This powerful poem describing the prostitutes of Harlem who are forced to work during night in order to make ends meet describes the girls as innocent figures caught up in a messy world that reduces them to selling their bodies for sex. Note how these girls are described in the second stanza and in particular how such imagery clearly depicts them as being innocent figures:
Through the long night until the silver break
Of day the little gray feet know no rest,
Through the lone night until the last snow-flake
Has dropped from heaven upon the earth's white breast,
The dusky, half-clad girls of tired feet
Are trudging, thinly shod, from street to street.
Imagery such as the "half-clad girls of tired feet" with their "thinly shod" feet and the "little gray feet" that "know no rest" clearly place the girls at odds with their environment. Such delicate figures, the imagery seems to suggest, should not be "trudging" the streets of Harlem at night trying to raise money by selling their bodies. Such innocence should be kept safe and not exposed to the dangers of the endless streets of Harlem at night.
Note how this impression of innocence is confirmed and developed in the final stanza, which makes reference to "the little feet of clay" and the "sacred brown feet" of the girls. These examples of imagery both promote the fragility of the girls and their state of innocence. This causes immense sadness on the part of the speaker, who ends the poem deploring a world which forces such girls to engage in such activity.