148 RESINOUS PRODUCTS. CAOUTCHOUC. 



assafoetida, from Narthex Assafoetida; and oil of Mustard, which is 

 obtained from the seeds of Sinapis nigra, by a kind of fermentation 

 induced by the action of a nitrogenous body, myrosine, on a substance 

 called myronic acid, or myronate of potash, when macerated in water. 

 A similar oil exists in many Cruciferae, as in Erysimum AUiaria, 

 Armoracia rusticana, and Cochlearia officinalis, and in several Umbel- 

 liferse, yielding gum-resin, as Opoponax, Ferula, Galbanum, &c. Many 

 of the essential oils deposit a solid crystalline matter, called Stearop- 

 tene, allied to camphor. This latter substance, which consists of carbon, 

 oxygen, and hydrogen, is procured from Camphora officinarum, a 

 native of Japan and India. There is also another kind of camphor, 

 produced hi Borneo, by Dryobalanops Camphora. 



318. Resinous Products. The milky and coloured juices of plants 

 contain frequently resins mixed with volatile oils, in the form of 

 balsams, besides a quantity of caoutchouc. The resinous substances 

 found in plants, are either fluid or solid. The former may be illus- 

 trated by Balsam of Tolu, procured from Myrospermum toluiferum; 

 Balsam of Peru, from Myrospermum peruiferum; Balsam of Copaiva, 

 from various species of Copaifera, especially Copaifera officinalis ; 

 Carpathian Balsam, from Pinus Pinea; Strasburg turpentine, from 

 Abies pectinata, or silver fir; Bourdeaux turpentine, from Pinus pin- 

 aster; Canada Balsam, from Abies balsamea, or Balm of Gilead fir; 

 Chian turpentine, from Pistacia Terebinthus, &c. The latter may be 

 illustrated by common resin or Colophony, and Burgundy pitch, from 

 Pinus sylvestris ; Mastich, from Pistacia Lentiscus; Sandarach, from 

 Callitris quadrivalvis ; Elemi, from several species of Amyris ; Guaiac, 

 from Guaiacum officmale ; Dragon's-blood, from Dracaena Draco, and 

 Calamus Draco ; Dammar, from Dammara australis and orientalis ; 

 Labdanum, from Cistus creticus, and others ; Tacamahaca, from Calo- 

 phyllum Cadaba, and from Elaphrium tomentosum ; Resin of Jalap, 

 from Exogonium Purga ; Storax, from Styrax officinale ; Benzoin, 

 from Styrax Benzoin ; Copal, from Vateria indica, &c. ; Lac, from 

 various species of Ficus, as Ficus indica, and benghalensis, after attacks 

 of Cocci, and from Aleurites laccifera, and Erythrina monosperma ; Eu- 

 phorbium, from Euphorbia officinarum, antiquorum, and canariensis. 



319. Caoutchouc is in some respects analogous to essential oils. It 

 is found associated with them and resinous matters, in the milky juice 

 of plants. It is procured from various species of Ficus, as Ficus 

 elastica, Eadula, elfiptica, and prinoides, from Urceola elastica, Siphonia 

 elastica, and Vahea gummifera, by wounding the plants. A kind of 

 caoutchouc, called gutta percha, imported from Singapore and Borneo, 

 is procured from Isonandra Gutta, one of the Sapotacese. The milky 

 juice of many plants, as of Euphorbiaceae, Asclepiadaceae, Apocynaceae, 

 Artocarpacea?, and Papayaceae, contain caoutchouc or gum elastic. 

 Some of these coloured juices are bland, as that produced by the Cow- 



