“Let us look at the matter like this. Here is a man, let us say, who sets out to poison his wife. He has lived by his wits as the saying goes. Presumably, therefore, he has some wits. He is not altogether a fool. Well, how does he set about it? He goes boldly to the village chemist’s and purchases strychnine under his own name, with a trumped up story about a dog which is bound to be proved absurd. He does not employ the poison that night. No, he waits until he has had a violent quarrel with her, of which the whole household is cognisant, and which naturally directs their suspicions upon him. He prepares no defence⁠—no shadow of an alibi, yet he knows the chemist’s assistant must necessarily come forward with the facts. Bah! do not ask me to believe that any man could be so idiotic! Only a lunatic, who wished to commit suicide by causing himself to be hanged, would act so!”

“Still⁠—I do not see⁠—” I began.

“Neither do I see. I tell you, mon ami , it puzzles me. Me⁠—Hercule Poirot!”