94 BACON. 



individual trees, together with botanical material corresponding to each 

 specimen. 



In spite of tlie very careful work on this subject, published from 

 this laboratory, the recent literature still abounds with inaccurate state- 

 ments as to this resin, especially as to its source. Tschireh - in his 

 handbook, states, "Das Manila Elemi stammt von Canarium commune," 

 and again,' "Es darf jetzt als festgestellt betrachtet werden, dass das 

 Manila Elemi von Canarium commune L. stammt." He also remarks 

 that the tree is called by the Tagalogs dbilo, a name which I find is wholly 

 unknown to natives in the districts where elemi is collected. The native 

 name for the tree is pili. Semmler * in discussing Manila elemi states 

 that it is now well established that the resin is a product of the tree 

 Canarium commune L. There is little doubt but that in India and Java 

 a resin very similar to Manila elemi has as its source Canarium com- 

 mune L., but for the Philippine elemi, the source has been definitely 

 shown by Merrill to be Canarium luzonicum A. Gray." 



Tschireh" divides Manila elemi into three classes, (a) soft elemi, (h) 

 hard elemi, (c) Tacamahac elemi. He speaks of the hard elemi as 

 containing from 7 to 8 j^er cent of essential oil as compared with about 

 30 per cent for the soft variety and he gives the following constants for 

 the two classes: 



Soft elemi. Harrl elemi. 

 Acid number, direct 19.6 22.4 



Acid nvmiber, indirect 22.4 25.2 



Saponification number, cold 29.4 30.8 



Saponification number, hot 33.6 - 37.8 



Manila elemi as it exudes from the trees is ah\'a}s soft. 'Wlien it has 

 remained on the trees exposed to the sun and air for several months it 

 loses the greater part of its volatile constituents through evaporation 

 and polymerization and becomes quite hard. There is no difference in 

 the source of the elemi, the so-called hard elemi simply being more 

 resinified by the action of the elements. There is but one elemi gum 

 collected in the Philippines. While there are many species of Canarium 

 in the Islands, only Canarium luzonicum yields an elemi-like resin in 

 sufficient quantities to render its collection profitable. Tscliirch gives 

 such meager data regarding the Tacamahac elemi that it is impossible 

 to identify it. It may possibly be the resin known in the Philippines 

 as pagsainguin from Canarium villosuin F.-Vill. Tliis resin occurs in 

 considerable quantities, but is always black or very dark, contains as 

 the principal constituents of its volatile oil pure cymol, it does not ha\e 



= Die Harze and die Harzbehalter (1908), 424. 



" Loc. cit., 427. 



'Ber. d. deutschen chem. Ges. (1908), 41, 1768. 



= Tlie source of Manila Elemi, Gov. Lab. Pub., Manila (1905), 29, 51 to 55. 



= Loc. cit. 



