After this night my visits to Horton became far more common than they had hitherto been. Having once admitted me into the region of his strange explorations, he seemed to welcome me there. Partly, as he had said, it clarified his own thought to put it into simple language, partly, as he subsequently admitted, he was beginning to penetrate into such lonely fields of knowledge by paths so utterly untrodden, that even he, the most aloof and independent of mankind, wanted some human presence near him. Despite his utter indifference to the issues of the war--for, in his regard, issues far more crucial demanded his energies--he offered himself as surgeon to a London hospital for operations on the brain, and his services, naturally, were welcomed, for none brought knowledge or skill like his to such work. Occupied all day, he performed miracles of healing, with bold and dexterous excisions which none but he would have dared to attempt. He would operate, often successfully, for lesions that seemed certainly fatal, and all the time he was learning. He refused to accept any salary; he only asked, in cases where he had removed pieces of brain matter, to take these away, in order by further examination and dissection, to add to the knowledge and manipulative skill which he devoted to the wounded. He wrapped these morsels in sterilised lint, and took them back to the Terrace in a box, electrically heated to maintain the normal temperature of a man’s blood. His fragment might then, so he reasoned, keep some sort of independent life of its own, even as the severed heart of a frog had continued to beat for hours without connection with the rest of the body. Then for half the night he would continue to work on these sundered pieces of tissue scarcely dead, which his operations during the day had given him. Simultaneously, he was busy over the needle that must be of such infinite delicacy. One evening, fatigued with a long day’s work, I had just heard with a certain tremor of uneasy anticipation the whistles of warning which heralded an air-raid, when my telephone bell rang. My servants, according to custom, had already betaken themselves to the cellar, and I went to see what the summons was, determined in any case not to go out into the streets. I recognised Horton’s voice. “I want you at once,” he said. “But the warning whistles have gone,” said I, “And I don’t like showers of shrapnel.” “Oh, never mind that,” said he. “You must come. I’m so excited that I distrust the evidence of my own ears. I want a witness. Just come.”