When we confront this fact boldly and plainly in the open market of vice, we are sick with horror. When we see the same economic relation made permanent, established by law, sanctioned and sanctified by religion, covered with flowers and incense and all accumulated sentiment, we think it innocent, lovely, and right. The transient trade we think evil. The bargain for life we think good. But the biological effect remains the same. In both cases the female gets her food from the male by virtue of her sex-relationship to him. In both cases, perhaps even more in marriage because of its perfect acceptance of the situation, the female of genus homo, still living under natural law, is inexorably modified to sex in an increasing degree. Followed in specific detail, the action of the changed environment upon women has been in given instances as follows: In the matter of mere passive surroundings she has been immediately restricted in her range. This one factor has an immense effect on man and animal alike. An absolutely uniform environment, one shape, one size, one color, one sound, would render life, if any life could be, one helpless, changeless thing. As the environment increases and varies, the development of the creature must increase and vary with it; for he acquires knowledge and power, as the material for knowledge and the need for power appear. In migratory species the female is free to acquire the same knowledge as the male by the same means, the same development by the same experiences. The human female has been restricted in range from the earliest beginning. Even among savages, she has a much more restricted knowledge of the land she lives in. She moves with the camp, of course, and follows her primitive industries in its vicinity; but the war-path and the hunt are the man’s. He has a far larger habitat. The life of the female savage is freedom itself, however, compared with the increasing constriction of custom closing in upon the woman, as civilization advanced, like the iron torture chamber of romance. Its culmination is expressed in the proverb: “A woman should leave her home but three times,—when she is christened, when she is married, and when she is buried.” Or this: “The woman, the cat, and the chimney should never leave the house.” The absolutely stationary female and the wide-ranging male are distinctly human institutions, after we leave behind us such low forms of life as the gypsy moth, whose female seldom moves more than a few feet from the pupa moth. She has aborted wings, and cannot fly. She waits humbly for the winged male, lays her myriad eggs, and dies,—a fine instance of modification to sex.