For Poirot, uttering a hoarse and inarticulate cry, again annihilated his masterpiece of cards and putting his hands over his eyes swayed backwards and forwards, apparently suffering the keenest agony.
“Good heavens Poirot!” I cried. “What is the matter? Are you taken ill?”
“No, no,” he gasped. “It is — it is — that I have an idea!”

What It Means

This is a placeholder explanation generated by the low-overhead model. It interprets "For Poirot, uttering a hoarse and inarticulate cry, again annihilated his masterpiece of cards and putting his hands over his eyes swayed backwards and forwards, apparently suffering the keenest agony.
“Good heavens Poirot!” I cried. “What is the matter? Are you taken ill?”
“No, no,” he gasped. “It is — it is — that I have an idea!”" in the context of "" to mean that wisdom is timeless.