Probably his being knocked out saved his life. The crash of his fall woke Lady Mary. For a stunned moment she lay, wondering. Then her mind rushed to the children, asleep in the next room. She turned on the light, calling out as she did so to ask whether they were all right. Receiving no answer, she sprang up, threw on a dressing-gown and ran into the nursery. All was peace. She stood puzzled, and asking herself whether she had dreamed the crash. Then she heard feet running down the staircase at headlong speed. She ran back into the bedroom, pulled out the revolver which always lay loaded in the dressing-table drawer and flung open the door which gave upon the landing. The light streaming from behind her showed her the crumpled body of her husband, and as she stared aghast at this unnerving sight, she heard the street-door slam heavily.

“What you ought to have done,” said Mr. Parker, acidly, “was not to have bothered about me, but dashed to the window and tried to get a squint at the bloke as he went down the street.”

Lady Mary smiled indulgently at this absurd remark, and turned to her brother.

“So that’s all I can tell you about it, and he’s uncommonly lucky to be alive, and ought to be jolly well thankful instead of grumbling.”

“You’d grumble all right,” said Parker, “with a bust collarbone and a headache like nothing on earth and a feeling as though bulls of Bashan had been trampling on your tummy.”

“It beats me,” said Wimsey, “the way these policemen give way over a trifling accident. In the Sexton Blake book that my friend Ginger Joe has just lent me, the great detective, after being stunned with a piece of lead-piping and trussed up for six hours in ropes which cut his flesh nearly to the bone, is taken by boat on a stormy night to a remote house on the coast and flung down a flight of stone steps into a stone cellar. Here he contrives to release himself from his bonds when the villain gets wise to his activities and floods the cellar with gas. He is most fortunately rescued at the fifty-ninth minute of the eleventh hour and, pausing only to swallow a few ham sandwiches and a cup of strong coffee, instantly joins in a prolonged pursuit of the murderers by aeroplane, during which he has to walk out along the wing and grapple with a fellow who has just landed on it from a rope and is proposing to chuck a hand-grenade into the cockpit. And here is my own brother-in-law-a man I have known for nearly twenty years-giving way to bad temper and bandages because some three-by-four crook has slugged him one on his own comfortable staircase.”

Parker grinned ruefully.

“I’m trying to think who it could have been,” he said. “It wasn’t a burglar or anybody like that-it was a deliberate attempt at murder. The light-bulb had been put out of action beforehand and he had been hiding for hours behind the coal-bunker. You can see the marks of his feet. Now, who in the name of goodness have I got it in for to that extent? It can’t be Gentleman Jim or Dogsbody Dan, because that’s not their line of country at all. If it had happened last week, it might well have been Knockout Wally-he uses a cosh-but we jailed him good and hard for that business down in Limehouse on Saturday night. There are one or two bright lads who have it in for me one way or another, but I can’t exactly fit it on to any of them. All I know is, that whoever it was, he must have got in here before 11 p.m., when the housekeeper shuts the street door and puts out the hall light. Unless, of course, he had a latch-key, but that’s not so likely. He wasn’t obliging enough to leave anything behind to identify him, except a Woolworth pencil.”

“Oh, he left a pencil, did he?”

“Yes-one of those pocket propelling things-not a wooden one-you needn’t hope for a handy mould of his front teeth on it, or anything like that.”

“Show, show!” pleaded Wimsey.

“All right; you can see it if you like. I’ve tried it for fingerprints, but I can’t get much-only vague smudges, very much superimposed. I’ve had our finger-print wallah round to look at ’em, but he doesn’t seem to have made anything of ’em. See if you can find the pencil, Mary dear, for your little brother. Oh, and by the way, Peter, there’s a letter for you. I’ve only just remembered. In my left coat-pocket, Mary. I’d just taken it out of the Flat 4 box when all this happened.”

Mary sped away, and returned in a few minutes with the pencil and the coat.

“I can’t find any letter.”

Parker took the coat and, with his available hand, searched all the pockets carefully.

“That’s funny,” he said. “I know it was there. One of those fancy long-shaped mauve envelopes with gilt edges, and a lady’s fist, rather sprawly.”

“Oh!” said Wimsey, “the letter’s gone, has it?” His eyes glinted with excitement. “That’s very remarkable. And what’s more, Charles, this isn’t a Woolworth pencil-it’s one of Darling’s.”

“I meant Darling’s-same thing. Anybody might carry one of them.”

“Ah!” said Wimsey, “but this is where my expert knowledge comes in. Darling’s don’t sell these pencils-they give them away. Anybody buying more than a pound’s worth of goods gets a pencil as a good-conduct prize. You observe that it carries an advertising slogan: IT ISN’T DEAR, IT’S DARLING. (One of Pym’s best efforts, by the way.) The idea is that, every time you make a note on your shopping list, you are reminded of the superior economy of purchasing your household goods from Darling’s. And a very remarkable firm it is, too,” added his lordship, warming to the subject. “They’ve carried the unit system to the pitch of a fine art. You can sit on a Darling chair, built up in shilling and sixpenny sections and pegged with patent pegs at sixpence a hundred. If Uncle George breaks the leg, you buy a new leg and peg it in. If you buy more clothes than will go into your Darling chest of drawers, you unpeg the top, purchase a new drawer for half a crown, peg it on and replace the top. Everything done by numbers, and kindness. And, as I say, if you buy enough, they give you a pencil. If you mount up to five pounds’ worth, they give you a fountain pen.”

“That’s very helpful,” said Parker, sarcastically. “It ought to be easy to identify a criminal who has bought a pound’s worth of goods at Darling’s within the last six months or so.”

“Wait a bit; I said I had expert knowledge. This pencil-a natty scarlet, as you observe, with gold lettering-didn’t come from any of Darling’s brandies. It’s not on the market yet. There are only three places it could have come from: one, from the pencil manufacturer’s; two, from Darling’s head office; three, from our place.”

“Do you mean Pym’s?”

“I do. This is the new pencil design, with an improved propelling mechanism. The old ones only propelled; this repels also, with a handy twist of the what-d’ye-call. Darling’s obligingly presented us with half a gross of them to try out.”

Mr. Parker sat up so suddenly that he jarred his shoulder and his head, and groaned dismally.

“I think it highly improbable,” went on Lord Peter, lusciously, “that you have a deadly enemy at the pencil manufacturer’s or at Darling’s head office. It seems to me much more likely that the gentleman with the cosh, or knuckle-duster, or sand-bag, or lead-piping, in short, the blunt instrument, came from Pym’s, guided by the address which, with your usual amiability, you kindly allowed me to give as mine. Observing my name neatly inscribed on the letter-box of Flat 4, he mounted confidently, armed with his cosh, knuckle-”

“Well, I’m dashed!” exclaimed Lady Mary, “do you mean to say that it’s really you, you devil, who ought to be lying there mangled and bruised in the place of my afflicted husband?”

“I think so,” said Wimsey, with satisfaction, “I certainly do think so. Particularly as the assailant seems to have walked off with my private correspondence. I know who-or to be grammatical, whom-that letter was from, by the way.”