Sound or scent, or both, had been arrested by some unusual presence.

And he paused to verify the warning.
As he stood there, an instant, in the shade-flecked driveway, the girl saw he was a collie; massive, graceful, majestic; in the full strength of his early prime; his shaggy coat of burnished mahogany-and-snow glinting back the showers of sun-rays that filtered down through the leaves.
Before the watching girl could take further note of him, the dog's aspect of tense listening merged into certainty.

With no further shadow of doubt as to direction, he set off at a sweeping run past the house and toward the point.
He ran with head down; and with tawny ruff abristle.

There was something in his lithe gallop that was as ominous as it was beautiful.
And, nervous at the great collie's approach, the girl squealed.
It had been a dull morning for Lad.

The Mistress was in town for the day.