AGRICULTURAL BULLETIN 



OF THE 



STRAITS 



AND 



PEDERATED MALAY STATES. 



No. 9.] SEPTEMBER 1911. [Vol. X 



LATEX AND ITS RELATION TO THE LIFE OF THE 

 PARENT PLANT. 



There are present in many plants chemical substances which, 

 although recognised as products of activity of the living cell, neither 

 in their exact mode of formation nor in their full significance are 

 clearly understood. Among such substances are the alkaloids, 

 glucosides, colouring matters, ethereal oils, resins and caoutchouc or 

 india rubber. Many of these products are of some considerable 

 economic importance. The alkaloids include strychnine, quinine, 

 morphine and other drugs and violent poisons. Of the glucosides, 

 which are compounds of sugars with various substances, some too 

 are poisonous, yielding on decomposition prussic acid. The Lima 

 bean or Java bean contains such a glucoside; and when it is growing 

 wild the percentage of prussic acid in the stems and leaves may be 

 •sufficiently high to be fatal to animals wliich feed on it. There is 

 good reason to believe that such a glucoside occurs in the shoots of 

 the Para rubber; and an example of its poisonous properties occurred 

 several years ago, when some Para rubber trees growing in the garden 

 •of the Residency in Taiping were felled because they had proved 

 poisonous to horses. 



The presence of such poisonous substances in plants serves no 

 doubt to check the ravages of animals; but this can scarcely be 

 regarded as a primary function. 



The colouring matters in plants serve to attract insects, whose 

 .association with plants is frequently beneficial. 



