“What is a great discovery?”

“Why, that it was the cocoa and not the coffee that was poisoned. That explains everything! Of course it did not take effect until the early morning, since the cocoa was only drunk in the middle of the night.”

“So you think that the cocoa⁠—mark well what I say, Hastings, the cocoa⁠—contained strychnine?”

“Of course! That salt on the tray, what else could it have been?”

“It might have been salt,” replied Poirot placidly.

I shrugged my shoulders. If he was going to take the matter that way, it was no good arguing with him. The idea crossed my mind, not for the first time, that poor old Poirot was growing old. Privately I thought it lucky that he had associated with him someone of a more receptive type of mind.

Poirot was surveying me with quietly twinkling eyes.