— 71 — 
Oil of Wintergreen {01. Gaultheriae). Colourless, subsequently 
reddish-yellow; d^50= 1,175 to 1,188^); feeble acid reaction; scarcely 
soluble in water, readily soluble in Spiritus fortior; the aqueous solu- 
tion should be coloured violet by ferric chloride; when shaken with 
an equal vol. nitric acid no red colouration should occur 2). 
^) The following limits are more correct: 1,185 1,190. 
^) Test for adulteration with sassafras oil. 
Oil of Wormwood (OL Absinthii). d-^50 = 0,925 to 0,955^); 
neutral reaction; soluble in equal vol. alcohol; wormwood oil is coloured 
by nitric acid first green, then blue; by sulphuric acid, first blue, then violet. 
^) "We recommend the lower limit as 0,900. 
^ We have already referred under oil of parsley to the low value of such 
colour-reactions. 
Belgian Pharmacopoeia. 
(The following particulars are taken from the "Annales de pharmacie'* 9 (1903), 193.) 
AnethoL dgs© = 0,984 to 0,986; = + 0°; boiling point 232^ 
to 234°; sparingly soluble in water, soluble in alcohol; freshly prepared 
anethol melts at 22° to a colourless, strongly refractive liquid. 
Oil of Balm [Melissae essentia). Colourless or yellowish; d^50 = 
0,850 to 0,920; soluble in 5 to 6 vol. alcohol; insoluble in carbon 
disulphide^). 
The test for solubiHty in carbon disulphide is of no value, as the strong 
turbidity which thereby occurs is simply due to the small content of water in the 
oil; there is, however, no question of an actual insolubility of the oil. 
Benzaldehyde [Aldehydum benzoicuni). Produced from oil of 
bitter almonds or oil of cherry laurel, or synthetically. Colourless, 
d^^o = 1,050 to 1,055; — i 0°; boiling point 179°; sparingly 
soluble in water; soluble in every proportion in alcohol; when freshly 
produced it is neutral, but soon acquires an acid reaction on exposure 
to the air; test for absence of hydrocyanic acid, foreign oils, and 
nitrobenzene. 
(^^ii O^.^^Y^?iViiot {Bergamottae essentia). Green colour^); d^50 = 
0,880 to 0,890; makes clear solution with 1/4 ^o^- t)y weight of 
alcohol or carbon disulphide, which becomes cloudy when more solvent 
is added 2); residue on evaporation five to six per cent.; ester-content 
(determined after neutralising the free acid): 30 to 45 per cent, linalyl 
acetate (ester number = 85,4 to 128,8). 
^) With regard to the colour, the same remarks apply which have already been 
made with reference to the Dutch Pharmacopoeia; compare p. 70. 
^) The solution of bergamot oil in 92 per cent, alcohol remains clear even when 
more alcohol is added; cloudiness of the carbon disulphide solution points to a 
slight content of water always present in the oil; the last-named test is moreover useless. 
