‘You read the papers, I think, Mr Dinsmead? I am sure you do. Sometimes one reads accounts of a whole family being poisoned, some of them recover, some do not. In this case, one would not. The first explanation would be the tinned brawn you were eating, but supposing the doctor to be a suspicious man, not easily taken in by the tinned food theory? There is a packet of arsenic in your larder. On the shelf below it is a packet of tea. There is a convenient hole in the top shelf, what more natural to suppose then that the arsenic found its way into the tea by accident? Your son Johnnie might be blamed for carelessness, nothing more.’

‘I—I don’t know what you mean,’ gasped Dinsmead.

‘I think you do,’ Mortimer took up a second teacup and filled a second test-tube. He fixed a red label to one and a blue label to the other.

‘The red-labelled one,’ he said, ‘contains tea from your daughter Charlotte’s cup, the other from your daughter Magdalen’s. I am prepared to swear that in the first I shall find four or five times the amount of arsenic than in the latter.’

‘You are mad,’ said Dinsmead.

‘Oh! dear me, no. I am nothing of the kind. You told me today, Mr Dinsmead, that Magdalen is your daughter. Charlotte was the child you adopted, the child who was so like her mother that when I held a miniature of that mother in my hand today I mistook it for one of Charlotte herself. Your own daughter was to inherit the fortune, and since it might be impossible to keep your supposed daughter Charlotte out of sight, and someone who knew the mother might have realized the truth of the resemblance, you decided on, well—a pinch of white arsenic at the bottom of a teacup.’

Mrs Dinsmead gave a sudden high cackle, rocking herself to and fro in violent hysterics.

‘Tea,’ she squeaked, ‘that’s what he said, tea, not lemonade.’

‘Hold your tongue, can’t you?’ roared her husband wrathfully.

Mortimer saw Charlotte looking at him, wide-eyed, wondering, across the table. Then he felt a hand on his arm, and Magdalen dragged him out of earshot.

‘Those,’ she pointed at the phials—‘Daddy. You won’t—’

Mortimer laid his hand on her shoulder. ‘My child,’ he said, ‘you don’t believe in the past. I do. I believe in the atmosphere of this house. If he had not come to it, perhaps—I say perhaps—your father might not have conceived the plan he did. I keep these two test-tubes to safeguard Charlotte now and in the future. Apart from that, I shall do nothing, in gratitude, if you will, to that hand that wrote S.O.S.’

The Adventure of the Egyptian Tomb

I have always considered that one of the most thrilling and dramatic of the many adventures I have shared with Poirot was that of our investigation into the strange series of deaths which followed upon the discovery and opening of the Tomb of King Men-her-Ra.