GROWTH AXD MATUKATION OF THE WOOD OF PLANTS. 199 



will prove failures. Let us inquire into these failures. The 

 success in grafting the walnut, recorded by that most acute ob- 

 server and profoundly scientific horticulturist, Mr. Knight, is, I 

 am inclined to imagine, to be attributed not so mucli to the 

 changes in the chemical composition of tlie sap in that tree at 

 particular periods, and in deferring the operation of grafting till 

 that period, as to the fact that the elaboration and accumulation 

 of organic matter is subsequent to the elongation of the current 

 growth. It is an axiom in the practice of grafting that the 

 " stock " should be in advance of the scion. In ordinary cases, 

 such as the apple, pear, all our common fruits, and many other 

 instances, it is sufficient that this be the case only in a slight de- 

 gree. In the apple it is not necessary at all. Countrymen are 

 constantly in the habit of grafting the apple on crab-stocks by 

 their fire-sides, after their day's work is finished, in early spring, 

 and transplanting them in their gardens at pleasure, and failures 

 are but slight exceptions to the general rule. The true prin- 

 ciple upon which this readiness to unite between stock and scion 

 is to be accounted for is, that the process of organic development 

 in the apple is of a nature to admit of such, its phenomena of 

 growth being totally opposite to a Scotch fir or a rliododendron. 

 Every gardener knows perfectly^ well that in grafting camellias, 

 or any of the Conifers, if the scion can be kept alive after 

 the operation till the stock has made its growth,* success is 

 certain. At that period the stock is beginning to increase its 

 bulk, and new matter is secreted to repair the wound made 

 to insert the scion, and an union is the inevitable result. f 



From this circumstance is inferred tlie advantage, the greater 

 probability of success, in deferring the operation of increasingmany 

 plants by the various modifications of grafting and inarching till 

 tlie season's wood is completed. Here is one of the many appli- 

 cations of scientific data, of theoretical reasoning, to ordinary prac- 

 tical operations. Every operation which we perform, guided by- 

 practical experience, may be successfully calculated upon by 



* I am here speaking of grafting, without heading down the " stock," a 

 mode adopted to preserve the " stocks " for a successive operation in cases of 

 faihire. 



t Here we see the true causes of almost invariable success in what is 

 technically termed " bottle grafting." The facts are simply these: — if the 

 scion is bound to the stock at a period when its condition is such as not to 

 allow of a sufficient deposition of organic matter to repair the wound and 

 effect an union of tissues, the chances are that the scion will perish before 

 that union can be attained, unless some provisions are made to obviate this 

 inconvenience and consequent failure. The phial effects this, by affording 

 nourishment sufficient to prevent decay, and preserve vital energy in the 

 scion, till the scion and stock are, as regards the phenomena of life, one 

 individual. 



