Poirot sat in silence for some minutes, then he said: "What exactly did you do when you left her?"

"I took the chair I had brought out back into my cave, then I went down to the marquee. My husband was there."

Poirot watched her closely as he said: "Did you tell him of your decision? Or had you already told him?"

There was a pause, an infinitesimal pause, before Nadine said: "I told him then."

"How did he take it?"

She answered quietly: "He was very upset."

"Did he urge you to reconsider your decision?"

She shook her head. "He—he didn't say very much. You see, we had both known for some time that something like this might happen."

Poirot said: "You will pardon me, but the other man was, of course, M. Jefferson Cope?"

She bent her head. "Yes."

There was a long pause, then, without any change of voice, Poirot asked: "Do you own a hypodermic syringe, Madame?"

"Yes—no."

His eyebrows rose.

She explained. "I have an old hypodermic amongst other things in a traveling medicine chest, but it is in our big luggage which we left in Jerusalem."

"I see."

There was a pause, then she said with a shiver of uneasiness: "Why did you ask me that, M. Poirot?"

He did not answer the question. Instead he put one of his own. "Mrs. Boynton was, I believe, taking a mixture containing digitalis?"

"Yes."

He thought that she was definitely watchful now. "That was for her heart trouble?"

"Yes."

"Digitalis is, to some extent, a cumulative drug?"

"I believe it is. I do not know very much about it."

"Mrs. Boynton had taken a big overdose of digitalis—"

She interrupted him quickly but with decision. "She did not. She was always most careful. So was I, if I measured the dose for her."

"There might have been an overdose in this particular bottle. A mistake of the chemist who made it up?"

"I think that is very unlikely," she replied quietly.

"Ah well, the analysis will soon tell us."

Nadine said: "Unfortunately the bottle was broken."

Poirot eyed her with sudden interest. "Indeed! Who broke it?"

"I'm not quite sure. One of the servants, I think. In carrying my mother-in-law's body into her cave, there was a good deal of confusion and the light was very poor. A table got knocked over."

Poirot eyed her steadily for a minute or two. "That," he said, "is very interesting."

Nadine Boynton shifted wearily in her chair. "You are suggesting, I think, that my mother-in-law did not die of shock, but of an overdose of digitalis?" she said and went on: "That seems to me most improbable."

Poirot leaned forward. "Even when I tell you that Dr. Gerard, the French physician who was staying in the camp, had missed an appreciable quantity of a preparation of digitoxin from his medicine chest?"

Her face grew very pale. He saw the clutch of her other hand on the table. Her eyes dropped. She sat very still. She was like a Madonna carved in stone.