Steel lay sleepily back in the cab, not quite sure whether his cigarette was alight or not. They were well into the main road again before Bell spoke.

"It is pretty evident that you and I are on the same track," he said.

"I am certain that I am on the right one," David replied; "but, when I come to consider the thing calmly, it seems more by good luck than anything else. I came out with you to-night seeking adventure, and I am bound to admit that I found it. Also, I found the lady who interviewed me in the darkness, which is more to the point."

"As a matter of fact, you did nothing of the kind," said Bell, with the suggestion of a laugh.

"Oh! Case of the wrong room over again. I was ready to swear it. Whom did
I speak to? Whose voice was it that was so very much like hers?"

"The lady's sister. Enid Henson was not at 218, Brunswick Square, on the night in question. Of that you may be certain. But it's a queer business altogether. Rascality I can understand. I am beginning to comprehend the plot of which I am the victim. But I don't mind admitting that up to the present I fail to comprehend why those girls evolved the grotesque scheme for getting assistance at your hands. The whole thing savours of madness."

"I don't think so," David said, thoughtfully. "The girls are romantic as well as clever. They are bound together by the common ties of a common enmity towards a cunning and utterly unscrupulous scoundrel. By the merest accident in the world they discovered that I am in a position to afford them valuable advice and assistance. At the same time they don't want me to be brought into the business, for two reasons—the first, because the family secret is a sacred one; the second, because any disclosures would land me in great physical danger. Therefore they put their heads together and evolve this scheme. Call it a mad venture if you like, but if you consider the history of your own country you can find wilder schemes evolved and carried out by men who have had brains enough to be trusted with the fortunes of the nation. If these girls had been less considerate for my safety—"

"But," Bell broke in eagerly, "they failed in that respect at the very outset. You must have been spotted instantly by the foe, who has cunningly placed you in a dangerous position, perhaps as a warning to mind your own business in future. And if those girls come forward to save you—and to do so they must appear in public, mind you—they are bound to give away the whole thing. Mark the beautiful cunning of it. My word, we have a foe worthy of our steel to meet."

"We? Do you mean to say that your enemy and mine is a common one?"

"Certainly. When I found my foe I found yours."

"And who may he be, by the same token?"

"Reginald Henson. Mind you, I had no more idea of it than the dead when I went to Longdean Grange to-night. I went there because I had begun to suspect who occupied the place and to try and ascertain how the Rembrandt engraving got into 218, Brunswick Square. Miss Gates must have heard us talking over the matter, and that was why she went to Longdean Grange to-night."

"I hope she got home safe," said David. "The cab man says he put her down opposite the Lawns."

"I hope so. Well, I found out who the foe was. And I have a pretty good idea why he played that trick upon me. He knew that Enid Henson and myself were engaged; he could see what a danger to his schemes it would be to have a man like myself in the family. Then the second Rembrandt turned up, and there was his chance for wiping me off the slate. After that came the terrible family scandal between Lord Littimer and his wife. I cannot tell you anything of that, because I cannot speak with definite authority. But you could judge of the effect of it on Lady Littimer to-night."

"I haven't the faintest recollection of seeing Lady Littimer to-night."

"My dear fellow, the poor lady whom you met as Mrs. Henson is really Lady Littimer. Henson is her maiden name, and those girls are her nieces. Trouble has turned the poor woman's brain. And at the bottom of the whole mystery is Reginald Henson, who is not only nephew on his mother's side, but is also next heir but one to the Littimer title. At the present moment he is blackmailing that unhappy creature, and is manoeuvring to get the whole of her large fortune in his hands. Reginald Henson is the man those girls want to circumvent, and for that reason they came to you. And Henson has found it out to a certain extent and placed you in an awkward position."

"Witness my involuntary guest and the notes and the cigar-case," David said. "But does he know what I advised one of the girls—my princess of the dark room—to do?"

"I don't fancy he does. You see, that advice was conveyed by word of mouth. The girls dared not trust themselves to correspondence, otherwise they might have approached you in a more prosaic manner. But I confess you startled me to-night."

"What do you mean by that?"

"When you sent me that note. What you virtually asked me to do was to countenance murder. When I went into the sick room I saw that Christiana Henson was dying. The first idea that flashed across my mind was that Reginald Henson was getting the girl out of the way for his own purposes. My dear fellow, the whole atmosphere literally spoke of albumen. Walker must have been blind not to see how he was being deceived. I was about to give him my opinion pretty plainly when your note came up to me. And there was Enid, with her whole soul in her large eyes, pleading for my silence. If the girl died I was accessory after and before the fact. You will admit that that was a pretty tight place to put a doctor in."

"That's because you didn't know the facts of the case, my dear Bell."

"Then perhaps you'll be so good as to enlighten me," Bell said, drily.

