"That is a fairly good suggestion, but there were not—there was only a single ash, corresponding in every way to that on the cigar. Don't you remember anything that I did as we went downstairs?"
"You returned a bottle of oil to the housekeeper's daughter, I think."
"I did. Doesn't that give you a hint? Come, you surely have it now?"
"I haven't."
"DOESN'T THAT GIVE YOU A HINT?"
"Then I shan't tell you; you don't deserve it. Think, and don't mention the subject again till you have at least one guess to make. The thing stares you in the face—you see it, you remember it, and yet you won't see it. I won't encourage your slovenliness of thought, my boy, by telling you what you can know for yourself if you like. Good-bye—I'm off now. There is a case in hand I can't neglect."
"Don't you propose to go further into this, then?"
Hewitt shrugged his shoulders. "I'm not a policeman," he said. "The case is in very good hands. Of course, if anybody comes to me to do it as a matter of business, I'll take it up. It's very interesting, but I can't neglect my regular work for it. Naturally, I shall keep my eyes open and my memory in order. Sometimes these things come into the hands by themselves, as it were; in that case, of course, I am a loyal citizen, and ready to help the law. Au revoir."