LARCH (VENICE) TURPENTINE 



281 



Table 8 gives a comparison of the solubilities of the oleoresins of 

 the two species of larch. Complete solubility in glacial acetic acid is 

 indicative of larch turpentine. In this solvent the product from western 

 larch is soluble only to the extent of about 9() to 9T per cent. 



Table 8. 



" Von Schmidt and Erban. 

 " E. Dieterich. 



Unlike that from L. decidua ^® the oleoresin from L occidentalis 

 does not dissolve completely in three parts of 80 per cent alcohol, nor 

 does its alcoholic solution remain clear when made alkaline with 10 

 per cent potassium hydroxide. On the other hand, both oleoresins 

 possess a slight greenish fluorescence in reflected light, and neither 

 solidifies with one-sixteenth its weight of magnesium oxide. 



The oleoresin from L- occidentalis contains approximately Ki per 

 fent of a volatile oil consisting chiefly of a-pinene together with 

 smaller amounts of (3-pinene and a-limonene. The non-volatile portion 

 is a resin possessing acid properties but yielding no crystal-line product 

 by the usual methods of crystallization. 



The oleoresin does not conform to some of the accepted test for 

 Venice turpentine. The acid value, for example, is high, and the ester 

 value low, as compared with the commercial standard. However, the 

 values agree very well with the results obtained by Beckerts and Bruche 



See National Formulary IV. 



