“You had to go out to get some fresh air?”

“I did.  If I had not, I think I should have suffered much more.”

“And you found no trace of any poison, or anything of that sort?”

“Not the slightest.  Another doctor was called in, and then I went back.  The peculiar odor, or whatever it was, was gone, and I could find no further trace of it.”

“You think it must have evaporated?”

“What else is there to think?  The windows and blinds had been thrown wide open, and the sun was shining into the room.”

This was all the young doctor could tell, and as he was in a hurry to get away on more business, the detective did not detain him further.  He ascertained that Mrs. Bardon was also away, and then left the house.

In his pocket he still carried the bit of paper which he had picked up from under the safe.  It had evidently been part of the wrapper around some small object, and bore the following, printed in blue ink: 

nder & Co., ley Street, ter, N. Y. ark.

The paper might be valuable, and it might be worthless.  It had evidently been around a small box or bottle.  The address was evidently that of some firm doing business in some town in New York State.  What the “ark” could stand for, he could not surmise.

As the detective left the Bardon house, he saw a middle-aged man entering the Langmore mansion.  The man was well dressed and carried a dress-suit case.

“A visitor of some sort,” he mused.  “Perhaps a relative.”

When he stepped up on the piazza Raymond Case came out to meet him.  The young man wished to know if he had learned anything from the doctor.

“Not a great deal,” answered Adam Adams.  “Who was that man who just came in?”

“Thomas Ostrello, one of Mrs. Langmore’s sons by her first husband.”

“Is he a frequent visitor here?”

“I believe not.  He is a commercial traveler, and on the road nearly all the time.”

“Has he been here since the tragedy?”

“No.  He was here the day before it occurred, but went away in the evening.  I suppose his mother’s death has shocked him a good deal.”

“I believe you said the Ostrellos are not well off?”

“No; they are poor, so Margaret told me.  Both of the sons are on the road, one for a paint house and this one for a drug house.  By the way, I am going to town, to see the coroner.  Do you want to come along?”

“No, I’ll see him later.  I want to take a walk around this place first.  I may pick up a stray clue.”

Left to himself, Adam Adams walked slowly around the mansion, noting the several approaches.  He looked in at the stable and the automobile shed, and strolled down to the brook.  He made no noise, for it was his practice to move about as silently as possible and without attracting attention.

Suddenly he halted and stepped out of sight behind some bushes not far away from the brook.  He heard a splashing, which told him that somebody was near.