OIL OF ANISE. 895 



fectly white inodorous substance, fusible at a temperature above 

 212,, of which the formula is C 20 H 12 O 2 , or it is isomeric with 

 the original concrete essence. By the action of dilute nitric 

 acid on the essence of anise, anisic acid, HO-f C 16 H 6 O 5 , is 

 formed^ which crystallizes in fine needles and is volatile without 

 decomposition ; it belongs to the class of benzoic and cinnamic 

 acids. When distilled with an excess of barytes, hydrated 

 anisic acid loses 2 atoms of carbonic acid and yields anisole 

 C 14 H 7 O 2 , a colourless highly mobile liquid, boiling above 302 

 (150 centig.), of an agreeable aromatic odour, insoluble in 

 water, soluble in alcohol. Anisole gives crystallizable and 

 volatile compounds with chlorine and bromine ; it is evidently 

 allied to benzole. Boiled with stronger nitric acid the con- 

 crete essence of anise, gives nitranisic acid, HO + C 16 H 5 NO 9 . 

 Nitraniside is a yellow resinous substance, produced by the 

 action of fuming nitric acid upon the concrete essence ; its 

 probable formula is C 20 H 10 N 2 O 10 . (Cahours, Ann. de Chim., 

 &c., 3 ser. ii, 274.) 



The concrete essences of fennel and badian are found by 

 Cahours to be absolutely identical with that of anise. The 

 concrete essence of anise is not affected by alkalies, in which 

 respect it differs from camphor, the solid essence of cedar, oil of 

 mint and certain other essences. 



Oil of bitter fennel consists principally of two oils, one pos- 

 sessing the composition of the concrete essence of anise ; and 

 the other and more volatile oil which is much more difficult to 

 purify, appearing to correspond in composition with essence of 

 lemons and turpentine, but perhaps with a different state of 

 condensation. The more volatile portion, when exposed to a 

 slow stream of deutoxide of nitrogen, becomes thick and turbid, 

 and alcohol then throws down from it a white silky matter, of 

 which the composition is C 15 H 12 N 2 O 4 . (Cahours.) 



Oil of hyssop from the Hyss opus officinalis, begins to boil at 

 288, but its boiling point rises to 325. It is a mixture of 

 several oils, one of which probably contains no oxygen, as by 

 repeated rectification of a portion of the oil containing 9 per 

 cent of oxygen with fused potash, the quantity of oxygen was 

 reduced to If per cent, the greater part of the oxygenated oil 

 being converted into a brownish resin. (Stenhouse.) 



Cajeput oil, C 10 H 9 O, is obtained from the leaves of the Mela- 



