48 PHILIPPINE RESINS, GUMS, AND OILS 



although such cases would be rare and the substances themselves would 

 constitute so small a proportion of the aggregate oil tha\, they would 

 scarcely need to be taken into account. 



It is obvious that in considering Manila elemi or the oil obtained there- 

 from as products of a species, we must deal with an aggregate sample 

 of these products; a sample derived from so great a niunber of individual 

 trees that the peculiarities of the individuals disappear. If the native 

 gatherer of resin utilizes a large number of trees and regularly removes 

 the resin from them in small portions, the product which he places upon 

 the market will be nearly homogeneous and a representative sample; but 

 if he obtains his resin from a limited number of individuals his product 

 will not be representative and, if he utilizes resin which has accumulated 

 upon the trees in large quantity, it will not be homogeneous. 



The great variation which I found at different times in the oil obtained 

 from commercial elemi is readily explained. It is plain what the com- 

 position of elemi oil is when considered as an aggregate product; it should 

 be remembered that to the laevo-limonene which accompanies phellandrene 

 should be added an equal amount of dextro-limonene and the whole con- 

 sidered as dipentene. 



Granted that we have a representative sample of resin, the cornposition 

 of the oil will also be influenced by the following factors: 



(1) The age of the resin. 



(2) The temperature of the distillation. This factor will largely de- 

 termine the proportion of the high-boiling part of the oil and will influence 

 the composition of the terpene portion, because some of the terpenes suffer 

 a change at higher temperatures. 



(3) The length of time used in the distillation. This factor will in- 

 fluence only the proportion of high-boiling oil. 



Yield of oil. — In the first seven samples examined considerable differ- 

 ence was found in the oil content. While there may be a certain amount 

 of variation shown by the individual samples in this respect, it is thought 

 that the differences found are more directly connected with the age of the 

 resin. As previously noted, Schimmel & Co. state that the yield of oil 

 is from 15 to 30 per cent. In several cases where I have examined 

 samples of fresh, soft, resin purchased in Manila, I have always found 

 the total yield to be from 25 to 30 per cent of the weight of the resin. 



This species has been grown in plantations at Los Baiios. 

 Thirty-nine per cent of the seeds planted germinated. At the 

 end of 7 years the trees averaged 4.37 meters in height and 4 

 centimeters in diameter. 



Canarium luzonicum is a tree reaching a height of about 35 

 meters and a diameter of 1 meter or more. The leaves are 

 pinnate, with usually three pairs of opposite leaflets and a ter- 

 minal leaflet. The leaflets are smooth, pointed at the apex, 

 rounded or obtusely pointed at the base, and from 12 to 20 

 centimeters in length. The flowers are fairly small and are 

 borne on large compound inflorescences. The fruits are some- 

 what oval in shape, about 3 centimeters long, and contain a thick- 

 shelled, triangular, edible nut. 



