His reply startled me somewhat. I stopped and looked at him.
"That is a quaint situation, Thorndyke. I hadn't thought of it. Why she may actually come to the house while we are here; in fact, she may be in the house at this moment."
"I hope not," said he. "We don't particularly want Mr. Weiss to be put on his guard, for I take it, he is a pretty wide-awake gentleman under any circumstances. If she does come, we had better keep out of sight. I think we will look over the house first. That is of the most interest to us. If the lady does happen to come while we are here, she may stay to show us over the place and keep an eye on us. So we will leave the stables to the last."
We walked down the entry to the side door at which I had been admitted by Mrs. Schallibaum on the occasion of my previous visits. Thorndyke inserted the latch-key, and, as soon as we were inside, shut the door and walked quickly through into the hall, whither I followed him. He made straight for the front door, where, having slipped up the catch of the lock, he began very attentively to examine the letter-box. It was a somewhat massive wooden box, fitted with a lock of good quality and furnished with a wire grille through which one could inspect the interior.
"We are in luck, Jervis," Thorndyke remarked. "Our visit has been most happily timed. There is a letter in the box."
"Well," I said, "we can't get it out; and if we could, it would be hardly justifiable."
"I don't know," he replied, "that I am prepared to assent off-hand to either of those propositions; but I would rather not tamper with another person's letter, even if that person should happen to be a murderer. Perhaps we can get the information we want from the outside of the envelope."
He produced from his pocket a little electric lamp fitted with a bull's-eye, and, pressing the button, threw a beam of light in through the grille. The letter was lying on the bottom of the box face upwards, so that the address could easily be read.
"Herrn Dr. H. Weiss," Thorndyke read aloud. "German stamp, postmark apparently Darmstadt. You notice that the 'Herrn Dr.' is printed and the rest written. What do you make of that?"
"I don't quite know. Do you think he is really a medical man?"