My cough asserts its presence by acquiring a chorus of bass notes. My ailment creates a division of sleeping arrangements. As I settle into my heightened pillows, I hear an echo from the flat below. I suspect it is an imitation designed to illustrate how easily sound travels in cheaply converted Victorian buildings. But I have perfected an ear for an authentic cough and the neighbour's version is textured with the same glutteral chords as mine. Perhaps the floors are membrane-like thin and capable of permeating microbes in mutual directions? The night is a chamber of shared and reciprocated notes.