166 ODOROGRAPHIA. 



per cent. This sophistication is easily detected by heating the 

 suspected sample, when, if anethol of Fennel be present, its odour 

 becomes apparent. 



Anethol requires for solution three parts of rectified spirit and 

 200 parts of proof spirit. As oxidation proceeds, the solubility 

 increases, till the oil mixes with rectified spirit in all proportions 

 and dissolves in about 100 parts of proof spirit. Star anise oil, 

 however, appears to contain a small quantity of some constituent 

 insoluble in proof spirit, as even after warming the solution is 

 slightly turbid (Squire). Spermaceti may be detected in oil of 

 anise by agitation with cold rectified spirit; the spermaceti being 

 insoluble therein. Pure oil of anise is recorded as being 

 soluble, in all proportions, in cold alcohol of sp. gr. 0-806, and in 

 24 parts alcohol of sp. gr. 0-84 at 25° C. 



The new United States Pharmacopa^ia says : — Absence of 

 volatile oils containing phenols can be ascertained by adding a 

 drop of ferric chloride solution, when the oil should not assume 

 a blue or greenish colour. When dropped into water without 

 agitation, the oil should not produce a milky turbidity, indicative 

 of the presence of alcohol. 



It is averred that by the " Eykmann test " oil of pimpinella 

 may be distinguished from oil of star anise. This test depends 

 on a colour re-action ; the reagent consists of a saturated solution 

 of hydrochloric acid gas in absolute alcohol ; it has a sp. gr. of 

 0-970, and contains 27 per cent, by weight of hydrochloric acid 

 gas. On addition of this reagent, which is best used in consider- 

 able excess, the pimpinella oil should give a rich blue coloration, 

 changing into a more or less brownish red, and the star anise oil 

 a yellow or brownish-yellow colour, usually (but not always) 

 changing to a rich red. Mr. Squire remarks* that with an acid 

 of half the above-named streno-th, the characteristic blue colour 

 with the pimpinella oil is not produced. 



Aniso'in (better called JnetJioin) may be obtained by the 

 action of stannic chloride or of strong sulphuric acid either on 

 solid or liquid Anethol. Anisoin is a w^hite, inodorous solid, which 

 fuses a little above 100° C, and, when further heated, burns 

 with a brilliant flame and an aromatic odour. It is heavier than 



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



