RESINS 
Resins and gums are products obtained from the exudations 
of plants. The products may exude spontaneously, but are more 
often secured by making incisions in the bark or trunk. It 
is somewhat difficult to draw a sharp distinction between gums 
and resins, as there are a number of plant exudations known as 
oleoresins, balsams and gum resins which have properties in- 
termediate between those of true gums and resins. In general, 
plant products of this nature contain resins, gums, volatile oils, 
and aromatic acids. Allen * gives a very satisfactory discussion * 
of resins and the methods used in analyzing them. 
Resins are solid or semi-solid and are usually insoluble in 
water, but soluble in alcohol, ether, and volatile oils. They are 
formed usually by the spontaneous evaporation of resinous 
juices which exude naturally from the trunks of trees or when 
the trunks are cut. Frequently resins may be extracted from 
various parts of plants by solvents such as alcohol and ether. 
They are also found as minerals (mineral resin) which are, no 
doubt, products of extinct vegetation. Resins from different 
sources frequently show great differences in their chemical com- 
position and properties. Commercially, Manila copal, which is 
used in making varnishes, is the most important Philippine resin. * 
Oleoresins are the plant exudations consisting of resins dis- 
solved in volatile essential oils. Manila elemi, employed in var- 
nish making, and turpentine are examples of this class of sub- 
stances occurring in the Philippines. 
Gum resins are plant exudations, like gamboge, which consist 
of a mixture of resin and gum. Gamboge of an inferior quality 
can be obtained in the Philippines from Garcinia venulosa and 
probably from other species of Garcinia. 
Certain of the dipterocarp resins can be collected in large 
quantities and appear to offer commercial possibilities as ma- 
terials for the manufacture of varnishes. 
Family PINACEAE 
Genus AGATHIS 
AGATHIS ALBA (Lam.) Foxw. (Figs. 2-4). ALMACIGA. 
Local names: Adidfigau (Camarines); alinsagéd (Benguet); almdciga 
(Mindoro, Lepanto, Bataan, Tayabas, Benguet, Zambales, Palawan, Cama- 

* Allen, Commercial organic analysis, Volume 4 (1911), page 1. 
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