FEKMEXT OILS. * 351 



Ferment oil of Quercus Robur (the " Cork Oak "). Obtained 

 from the fresh oak-leaves by fermentation, distillation and treat- 

 ment of the distillate with ether as above. The oil is pale green. 

 Sp. ^r. 0-695 ; has an agreeable and enlivening odour, and sweet, 

 burning taste. It reddens litmus and is easily inflammable, giving 

 first a bluish, then whitish, non-fuliginous flame which emits a 

 penetrating odour. With fuming nitric acid it froths up and 

 becomes very hot, but does not lose its odour. It dissolves 

 sparingly in water ; rapidly in alcohol, ether, and oils both fixed 

 and volatile.* 



Ferment oil of Salix pentandra. (This willow is common in 

 the N'orth of England and Ireland ; it is remarkable for its large 

 glossy leaves, more like those of a Portugal Laurel than of the 

 other willows. Its foliage is fragrant.) The oil is obtained from 

 the fresh leaves in the same manner as above. It is yellow, 

 lighter than water, has an agreeable aromatic odour like that of 

 castoreum and, at the same time, like that of the leaves. It 

 reddens litmus; smells strongly when heated, and burns with a 

 very smoky flame, leaving a small quantity of charcoal. 



Ferment oil of TussilagO farfara ("Coltsfoot"). The fresh 

 bruised herb is macerated in water for 10 or 12 days, during 

 which it turns light green and acc^uires the odour of pickled 

 gherkins. The whole is then distilled. The distillate, which has 

 a vinous odour, is saturated with common salt and re-distilled; this 

 second distillate is shaken up with a large quantity of ether and 

 the ether taken off and evaporated, the oil remaining behind. It 

 is yellowish, lighter than water, very volatile, has a peculiar, 

 strongly aromatic, penetrating odour and an aromatic taste — 

 neither burning nor cooling. It easily takes fire and burns at 

 first with a whitish afterwards with a reddish smoky flame. It 

 dissolves sparingly in water ; rapidly in alcohol or ether.f 



Ferment oil of Trifolium fi brini (a species of clover). This 

 oil is obtained from the dried plant. After the plant has been well 

 boiled with water and no longer has a bitter smell, by fermenta- 

 tion, distillation, saturating the distillate with common salt and 

 abstraction by ether as before described. It is pale yellow, lighter 

 than water, smells strongly aromatic, like the ferment oil of 



* Bley, N. Br. Arcliiv., xxvi., p. 48. 

 + Bley, Kepert. Pharm., Ixii., p. 406. 



