“That’s an odd coincidence,” said Pender. “At Rugby. I should think my unknown friend would be interested — if he is still there, doing his bit of business. I wonder what his business is, by the way.”

It is a very curious thing how, when once your attention is attracted to any particular set of circumstances, that set of circumstances seems to haunt you. You get appendicitis: immediately the newspapers are filled with paragraphs about statesmen suffering from appendicitis and victims dying of it; you learn that all your acquaintances have had it, or know friends who have had it and either died of it, or recovered from it with more surprising and spectacular rapidity than yourself; you cannot open a popular magazine without seeing its cure mentioned as one of the triumphs of modern surgery, or dip into a scientific treatise without coming across a comparison of the vermiform appendix in men and monkeys. Probably these references to appendicitis are equally frequent at all times, but you only notice them when your mind is attuned to the subject. At any rate, it was in this way that Pender accounted to himself for the extra-ordinary frequency with which people seemed to die in their baths at this period.

The thing pursued him at every turn. Always the same sequence of events: the hot bath, the discovery of the corpse, the inquest. Always the same medical opinion: heart failure following immersion in too hot water. It began to seem to Pender that it was scarcely safe to enter a hot bath at all. He took to making his own bath cooler and cooler each day, until it almost ceased to be enjoyable.

He skimmed his paper each morning for headlines about baths before settling down to read the news; and was at once relieved and vaguely disappointed if a week passed without a hot-bath tragedy.

One of the sudden deaths that occurred in this way was that of a young and beautiful woman whose husband, an analytical chemist, had tried without success to divorce her a few months previously.