202 
PROPAGATION BY GRAFTING. 
From the fact that each bud of some layered plants seemed capable of pro- 
ducing both stem and roots when it chanced to lie just beneath the face of the 
ground, or probably from the development of branches and roots on stakes employed 
for the support of the more gracile species, the system of propagation by cuttings 
appears to have had its rise. But by the time this had arrived at some degree of 
perfection, and certain tribes of plants, wholly the productions of man's skill, were 
found to be dijSicult of rapid perpetuation, a sufficient acquaintance with the 
physiology of vegetables had been reached to admit of the introduction of grafting 
and inoculation. 
Various methods of grafting plants were known and adopted centuries ago. 
With the ancients, however, and till within a very short period before the present 
year, the operation was restricted to fruit-trees and one or two particular kinds of 
ornate shrubs. The process termed inarching may be supposed to be the primitive 
plan pursued in this kind of propagation, since this augurs a less insight into the 
economy of vegetation, and would at first seem to require less tact in the operator, 
and to entail a greater certainty of success. It was with the more tender species 
of plants, such as Camellias and Pines, that inarching was usually practised up to the 
last two or three years ; but it is, in the present day, quite superseded by grafting. 
We come now more directly to the illustration of the position with which we 
set out. It has been said that grafting was, for an indefinite time, made use of 
by the orchardist only, and in the multiplication of trees and shrubs, which, on 
account of their peculiar nature as seedlings or hybrids generated by superior 
cultivation, could not readily be perpetuated by other means. In this age of pro- 
gression, it has been shown first, that camellias, rhododendrons, and their allies, 
can be more easily grafted than inarched, and papers on that subject w^ere inserted 
at pages 93 and 111 of the last volume of our magazine. And since then, continental 
nurserymen, as well as those of Britain, have demonstrated the advantage of apply- 
ing the process to an infinite variety of exotics, and even to the better kinds of 
dwarf roses which adorn our flower borders. 
Before specifying any rules for treatment, it will be well to touch briefly on the 
rationale of grafting, and mention the objects for which it may be usefully 
employed. Exogenous plants, which are the chief subjects of cultivation in this 
country that can be increased by that means, are generally known to be composed 
of distinct layers of wood, one being added yearly to the exterior surface. Of such 
series, all the inner ones, exclusive of that in the course of formation, constitute 
what is called the duramen or heart-wood, and are, for all the purposes of the 
vegetable, virtually dead after they become encased in a new layer. This last 
layer, which is situated closely under the bark, and is of the same tissue as those it 
surrounds, but in an immature state, receives the name of alburnum, and is the 
sole seat of vitality. In endeavouring, therefore, to cause cohesion between two 
stems or branches, and so to continue the circulation of fluids in the stock 
uninterruptedly through the scion, it is of the utmost moment that there be 
