"Warm" was a word which had a special significance in relation to Mr. Johnson. He seemed to radiate a warming and quickening influence. Even Dick Gordon, who was not too ready to respond, came under the immediate influence of his geniality.

    "You're Mr. Gordon of the Public Prosecution Department—Ray was telling me," he said. "I should like you to come one day and prosecute old man Maitland! He is certainly the most prosecutable gentleman I've met for years!"

    The jest tickled Mr. Johnson. He was, thought Dick, inclined to laugh at himself.

    "I've got to get back: he's in a tantrum this morning. Anyone would think the Frogs were after him."

    Philo Johnson, with a cheery nod, hurried back to the lift. Was it imagination on Dick's part? He could have sworn the face of Ray Bennett was a deeper shade of red, and that there was a look of anxiety in his eyes.

    "It's very good of you to keep your promise and call…yes, I'll be glad to lunch with you, Gordon. And my sister will also, I'm sure. She is often in town."

    His adieux were hurried and somewhat confused. Dick Gordon went out into the street puzzled. Of one thing he was certain: that behind the young man's distress lay that joking reference to the Frogs.

    When he returned to his office, still sore with himself that he had acted rather like a moon-calf or a farm hand making his awkward advances to the village belle, he found a troubled-looking chief of police waiting for him, and at the sight of him Dick's eyes narrowed.

    "Well?" he asked. "What of Genter?"

    The police chief made a grimace like one who was swallowing an unpleasant potion.

    "They slipped me," he said. "The Frog arrived in a car—I wasn't prepared for that. Genter got in, and they were gone before I realized what had happened. Not that I'm worried. Genter has a gun, and he's a pretty tough fellow in a rough house."

    Dick Gordon stared at and through the man, and then: "I think you should have been prepared for the car," he said. "If Genter's message was well founded, and he is on the track of the Frog, you should have expected a car. Sit down, Wellingdale."

    The grey-haired man obeyed.

    "I'm not excusing myself," he growled. "The Frogs have got me rattled. I treated them as a joke once."

    "Maybe we'd be wiser if we treated them as a joke now," suggested Dick, biting off the end of a cigar. "They may be nothing but a foolish secret society. Even tramps are entitled to their lodges and pass-words, grips and signs." Wellingdale shook his head.

    "You can't get away from the record of the past seven years," he said. "It isn't the fact that every other bad road-criminal we pull in has the frog tattooed on his wrist. That might be sheer imitation—and, in any case, all crooks of low mentality have tattoo marks. But in that seven years we've had a series of very unpleasant crimes. First there was the attack upon the chargé d'affaires of the United States Embassy—bludgeoned to sleep in Hyde Park. Then there was the case of the President of the Northern Trading Company—clubbed as he was stepping out of his car in Park Lane.