See the very interesting work of Alfred Espinas, Des Sociétés Animales, which contains many fruitful suggestions for the student of human sociology.

The subtle and complex character of the sexual relationships in a high civilization, and the unhappy results of their State regulation, was well expressed by Wilhehm von Humboldt in his Ideen zu einen Versuch, die Grenzen der Wirksamkeit des Staates zu bestimmen, so long ago as 1792: "A union so closely allied with the very nature of the respective individuals must be attended with the most hurtful consequences when the State attempts to regulate it by law, or, through the force of its institutions, to make it repose on anything save simple inclination. When we remember, moreover, that the State can only contemplate the final results of such regulations on the race, we shall be still more ready to admit the justice of this conclusion. It may reasonably be argued that a solicitude for the race only conducts to the same results as the highest solicitude for the most beautiful development of the inner man. For after careful observation it has been found that the uninterrupted union of one man with one woman is most beneficial to the race, and it is likewise undeniable that no other union springs from true, natural, harmonious love. And further, it may be observed that such love leads to the same results as those very relations which law and custom tend to establish.