Chinese doctor, the memory of his face, with its filmed green
eyes, could never leave me. The idea that he might be near at that
moment was a poor narcotic.

The howling and baying of the mastiff was almost continuous.

When all else in Redmoat was still the dog's mournful note yet rose on
the night with something menacing in it. I sat looking out across the
sloping turf to where the shrubbery showed as a black island in a green
sea. The moon swam in a cloudless sky, and the air was warm and
fragrant with country scents.

It was in the shrubbery that Denby's collie had met his mysterious
death--that the thing seen by Miss Eltham had disappeared. What
uncanny secret did it hold?

Caesar became silent.

As the stopping of a clock will sometimes awaken a sleeper, the abrupt
cessation of that distant howling, to which I had grown accustomed, now
recalled me from a world of gloomy imaginings.

I glanced at my watch in the moonlight. It was twelve minutes past
midnight.

As I replaced it the dog suddenly burst out afresh, but now in a tone
of sheer anger. He was alternately howling and snarling in a way that
sounded new to me. The crashes, as he leapt to the end of his chain,
shook the building in which he was confined. It was as I stood up to
lean from the window and commanded a view of the corner of the house
that he broke loose.

With a hoarse bay he took that decisive leap, and I heard his heavy
body fall against the wooden wall. There followed a strange, guttural
cry . . . and the growling of the dog died away at the rear of the house.
He was out! But that guttural note had not come from the throat of a
dog. Of what was he in pursuit?

At which point his mysterious quarry entered the shrubbery I do not
know. I only know that I saw absolutely nothing, until Caesar's lithe
shape was streaked across the lawn, and the great creature went
crashing into the undergrowth.

Then a faint sound above and to my right told me that I was not the
only spectator of the scene. I leaned farther from the window.

"Is that you, Miss Eltham?" I asked.

"Oh, Dr. Petrie!" she said. "I am so glad you are awake. Can we do
nothing to help? Caesar will be killed."

"Did you see what he went after?"

"No," she called back, and drew her breath sharply.

For a strange figure went racing across the grass. It was that of a
man in a blue dressing-gown, who held a lantern high before him, and a
revolver in his right h