GRAFTING. 113 



strength, and to prevent them from getting displaced in case 

 of knocks or wind. String, raffia, rubber, and flexible 

 metal foil are used with this object. 



In the South of France string is generally used without 

 any previous preparation. It gives great strength to the 

 joint, and if it is a dry year, it has to be cut away after the 

 knitting has taken place, if not, it might hinder the growth 

 of the plant in diameter. In damper climates, on the contrary, 

 the string must be dipped in sulphate of copper, or tar, so 

 that it will last longer. Raffia (fibre of sagus raphia, of 

 Japan, or raphia taedigera, of Madagascar) is very strong, its 

 flat reedy nature greatly facilitates the operation of binding. 

 It rots quickly when the season is very wet. Champin 

 recommends dipping it in a solution of sulphate of copper, 

 more or less concentrated, in accordance with the desired 

 duration. Vulcanized rubber has even been recommended, 

 used in the shape of tube or rings passed over the graft by 

 means of special tools, or in the shape of fine thongs of about 

 one-fifth inch square section. Rubber tubes have generally 

 been discarded, and the thongs alone are now used. They 

 are more particularly used for grafted cuttings. Their 

 elasticity insures a continuous and regular pressure, never 

 excessive, and forms an excellent ligature. Unfortunately 

 they are rather expensive. The steel ligatures are formed 

 of a flat flexible plate, curved like a kind of collar open on 

 one side. The sides are kept open by means of special pin- 

 cers, and the collar passed over the cane compresses against 

 the joint as soon as it is released. This system has several 

 disadvantages, and has been very little used. 



Cork was recommended some time ago to protect the joint 

 against desiccation, and the action of water. The corks are 

 split in two along their axis, and slightly hollowed in the 

 centre. They are placed on each side of the joint, tightened 

 together by means of special pincers, and kept in position 

 by three ties fastened and tightened with pliers before 

 releasing the pincers (Fig. 93). 



The Cork graft, as it is commonly termed, has sometimes 

 given very satisfactory knittings, but has generally resulted 

 in failure. The difficulty of execution, and the great 'care it 

 requires to give good results, greatly restricted its use, and it 

 is only advantageous for grafts made above ground, and in 

 small numbers. 



The object of waxing is to cover the section of the grafts, 

 o as to prevent their desiccation, and to protect them against 



10890. H 