"Certainly. That was part of my scheme. In that synopsis of the story obtained by the girls by some more or less mechanical means, the reputed death of a patient forms the crux of the tale. The idea occurred to me after reading a charge against a medical student some time ago in the Standard. The man wanted to get himself out of the way; he wanted to be considered as dead, in fact. By the artful use of albumen in certain doses he produced symptoms of disease which will be quite familiar to you. He made himself so ill that his doctor naturally concluded that he was dying. As a matter of fact, he was dying. Had he gone on in the same way another day he would have been dead. Instead of this he drops the dosing and, going to his doctor in disguise, says that he is dead. He gets a certificate of his own demise, and there you are. I am not telling you fiction, but hard fact recorded in a high-class paper. The doctor gave the certificate without viewing the body. Well, it struck me that we had here the making of a good story, and I vaguely outlined it for a certain editor. In my synopsis I suggested that it was a woman who proposed to pretend to die thus so as to lull the suspicions of a villain to sleep, and thus possess herself of certain vital documents. My synopsis falls into certain hands. The owner of those hands asks me how the thing was done. I tell her. In other words, the so-called murder that you imagined you had discovered to-night was the result of design. Walker will give his certificate, Reginald Henson will regard Miss Christiana as dead and buried, and she will be free to act for the honour of the family."

"But they might have employed somebody else."

"Who would have had to be told the history of the family dishonour. So far I fancy I have made the ground quite clear. But the mystery of the cigar-case and the notes and the poor fellow in the hospital is still as much a mystery as ever. We are like two allied forces working together, but at the same time under the disadvantage of working in the dark. You can see, of course, that the awful danger I stand in is as terrible for those poor girls."

"Of course I do. Still, we have a key to your trouble. It is a dreadfully rusty one and will want a deal of oiling before it's used, but there it is."

"Where, my dear fellow, where?" David asked.

"Why, in the Sussex County Hospital, of course. The man may die, in which case everything must be sacrificed in order to save your good name. On the other hand, he may get better, and then he will tell us all about it."

"He might. On the other hand, he might plead ignorance. It is possible for him to suggest that the whole affair was merely a coincidence, so far as he was concerned."

"Yes, but he would have to explain how he burgled your house, and what business he had to get himself half murdered in your conservatory. Let us get out here and walk the rest of the way to your house. Our cabby knows quite enough about us without having definite views as to your address."

The cabman was dismissed with a handsome douceur, and the twain turned off the front at the corner of Eastern Terrace. Late as it was, there were a few people lounging under the hospital wall, where there was a suggestion of activity about the building unusual at that time of the night. A rough-looking fellow, who seemed to have followed Bell and Steel from the front, dropped into a seat by the hospital gates and laid his head back as if utterly worn out. Just inside the gates a man was smoking a cigarette.

"Halloa, Cross," David cried, "you are out late tonight!"

"Heavy night," Cross responded, sleepily, "with half a score of accidents to finish with. Some of Palmer of Lingfield's private patients thrown off a coach and brought here in the ambulance. Unless I am greatly mistaken, that is Hatherly Bell with you."

"The same," Bell said, cheerfully. "I recollect you in Edinburgh. So some of Palmer's patients have come to grief. Most of his special cases used to pass through my hands."

"I've got one here to-night who recollects you perfectly well," said
Cross. "He's got a dislocated shoulder, but otherwise he is doing well.
Got a mania that he's a doctor who murdered a patient."

"Electric light anything to do with the story?" Bell asked, eagerly.

"That's the man. Seems to have a wonderfully brilliant intellect if you can only keep him off that topic. He spotted you in North Street yesterday, and seemed wonderfully disappointed to find you had nothing whatever to do with this institution."

"If he is not asleep," Bell suggested, "and you have no objection—"

Cross nodded and opened the gate. Before passing inside Bell took the rolled-up Rembrandt from his deep breast-pocket and handed it to David.

"Take care of this for me," he whispered. "I'm going inside. I've dropped upon an old case that interested me very much years ago, and I'd like to see my patient again. See you in the morning, I expect. Good-night."

David nodded in reply and went his way. It was intensely quiet and still now; the weary loafer at the outside hospital seat had disappeared. There was nobody to be seen anywhere as David placed his key in the latch and opened the door. Inside the hall-light was burning, and so was the shaded electric lamp in the conservatory. The study leading to the conservatory was in darkness. The effect of the light behind was artistic and pleasing.

It was with a sense of comfort and relief that David fastened the door behind him. Without putting up the light in the study David laid the Rembrandt on his table, which was immediately below the window in his work-room. The night was hot; he pushed the top sash down liberally.

"I must get that transparency removed," he murmured, "and have the window filled with stained glass. The stuff is artistic, but it is so frankly what it assumes to be."