Had Petrovitch not told him that Marion was dining at Cromwell Road and going to a concert with Maud afterwards, he would have wired to her to meet him. But he knew how devoted the two girls were to each other, notwithstanding the difference of their stations, and how Maud welcomed Marion’s company at concerts or theatres to which her father so seldom cared to go.

Suddenly it occurred to him that if he returned to the Doctor’s he would meet Marion there later on, when she came back from Queen’s Hall, and be able to drive her home to that dull street at the back of Oxford Street where the assistants of Cunnington’s, Limited, “lived in.”

This reflection aroused him, and, glancing at the smoking-room clock, he saw it wanted a quarter to ten.

Two other men, friends of his, were sitting near, discussing motoring matters, and their eternal chatter upon cylinders, tyres, radiators, and electric horns bored him. Therefore he rose, put on his coat, and, hailing a cab, told the man to drive to Victoria, where he took the underground railway to Gloucester Road Station.

From there to the house of the ex-Minister was only a very short walk. The night was mild, bright, and starlight, for the haze of sundown which had threatened rain had been succeeded by a brilliant evening. Cromwell Road is always deserted at that hour before the cabs and carriages begin to return from restaurants and theatres, and as he strolled along, knowing that he was always welcome at the Doctor’s house to chat and smoke, his was the only footfall to be heard in the long open thoroughfare.

Ascending the steps beneath the wide portico, he pressed the visitors’ bell, but though he waited several minutes, there was no response. Again and again he rang, but the bell was apparently out of order, so he gave a sounding rat-tat with the knocker.

Then he listened intently; but to his surprise no one stirred.

Over the door was a bright light, as usual, revealing the number in great white numerals, and through the chinks of the Venetian blinds of the dining-room he could see that the electric lamps were on.

Again and again he rang and knocked. It was surely curious, he thought, that all the servants should be out, even though the Doctor might be absent. The failure to arouse anybody caused him both surprise and apprehension. Though the electric bell might be out of order, yet his loud knock must be heard even up to the garrets. London servants are often neglectful in the absence of their masters, and more especially if there is no mistress, yet it seemed hardly creditable that they would go out and leave the place unattended.

Seven or eight times he repeated his summons, standing upon the door-steps with his ears strained to catch the slightest sound.