Some dancing academies, even in tenement house quarters, are reputable institutions, but to most of them the lowest of the low, both men and women, resort.
There, as in the dance halls, the "White Slaver" plies his trade, and the destroyer of womanliness lays his nets.
Annie Donnelly soon learned the ways of all these places.

She learned to "spiel." You spiel by holding hands with your partner at arms' length, and whirling round and round at the highest possible speed.

The girl's skirts are blown immodestly high, which is a detail.

The effect of the spiel is a species of drunkenness which creates an instant demand for liquor, and a temporary recklessness of the possible results of strong drink.
Annie also learned to dance what is known as the "half time," or the "part time" waltz.

This is a dance accompanied by a swaying and contorting of the hips, most indecent in its suggestion.