He read on, striving to escape from that shadowy apprehension, but as he read he was listening to the night sounds of London, to the whirring of distant motors, the whistling of engines upon the railway and dim hooting of sirens from the Thames. A slight breeze had arisen and it rustled in the feathery foliage of the acacias and made a whispering sound as it stirred the leaves of the privet hedge.
The drone of an approaching car reached his ears. Pencil in hand, he sat listening. The sound grew louder, then ceased. Either the car had passed or had stopped somewhere near the house. Came a rap on the door.
"Yes," called Stuart and stood up, conscious of excitement.
Mrs. M'Gregor came in.
"There is nothing further you'll be wanting to-night?" she asked.
"No," said Stuart, strangely disappointed, but smiling at the old lady cheerfully. "I shall turn in very shortly."
"A keen east wind has arisen," she continued, severely eyeing the opened windows, "and even for a medical man you are strangely imprudent. Shall I shut the windows?"
"No, don't trouble, Mrs. M'Gregor. The room gets very stuffy with tobacco smoke, and really it is quite a warm night. I shall close them before I retire, of course."
"Ah well," sighed Mrs. M'Gregor, preparing to depart. "Good-night,
Mr. Keppel."
"Good-night, Mrs. M'Gregor."