COMPOSITION OF LATEJX 4§ 



A sample of Funtumia elastica latex from West Africa 

 was found by Spence to have the following composition : 



Per cent. 



Water 7620 



Caoutchouc . . . . .19*85 



Resins (soluble in acetone) . . . 200 



Organic crystalloids (sugars, organic 

 acids, and certain nitrogenous com- 

 pounds) . . . . . 139 

 Insoluble constituents (largely protein) . 0"36 

 Protein (calculated from nitrogen 0438) 2" 73 

 Mineral matter (ash) . . . .0-266 



Fickendey examined a sample of Funtumia elastica 

 latex from the Cameroons and found it to have the follow- 

 ing composition : 



The proportion of rubber present in latex varies con- 

 siderably in different plants and also in the same plant at 

 different seasons according to the consistence of the 

 latex, which in its turn depends upon the supply of water. 

 In the case of plants growing in districts which have a 

 marked wet and dry season, the latex is usually thin 

 and watery during the rainy period and then contains 

 only a low percentage of rubber, whereas during the dry 

 season it becomes very much thicker owing to the utilisa- 

 tion by the plant of the water of the latex, and the pro- 

 portion of rubber is correspondingly increased. Further, 

 the amount of rubber in latex is considerably affected 

 by the manner and frequency of tapping. It has been 

 found that if Para trees are regularly tapped at frequent 

 intervals the percentage of rubber in the latex is dimin- 

 ished ; whereas if longer intervals are allowed between 



