“I’m not counting the dog used to bring the warning note to Hill. Since it conveyed a warning to Hill and not to you, Mr. Priam, we must consider the dead dog entirely apart from the warnings sent to you. Still, it’s interesting to note in passing that Hill’s series of warnings, which never got beyond the first, began with an animal, too.
“Omitting for the moment the contents of the first box you received, Mr. Priam,” Ellery said, “let’s see how the concept ‘animal’ derives from the warnings we had direct knowledge of. Your second warning was a poisoning attack, a non-fatal dose of arsenic. The animal? Tuna fish, the medium by which the poison was administered.
“The third warning? Frogs and toads.
“The fourth warning was one step removed from the concept ― a wallet. But the wallet was leather, and the leather came from an alligator.
“There was no mistaking the animal in the fifth warning. The ancient Greek comedy by Aristophanes ― The Birds.
“And the sixth warning, Mr. Priam ― some worthless old stock certificates ― would have given me a great deal of trouble if you hadn’t suggested the connection yourself. There’s a contemptuous phrase applied to such stocks by market traders, you said ― ‘cats and dogs! ’ And you were quite right ― that’s what they’re called.
“So... fish, frogs, alligator, birds, cats and dogs. The fish, frogs, and alligator suggested literally, the birds and the cats and dogs suggested by allusion. All animals. That was the astonishing fact. What did you say, Mr. Priam?”
But Priam had merely been bumbling in his beard.
“Now the fact that each of the five warnings I’d had personal contact with concealed, like a puzzle, a different animal ― astonishing as it was ― told me nothing,” continued Ellery, throwing his cigaret into Priam’s fireplace. “I realized after some skull work that the meaning must go far deeper. It had to be dug out.
“But digging out the deeper meaning was another story.