‘Human nature is always interesting, Sir Henry. And it’s curious to see how certain types always tend to act in exactly the same way.’

‘Two women and a man,’ said Sir Henry. ‘The old eternal human triangle. Is that the base of our problem here? I rather fancy it is.’

Dr Lloyd cleared his throat.

‘I’ve been thinking,’ he said rather diffidently. ‘Do you say, Mrs Bantry, that you yourself were ill?’

‘Was I not! So was Arthur! So was everyone!’

‘That’s just it—everyone,’ said the doctor. ‘You see what I mean? In Sir Henry’s story which he told us just now, one man shot another—he didn’t have to shoot the whole room full.’

‘I don’t understand,’ said Jane. ‘Who shot who?’

‘I’m saying that whoever planned this thing went about it very curiously, either with a blind belief in chance, or else with an absolutely reckless disregard for human life. I can hardly believe there is a man capable of deliberately poisoning eight people with the object of removing one amongst them.’

‘I see your point,’ said Sir Henry, thoughtfully. ‘I confess I ought to have thought of that.’

‘And mightn’t he have poisoned himself too?’ asked Jane.

‘Was anyone absent from dinner that night?’ asked Miss Marple.

Mrs Bantry shook her head.

‘Everyone was there.’

‘Except Mr Lorimer, I suppose, my dear. He wasn’t staying in the house, was he?’

‘No; but he was dining there that evening,’ said Mrs Bantry.

‘Oh!’ said Miss Marple in a changed voice. ‘That makes all the difference in the world.’

She frowned vexedly to herself.

‘I’ve been very stupid,’ she murmured. ‘Very stupid indeed.’

‘I confess your point worries me, Lloyd,’ said Sir Henry.

‘How ensure that the girl, and the girl only, should get a fatal dose?’

‘You can’t,’ said the doctor. ‘That brings me to the point I’m going to make. Supposing the girl was not the intended victim after all?’

‘What?’

‘In all cases of food poisoning, the result is very uncertain. Several people share a dish. What happens? One or two are slightly ill, two more, say, are seriously indisposed, one dies. That’s the way of it—there’s no certainty anywhere. But there are cases where another factor might enter in. Digitalin is a drug that acts directly on the heart—as I’ve told you it’s prescribed in certain cases. Now, there was one person in that house who suffered from a heart complaint. Suppose he was the victim selected? What would not be fatal to the rest would be fatal to him—or so the murderer might reasonably suppose. That the thing turned out differently is only a proof of what I was saying just now—the uncertainty and unreliability of the effects of drugs on human beings.’

‘Sir Ambrose,’ said Sir Henry, ‘you think he was the person aimed at? Yes, yes—and the girl’s death was a mistake.’

‘Who got his money after he was dead?’ asked Jane.

‘A very sound question, Miss Helier. One of the first we always ask in my late profession,’ said Sir Henry.