NEW PHARMACOPOEFIAS. 45 
viz., the inclusion of the refractive index. Several years ago (Report April 1910, 134), 
when discussing the suggestions made by Hill and Umney for the B. P., we stated 
that we did not consider it advisable to embody such a constant in a pharmacopoeia, 
seeing that its limits of value have not by any means been laid down with the 
required degree of accuracy, and seeing also that for the individual oil this value is, 
almost without exception, less characteristic than any of the other constants. Our 
opinion has not altered since then. The figures indicated can only be looked upon 
as approximate and the limits of value cannot be considered reliable. In part they 
differ considerably from our own observations. Yet, strange to say, this constant 
is looked for in vain with artificial wintergreen oil. As this is a uniform chemical 
body, indications as to refractive index would have been much more called for in this 
instance than with essential oils. In the discussion which now follows the refractive 
index is not touched upon any more, for obvious reasons. 
Specific gravity and solubility are based on 155° C. This makes but little 
difference with specific gravity (about 0.0004 lower), as compared with usual temperature 
of 15°; but with solubility, which is usually observed at 20°, this must not be lost 
sight of. The requirements SECURE are of such a nature, however, that difficulties 
are not likely to ensue. 
Among official oils, pine needle oil and pimento oil are ne to be found any 
longer, on the other hand several oils have been admitted, as for instance ajowan oil, 
Siberian fir oil, lemongras oil, natural and artificial wintergreen oil: crude turpentine 
oil has been replaced by the rectified article. 
We will now proceed to the discussion of the several articles. 
Oil of Ajowan (Olewm Ajowan). Colourless; dis.50 0.910 to 0.930; ¢p +1 to + 2°4). 
Thymol content not below 40 p.c. (determined with 20 p.c. solution of sodium hydroxide). 
1) The limits of value are not in keeping with facts. In oils of our own distillation we observed values | 
between + 0° 24’ and + 5°. : 
‘Oil of Anise (Oleum Anisi). The ordinary oil as well as star anise oil are official. 
Colourless or pale yellow; d= 0.975 to 0.990; ap —2 to +1°; npaso 1.552 to 1.558; 
soluble in 3 parts of 90 p.c. alcohol; congeals at about 15.59 and does not again 
liquefy below 17°. At least 80 p.c. boil between 225 and 235°. 
Oil of Cade (Oleum cadinum). Dark reddish-brown or nearly black; dis.;0 about 
0.990*); soluble in ether®) and in chloroform; partially soluble in cold, almost wholly 
soluble in hot alcohol of 90 p.c. strength; very slightly soluble in water, the filtered 
aqueous solution being almost colourless and acid to litmus; test for pine tar: 1 cc. 
of the oil is vigorously shaken with 15 cc. of petroleum spirit and filtered; to 10 cc. 
of the filtrate 10 cc. of a solution of copper acetate are added, the mixture is again 
well shaken and set aside until separation into two layers is complete; 5 cc. of the 
upper layer, when mixed with 10 cc. of ether, become pale brownish-yellow, but not 
green (absence of pine tar). . 
1) The specific gravity may exceed 1. Compare Report April 1909, 58. 
2) The solution mostly shows a flocculent deposit after a short time. 
Oil of Cajuput (Olewm Cajuputi). Green or bluish green; dj5.50 0.919 to 0.930; 
&, not more than —4°; fp»;0 1.460 to 1.467; cineol content not less than 45 p.c. 
(phosphoric acid method)*). 
*) On previous occasions (Report April 1910, 134), when discussing the suggestions made by Hill and 
Umney for the B. P., we gave vent to our surprise that such an unreliable method should be recommended 
for a pharmacopoeia. The fact of its having been adopted after all does not make it any better. We shall 
certainly not give any guarantees based on such a method of determination. 
