At least, that was the vague conclusion that came into the Doctor's mind and stuck there. It was the only theory at all consonant with his own knowledge of human anatomy. All physiological action could be traced to the passage of nervous energy from one centre to another, and it was obvious that, in the case of the Clockwork man, such energy was subjected to enormous acceleration and probably distributed along specially prepared paths. There was nothing in the science of neuropathy to account for such disturbances and reactions. There were neural freaks--the Doctor had himself treated some remarkable cases of nervous disorder--but the behaviour of the Clockwork man could not be explained by any principle within human knowledge. Not the least puzzling circumstance about him was the fact that now and again his speech and manner made it impossible to accept the supposition or mechanical origin; whilst at other times his antics induced a positive conviction that he was really a sort of highly perfected toy. Presently the Clockwork man got up and began walking up and down the room, in his slow, flat-footed manner. "How do you feel now?" ventured the Doctor, arousing himself with an effort. "Oh, so, so," sighed the other, "only so, so--I can't expect to feel myself, you know." He reached to the end of the room, and jerking himself round, started on the return journey. The Doctor arose slowly and remained standing. There was barely room for two people to walk up and down. "Anything might happen," the Clockwork man continued, plaintively, "I feel as though I might slip again, you know--slip back another thousand years or so." He turned again. "I've got to get worse before I get better," he sighed, and then stopped to examine the rows of bottles arranged along the shelves. "What are these?" he enquired. "Medicines," said the Doctor, without enthusiasm. "Do they help people to work?" "H'm, yes--chemical action--tonics. People get run down, and I have to give them something to stimulate the system." "I see," the Clockwork man nodded sagely. "But they wouldn't be any use to me. What I need is adjustment, regulation." He looked hard at the doctor, with a pathetic expression of enquiry. "My clock--" he began, and stopped abruptly.