28 



PROPAGATION. 



remarks, therefore, are more for the "purpose of laying down 

 reasons on which success depends, than for pointing out the 

 peculiar modes of operation, which may be varied according 

 to convenience, provided attention is given to the essential 

 particulars. 



Propagation by grafting differs ftiainly and essentially from 

 increasing by cuttings, by inserting the cutting into the grow- 

 ing stock of another tree instead of directly into the soil. 

 The stock thus supplies the sap, as the soil does in the case of 

 a cutting ; and the graft, instead of making roots of its own, 

 becomes firmly united with the stock by means of the new- 

 growing wood. Hence there are two chief requisites for suc- 

 cess ; the first, that the graft be so set in the stock, that the 



sap may flow up- 

 ward without in- 

 terruption ; and 

 the second, that 

 the forming- 

 wood may ex- 

 tend downward uninterruptedly through the 

 inner bark. To effect these two requisites, it 

 is needful, first, that the operation be performed 

 with a sharp knife or grafting chisel. Fig. 28, that 

 the vessels and pores may be cut smoothly and 

 evenly, and the two parts brought into immedi- 

 ate and even contact. Secondly, that the opera- 

 tion be so contrived that a permanent and con- 

 siderable pressure be applied to keep all parts 

 of these cut faces closely together. Thirdly, 

 that the line of division between the inner bark 

 and the wood coincide or exactly correspond in 

 each; for if the inner bark of the one sets wholly 

 on the wood of the other, the upward current through the wood 

 and back through the bark is broken, and the graft cannot 

 flourish or grow. And, fourthly, that the wounded parts made 

 by the operation be effectually excluded from the external air, 

 chiefly to retain a due quantity of moisture in the parts, but 

 also to exclude the wet, until, by the growth of the graft, the 

 union is effected. 



I. The first requisite is best attained by keeping a keen, 



Fig. 28. 



ing Chisel, 



Graft- 



