_ NOTES ON SCIENTIFIC RESEARCH. | ed 
Notes on Scientific Research in the Domain of the 
& Terpenes and Essential Oils. 
yt os General. 
F. B. Power!) has published a paper on the occurrence, the winning and the 
chemical composition of plant perfumes, which in a condensed form gives an interesting 
' and instructive ‘view over the domain of the essential oils. The multiplicity of the 
substances which condition the odour is great. Every plant family, almost every 
species has its own characteristic odour; indeed, even the various parts of one and 
the same plant may form quite various odorous substances. The oil got from the 
roots of the sassafras tree Sassafras variifolium, Kuntze (similar to S. officinale, Nees) 
contains safrole, camphor, eugenol, &c., i. e., substancés which are not present in the 
leaves; on the other hand myrcene, citral, linalool and geraniol are found in the leaves 
only af this plant. We have a similarly known example in the Ceylon cinnamon tree 
- Cinnamomum ceylanicum, Nees, whose roots contain camphor, whose leaves chiefly 
contain eugenol, whilst in the bark oil cinnamic aldehyde prevails. 
Environment, difference in the soil and climate have great influence on the com- 
position of plant perfumes of otherwise similar origin. Thus in oil of thyme, instead 
of the generally occurring thymol (isopropyl-m-cresol), the isomeric, fluid carvacrol 
(isopropyl-o-cresol)?) is occasionally found. Oil of lavender, that is distilled in France 
__ from the wild growing Lavandula vera, DC., is characterised by its amount of pleasant- _ 
smelling linalool Cio>HisO and its ester, together with geraniol, whilst the oil got from 
the cultivated English plant contains much less ester and a comparatively large 
quantity of the camphor-like smelling cineole CioH1sO. : 
_ A single substance seldom conditions the characteristic odour of plants; generally 
a mixture of substances is present, amongst which, perhaps, one prevails. 
2 ‘These odorous substances— called essential or volatile oils —are generally obtained 
by steam-distillation. In cases, where the oil first originates through the splitting up 
of -a glucoside, as in mustard seed, bitter almonds, gaultheria leaves and birch bark, 
the drug must be first digested in water for some time before being distilled. A few 
essential oils, whose aroma might be lessened by being distilled, particularly those 
the “Agrumen fruits”, orange (sweet and bitter), lemon, and bergamot are obtained by 
_ pressure. In other cases the scent of certain flowers is of so delicate a nature that it 
is only obtainable in fair quantities when extracted with a volatile solvent, or macerated 
with oil or fat. The use of heat in‘such macerations appears advantageous for obtaining 
the odorous substances from violet, orange, and cassie flowers. Together with this 
method of extraction, named enflewrage & chaud, a process of cold maceration — enfleurage 
a froid—is used for other blossoms, such as'jasmine, tuberose, jonquille, lily of the 
valley, and mignonette. The odorous substances in the plants named in the last process, 
are only present in very small amounts, but are being continually produced by the 
1) Journ. ind. eng. Chem. un (1919), 344. According to kindly forwarded special print: — 7%) Cf. also 
oil of Mosla japonica: this Report p. 40. 
aneee 
2 
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