— 77 — 



Thyme Oil (Oleum thy mi). Colourless 1 ); d 2 5o 0,900 to 0,930 2 ); 

 feeble laevorotation , «p25° not above — 3° 3 ); phenol-content a least 

 20 per cent, by volume; soluble in 0,5 vol. alcohol and in 1 to 2 vol. 

 80 per cent, alcohol. 



*) The rectified oils also frequently acquire again the red-brown colour of the 

 crude oil. 



2 ) 0,900 is too high as lowest limit of value, and this should be 0,894 

 (comp. table). 



3 ) "We have also repeatedly observed oils with a feeble dextrorotation ; further, 

 the rotation is sometimes a little higher than indicated in the Pharmacopoeia. In 

 most cases, the optical behaviour of the oil can only be determined approximately 

 on account of the dark colour. 



Thymol. Large colourless, transparent rhombic prisms; d25o 1,030; 

 melting point 50 to 51 ; the alcoholic solution is optically inactive. 



Turpentine Oil (Oleum terebinthince). Colourless ; &2o° 0,860 

 to 0,870 1 ); on distillation the bulk should pass over between 155 

 and 162 ; soluble in 3 vol. alcohol. 



*) It would be more correct to fix 0,858 as the lowest limit of value 

 (comp. table). 



Turpentine Oil, rectified (Oleum terebinthince rectificatum) . 

 Colourless; d25© 0,860 to 0,865 *), 



1 ) The lower limit applies to a temperature of 15 ; for 25 it is 0,853 

 (comp. table). 



Vanillin. Fine, white, crystalline needles; soluble in about 

 100 parts water of 25 , and in 15 parts of 8o°; readily soluble in 

 alcohol; melting point 80 to 8i°. 



Wintergreen Oil: 



a) from Betula lenta L. (Oleum betulce). «d + o°; for the rest, 

 the same properties as Oleum gaultherice. 



b) from Gaultheria procumbens L. (Oleum gaultherice) . Colourless 

 or almost colourless 1 ); d25o 1,172 to 1,180; feeble laevorotation, 

 a D25° U P to — i°; boiling point 218 to 22 1°. 



1 ) The oils are frequently of a reddish colour, owing to traces of iron. 



c) Artificial Wintergreen Oil (Methylis salicylas). Colourless; 

 d 2 5o 1,180 to 1,185 *); a L>io ; boiling point 219 to 221 ; soluble 

 in every proportion in alcohol. 



x ) The lower limit is given too high; it should be 1,177 (comp. table). 



Austrian Pharmacopceia. 



(Pharmacopoeia Austriaca ed. VIII). 



Owing to the many incorrect statements regarding essential oils 

 contained in the seventh Edition of the Austrian Pharmacopoeia, the 

 eighth Edition just issued is all the more welcome, as the defects 



