PROPAGATION. 209 



diness with which the cellular elements of the scion 

 and stock unite. The envelope of the former imping- 

 ing on that of the latter, at the season when both 

 have begun, or are about to begin, to swell under the 

 flowing sap, instantly amalgamate and coalesce. If 

 the scion and stock be nearly of a size, the junction 

 becomes so complete, that in a few years it is scarcely 

 discernible, more especially if both are equal as to 

 their habit of growth. But if one be of a more 

 robust habit than the other, they increase in dia- 

 meter unequally. If an apple scion be grafted on a 

 whitethorn, or a pear on a quince stock, the grafts in 

 both cases are engrossed much faster than the dwarfer 



Fig. 52. 



Perpendicular sectiou of a graft inserted on a dwarf stock. 

 P 



