ESSENTIAL OILS 195 
9 
considerable extent, so that a steam-distilled oil but rarely has exactly the 
same odor as the flowers from which it was obtained. Extraction with 
cold solvents and the removal of the solvent in vacuo, the temperature 
never being allowed to rise above 40°, gives oils which have exactly the 
same aroma as the flowers. This process has the further commercial 
advantage that such extracted flower oils can not be imitated synthetically, 
as the change in aroma is undoubtedly due to traces of very easily de- 
composable compounds which it will be difficult, if not impossible, ever to 
isolate and identify. The extracted oil need fear no competition with syn- 
thetic oils. Alcohol, ether, chloroform and petroleum ether have been used 
as solvents for ilang-ilang oil, and the last named has given the best 
results. Naturally, a very high grade of petroleum ether, which leaves 
no bad smelling residue when distilled up to 40° in a vacuum of 40 milli- 
meters, must be used as the solvent for the essential oil. Operating in 
this manner, we have obtained oil yields of from 0.7 to 1.0 per cent. The 
oil is of a very dark color and contains a considerable amount of resin in 
solution. When in bulk, the odor is not particularly pleasant or very 
strong, but when the extract is greatly diluted the pleasant aroma of the 
flowers becomes very apparent. The physical constants of one sample of 
this oil were as follows: Specific gravity, a7 0.940; i =1.4920; ester 

number 135; acetyl number 208. 
The oil is too dark to permit readings of its optical rotation to be prac- 
ticable. These constants are seen to agree quite well with those of a very 
high grade distilled oil, and as was stated above, the different odor is 
probably due to traces of delicate compounds present in the extracted oil, 
which are destroyed during the process of distillation. It is rather curious 
to note that when this extracted oil is shaken out with water, a considerable 
» amount of resin separates, carrying the distinctive flower aroma, and the 
separated oil then has an odor resembling that of methyl-p-kresol. 
These extracted oils should sell for a considerably higher price than 
the best distilled oils, which fact, taken in consideration with the increased 
yield and the impossibility of competition from synthetic oils, offers a very - 
attractive new industry to the Philippines. 
ADULTERANTS 
Regarding the use of adulterants of ilang-ilang oil, Bacon says 
that he does not believe the practice is very general in the Phil- 
ippines. The common adulterants are said to be turpentine, 
coconut or other fixed oils, and kerosene. Bacon suggests va- 
rious tests for these substances, if their presence is suspected.” 
The use of any adulteration is more emphatically the height of com- 
mercial folly for ilang-ilang than it is for any other essential oil, for only 
the product of the highest quality brings a remunerative price. A 10 per 
cent increase in quantity by means of adulteration may cut the price in 
two, or may result in an oil which can not be sold at any price. * * * 

* Bacon, R. F., Philippine terpenes and essential oils, II. Ylang-ylang 
»oil. Philippine Journal of Science, Section A, Volume 3 (1908), page 76. 
