previous 

 year. When these vegetable stores are in sufficient supply 

 to do this, and nourish the fruit germs also, then we shall 

 hear little about imperfect fertilization. On the other hand, 

 had the food been consumed the previous year, by ripening 

 an over-crop of fruit, or by making a very succulent growth, 

 then the tree would not store a sufficient amount of plant- 

 food to perform its threefold office in the production of 

 leaves, roots with their spongioles, and fruit. In this con- 

 dition, a part of the leaf, and a larger part of all the fruit- 

 buds, yield up their nourishment, which goes to the produc- 

 tion of root and leaf growth. The tree, therefore, is barren 

 of fruit for the summer, its whole growth being required 

 to recuperate its own vigor. Such trees often bloom freely, 

 and then cast their blossoms. When this occurs, unin- 

 formed persons often attribute its barrenness to want of 



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