GUMS 



Gums are amorphous substances which exude from plants or 

 which may be extracted by solvents. The true gums, such as 

 acacia and tragacanth, have the property of either dissolving in 

 water or taking up a sufficient amount of water to become gluti- 

 nous and form a sticky liquid (mucilage). There are, however, a 

 number of well-known substances like rubber and gutta-percha, 

 which resemble the true gums, but are insoluble in water. 

 Substances of this nature are obtained from plants which have 

 capillary tubes containing a milky juice. This juice (latex) 

 may occur in the stems, leaves, or roots. The latex ap- 

 pears to be an emulsion which contains a number of substances 

 in varying proportions. An idea of the composition of one of 

 these milky juices may be obtained from the following figures * 

 which represent the analysis of the latex of Hevea braziliensis, 

 the plant from which para rubber is obtained. 



Per cent. 



Water 55.0 



Rubber 38.5 



Proteins 3.0 



Resins 3.0 



Mineral matter 0.5 



The latex may be obtained by making incisions in the trunk 

 of the tree. This cuts the latex tubes and allows the milky 

 juice to exude. The juice thus obtained is collected in small 

 vessels and may be coagulated in various ways, such as by 

 smoking or by treatment with a salt solution. The latex may 

 also be extracted by other mechanical or chemical methods. 



The most important substances produced in the Philippines 

 which may be classified as gums are rubber and gutta-percha. 

 The wild rubber is small in amount, and the native plants do 

 not appear to off'er any prospect for a considerable industry. 

 The southern Philippines seem, however, to be well suited for 

 the production of plantation rubber, and the rates of growth 

 of Hevea braziliensis in this region compare favorably with 

 rates elsewhere.f 



* Rogers, A., Industrial chemistry, 1915, page 704. 



t Yates, H. S., The growth of Hevea braziliensis in the Philippine Islands. 

 Pliilippine Journal of Science, Volume 14 (1919), pages 501-523. 



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