The girl Katrina looked even more sallow and sullen than ever.
Poirot spoke to her very gently. ‘Mademoiselle, I want you to believe that I am not your enemy. I want you to tell me the truth.’
Her eyes snapped defiantly. ‘I have told the truth. To everyone I have told the truth! If the old lady was poisoned, it was not I who poisoned her. It is all a mistake. You wish to prevent me having the money.’ Her voice was rasping. She looked, he thought, like a miserable little cornered rat.
‘Did no one handle it but you?’
‘I have said so, have I not? They were made up at the chemist’s that afternoon. I brought them back with me in my bag—that was just before supper. I opened the box and gave Miss Barrowby one with a glass of water.’
‘No one touched them but you?’
‘No.’ A cornered rat—with courage!
‘And Miss Barrowby had for supper only what we have been told. The soup, the fish pie, the tart?’
‘Yes.’ A hopeless ‘yes’—dark, smouldering eyes that saw no light anywhere.
Poirot patted her shoulder. ‘Be of good courage, mademoiselle. There may yet be freedom—yes, and money—a life of ease.’
She looked at him suspiciously.
As she went out Sims said to him, ‘I didn’t quite get what you said through the telephone—something about the girl having a friend.’
‘She has one. Me!’ said Hercule Poirot, and had left the police station before the inspector could pull his wits together.
IV
At the Green Cat tearooms, Miss Lemon did not keep her employer waiting. She went straight to the point.
‘The man’s name is Rudge, in the High Street, and you were quite right. A dozen and a half exactly. I’ve made a note of what he said.’ She handed it to him.
‘Arrr.’ It was a deep, rich sound like a purr of a cat.
V
Hercule Poirot betook himself to Rosebank. As he stood in the front garden, the sun setting behind him, Mary Delafontaine came out to him.
‘M. Poirot?’ Her voice sounded surprised. ‘You have come back?’
‘Yes, I have come back.’ He paused and then said, ‘When I first came here, madame, the children’s nursery rhyme came into my head:
‘Mistress Mary, quite contrary,
How does your garden grow?
With cockle-shells, and silver bells,
And pretty maids all in a row.
‘Only they are not cockle shells, are they, madame? They are oyster shells.’ His hand pointed.
He heard her catch her breath and then stay very still. Her eyes asked a question.
He nodded. ‘Mais, oui, I know! The maid left the dinner ready—she will swear and Katrina will swear that that is all you had. Only you and your husband know that you brought back a dozen and a half oysters—a little treat pour la bonne tante. So easy to put the strychnine in an oyster. It is swallowed—comme ça! But there remain the shells—they must not go in the bucket. The maid would see them. And so you thought of making an edging of them to a bed. But there were not enough—the edging is not complete. The effect is bad—it spoils the symmetry of the otherwise charming garden. Those few oyster shells struck an alien note—they displeased my eye on my first visit.’
Mary Delafontaine said, ‘I suppose you guessed from the letter. I knew she had written—but I didn’t know how much she’d said.’
Poirot answered evasively, ‘I knew at least that it was a family matter. If it had been a question of Katrina there would have been no point in hushing things up. I understand that you or your husband handled Miss Barrowby’s securities to your own profit, and that she found out—’
Mary Delafontaine nodded. ‘We’ve done it for years—a little here and there. I never realized she was sharp enough to find out. And then I learned she had sent for a detective; and I found out, too, that she was leaving her money to Katrina—that miserable little creature!’
‘And so the strychnine was put in Katrina’s bedroom? I comprehend. You save yourself and your husband from what I may discover, and you saddle an innocent child with murder. Had you no pity, madame?’