“I’m sure I beg your pardon, Mr. Plonk. I didn’t reckernize you in the dark.”

“No, of course you wouldn’t,” replied the plain-clothes officer. “Did you see two men run past here just now?”

“I did,” answered the constable. “One after the other, and both running as if the devil was after them. I was half-way up the street, but I popped down to have a look at them, and when I got to the corner I heard you coming. So I just kept out of sight and waited for you.”

“Quite right too,” said Mr. Plonk. “Well, I don’t see or hear anything of those chaps now.”

“No,” agreed the constable, “and you are not likely to. There’s a regular maze of new streets about here. You can take it that they’ve got clear away.”

“Yes, I’m afraid they have,” said Plonk. “Well, it can’t be helped, and there’s nothing much in it. Good night, constable.”

He moved off briskly, not wishing, apparently, to discuss the affair, and in a few minutes we came to the wide cross-roads. Here he halted and looked me over by the light of a street lamp. Apparently the result was satisfactory, for he said: “It’s hardly worth while to take you all the way back to the station at this time of night. Where do you live?”

I told him Camden-square and offered a card in corroboration.

“Then you are pretty close home,” said he, inspecting my card. “Very well, Doctor. I’ll speak to Inspector Follett about this affair, and if you have any further trouble of this sort you had better let us know. And you had better let us have a description of the men in any case.”

I promised to send him the particulars on the following day, and we then parted with mutual good wishes, he making his way towards Holloway-road and I setting my face homeward by way of the Brecknock-road and keeping an uncommonly sharp look-out as I went.