GRAFTING AND NURSERIES. 215 



a greater or lesser degree, of the characteristics of stock and 

 scion. 



Grafting would, therefore, seem to have in some cases an 

 action similar to that of hybridization. These facts are, 

 nevertheless, contradicted by Warming. With -vines, how- 

 ever, no action of this kind has ever been observed. Berries 

 of vines grafted with Labrusca, Clinton, Taylor, etc., have the 

 same taste as if they were grafted on Jacquez, or on their 

 own roots, or even not grafted at all. 



The effects of grafting are the same as those of the 

 annular incision. We know that trees or branches sub- 

 mitted to this operation become more fertile, set better, and 

 bear larger fruit, ripening earlier, than branches not sub- 

 mitted to this operation. This induced some agriculturists 

 to think that the mode of action was similar. In reality 

 it is not. Annular incision only acts as long as the tissues 

 are not knitted; it only increases the fertility while the 

 communication between the tissues of the bark of the branch 

 is interrupted. But directly those tissues knit and the 

 liber at the top of the incision reaches that of the bottom, the 

 effect of the incision disappears ; the branch ceases to 

 be more fertile, or to give sweeter fruit, ripening earlier; in 

 fact, the branch resumes its normal functions. Nothing of 

 the kind happens with grafts, except, perhaps, during the 

 first or second year. As long as the knitting is incomplete, 

 the effects may be compared to those of a partial annular 

 incision or, better, to those of any wound. But once the 

 knitting is completed, once all the tissues of the scion are in 

 direct communication with those of the stock, there is no 

 further similarity between grafting and the annular in- 

 cision. 



We are of opinion that this process operates in a different 

 manner. The effects of grafting do not result from 

 mechanical action ; they are not due to the operation itself, 

 but they are a consequence of the new conditions under which 

 the grafted plant has to develop; and, therefore, the cause is 

 rather of a physiological order. 



There seems to exist, if we may so express it, perfect har- 

 mony between the different organs of a plant. Each of them 

 contribute to the development of the others under the best 

 possible conditions. Grafting breaks this harmony. The 

 new stem works under conditions different to that of the 

 stem it has substituted ; the matters it elaborates do not 



