“There are two fundamental reasons why the endeavor should be made to obtain a broad basis of clear information on the subject. In the first place, the normal phenomena give the key to the abnormal, and the majority of sexual perversions, including even those that are most repulsive, are but exaggerations of instincts and emotions that are germinal in normal human beings. In the second place, what is normal cannot be determined until the sexual life of a large number of healthy individuals is known, and until the limits of normal sexuality are known the physician is not in a position to lay down any reasonable rules of sexual hygiene.” Although very short, the analysis of the sex passions in adults by Herbert Spencer[4] in a part of one section in his “Principles of Psychology,” is one of the best. Bain[5] devotes one chapter to the Tender Emotion which he makes include Sex-love, the parental feelings, the benevolent affection, gratitude, sorrow, admiration and esteem. A very few pages are given to sex-love proper. Very suggestive paragraphs bearing either directly or indirectly upon the subject are to be found in the works of such writers as Moll, Sergi, Mantegazza, James, Janet, Delboeuf, Feré, Boveri, Kiernan, Hartmann, Dessoir, Fincke and others. There is a vast amount of literature upon the pathological phases of the subject which is to be considered in another chapter. The analyses thus far given by scientists are limited to the emotion as it is manifested in the adult. A few writers have referred to it in dealing with the psychology of adolescence, but in this connection refer to it as one of the many ways in which the adolescent spirit shows its intensity, turbulence and capriciousness. I know of no scientist who has given a careful analysis of the emotion as it is seen in the adolescent. It is true that it has been the chosen theme of the poet, romancer and novelist. But in the products of such writers we may look for artistic descriptions of the emotion and for scenes and incidents that very truly portray its nature; we have no right to expect a scientific analysis.