RESINS 45 



The trees must be visited regularly to get good returns. The 

 resin can be gathered at almost all seasons, but toward the end 

 of the dry season the flow is very slight. Resin is collected from 

 the same trees year after year. Clover * says that he has seen 

 large-sized trees on which at least ten pounds of resin had ac- 

 cumulated, probably within a month. Bacon f estimates that 

 mature trees will yield an average of 45 kilos per year. He 

 says that he has seen as much as 32 kilos of resin on a large tree. 

 This amount represented a two months' flow. 



In some localities where the resin is collected, it sells for about 

 50 centavos per arroba of 11.5 kilos if clean and white, but when 

 dark for about 30 centavos. In larger towns the best quality 

 sells for about a peso a kilo and in Manila for about 3 pesos. 

 If the industry of collecting the resin w^ere systematized, the 

 cost in Manila would certainly be greatly reduced. 



Bacon $ collected over one hundred specimens of elemi resin 

 from individual trees. These samples of fresh elemi resin were 

 distilled in vacuo, the volatile oils were then separated from the 

 water, shaken out with dilute alkalies, dried over calcium 

 chloride, and redistilled in vacuo; only the terpene fraction was 

 collected. The terpenes were then distilled at ordinary pressure. 

 These results verified the conclusions of Clover that the terpene 

 oils of elemi resin obtained from different trees showed great 

 differences in their boiling points and especially in optical rota- 

 tion. For purposes of purification and identification, the various 

 distillates of elemi resin were divided into different groups ac- 

 cording to their boiling points. Bacon found that these dis- 

 tillates consisted largely of various terpenes such as alpha and 

 beta phellandrene, dipentene, limonene, etc. He prepared va- 

 rious derivatives of these terpenes, such as phellandrene nitrite, 

 dipentene tetrabromide, limonene tetrabromide, etc. Judging 

 from Bacon's experiments, the best method for purifying elemi 

 resin is by solution in benzene, filtering off the impurities such 

 as bark and dirt, and distilling the filtrate. A white resin of 

 leafy appearance is thus obtained. 



Bacon investigated nine samples of carefully purified terpenes 

 from elemi resin obtained in Gumaca, Tayabas. The results are 

 recorded in Table 5. 



* Clover, A. M., The terpene oils of Manila elemi. Philippine Journal 

 of Science, Section A, Volume 2 (1907), pages 1 to 40. 



t Bacon, R. F., Philippine terpenes and essential oils, III. Philippine 

 Journal of Science, Section A, Volume 4 (1909), pages 93 to 265. 



t Bacon, R. F., Philippine terpenes and essential oils, III. Philippine 

 Journal of Science, Section A, Volume 4 (1909), page 93. 



