"That also is quite simple. The tide is now about halfway out; it is thus about three hours since high water. Now, the fisherman walked just about the neap-tide, high-water mark, sometimes above it and sometimes below. But none of his footprints have been obliterated; therefore he passed after high water--that is, less than three hours ago; and since his footprints are all equally distinct, he could not have passed when the sand was very wet. Therefore he probably passed less than an hour ago. The other man's footprints, on the other hand, reach only to the neap-tide, high-water mark, where they end abruptly. The sea has washed over the remainder of the tracks and obliterated them. Therefore he passed not less than three hours and not more than four days ago--probably within twenty-four hours."
As Thorndyke concluded his demonstration the sound of voices was borne to us from above, mingled with the tramping of feet, and immediately afterwards a very singular party appeared at the head of the gap descending towards the shore. First came a short burly fisherman clad in oilskins and sou'-wester, clumping along awkwardly in his great sea-boots, then the local police-sergeant in company with my professional rival Dr. Burrows, while the rear of the procession was brought up by two constables carrying a stretcher. As he reached the bottom of the gap the fisherman, who was evidently acting as guide, turned along the shore, retracing his own tracks, and the procession followed in his wake.
"A surgeon, a stretcher, two constables, and a police-sergeant," observed Thorndyke. "What does that suggest to your mind, Jervis?"
"A fall from the cliff," I replied, "or a body washed up on the shore."
"Probably," he rejoined; "but we may as well walk in that direction."
We turned to follow the retreating procession, and as we strode along the smooth surface left by the retiring tide Thorndyke resumed:
"The subject of footprints has always interested me deeply for two reasons. First, the evidence furnished by footprints is constantly being brought forward, and is often of cardinal importance; and, secondly, the whole subject is capable of really systematic and scientific treatment. In the main the data are anatomical, but age, sex, occupation, health, and disease all give their various indications. Clearly, for instance, the footprints of an old man will differ from those of a young man of the same height, and I need not point out to you that those of a person suffering from locomotor ataxia or paralysis agitans would be quite unmistakable."