OUTSIDE the house Crang continued to run. He was unconscious that he had forgotten his hat. His face worked in livid fury. Alternately he burst out into short, ugly gusts of laughter that made of laughter an evil thing; alternately, racked with unbridled passion, he mouthed a flood of oaths.

He ran on for some three blocks, and finally dashed up the steps of a small, drab-looking, cheap frame house. A brass sign, greenish with mold from neglect, flanked one side of the door. Under the street light it could just barely be deciphered: SYDNEY ANGUS CRANG, M.D.

He tried the door. It was locked. He searched impatiently and hastily in his pockets for his pass-key, and failing to find it instantly he rang the bell; and then, without waiting for an answer to the summons, he immediately began to bang furiously upon the panels.

An old woman, his housekeeper, whose bare feet had obviously been thrust hurriedly into slippers, and who clutched at the neck of a woolen dressing gown that also obviously, and with equal haste, had been flung around her shoulders over her nightdress, finally opened the door.

“Get out of the road!” Crang snarled—and brushed his way roughly past her.

He stepped forward along an unlighted hall, opened a door, and slammed it behind him. He switched on the light. He was in his consulting room. The next instant he was standing beside his desk, and had wrenched John Bruce's letter from his pocket. He spread this out on the desk and glared at it. Beyond any doubt whatever, where Claire's tears had fallen on the paper, traces of writing were faintly discernible. Here, out of an abortive word, was a well-formed “e”; and there, unmistakably, was a capital “L.”

Crang burst into a torrent of abuse and oaths; his fists clenched, and he shook one of them in the air.

“Double-crossed—eh?—damn him!” he choked. “He tried to double-cross me—did he?”

Carrying the letter, he ran now into a little room behind his office, where he compounded his medicines, and that was fitted up as a sort of small laboratory.

“I'm a clever man,” Crang mumbled to himself. “We'll see about this!”

With sudden complacence he began to study the sheet of paper. He nodded curtly to himself as he noted that the traces of the secret writing were all on the lower edge of the paper.

“We'll be very careful, very careful”—Doctor Crang was still mumbling—“it may be useful in more ways than one.”

He turned on the water faucet, wet a camel's-hair brush, and applied the brush to the lower edge of the letter. The experiment was productive of no result. He stared at the paper for a while with wrinkled brow, and then suddenly he began to laugh ironically.

“No, of course, not!” He was jeering at himself now. “Clever? You are not clever, you are a fool! She cried on the paper. Tears! Tears possess a slight trace of”—he reached quickly for a glass container, and began to prepare a solution of some sort—“a very slight trace... that's why the characters that already show are so faint. Now we'll see, Mr. John Bruce, what you've got to say.... Salt!... A little salt, eh?”

He dipped the camel's-hair brush in the solution and drew it across the bottom edge of the paper again.

“Ha, ha!” exclaimed Doctor Crang in eager excitement. Letters, words and sentences began to take form under the brush. “Ha, ha! He'd play that game with me, would he? Damn him!”

Very carefully Sydney Angus Crang, M.D., worked his brush upward on the paper line by line, until, still well below the signature that John Bruce had affixed in his, Crang's, presence, there failed to appear any further trace of the secret writing. He read as fast as a word appeared—like a starving beast snatching in ferocious greed at morsels of food. It made whole and complete sense. His eyes feasted on it now in its entirety:

Keep away. This is a trap. Stall till you can turn tables. Information obtained while I was delirious. Am a prisoner in hands of a gang whose leader is a doctor named Crang. Veniza will tell you where Crang lives. Get Veniza's address from Lavergne at the house. The only way to save either of Us is to trick Crang. Look out for yourself. Bruce.

He tossed the camel's-hair brush away, returned to his desk, spread the letter out on a blotter to allow the lower edge to dry, and slumping down in his desk chair, glued his eyes on the secret message, reading it over and over again.

“Trick Crang—eh?—ha, ha!” He began to chuckle low; then suddenly his fingers, crooked and curved until they looked like claws, reached out as though to fasten upon some prey at hand. And then he chuckled once more—and then grew somber, and slumped deeper in his chair, and his eyes, brooding, were half closed. “Not to-night,” he muttered. “One job of it to-morrow... squeal like a pair of rats that——”

He sat suddenly bolt upright in his chair. It came again—-a low tapping on the window; two raps, three times repeated. He rose quickly, crossed the room, opened the door, and stood motionless for a moment peering out into the hall. It was a purely precautionary measure—he had little doubt but that his old housekeeper had long since mounted the stairs and returned to her bed. He stepped rapidly then along the hall, and opened the front door.

