"That's interestin'. Why, Miss Bohun?"
"Just before you came in here, I heard all about Uncle Maurice's theory. I heard every bit of it. Oh, it's clever. It sounds like him. I don't know whether that man Rainger committed the murder. But I do know that the whole case against him, so far as I can see it, is built up on one person. Without that one person, it may not mean that the case goes to smash. "
"You mean-'
"Louise." She brought her fingers down sharply on the table. Then she began to speak more rapidly. "That Louise went to the pavilion. That afterwards there really wasn't anybody walking in the gallery; who smeared blood on her wrist, and that she invented it all… Now I'll tell you. I heard it all from Dr. Wynne, and he'll swear to it. This morning, after he'd examined Louise, he took Jervis Willard out in the gallery and was going to tell him something. That was when they heard the shot. " Her eyes darted to the scrubbed space on the gray carpet; and she could not continue. "That was when they heard it. And Dr. Wynne was so busy taking care of John that he didn't mention it again then.
"But it's this. Some time late last night, he says Louise must have taken a terrific overdose of some sleeping-drug like veronal. You may be able to guess why. Well, she took so much that it had exactly the opposite effect: that is, it kept her mind awake and wild, but it partly paralyzed her body. She might have had the idea of going down to that pavilion; she might get hallucinations and even try to go. That may have been where she was going when she collapsed outside my room. But Dr. Wynne is willing to swear after his examination that she took the drug not later than one o'clock, and that for the next four or five hours it would have been absolutely impossible to have walked more than twenty or thirty feet from her own room. It simply couldn't have been done. The farthest she could get was where she did get. She bumped into this person in the dark because she was stumbling all over the gallery; and there was a person, and she didn't imagine it, and, finally, it proves you can't possibly accuse her of murder."
Masters, who had got out his notebook, lowered it to the table and swore. He stared at H. M. "Is that possible, sir?"
"Uh-huh. Quite possible. Depends on the dose, and depends on the person even more. Bit reckless to speculate without knowin' a patient's nerve status, but let Wynne have his way. He may be right, he may be wrong. I rather imagine he's wrong, but suit yourself." A sluggish grin crept over H. M.'s face. "Well, Masters?"
"You mean, sir, that you believe in Mr. Bohun's explanation?"
H. M. shifted uncomfortably.
"Look here, Masters, I don't want to mix you up any more than's necessary for a very definite purpose. This business is black enough, and tangled enough, as it is. All I can tell you is that I'm not wavin' my hands over the crystal and makin' mysterious noises out of pure cussedness. But there's somethin' you can see for yourself. Miss Bohun's right about one thing. If you accept the hypothesis that Rainger is guilty, then you can't take only the parts of it that appeal to you: you've got to accept all of it or none of it. And the keystone arch of that theory is the girl who says somebody smeared her wrist with blood. If you believe that prowler-in-thegallery was a myth, all right. But, if you believe he was a real person, then you've got to discard the theory of Rainger's guilt. Because why? Because it would be too staggerin' and monstrous a coincidence to imagine two people with bloodstained hands wanderin' about these grounds. And, at the time that girl says she bumped into her man in this house, by the very basis of Maurice Bohun's theory Rainger must have been at the pavilion. He never left the pavilion until he walked back in John's tracks. Right you are, then. Either the prowler-in-the-gallery is a myth, or else he ain't. But if he ain't a myth, then you've shaken the theory and done some towards establishin' Rainger's innocence."