She stared. They all stared at Miss Marple.

‘Then that seems to settle it,’ said Miss Marple. She shook her head regretfully. ‘And the wasp season and everything. And of course the gas.’

‘It reminds you, I suppose, of countless village tragedies?’ said Sir Henry.

‘Not tragedies,’ said Miss Marple. ‘And certainly nothing criminal. But it does remind me a little of the trouble we are having with the District Nurse. After all, nurses are human beings, and what with having to be so correct in their behaviour and wearing those uncomfortable collars and being so thrown with the family—well, can you wonder that things sometimes happen?’

A glimmer of light broke upon Sir Henry.

‘You mean Nurse Carstairs?’

‘Oh no. Not Nurse Carstairs. Nurse Copling. You see, she had been there before, and very much thrown with Mr Pritchard, who you say is an attractive man. I dare say she thought, poor thing—well, we needn’t go into that. I don’t suppose she knew about Miss Instow, and of course afterwards, when she found out, it turned her against him and she tried to do all the harm she could. Of course the letter really gave her away, didn’t it?’

‘What letter?’

‘Well, she wrote to the fortune-teller at Mrs Pritchard’s request, and the fortune-teller came, apparently in answer to the letter. But later it was discovered that there never had been such a person at that address. So that shows that Nurse Copling was in it. She only pretended to write—so what could be more likely than that she was the fortune-teller herself?’

‘I never saw the point about the letter,’ said Sir Henry. ‘That’s a most important point, of course.’

‘Rather a bold step to take,’ said Miss Marple, ‘because Mrs Pritchard might have recognized her in spite of the disguise—though of course if she had, the nurse could have pretended it was a joke.’

‘What did you mean,’ said Sir Henry, ‘when you said that if you were a certain person you would not have trusted to fright?’

‘One couldn’t be sure that way,’ said Miss Marple. ‘No, I think that the warnings and the blue flowers were, if I may use a military term,’ she laughed self-consciously—‘just camouflage.’

‘And the real thing?’

‘I know,’ said Miss Marple apologetically, ‘that I’ve got wasps on the brain. Poor things, destroyed in their thousands—and usually on such a beautiful summer’s day. But I remember thinking, when I saw the gardener shaking up the cyanide of potassium in a bottle with water, how like smelling-salts it looked. And if it were put in a smelling-salt bottle and substituted for the real one—well, the poor lady was in the habit of using her smelling-salts. Indeed you said they were found by her hand. Then, of course, while Mr Pritchard went to telephone to the doctor, the nurse would change it for the real bottle, and she’d just turn on the gas a little bit to mask any smell of almonds and in case anyone felt queer, and I always have heard that cyanide leaves no trace if you wait long enough. But, of course I may be wrong, and it may have been something entirely different in the bottle; but that doesn’t really matter, does it?’