"The hint that ultimately guided me into new fields of research came to me by the merest chance. A few days after the visit of the detective I received a letter from one of my few remaining friends, a Dr. Grayson, who had formerly practiced in London as a physician, but who, owing to age and infirmity, had retired to his native place, the village of Shome, near Rochester. Grayson asked me to spend a day with him, that we might talk over some matters in which we were both interested; and, being now rather at a loose end, I accepted the invitation, but declined to sleep away from home and my collection.
"It is significant of my state of mind at this time that, before starting, I considered what weapon I should take with me. Formerly I should no more have thought of arming myself for a simple railway journey than of putting on a coat of mail; but now a train suggested a train robber—a Lefroy, with a very unsubmissive Mr. Gold—and the long tunnel near Strood was but the setting of a railway tragedy. My ultimate choice of weapon, too, is interesting. The familiar revolver I rejected utterly. There must be no noise. My quarrel with the criminal was a personal one in which no outsiders must be allowed to meddle. I should have preferred the concussor, which I now handled with skill, but it was hardly a portable tool, and my choice ultimately fell on a very fine swordstick, supplemented by a knuckle-duster which had been bequeathed to me by one of my clients after trial on my own countenance.
"And after all, nothing happened. I got into an empty first-class compartment and when, just as the train was starting, a burly fellow dashed in and slammed the door, I eyed him suspiciously and waited for developments. But there were none. The fellow sat huddled in a corner, watching me and keeping an eye on the handle of the alarm over his head; but he made no sign. When we emerged from the long tunnel he was as white as a ghost and he hopped out on to Strood platform almost before the train had begun to slow down.
"I reached my bag down from the rack and got out after him, smiling at my own folly. The criminal was becoming an obsession of which I must beware if I would not end my days in an asylum; a fact which was further impressed on me when I saw my late fellow-passenger, who had just caught sight of me, 'legging it' down the station approach like a professional pedestrian and looking back nervously over his shoulder. Resolving firmly to put the subject out of my mind, I walked slowly into the town and betook myself to the London Road; and though, as I passed the Falstaff Inn and crossed Gad's Hill, fleeting reminiscences of Prince Henry and the men in buckram came unsought, with later suggestions of a stagecoach struggling up the hill in the dark and masked figures creeping down the banks into the sunken road, I kept to my good resolution. The bag was a little cumbersome—it contained a large parcel of bulbs from Covent Garden that Grayson had asked me to bring—and yet it was pleasant to break off from the high road and stray by well-remembered tracks and footpaths across the fields. It was all familiar ground; for in years gone by, when Grayson was in practice, we would come down together for weekends to his little demesne, and often I would stay on alone for a week or so and ramble about the country by myself. So I knew every inch of the country side and was so much interested in renewing my acquaintance with it that I was twenty minutes late for lunch.
"I had a most agreeable day with Grayson (who was working at the historical aspects of disease), and would have stayed later than I did. But at about half-past eight—we had dined at seven—Grayson began to be restless and fidgetty and at last said apologetically:
"'Don't think me inhospitable, Challoner, but if you aren't going to stay the night you had better be going. And don't go by Gad's Hill. Take the road down to Higham and catch the train there.'
"'Why, what is the matter with Gad's Hill?' I asked.
"'Nothing much by daylight, but a great deal at night. It has always been an unsafe spot and is especially just now. There has been quite an epidemic of highway robberies lately. They began when the hoppers were here last autumn, but some of those East-end ruffians seem to have settled in the neighborhood. I have seen some very queer-looking characters even in this village; aliens, apparently, of the kind that you see about Stepney and Whitechapel.
"'Now, you get down to Higham, like a good fellow, before the country settles down for the night.'
"Needless to say, the prowling alien had no terrors for me, but as Grayson was really uneasy, I made no demur and took my leave almost immediately. But I did not make directly for Higham. The moon was up and the village looked very inviting. Tree and chimney-stack, thatched roof and gable-end cut pleasant shapes of black against the clear sky, and patches of silvery light fell athwart the road on wooden palings and weather-boarded fronts. I strolled along the little street, carrying the now light and empty bag and exchanging greetings with scattered villagers, until I came to the lane that turns down towards the London Road. Here, by a triangular patch of green, I halted and mechanically looked at my watch, holding it up in the moonlight. I was about to replace it when a voice asked: