Before describing the preparation of true perfumes, it is necessary to become acquainted with the several raw materials required in their manufacture; that is to say, the simple odorous substances, their origin, their preparation, and their peculiar qualities. Besides these odorous raw materials, the art of perfumery makes use of a number of chemical and mineral products, whose quality largely influences that of the perfume to be made. These, therefore, likewise call for an appropriate description. Among these auxiliary substances are alcohol, glycerin, fixed oils, and solid fats, which play an important part not only in the preparation of the perfumes, but also enter into the composition of many. The liquid handkerchief perfumes always contain a large quantity of alcohol, the scented hair oils consist largely of fixed oils, while solid fats of animal or vegetable origin occur in the so-called pomades. As we shall see, the actual odors, owing to their extraordinary productiveness, constitute generally only a small percentage of the perfumes; the greatest bulk is usually either alcohol, fixed oil, or solid fat. Hence, as the last-named substances, aside from the odoriferous materials, form the foundation of all articles of perfumery, the manufacturer must devote particular attention to their purity, and their qualities must be discussed in detail. CHAPTER III. ODORS FROM THE VEGETABLE KINGDOM. The odors occurring in plants have their seat mostly in peculiar receptacles called oil glands in which the aromatic substances are stored and seem to take no further part in the vital processes of the plant. As has been intimated, the parts of the plant in which the aromatic substances are stored differ greatly; but in general it may be said that in most cases the flowers and fruits contain the odors; more rarely they may be found in the roots, in the bark, or in the wood, and in very few instances equally distributed throughout the whole plant. In some cases, however, we can obtain totally different odors from various parts of the same plant; this applies, for instance, to the orange-tree, whose blossoms furnish a different odor from the ripe fruits, and the latter must be distinguished from that obtainable from the leaves. The odorous substances occurring in the vegetable kingdom are either mobile liquids (essential oils), or they have a thicker consistence ranging from that of cream to that of soft cheese (balsams or gum-resins), or they are solid (resins). Aside from the fact that the term “essential oils” is quite incorrect, since the substances called by that name have nothing in common with oils except perhaps the liquid state, we are forced from a chemical standpoint to include among them even solid substances; the well-known camphor, a firm and waxy-looking body, belongs according to all its chemical properties into the same group as the so-called essential oils. The name