The Chemistry of Essential Oils and Artificial Perfumes

Abstract

THE chemistry of the essential oils is one of the most interesting, and at the same time one of the most complicated, sections of plant chemistry. To begin with, the true function of an essential oil in the economy and life-history of a plant is by no means clear. It might at first sight be thought to be connected with the reproductive agencies of the plant, and possibly as regards the flower this may be the case; a fragrant smell in the flower may be the means of attracting the insects which carry the fecundating pollen. But that the attraction of insects is not the sole function of an odoriferous oil must be obvious from the circumstance that many essential oils, as in the conifers, are to be met with in practically all parts of the plant; some are found in the fruits, and a few even in the roots. At the same time, there is much evidence to show that the occurrence of an essential oil in a plant is frequently directly related to processes which ensure the continuance of the species. The amount increases with the growth of inflorescence and decreases after the flowering period is past. But certain oils appear to be the result of metabolic changes which are not necessarily connected with reproductive processes. Thus the essential oil of almonds is a product of the decomposition of amygdalin under the influence of the ferment emulsin. Oil of mustard is similarly produced from a specific glucoside by the agency of myrosin.

The Chemistry of Essential Oils and Artificial Perfumes.

By Ernest J. Parry. Second edition, revised and enlarged. Pp. viii+546. (London: Scott, Greenwood and Son, 1908.) Price 12s. 6d. net.