Once in his room, he paced to and fro for a few minutes, nervously; then he took off his coat and bathed his head and face with cold water, pouring it over his head repeatedly. When he had rubbed his head partially dry he appeared to feel somewhat better, and he seated himself, frowning, at his desk, and tried to apply himself to his work. In this, as he undoubtedly expected, he was not very successful. He would not have expected one of his own students to be able to apply himself to work with any success under similar circumstances, whatever those circumstances were. So he pushed his work aside with some impatience, got up, took the skull from the desk and handled it absently. The feel of the skull seemed to suggest some ideas to him, for he put it down, went to the half-mounted skeleton of that ancient reptile that I have mentioned as lying between his windows, and began to work in earnest. He soon became interested; so much interested that he was forgetting about his head, which felt as if it had been pounded with hammers,--tiny hammers which had not yet finished their work, whatever it was,--and he was forgetting about his eyes, which ached as if the pressure of blood behind the eyeballs was forcing them out of his head. He didn't know but it was; but it didn't matter. And he was forgetting about his body, every bone and muscle of which was crying out for rest and sleep. He sat there, on the floor under one of his windows, puzzling over a bone which he held in his hand, and completely absorbed. Suddenly he glanced involuntarily out of the window. There sat Sally, astride a limb of the great tree, looking in at him intently. She was a most annoying child; yes, a most devilishly annoying child. He sprang to his feet and threw up the window, almost in one motion. Sally did not move a muscle; not even her eyes. He did not say the sharp things that were on the tip of his tongue, he could not have told why; he did not say anything for very nearly a minute. Under such circumstances, a minute is a long time. Nor did Sally say anything. She only gazed solemnly at him. "Sally," he demanded at last, "what are you doing there?" The look in his eyes had softened. You might have mistaken it for a look of affection. "Nothing, father," Sally answered, briefly and respectfully. "Well, what the--" Professor Ladue was at a loss for words in which to express his exasperation. This was an unusual condition for him to be in. "Well, why don't you get down?" "I don't want to get down," Sally returned. "I like being up here." "You'll break your neck." Sally made no reply. "Can you get down safely?" "Yes, father." "Get down, then," said Professor Ladue, less sharply than he had meant to speak. "Don't you know that it must annoy me very much to have you spying in upon me in that way?"