Instead of being merely a transient malady of youth, as cynics aver, or only an epicurean episode in our emotional life, Love is thus seen to be one of the greatest (if not _the_ greatest) moral, æsthetic, and hygienic forces that control human life. And in face of this fact the few pages, or lines, commonly devoted to this passion in psychologic text-books, seem wofully inadequate. No apology is therefore needed for our attempt to subject Romantic Love to a thorough chemical analysis, and to discover its ingredients. We shall first enumerate and briefly characterise these ingredients; then proceed to examine how many of them are to be found in the love of animals and savages, of the ancient nations and of our mediæval ancestors; and finally, we shall attempt to describe these various component parts of the passion, as fully developed in Modern Love. OVERTONES OF ROMANTIC LOVE First of all it is necessary to get rid of the prevalent illusion that Love is a single emotion. It is, on the contrary, a most complex and ever-varying _group_ of emotions. Love is not a diamond which drops from a celestial body, cut and polished, and ready to be set into the human soul. Rather is it the crown of life, composed of various jewels, some of which, mixed with much coarse ore, may be found in the animal kingdom, among primitive men and ancient civilised nations; but of which no complete specimens are to be found till we come to comparatively modern times. Each lover has his own crown, but no two of them are exactly alike. The component jewels vary in size and brilliancy. Some—as Coyness, Adoration, Gallantry, Jealousy—are occasionally missing or lacking in lustre; and in Ancient Love those are habitually absent which in Modern Love are most prominent and cherished. Perhaps the composite nature of Love can be still better illustrated by a comparison with colours, and with “overtones” in music, between which and the elements of Love there exists a wonderfully close analogy. Professor Helmholtz has proved that just as white is not a simple colour, but a combination of all the hues of the rainbow, so any single tone produced by the voice or a musical instrument is not simple, as it seems, but contains, besides the _fundamental_ tone which the ordinary listener alone hears, several partial or “overtones,” which blend so closely with the fundamental tone, that it takes a very delicate ear and close attention to distinguish them. Were it not for these overtones, all instruments would sound alike, and music would lose all its charms of “colour.” For the fundamental tones of instruments and voices are identical, and the only thing that enables a musician to tell at a distance whether a given note proceeds from a piano, voice, or violin, is the presence of these overtones, which vary in their number, relative loudness and pitch (or height), thus giving rise to the differences of quality or _timbre_ in instruments.