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. 
Vier SS es ae ae et ae ore lee oae_ia ge ree ee a 55.0 
[sb e St ae ee ee A ee I ae. a” 38.5 
IEA O Ge) Spee eae ee ete OL a A ee a 3.0 
JESSIE) ~ ge we SS SA 2 ee ae a 3.0 
’ Nitin ere derneutve tee eee a eo ee ae te 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 offer 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.+ 

* Rogers, A., Industrial chemistry, 1915, page 704. 
+ Yates, H. S., The growth of Hevea braziliensis in the Philippine Islands. 
®» Philippine Journal of Science, Volume 14 (1919), pages 501-523. 
168837——5 65 
