238 



AMERICAN VINES. 



formation of knitting tissue ; it also prevents, when per- 

 formed underground, the lignification of the knitting tissue. 



This method of binding is only 

 advisable for grafts made above 

 ground. 



Corks simply perforated con- 

 stitute an excellent but expen- 

 sive binding. 



Other methods of binding- 

 may be used. All those are 

 good which allow the access of 

 air and the increase of the joint 

 in diameter (for the thicker the 

 layers of wood and liber are, 

 the more perfect the knitting 

 is), and resist rotting suffi- 

 ciently, or are easy to remove 

 at opportune times; which are 

 not detrimental to the young 

 cells of knitting tissue in the 

 formative stage, and, finally, 

 cheap and easily applied. Raffia 

 seems to us to possess all the 

 required qualities, if, according 



to circumstances, precautions are taken as indicated above. 

 Consequently, early grafts should be tied with sulphated 

 raffia, washed with water to remove the excess of sulphate 

 of copper, or, again, lead or tin foil may be interposed 

 between the ligature and the joint (Figs. 117 to 121). For 

 late grafts, made in April or May, non-sulphated raffia should 

 be used without lead or tin (Figs. 116, 120). 



To increase the solidity of the joint, and to guard against 

 the too rapid decomposition of the ligature, a lead ring 3 or 

 4 mm. wide (y% inch) may be fixed around the joint by bring- 

 ing its two extremities together. 



Grafts stratified in moss may do without ligatures ; how- 

 ever, no inconvenience results from consolidating them by 

 means of a few turns of raffia. Finally, the solidity of the 

 joint may be increased by means of an iron dowel introduced 

 into the pith of both stock and scion. This method of 

 grafting is called the End-to-End or dowel graft. Both stock 

 and scion are cut slantingly ; the dowel or piece of galvanized- 

 iron wire is introduced into the pith of stock and scion, 



Fig. 123. Cork Graft. 



