He walked straight ahead at random, absorbed in thought, and as calm as a mathematician.
On the Pont des Arts he became aware that a dog was following him.

He was a big, long-haired farm dog, with eyes of different colours, which were full of gentleness, and an expression of infinite distress.
Chevalier spoke to him: "You've no collar.

You are not happy.

Poor fellow, I can't do anything for you." By four o'clock in the morning he found himself in the Avenue de l'Observatoire.

On seeing the houses of the Boulevard Saint-Michel he experienced a painful impression and abruptly turned back toward the Observatory.