So far we have been mainly concerned with purely personal odors. It is, however, no longer possible to confine the discussion of the sexual significance of odor within the purely animal limit. The various characteristics of personal odor which have been noted--alike those which tend to make it repulsive and those which tend to make it attractive--have led to the use of artificial perfumes, to heighten the natural odor when it is regarded as attractive, to disguise it when it is regarded as repellent; while at the same time, happily covering both of these impulses, has developed the pure delight in perfume for its own agreeableness, the æsthetic side of olfaction. In this way--although in a much less constant and less elaborate manner--the body became adorned to the sense of smell just as by clothing and ornament it is adorned to the sense of sight. But--and this is a point of great significance from our present standpoint--we do not really leave the sexual sphere by introducing artificial perfumes. The perfumes which we extract from natural products, or, as is now frequently the case, produce by chemical synthesis, are themselves either actually animal sexual odors or allied in character or composition, to the personal odors they are used to heighten or disguise. Musk is the product of glands of the male _Moschus moschiferus_ which correspond to preputial sebaceous glands; castoreum is the product of similar sexual glands in the beaver, and civet likewise from the civet; ambergris is an intestinal calculus found in the rectum of the cachelot.[53] Not only, however, are nearly all the perfumes of animal origin, in use by civilized man, odors which have a specially sexual object among the animals from which they are derived, but even the perfumes of flowers may be said to be of sexual character. They are given out at the reproductive period in the lives of plants, and they clearly have very largely as their object an appeal to the insects who secure plant fertilization, such appeal having as its basis the fact that among insects themselves olfactory sensibility has in many cases been developed in their own mating.[54] There is, for example, a moth in which both sexes are similarly and inconspicuously marked, but the males diffuse an agreeable odor, said to be like pineapple, which attracts the females.[55] If, therefore, the odors of flowers have developed because they proved useful to the plant by attracting insects or other living creatures, it is obvious that the advantage would lie with those plants which could put forth an animal sexual odor of agreeable character, since such an odor would prove fascinating to animal creatures. We here have a very simple explanation of the fundamental identity of odors in the animal and vegetable worlds. It thus comes about that from a psychological point of view we are not really entering a new field when we begin to discuss the influence of perfumes other than those of the animal body. We are merely