He wondered where she had got that item of etiquette, and whether it had filtered down from above and was all right.
It wouldn't do any harm to try it, he decided, by the time they had reached the sidewalk; and he swung behind Ruth and took up his station on the outside.

Then the other problem presented itself.

Should he offer her his arm?
He had never offered anybody his arm in his life.

The girls he had known never took the fellows' arms.

For the first several times they walked freely, side by side, and after that it was arms around the waists, and heads against the fellows' shoulders where the streets were unlighted.