Marie had discovered this.

She had placed a rose-leaf on the silken coverlet every evening, and found it still there in the morning.

If any one had slept on the lounge, the rose-leaf would have fallen to the floor.
The following day Ludwig was more silent than usual.

He did not speak once during their drive, and ate hardly anything at meals.
One could easily see how impatiently he waited for evening, when he might go down to the lake and search for the monster--a sorry object for a fury such as his! An otter, most likely, or a beaver--mayhap an abortion of the Dead Sea, which had survived the ages since the days of Sodom! All the same, it was a living creature, and must become food for fishes.

Marie, however, prayed so fervently that nothing might come of Ludwig's fury that Heaven heard the prayer.