"Suppose that I did buy poison, how should you identify me with the purchaser, and how came you to know where I lived?"

"I sent a boy to follow you home," said Cromwell.

"You dared to do that?"

"Why not? We have no curiosity about our ordinary customers, but when a person makes such a purchase as you did, we feel inclined to learn all we can about him."

"A praiseworthy precaution! Well, I admit that I did buy the poison. What then?"

"I asked to what purpose you had put it?"

"Very well, I have no objection to tell you, although I deny your right to intrude in my private affairs, which I regard as a piece of gross impertinence. I bought it, as I think I stated to you at the time, at the request and for the use of a friend."

"Would you tell me the friend's name?" asked the clerk, imperturbably.

"He lives in Thirty-seventh Street."

"What is his name?"