The buyer of this oil should take care to secure the true oil of lavender (from Lavandula vera); for the oil of spike-lavender is sold under the same name. This, prepared from Lavandula Spica, has a similar odor to the genuine, but cannot be compared with it in delicacy. For this reason, too, the difference in the price between the two is considerable. True English oil of lavender costs ten times as much as oil of spike-lavender. The English brand of the true oil is of so excellent a quality that it brings four or five times as much as the best French oil, which is sold under the name of huile de lavande des Alpes. Yet during the last decade or so the French oil of lavender flowers has become so much improved in quality that it has become a serious rival to the Mitcham oil. OIL OF WALLFLOWER made from the flowers of the well-known garden plant, and OIL OF LILY likewise from the ornamental plant, are, strange to say, not manufactured in any place, to our knowledge. Experiments made by us in this direction prove that the odors of these plants can be obtained either by absorption or, more readily, by extraction. The perfumes thus far occurring under these names are always combinations of different scents which, though pleasant, have but little in common with the plants whose names they bear. In this connection we may say that the perfumes sold under the names of various flowers often have no relation to them, but are mixtures of various odors. While it cannot be denied that perfumes may be made in this manner which resemble those of the respective plants, it is unquestionably an imperfection in the art of perfumery that these odors are not really made from the flowers mentioned. To give another characteristic instance, we may add that the delightful odor of the well-known lily of the valley (Convallaria majalis)—a plant which grows wild abundantly in many of our forests—has not yet been produced, and that even imitations of this odor, which in delicacy and fragrance stands next to those of the rose and violet, are seldom met with in commerce. OIL OF LEMON (OLEUM LIMONIS), obtained from the fruits of the lemon-tree, is one of the most important products, both statistically and economically, of the Citrus family. In German works there is often a confusion between “oil of citron” and “oil of lemon,” it being supposed by the authors that the “Citronen-öl” is derived from the citron (Citrus medica), and the “Limonen-öl” from the lemon (Citrus Limonum). There is, indeed, some oil made, occasionally, from the citron, but it does not figure in price-lists. The oil of the lemon, on the other hand, is very commonly called “Citronen-öl,” and the fruit itself “Citrone.” Hence, when “Citronen-öl” is quoted in a formula, it may be assumed at once that oil of lemon is intended. It is very liable to resinify, when it loses its fragrance. OIL OF SWEET BAY (LAUREL) (OLEUM LAURI)