The doctor would not hear of it at first. Eventually he said he should have to inspect the letter before it went; and this proved the thin edge of consent. In the end it was arranged that Pocket should write what he liked to his sister only, and that Baumgartner should read and enclose it in a covering letter, so that everybody need not know it was a letter from the missing boy. Baumgartner was to have it posted from St. Martin’s-le-Grand, to destroy all trace of a locality which he now refused point-blank to disclose even to the writer. And in return for the whole concession the schoolboy was to give his solemn word and sacred promise on the following points. He was not to set foot outside the house without Baumgartner, nor to show himself for a moment at the windows back or front. On no account was he to confide in the doctor’s niece Phillida, to give her the slightest inkling of his connection with the latest of London mysteries, or even of the scene, or any of the circumstances of his first meeting with Baumgartner. “You are bound to see something of each other; the less you say about yourself the better.” “But what can she think?” “What she likes, my young fellow! I am a medical man; medical men may bring patients to their houses even when they have ceased to practise in the ordinary way. It is no business of hers, and what she chooses to think is no affair of ours. She has seen you very ill, remember, and she had your doctor’s orders not to let you out of the house in his absence.” “She obeyed them like a little brick!” muttered Pocket, with a wistful heaviness.