334 TRANSACTIONS OP THE AMERICAN INSTITUTE. 



would never produce its young, and without ammonia the tree would never 

 produce its flowers and fruit. The aroma of flowers and fruit is aramonial. 

 Where the cultivator or g-ardener can govern the sap, he can produce wood 

 or fruit in trees at his option. This is evidently tlie principle on which 

 the honey bee will produce a queen when the old one is lost — that is, by 

 feeding a young grub or bee in a peculiar manner. 



The pruning of trees and grafting are subordinate to this principle. If 

 we cut off the heads or bend down the trunks of the trees, or compress 

 them against a wall or stake, we shall check the flow of the sap, the sap 

 is delayed in its return passage, so that it produces flowers and fruit. By 

 bending down a branch into a horizontal position, the bearing vessels are 

 strangled to some extent at the point of curvature of the limb, at the same 

 time the branch is withdrawn from the vertical position, which is favorable 

 to the circulation of the sap; by bending down the branch or twig, there 

 is a retardation of the sap in its developing process, and hence it works 

 slower through the wood, and there is time for reproduction of fructifica- 

 tion of the sap at the extremities or buds of the tree; when the leaf buds 

 are cut off the flow of the sap is checked, and then one or more spurs are 

 developed at or near the end which produces flower buds the next season. 

 Grape vines produce large quantities only when they are kept in a horizon- 

 tal position, and as near the ground as possible, or at least where the 

 wood is trimmed off at the ends. Cut close a stock filled with shoots, and 

 you will see the greater part of the shoots left changed into sterile 

 branches instead of fruitful ones. By practising close trimming, the 

 branches become disproportionate to the roots of the trees which supply 

 sap, and then the tree runs to wood, the sap being no longer used up for 

 the branches, it will turn aside to produce new branches and to form new 

 wood, or perish under the bark for want of new issues, whereas if the 

 branches are bent down from a vertical to a horizontal position, instead of 

 cutting them off, the tree will be abundantly fruitful. If there is an im- 

 petuous sap, there will be little fruit, and it is not by cutting away largely 

 the branches that the impetuosity of the sap is stopped, it is turned aside 

 and nothing more. The best cultivator of fruit restricts himself to light 

 trimming, and endeavors to moderate the circulation of the sap by heading 

 down the boughs of the tree from a vertical to a horizontal position, the 

 sap then moderates its flow, and fructification ensues ; where the soil is 

 wet and moist the tree produces an abundance of sap, and runs to wood, 

 which is not favorable to the production of fruit. The land wants drain- 

 ing. The tree should be set out on a dry and warm soil; on this there is 

 less sap, and the tree will not run to wood so fast, but more to fruit. 



We see now why trees that are grafted are better for fruit than the 

 natural tree, the sap is obstructed in its descent from the extremities, and 

 runs to fruit; so where one kind of fruit tree is grafted on the stock of 

 another kind of tree, like the pear on the quince, and the apple or plum on 

 the rock maple, the sap ascending is supplied in sufficient quantities to 

 furnish a growth of the necessary wood, but without a redundancy, and 

 when the sap returns by the vessels in its downward course, it is checked 

 at the junction of the graft with the stock of the tree. The same law holds 

 good with all vegetables — the gardener breaks down his onion tops to ena- 



