If it be ever true that a man may be known by his books, it was certainly so to some extent in the case of Dr. Otto Baumgartner. His library was singularly small for an intellectual man who wrote himself, and a majority of the volumes were in languages which no public schoolboy could be expected to read; but of the English books many were on military subjects, some few anthropological; there were photographic year-books and Psychical Research Reports by the foot or yard, and there was an odd assortment of second-hand books which had probably been labelled “occult” in their last bookseller’s list. Boismont on _Hallucinations_ was one of these; it was the book for Pocket. He took the little red volume down, and read a long chapter on somnambulism in the big chair. In a way it comforted him. It was something to find that he was far from being the only harmless creature who had committed a diabolical deed in his sleep; here among several cases was one of another boy who had made an equally innocent and yet determined attempt on his own father. But there was something peculiar in poor Pocket’s case, something that distinguished it from any of those cited in the book, and he was still ferreting for its absolute fellow when Phillida came in long before he expected her. Boismont had made the time fly wonderfully, in spite of everything; the girl, too, appeared to have been taken out of herself, and talked about her concert as any other young girl might have done, both to Pocket and her uncle, who glided in at once from the garden. The doctor, however, was himself in mellower mood; and they were having tea, for all the world like any ordinary trio, the girl still making talk about sundry songs, the man quizzing them and her, and the boy standing up for one that his sister sang at home, when a metallic tattoo put a dramatic stop to the conversation. The two young people, but not their elder, were startled quite out of their almost inadvertent tranquillity; and the knocker was not still before Pocket realised that it was the first time he had heard it. No letters were delivered at that house; not a soul had he seen or heard at the door before. Even in his excitement, however, with its stunning recrudescence of every reality, its instantaneous visions of his people or the police, there was room for a measure of disgust when the girl got up, at an ungallant nod from the German, to go to the door. “It’s a huge fat man,” whispered Phillida, on her return to the big room at the back of the house. “Here’s his card.” “Thrush!” muttered Baumgartner as though he knew the name, and he glowered at the two young faces on which it made no impression whatever. It was plain how he hated leaving them together; but for once it must be done, and done quickly—with both doors open and the visitor’s very movements audible on the steps. To the door the doctor must go, and went, shutting that one pointedly behind him.