g agents" or "fixateurs," and
among the most important of these may be mentioned musk, both natural
and artificial, civet, the oils of Peru balsam, sandalwood, and
patchouli, and benzyl benzoate.

The natural perfumes employed for addition to soaps are almost entirely
of vegetable origin, and consist of essential oils, balsams, and resins,
animal perfumes such as musk, civet, and ambergris being reserved
principally for the preparation of "extraits".

As would be expected with products of such diverse character, the
methods employed for the preparation of essential oils vary
considerably. Broadly speaking, however, the processes may be divided
into three classes--(1) _expression_, used for orange, lemon, and lime
oils; (2) _distillation_, employed for otto of rose, geranium,
sandalwood, and many other oils; and (3) _extraction_, including
_enfleurage_, by which the volatile oil from the flowers is either first
absorbed by a neutral fat such as lard, and then extracted therefrom by
maceration in alcohol, or directly extracted from the flowers by means
of a volatile solvent such as benzene, petroleum ether, or chloroform.
The last process undoubtedly furnishes products most nearly resembling
the natural floral odours, and is the only one which does not destroy
the delicate fragrance of the violet and jasmine. The yield, however, is
extremely small, and concrete perfumes prepared in this way are
therefore somewhat costly.

The essential oils used are derived from upwards of twenty different
botanical families, and are obtained from all parts of the world. Thus,
from Africa we have geranium and clove oils; from America, bay, bois de
rose, Canadian snake root, cedarwood, linaloe, peppermint, petitgrain,
and sassafras; from Asia, camphor, cassia, cinnamon, patchouli,
sandalwood, star anise, ylang-ylang, and the grass oils, _viz._,
citronella, lemongrass, palmarosa, and vetivert; from Australia,
eucalyptus; while in Europe there are the citrus oils, bergamot, lemon,
and orange, produced by Sicily, aspic, lavender, neroli, petitgrain, and
rosemary by France, caraway and clove by Holland, anise by Russia, and
otto of rose by Bulgaria.

Attempts have been made to classify essential oils either on a botanical
basis or according to their chemical composition, but neither method is
very satisfactory, and, in describing the chief constituents and
properties of the more important oils, we have preferred therefore to
arrange them