AXISE. 165 



of the tin or bottle subject to examination are completely melted 

 and uniformly mixed. 



The " melting point" of pure anethol — i.e., the temperature at 

 which a sample, after freezing, becomes completely liquid, is 

 constant between 21^ and 22 C^. It is ascertained by simply 

 inserting a thermometer into a flask with melting anethol. The 

 sp. gr. of pure anethol at 25° C. is 0-986. Its boiling point is 

 constant at 234° C. 



Pure, fresh oil of anise has a sp. gr. of 0-985 at 15° and 0-980 

 at 20° C. (The new United States Pharmacopeeia, seventh 

 decennial revision, 1890, states it 0-980 to 0-990 at 17° C.) Of 

 course the sp. gr. of any given sample depends on its anethol 

 content. Commenting on this fact. Squire observes in a recent 

 paper on oils of anise, * " supposing melted anethol to have a sp. 

 gr. at 60° F. of I'OIO and the terpene '870, then 10, 20 and 25 

 per cent, of terpene will give specific gravities of '996, "992, and 

 •975 respectively, which covers the maximum and minimum of 

 fresh oils as generally met with. The sp. gr. of the oil depends, 

 secondly, on the amount of oxidation of the anethol into anisic 

 aldehyde " (the sp. gr. of which is 1-126 at 15° C). 



In the samples of anise oils examined by Squire,f the polarising 

 rotation in a 200 m. m. tube varied between + 2J° and — 4J°, but 

 were usually slightly Isevogyre, a property which apparently had 

 no connection with the source of the oil, was unalterable in a 

 year, and was greater in the more liquid portion of the oil than in 

 the solid. Pure anethol being probably optically inactive. 



Oil of anise is sometimes adulterated with oil of Fennel. This can 

 detected by the polariscope ; pure recent oil of anise examined by be 

 Fllickiger and Hanbury in a 50 m. m. tube deviated the ray only 

 l°-7 to the left; oil of Sweet Fennel examined in the same way 

 deviated the ray 29°-8 to the right ; oil of Bitter Fennel (French), 

 4° -8 to the right, and that of German Fennel 9°-l to the right. 

 This dextrogyre power is attributed to the hydrocarbon in the 

 Fennel oil differing in its properties to that in the Anise oil. 



Anethol is isomeric with the camphor of Fennel oil, which, for 

 this reason is imported from Eussia and Austria for the express 

 purpose of adulterating Anise oil, frequently to the extent of 90 



* Pharm. Journ. [3], xxiv., p. 105. 

 t Ibid. 



