The cylinder in the wall

In the corner of the gallery there's a sealed opening with a grille in front of it. A stone basin once stood here, and later a wooden cylinder that turned on its axis, big enough for a newborn child.

You laid the child inside, turned the cylinder a half turn, and pulled a bell. The sisters took over on the inside, and outside stood someone who could slip away unseen. That anonymity was the whole point, because a woman who openly gave up a child lost her name and her work, and a child left in an alley usually didn't survive the night.

Beside the child there was often a token. A ribbon, a scrap of fabric from a dress, a little picture of a saint, and most often a coin or a medal broken in two, with the parent keeping the other half. Anyone who ever came back to claim the child could identify themselves with it, and the two halves had to fit together.

Those tokens have been kept, thousands of them, and they lie in the museum next door. Most were never collected.

The entrance to that museum is along this same gallery, a few arches to the right.