166 THE AFRICAN RUBBER TREE 



of over-heating the rubber and rendering it sticky. 

 Recently, however, improvements have been made in 

 the process, which will be dealt with later in the section 

 relating to plantation methods (see p. 174). 



(3) Coagulation of the Latex by raeans of an Infusion of 

 Bauhinia reticulata Leaves. — This method of coagulating 

 Funtumia latex is employed by the natives in certain 

 districts of West Africa. A hot infusion of the leaves is 

 poured into a Cjuantity of the undiluted latex and the mix- 

 ture is stirred for a few mmutes until coagulation occurs. 

 The usual procedure has been described as follows : 



About 1 lb. of the leaves is put into 3 gallons of water 

 and boiled for 15 minutes ; the infusion is then strained 

 tlu'ough calico and the hot liquid is added to about one 

 gallon of latex, stirring well. Complete coagulation takes 

 place quickly, usually within fom" or five minutes, and 

 the rubber obtained may be pressed out into sheets or 

 made into lumps or twists. 



It is not always possible to employ this method of 

 preparmg Funtumia rubber, as Bauhinia reticulata does not 

 invariably occur in the same localities as Fu7itumia 

 elastica. The infusion of the leaves is acid and contains 

 tannin, 8 per cent, of which was found in a sample of the 

 di'ied leaves examined at the Imperial Institute. The 

 tannin appears to be the active coagulating agent, and 

 infusions of other astringent products, such as the pods 

 of Acacia arabica, exert a similar action on the latex. 

 It is of interest that an infusion of Bauhinia reticulata 

 leaves is used by the natives of the French Sudan to 

 coagulate the latex of Landolphia Heudelotii. 



(4) Coagulation of the Latex by means of the Juice of 

 the " Diecha " Vine, Stro2)hanthus Preussii. — This method 

 is used by the natives in some districts of the Gold Coast, 

 and as it is very rapid and does not require the application 

 of heat, it has recently been adopted to a considerable 

 extent in that countr5^ The young Diecha vines yield 

 a milky latex when incisions are made in the bark, M'hilst 

 the older vines give a clear yellowish fluid which is stated 

 to be the most active as a coagulant. A small quantity 

 of this liquid when added to Funtumia latex quickly 

 causes coagulation in the cold on stirring, especially if 

 the latex is a few days old. The resulting rubber may 

 be made into sheets, lumps, or twists. 



