"A lovely spring afternoon, Doctor," he said, clearly and coldly, with the grimace which did duty for a smile. It was even less like one than usual. "Charming!" the doctor replied. "I should not suppose," continued the professor, almost snarling, "that a man of your engagements would have time for profitless excursions into the country." "Ah," the doctor returned, smiling, "but it was not profitless. I have been to a birthday party; the party of Miss Sally Ladue." What reply should the professor have made to that? The professor, at least, did not know. He turned, again, without a word. Doctor Galen looked after him, still smiling. Then he, too, turned again. "I am sorry for Sally," he murmured, sighing. "But Sanderson is there. He must get her out of it somehow." Sanderson could not get her out of it, as it happened. The little bunch of guests was halfway down the walk, laughing and talking; even Sally laughed a little, although she did not talk much, and her eye was alert for anybody who might come in at the gate. She hoped, fervently, that nobody would come in at that gate until the girls were out of it and safe at home. Then her father emerged from behind the screen of bushes along the wall and swung the gate wide. Sally gave one look. "Oh, Fox!" she cried. But Fox had seen and had run forward. "Why such haste, Mr. Sanderson?" sneered the professor. "Why such haste? I require no assistance." He went on toward the house, smiling at the girls as he passed. The way opened quickly before that smile of the professor's, and the laughter and the talk died. The effect was astonishing. And while he made his way rapidly onward, closely followed by Fox, the group of Sally's guests fairly melted away. Once outside the gate, and behind the sheltering screen, they ran. Sally met Fox just coming out. "It's all right, Sally," he said. "I persuaded him that no noise is to be made. I persuaded him." Sally looked at Fox in wonder. "It didn't take long." "No, it didn't take long." There were curious firm lines about Fox's mouth and his voice was not quite steady. What the nature of the persuasion was, which was so effective and in so short a time, Sally was not likely to know. CHAPTER X