for these events befell in the days before I had joined him as his assistant, and his special knowledge and powers of inference were not then fully appreciated by me.
"It is clear, Thorndyke," I said, "that footprints have a very different meaning to you from what they have for me. I don't see in the least how you have reached any of these conclusions."
"I suppose not," was the reply; "but, you see, special knowledge of this kind is the stock-in-trade of the medical jurist, and has to be acquired by special study, though the present example is one of the greatest simplicity. But let us consider it point by point; and first we will take this set of footprints which I have inferred to be a fisherman's. Note their enormous size. They should be the footprints of a giant. But the length of the stride shows that they were made by a rather short man. Then observe the massiveness of the soles, and the fact that there are no nails in them. Note also the peculiar clumsy tread—the deep toe and heel marks, as if the walker had wooden legs, or fixed ankles and knees. From that character we can safely infer high boots of thick, rigid leather, so that we can diagnose high boots, massive and stiff, with nailless soles, and many sizes too large for the wearer. But the only boot that answers this description is the fisherman's thigh-boot—made of enormous size to enable him to wear in the winter two or three pairs of thick knitted stockings, one over the other. Now look at the other footprints; there is a double track, you see, one set coming from the sea and one going towards it. As the man (who was bow-legged and turned his toes in) has trodden in his own footprints, it is obvious that he came from the sea, and returned to it. But observe the difference in the two sets of prints; the returning ones are much deeper than the others, and the stride much shorter. Evidently he was carrying something when he returned, and that something was very heavy. Moreover, we can see, by the greater depth of the toe impressions, that he was stooping forward as he walked, and so probably carried the weight on his back. Is that quite clear?"
"Perfectly," I replied. "But how do you arrive at the interval of time between the visits of the two men?"
"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."
"Yes, I see that plainly enough," I said.
"Here, now," he continued, "is a case in point." He halted to point with his stick at a row of footprints that appeared suddenly above high-water mark, and having proceeded a short distance, crossed the line again, and vanished where the waves had washed over them. They were easily distinguished from any of the others by the clear impressions of circular rubber heels.
"Do you see anything remarkable about them?" he asked.
"I notice that they are considerably deeper than our own," I answered.
"Yes, and the boots are about the same size as ours, whereas the stride is considerably shorter—quite a short stride, in fact. Now there is a pretty constant ratio between the length of the foot and the length of the leg, between the length of leg and the height of the person, and between the stature and the length of stride. A long foot means a long leg, a tall man, and a long stride. But here we have a long foot and a short stride. What do you make of that?" He laid down his stick—a smooth partridge cane, one side of which was marked by small lines into inches and feet—beside the footprints to demonstrate the discrepancy.
"The depth of the footprints shows that he was a much heavier man than either of us," I suggested; "perhaps he was unusually fat."
"Yes," said Thorndyke, "that seems to be the explanation. The carrying of a dead weight shortens the stride, and fat is practically a dead weight. The conclusion is that he was about five feet ten inches high, and excessively fat." He picked up his cane, and we resumed our walk, keeping an eye on the procession ahead until it had disappeared round a curve in the coast-line, when we mended our pace somewhat. Presently we reached a small headland, and, turning the shoulder of cliff, came full upon the party which had preceded us. The men had halted in a narrow bay, and now stood looking down at a prostrate figure beside which the surgeon was kneeling.
"We were wrong, you see," observed Thorndyke. "He has not fallen over the cliff, nor has he been washed up by the sea. He is lying above high-water mark, and those footprints that we have been examining appear to be his."
As we approached, the sergeant turned and held up his hand.
"I'll ask you not to walk round the body just now, gentlemen," he said. "There seems to have been foul play here, and I want to be clear about the tracks before anyone crosses them."
Acknowledging this caution, we advanced to where the constables were standing, and looked down with some curiosity at the dead man. He was a tall, frail-looking man, thin to the point of emaciation, and appeared to be about thirty-five years of age. He lay in an easy posture, with half-closed eyes and a placid expression that contrasted strangely enough with the tragic circumstances of his death.
"It is a clear case of murder," said Dr. Burrows, dusting the sand from his knees as he stood up. "There is a deep knife-wound above the heart, which must have caused death almost instantaneously."
"How long should you say he has been dead, Doctor?" asked the sergeant.
"Twelve hours at least," was the reply. "He is quite cold and stiff."
"Twelve hours, eh?" repeated the officer. "That would bring it to about six o'clock this morning."
"I won't commit myself to a definite time," said Dr. Burrows hastily. "I only say not less than twelve hours. It might have been considerably more."
"Ah!" said the sergeant. "Well, he made a pretty good fight for his