station, Dr. Cortelyon came out. Drillford stopped him.
"Found out anything more, Doctor?" he asked.
"Nothing beyond what I said at first," replied Cortelyon. "The man has been stabbed through the heart, from behind, in one particularly well-delivered blow. I should say the murderer had waited for him in that passage, probably knowing his habits. That passage, now—you know it really will have to be seen to! That wretched old lamp in the middle gives no light at all. The wonder is that something of this sort hasn't occurred before."
Drillford muttered something about local authorities and property-owners and went forward into an office, motioning Viner to follow. The divisional surgeon was there in conversation with the sergeant whom Drillford had left in charge of the body. "That is something on which I'd stake my professional reputation," he said. "I'm sure of it."
"What's that, Doctor?" asked Drillford. "Something to do with this affair?"
"I was saying that whoever stabbed this unfortunate man had some knowledge of anatomy," remarked the doctor. "He was killed by one swift blow from a particularly keen-edged, thin-bladed weapon which was driven through his back at the exact spot. You ought to make a minute search behind the walls on either side of that passage—the probability is that the murderer threw his weapon away."
"We'll do all that, Doctor," said Drillford. "As to your suggestion—don't you forget that there are a good many criminals here in London who are regular experts in the use of the knife—I've seen
