“Mr. Inspector Jacks,” he said, “your visit has been of great interest to me. If I can be of any further assistance, pray do not hesitate to call upon me.”

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CHAPTER XXIII. ON THE TRAIL

Inspector Jacks studied the brass plate for a moment, and then rang the patients’ bell. The former, he noticed was very much in want of cleaning, and for a doctor’s residence there was a certain lack of smartness about the house and its appointments which betokened a limited practice. The railing in front was broken, and no pretence had been made at keeping the garden in order. Inspector Jacks had time to notice these things, for it was not until after his second summons that the door was opened by Dr. Whiles himself.

“Good morning!” the latter said tentatively. Then, with a slight air of disappointment, he recognized his visitor.

“Good morning, doctor!” Inspector Jacks replied. “You haven’t forgotten me, I hope? I came down to see you a short time ago, respecting the man who was knocked down by a motor car and treated by you on a certain evening.”

The doctor nodded.

“Will you come in?” he asked.

He led the way into a somewhat dingy waiting room. A copy of The Field, a month old, a dog-eared magazine, and a bound volume of Good Words were spread upon the table. The room itself, except for a few chairs, was practically bare.

“I do not wish to take up too much of your time, Dr. Whiles,” the Inspector began,—