46 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 that 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 number 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 composition 
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 Banos. 
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. 
