Then an annoying thing happened.

I ran full into a stout old gentleman; Bauer had run into him before, and he was standing, as people will, staring in resentful astonishment at his first assailant's retreating figure.

The second collision immensely increased his vexation; for me it had yet worse consequences; for when I disentangled myself, Bauer was gone! There was not a sign of him; I looked up: the number of the house above me was twenty-three; but the door was shut.
I walked on a few paces, past twenty-two, past twenty-one--and up to nineteen.

Nineteen was an old house, with a dirty, dilapidated front and an air almost dissipated.

It was a shop where provisions of the cheaper sort were on view in the window, things that one has never eaten but has heard of people eating.