SECTION XVI 



OLEO-RESINS 



The drugs that are grouped together under the above heading are 

 mixtures of resins with volatile oils or oily liquids. They are secreted 

 in schizogenous or schizolysigenous ducts which may be of either 

 normal (Canada turpentine, copaiba) or pathological (balsam of Peru, 

 storax) origin. 



All of the constituents may vary considerably in their composition. 

 Those oleo-resins which contain benzoic or cinnamic acid are frequently 

 termed ' balsams.' 



CANADA TURPENTINE 



(Canada Balsam, Terebinthina Canadensis) 



Source, &c. Canada turpentine is an oleo-resin obtained by in- 

 cision from the balsam fir, Abies balsdmea, Miller, and the hemlock 

 spruce, A. canadensis (Linne), Miller (N.O. Conifer ce), trees widely 

 distributed over the northern United States and Canada, extending 

 to Hudson's Bay. The drug, which has long been known, is collected 

 in Lower Canada, especially in the province of Quebec. 



The tree contains schizogenous oleo-resin ducts, as most Coniferous 

 trees do, but they are restricted to the bark, none occurring normally 

 in the wood. In addition, however, to these secretion ducts, cavities 

 are formed which fill with oleo-resin and produce blisters on the 

 smooth trunk of the tree. From these blisters the oleo-resin is 

 obtained by puncturing them with the pointed spout of a can which 

 serves to receive the turpentine. 



Description. Canada turpentine is a clear, transparent liquid, 

 about as viscid as honey, and of a pale yellow or greenish yellow 

 colour, often exhibiting a slight greenish fluorescence. By keeping 

 it becomes more viscid, and finally it gradually dries to a hard resin 

 which remains transparent and shows little disposition to crystallise, 

 a quality that renders it particularly valuable as a medium in which 



