TEREBINTHINA CANADENSIS. 347 



easily fusible, and burns with a dense yellow flame and much 

 smoke. It is soluble in its own weight of oil of turpentine. 



Composition. Resin consists of three resinous acids, 

 abietic, sylvic, and pimaric, C 20 H 3o 2 ; neutral resins ; and a 

 trace of oil of turpentine. 



Preparations. 



1. 'Emplastrum Besinse. 1 in 9|. 



2. Unguentum Besinss. " Basilicon." 1 in 3 j. 



JResin is contained in many other plasters and ointments, 

 and in Charta Epispastica. 



ACTION AND USES. 



Resin is a mild local stimulant, either of the unbroken skin. 

 or of sores and wounds, and the Unguentum is used for this 

 purpose. Resin is also an ingredient of many plasters, to 

 which it gives consistence and adhesiveness. 



Terebinthina Caiiadensis CANADA BALSAM. 

 The turpentine obtained by incision from the stem 

 of Abies balsamea. Balm of Gilead Fir. From 



Characters. A pale yellow ductile oleo-resin, of the con- 

 sistence of thin honey, with a peculiar agreeable odour, and a 

 slightly bitter feebly acrid taste ; by exposure drying very 

 slowly into a transparent adhesive varnish ; solidifying when 

 mixed with a sixth of its weight of magnesia. 



Composition. Canada "balsam" contains 17 per cent, of 

 a volatile oil. The resin is dissolved in this. 



Dose. 20 to 30 gr. 



Canada Balsam is contained in Charta Epispastica and 

 Collodium Flexile. 



ACTION AND USES. 



Canada balsam is chiefly used for its physical properties. 

 It has been given internally to produce the effects of oil of 

 turpentine in a milder form. 



L.aricis Cortex LARCH BARK. The bark, de- 

 prived of its outer layer, of Larix europsea T 2).C. t 

 Abies Larix Rich.* the common Larch. 



