Dr. Mortimer looked strangely at us for an instant, and his voice sank almost to a whisper as he answered:--
"Mr. Holmes, they were the footprints of a gigantic hound!"
I confess at these words a shudder passed through me. There was a thrill in the doctor's voice which showed that he was himself deeply moved by that which he told us. Holmes leaned forward in his excitement and his eyes had the hard, dry glitter which shot from them when he was keenly interested.
"The marks were some twenty yards from the body and no one gave them a thought. I don't suppose I should have done so had I not known this legend."
"There are two lines of old yew hedge, twelve feet high and impenetrable. The walk in the centre is about eight feet across."
"Is there anything between the hedges and the walk?"
"Yes, there is a strip of grass about six feet broad on either side."
"I understand that the yew hedge is penetrated at one point by a gate?"
"Yes, the wicket-gate which leads on to the moor."
"So that to reach the Yew Alley one either has to come down it from the house or else to enter it by the moor-gate?"
"There is an exit through a summer-house at the far end."
"Now, tell me, Dr. Mortimer--and this is important--the marks which you saw were on the path and not on the grass?"
"Were they on the same side of the path as the moor-gate?"
"Yes; they were on the edge of the path on the same side as the moor-gate."
"You interest me exceedingly. Another point. Was the wicket-gate closed?"
"And what marks did you see by the wicket-gate?"
"It was all very confused. Sir Charles had evidently stood there for five or ten minutes."
"Because the ash had twice dropped from his cigar."
"Excellent! This is a colleague, Watson, after our own heart. But the marks?"
"He had left his own marks all over that small patch of gravel. I could discern no others."
Sherlock Holmes struck his hand against his knee with an impatient gesture.
"If I had only been there!" he cried. "It is evidently a case of extraordinary interest, and one which presented immense opportunities to the scientific expert. That gravel page upon which I might have read so much has been long ere this smudged by the rain and defaced by the clogs of curious peasants. Oh, Dr. Mortimer, Dr. Mortimer, to think that you should not have called me in! You have indeed much to answer for."