Early blues frequently took the form of a loose narrative. The singer voiced often his or her personal woes in a world of harsh reality: a lost love, the cruelty of police officers, oppression at the hands of white folk, and hard times. Many of the oldest blues records contain gritty, realistic lyrics, in contrast to much of the popular music being recorded at the time. For example, "Down in the Alley" by Memphis Minnie, is about a prostitute having sex with men in an alley.

Music such as this was called "gut-bucket" blues, a term which refers to a type of homemade bass instrument made from a metal bucket used to clean pig intestines for chitterlings (a soul food dish associated with slavery). "Gut-bucket" blues songs are typically "low-down" and earthy, about rocky or steamy man-woman relationships, hard luck and hard times. Gut-bucket blues and the rowdy juke-joint venues where it was played, earned blues music an unsavoury reputation; church-goers shunned it and some preachers railed against it.

Source: Wikepedia