“That you, Birdie?” he called in a low voice.

A man's form appeared from the shadow of the stoop.

“Sure!” the man answered.

“Come in!” Doctor Crang said tersely.

He led the way back into the consulting room, and slumped down again in his chair.

“Well?” he demanded.

“Peters arrived all right,” Birdie reported. “He registered at the Bayne-Miloy Hotel, and he's there now.”

“Good!” grunted Crang.

For a full five minutes he remained silent and without movement in his chair, apparently utterly oblivious of the other, who stood, shifting a little awkwardly from foot to foot, on the opposite side of the desk.

Then Crang spoke—more to himself than to Birdie.

“He'll be anxious, of course, and growing more so,” he said. “He might make a break of some kind. I'll have to fix that. I'm not ready yet. What?”

Birdie, from staring inanely at the wall, came to himself with a sudden start at what he evidently interpreted as a direct question.

“Yes—sure!” he said hurriedly. “No—I mean, no, you're not ready.”

Crang glared at the man contemptuously.

“What the hell do you know about it?” he inquired caustically.

He picked up the telephone directory, studied it for a moment, then, reaching for the desk telephone, asked for his connection. Presently the Bayne-Miloy Hotel answered him, and he asked for Mr. R. L. Peters' room. A moment more and a voice reached him over the phone.

“Is that Mr. Peters?” Crang inquired quietly. “Mr. R. L. Peters, of San Francisco?... Yes? Then I have a message for you, Mr. Peters, from the person who sent you a telegram a few days ago... I beg your pardon?... Yes, I am sure you do... Myself? I'd rather not mention any names over the phone. You understand, don't you? He told me to tell you that it is absolutely necessary that no connection is known to exist between you, and for that reason he does not dare take the chance of getting into touch with you to-night, but he will manage it somehow by early afternoon to-morrow... What say?... Yes, it is very serious, otherwise he would hardly have telegraphed you to come on from San Francisco... No, personally, I don't know. That was his message; but I was also to warn you on no account to leave your rooms, or have communication with anybody until you hear direct from him.... No, I do not know the particulars. I only know that he is apparently in a hole, and a bad one, and that he is now afraid that you will get into it too.... Yes. You are sure you fully understand?... No, not at all! I am only too glad.... Good-night.”

Crang, with a curious smile on his lips, hung up the receiver. He turned abruptly to Birdie.

“You get a taxi to-morrow,” he said brusquely. “We'll want it for two or three hours. Slip the chauffeur whatever is necessary, and change places with him. See? You'll know where to find one that will fall for that. Then you come here for me at—let's see—the boat sails at four—you come here at half past one sharp. Get me?”

“Sure!” said Birdie, with a grin. “That's a cinch!”

“All right, then!” Crang waved his hand. “Beat it!”

Birdie left the room. A moment later the front door closed behind him.

Crang picked up the letter and examined it critically. The lower three or four inches of the paper was slightly crinkled, but quite dry now; the body of the original letter showed no sign whatever of his work upon the lower portion.

Doctor Crang nodded contentedly.

He rose abruptly, secured his surgical bag, and from it selected a lance. With the aid of a ruler and the keen-bladed little instrument, he very carefully cut away the lower section of the paper. The slip containing the erstwhile secret message he tucked away in his inside pocket; then he examined the letter itself again even more critically than before. For all evidence that it presented to the contrary, it might have been the original size of the sheet. There was even a generous margin of paper still left beneath John Bruce's signature. He folded the letter, replaced it in its envelope—and now sealed the envelope.

“To-morrow!” said Doctor Sydney Angus Crang with a sinister smile, as he produced a hypodermic syringe from his pocket and rolled up the sleeve of his left arm. He laughed as the needle pricked his flesh. “To-morrow—John Bruce!”

He slumped far down in his chair once more. For half an hour he sat motionless, his eyes closed. Then he spoke again.

“Damn you!” he said.