90 PLANT COMPOUNDS 



in color, and has an unpleasant garlic odor and bitter char- 

 acteristic taste. Asafetida is composed of about 25 per cent, 

 of gum and the rest resin ester with a little volatile oil and 

 some other compounds in small amounts. Its use is restricted 

 now largely to veterinary practice, although it is used to 

 some extent in India and Persia as a flavoring agent in 

 sauces. 



(6) Frankincense or Olibanum is found on certain trees 

 in Arabia and Africa as yellow-brown tears, with aromatic 

 odor. It is composed of resin, gum, some volatile oil, and 

 bitter principle. It is used somewhat in pharmacy, but 

 more generally in preparing incense, 



(c) Gamboge is found on trees in the East Indies as an 

 orange-red substance which is soluble in alcohol. It is 

 composed of an ester, an acid, and a gum. It is used in 

 medicine and as a pigment. 



(d) Myrrh is found on a shrub growing in Arabia and some 

 other eastern countries. It occurs in reddish-brown lumps 

 of oily fracture, fragrant odor, and bitter taste. It is com- 

 posed of resin, gum, bitter principle, and volatile oil, being 

 used in medicine and in making incense. 



80. Some of the Oleo-resins and Balsams. — (a) Benzoin 

 is a balsam and comes from Sumatra and Siam, that from 

 the latter place being of the better quality. It occurs in tears 

 or masses usually reddish brown in color, having a very 

 pleasant, aromatic odor, and is soluble in alcohol. Benzoin 

 consists of a volatile oil, benzoic acid esterified with a resin 

 alcohol, and some other compounds. It is used in medicine 

 as an antiseptic and in perfumery. 



(6) Canada Balsam is incorrectly named, for it is not a 

 true balsam, since it contains no benzoic or cinnamic acid. 

 It is an exudate from the balsam fir, and is a thick liquid, 

 yellowish in color, clear and transparent, with very high 

 refractive index, hardening on exposure to the air. It is 

 composed of a volatile oil and two resins, and is used in 

 medicine, in preparing flexible collodion, and in mounting 

 microscopic specimens. 



(c) Crude Turpentine is the thick, viscous, yellowish 

 liquid which exudes from cuts in pine trees, usually the long- 



