18 OLEORESINS OF SOME WESTERN PINES. 



the degree of heating and with the concentration of the solution. 

 Acids isolated from the oleoresin of Pinus sabiniana and not heated 

 above 60 gave 95.82 for the specific rotation, which approaches 

 the rotation of the Z-sylvic acid for which Leskiewicz found [a] D = 

 -102.85. 



CONCLUSIONS. 



From the distillation data it has been estimated that the volatile 

 oil of Pinus ponderosa scopulorum contains 60 to 70 per cent d-a- 

 pinene, about 5 per cent /?-pinene, and 20 to 25 per cent limonene. 

 The rosin contains about 90 per cent abietic acid. 



Pinus Sabiniana Dougl. 



LITERATURE. 



The volatile oil obtained from the resinous exudation of the digger 

 pine (Pinus sabiniana), or coming apparently from this species, has 

 been the cause of considerable dispute. That a hydrocarbon, normal 

 heptane, should occur in a growing plant was a source of wonder to 

 phyto-chemists. Semmler ( 9 ), in the face of all the investigations 

 that have been carried out on this oil, thinks there is a strong possi- 

 bility that the material so far examined may have been adulterated 

 with a petroleum hydrocarbon, and recommends the careful examina- 

 tion of the volatile oil obtained from authentic samples of oleoresin. 



The question has been further complicated by contradictory state- 

 ments as to what species of pine really furnished heptane. Wen- 

 zell ( 14 ), who first discovered "abietene," or heptane, reported it as 

 coming from Pinus sabiniana and his later paper ( 15 ) is quite con- 

 clusive on this point. Sadtler ( 4 ) examined an oil having all the 

 properties of "abietene," but coming supposedly from Pinus ponde- 

 rosa. 2 Trimble ( n ) states that Pinus jeffreyi was considered the 

 main source of "abietene," although Pinus sabiniana and Pinus 

 ponderosa may have furnished samples of "abietene." The papers 

 of Wenzell ( 15 ) and Blasdale p) would indicate that both Pinus 

 sabiniana and Pinus jeffreyi 3 . yield heptane. The thorough chemical 

 investigations by Thorpe ( 10 ), Schorlemmer and Thorpe ( 8 ), and Ven- 

 able ( 12 ), as well as the work of Venable ( 13 ) and Grissom, and 

 Young ( le ), left little doubt but that the oil from Pinus sabiniana is 

 true normal heptane. 



1 The small numbers in parentheses refer to the bibliography on pp. 21-22. 



2 This seems erroneous, since the volatile oil from Pinus ponderosa consists of terpenes. (See pp. 12-13 

 of this paper. ) 



3 The oleoresin from Pinus jeffreyi has not been examined by the author, but it is hoped that this may 

 be done later. 



