“But Monsieur Lawrence is not a layman. You told me yourself that he had started by studying medicine, and that he had taken his degree.”

“Yes, that’s true. I never thought of that.” I was rather startled. “It is odd.”

Poirot nodded.

“From the first, his behaviour has been peculiar. Of all the household, he alone would be likely to recognize the symptoms of strychnine poisoning, and yet we find him the only member of the family to uphold strenuously the theory of death from natural causes. If it had been Monsieur John, I could have understood it. He has no technical knowledge, and is by nature unimaginative. But Monsieur Lawrence⁠—no! And now, today, he puts forward a suggestion that he himself must have known was ridiculous. There is food for thought in this, mon ami !”