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 hand. 
Coincident with my recognition of Mr. Eltham he leaped,
plunging into the shrubbery in the wake of the dog.

But the night held yet another surprise; for Nayland Smith’s voice came: 

“Come back!  Come back, Eltham!”

I ran out into the passage and downstairs.  The front door was open.  A terrible conflict waged in the shrubbery, between the mastiff and something else.  Passing round to the lawn, I met Smith fully dressed.  He just had dropped from a first-floor window.

“The man is mad!” he snapped.  “Heaven knows what lurks there!  He should not have gone alone!”

Together we ran towards the dancing light of Eltham’s lantern.  The sounds of conflict ceased suddenly.  Stumbling over stumps and lashed by low-sweeping branches, we struggled forward to where the clergyman knelt amongst the bushes.  He glanced up with tears in his eyes, as was revealed by the dim light.

“Look!” he cried.

The body of the dog lay at his feet.

It was pitiable to think that the fearless brute should have met his death in such a fashion, and when I bent and examined him I was glad to find traces of life.

“Drag him out.  He is not dead,” I said.

“And hurry,” rapped Smith, peering about him right and left.

So we three hurried from that haunted place, dragging the dog with us.  We were not molested.  No sound disturbed the now perfect stillness.

By the lawn edge we came upon Denby, half dressed; and almost immediately Edwards the gardener also appeared.  The white faces of the house servants showed at one window, and Miss Eltham called to me from her room: 

“Is he dead?”

“No,” I replied; “only stunned.”

We carried the dog round to the yard, and I examined his head.  It had been struck by some heavy blunt instrument, but the skull was not broken.  It is hard to kill a mastiff.