The error which has led to the identical education of the two sexes, and which prophecies their identical co-education in colleges and universities, is not confined to technical education. It permeates society. It is found in the home, the workshop, the factory, and in all the ramifications of social life. The identity of boys and girls, of men and women, is practically asserted out of the school as much as in it, and it is theoretically proclaimed from the pulpit and the rostrum. Woman seems to be looking up to man and his development, as the goal and ideal of womanhood. The new gospel of female development glorifies what she possesses in common with him, and tramples under her feet, as a source of weakness and badge of inferiority, the mechanism and functions peculiar to herself. In consequence of this wide-spread error, largely the result of physiological ignorance, girls are almost universally trained in masculine methods of living and working as well as of studying. The notion is practically found everywhere, that boys and girls are one, and that the boys make the one. Girls, young ladies, to use the polite phrase, who are about leaving or have left school for society, dissipation, or self-culture, rarely permit any of Nature's periodical demands to interfere with their morning calls, or evening promenades, or midnight dancing, or sober study. Even the home draws the sacred mantle of modesty so closely over the reproductive function as not only to cover but to smother it. Sisters imitate brothers in persistent work at all times. Female clerks in stores strive to emulate the males by unremitting labor, seeking to develop feminine force by masculine methods. Female operatives of all sorts, in factories and elsewhere, labor in the same way; and, when the day is done, are as likely to dance half the night, regardless of any pressure upon them of a peculiar function, as their fashionable sisters in the polite world. All unite in pushing the hateful thing out of sight and out of mind; and all are punished by similar weakness, degeneration, and disease.