It was the hypodermic needle!
Dumbfounded, she stared at it. How on earth did it get there? Then all at once the whole thing flashed on her. The book had lain open on the table in the boudoir; she had put the needle down upon it when she first began to minister to Roger. His aunt had cleared the table to make room for the basin of water and bandages, closed the book hastily, no doubt, and pushed it aside. Then at some time later one of the servants had removed it, with others in the same pile, to this room. She had not seen the book when she had searched for the needle, else she would have recalled the whole thing, and this suggested that the book had been taken away within the next half-hour or so. Of course! How plain it all was now!
Well, there was nothing to do but to restore it to the doctor and finish up that unfortunate episode. She would do so at once…. And yet—why reopen the matter? She had taken her scolding, why should she give him the satisfaction of… Stay! Was it possible, after all her theorising, that what the doctor had been so disturbed about was this actual needle itself? She had rejected that explanation as wholly absurd, but now that she held the concrete object in her hand, she began to wonder. Certainly he had made strong efforts to recover it, had even joined in the search. For that matter—why, what about that smell of tobacco in her room? What about her conviction that someone had gone through her things? Suppose, incredible as it seemed, the doctor had really been there while she was out of the house, turning everything over in the hope of finding his lost property? Odd that she had never thought of that possibility until now.
She turned the little instrument over, looking at it thoughtfully. If what she had been thinking was really true, why was it that he wanted this particular needle back? what was there about it? … All at once it came upon her like a thunderbolt that it was soon after the last injection, only a few hours, that she had noticed the change in Sir Charles. Iron and arsenic, that could have no bad effect—on the contrary, it put strength into one. With an idea forming in her mind, she furtively raised the needle to the light and examined it closely. A trace of palish liquid remained. Was it the exact hue of the familiar mixture? She could almost think it was slightly different in colour, but it was impossible to be sure. Fixedly she regarded it, recalling meantime the mottled red of the doctor's face, his unreasoning fury. If he had been only a little less enraged!
There was a tightness in her chest. The suspicion, monstrous, unthinkable, seemed likely to burst her head asunder. She heard within her two voices arguing. The first said, "What utter nonsense! Such things don't happen, at least, not to you, not in this atmosphere of safety." The second retorted promptly, "Why should it be nonsense? Such things do happen, why not to you?"
Chalmers entered softly, removed the coffee things and placed whisky and soda, although there was no one to want it. His quiet step, the ticking of the buhl clock, the very roses on the Aubusson carpet gave her gross suspicions the lie. And yet…
Now, to think clearly, she mustn't let the thing run away with her. What was it she had often heard? That the motive was everything. That was it, one must look for a motive. In this instance, was there a motive? She knew there was. Or at least it might be construed into one. But, after all, was she sure even of this? The young man Holliday had departed on his way to South America, Lady Clifford had let him go. Didn't that rather knock the bottom out of this dreadful idea? For a moment she felt contused, then came a revulsion. Of course, the whole thing was perfectly ridiculous; how could she ever have thought it for a moment? In this day and time, in this house! She was filled with unutterable relief, ready to laugh hysterically at her own mad notion.
A heavy step in the doorway, and she realised that the doctor was on the point of entering. Now was the opportunity to give him back his needle, get it over quickly. Her hand closed over it; the next instant Sartorius came and stood just inside the room.
"The consultation, nurse, is arranged for three o'clock to-morrow afternoon. I thought you might like to know."
"Yes, doctor. Thank you."