Jamieson, Fausset and Brown on Acts 16:23-24

23-24. when they had laid many stripes upon them--the bleeding wounds from which they were not washed till it was done by the converted jailer (Ac 16:33).

charged the jailer ... who ... thrust them into the inner prison--"pestilential cells, damp and cold, from which the light was excluded, and where the chains rusted on the prisoners. One such place may be seen to this day on the slope of the Capitol at Rome" [Howson].