The contrariety of human nature is a subject that has given a surprising amount of occupation to makers of proverbs and to those moral philosophers who make it their province to discover and expound the glaringly obvious; and especially have they been concerned to enlarge upon that form of perverseness which engenders dislike of things offered under compulsion, and arouses desire of them as soon as their attainment becomes difficult or impossible. They assure us that a man who has had a given thing within his reach and put it by, will, as soon as it is beyond his reach, find it the one thing necessary and desirable; even as the domestic cat which has turned disdainfully from the preferred saucer, may presently be seen with her head jammed hard in the milk-jug, or, secretly and with horrible relish, slaking her thirst at the scullery sink.

To this peculiarity of the human mind was due, no doubt, the fact that no sooner had I abandoned the clinical side of my profession in favour of the legal, and taken up my abode in the chambers of my friend Thorndyke, the famous medico-legal expert, to act as his assistant or junior, than my former mode of life--that of a locum tenens, or minder of other men's practices--which had, when I was following it, seemed intolerably irksome, now appeared to possess many desirable features; and I found myself occasionally hankering to sit once more by the bedside, to puzzle out the perplexing train of symptoms, and to wield that power--the greatest, after all, possessed by man--the power to banish suffering and ward off the approach of death itself.

Hence it was that on a certain morning of the long vacation I found myself installed at The Larches, Burling, in full charge of the practice of my old friend Dr. Hanshaw, who was taking a fishing holiday in Norway. I was not left desolate, however, for Mrs. Hanshaw remained at her post, and the roomy, old-fashioned house accommodated three visitors in addition. One of these was Dr. Hanshaw's sister, a Mrs. Haldean, the widow of a wealthy Manchester cotton factor; the second was her niece by marriage, Miss Lucy Haldean, a very handsome and charming girl of twenty-three; while the third was no less a person than Master Fred, the only child of Mrs. Haldean, and a strapping boy of six.

"It is quite like old times--and very pleasant old times, too--to see you sitting at our breakfast-table, Dr. Jervis." With these gracious words and a friendly smile, Mrs. Hanshaw handed me my tea-cup.

I bowed. "The highest pleasure of the altruist," I replied, "is in contemplating the good fortune of others."

Mrs. Haldean laughed. "Thank you," she said. "You are quite unchanged, I perceive. Still as suave and as--shall I say oleaginous?"

"No, please don't!" I exclaimed in a tone of alarm.

"Then I won't. But what does Dr. Thorndyke say to this backsliding on your part? How does he regard this relapse from medical jurisprudence to common general practice?"

"Thorndyke," said I, "is unmoved by any catastrophe; and he not only regards the 'Decline and Fall-off of the Medical Jurist' with philosophic calm, but he even favours the relapse, as you call it. He thinks it may be useful to me to study the application of medico-legal methods to general practice."

"That sounds rather unpleasant--for the patients, I mean," remarked Miss Haldean.

"Very," agreed her aunt. "Most cold-blooded. What sort of man is Dr. Thorndyke? I feel quite curious about him. Is he at all human, for instance?"

"He is entirely human," I replied; "the accepted tests of humanity being, as I understand, the habitual adoption of the erect posture in locomotion, and the relative position of the end of the thumb--"

"I don't mean that," interrupted Mrs. Haldean. "I mean human in things that matter."

"I think those things matter," I rejoined. "Consider, Mrs. Haldean, what would happen if my learned colleague were to be seen in wig and gown, walking towards the Law Courts in any posture other than the erect. It would be a public scandal."

"Don't talk to him, Mabel," said Mrs. Hanshaw; "he is incorrigible. What are you doing with yourself this morning, Lucy?"

Miss Haldean (who had hastily set down her cup to laugh at my imaginary picture of Dr. Thorndyke in the character of a quadruped) considered a moment.

"I think I shall sketch that group of birches at the edge of Bradham Wood," she said.

"Then, in that case," said I, "I can carry your traps for you, for I have to see a patient in Bradham."

"He is making the most of his time," remarked Mrs. Haldean maliciously to my hostess. "He knows that when Mr. Winter arrives he will retire into the extreme background."

Douglas Winter, whose arrival was expected in the course of the week, was Miss Haldean's fiance. Their engagement had been somewhat protracted, and was likely to be more so, unless one of them received some unexpected accession of means; for Douglas was a subaltern in the Royal Engineers, living, with great difficulty, on his pay, while Lucy Haldean subsisted on an almost invisible allowance left her by an uncle.

I was about to reply to Mrs. Haldean when a patient was announced, and, as I had finished my breakfast, I made my excuses and left the table.

Half an hour later, when I started along the road to the village of Bradham, I had two companions. Master Freddy had joined the party, and he disputed with me the privilege of carrying the "traps," with the result that a compromise was effected, by which he carried the camp-stool, leaving me in possession of the easel, the bag, and a large bound sketching-block.

"Where are you going to work this morning?" I asked, when we had trudged on some distance.

"Just off the road to the left there, at the edge of the wood. Not very far from the house of the mysterious stranger." She glanced at me mischievously as she made this reply, and chuckled with delight when I rose at the bait.

"What house do you mean?" I inquired.

"Ha!" she exclaimed, "the investigator of mysteries is aroused. He saith, 'Ha! ha!' amidst the trumpets; he smelleth the battle afar off."

"Explain instantly," I commanded, "or I drop your sketch-block into the very next puddle."

"You terrify me," said she. "But I will explain, only there isn't any mystery except to the bucolic mind. The house is called Lavender Cottage, and it stands alone in the fields behind the wood. A fortnight ago it was let furnished to a stranger named Whitelock, who has taken it for the purpose of studying the botany of the district; and the only really mysterious thing about him is that no one has seen him. All arrangements with the house-agent were made by letter, and, as far as I can make out, none of the local tradespeople supply him, so he must get his things from a distance--even his bread, which really is rather odd. Now say I am an inquisitive, gossiping country bumpkin."

"I was going to," I answered, "but it is no use now."

She relieved me of her sketching appliances with pretended indignation, and crossed into the meadow, leaving me to pursue my way alone; and when I presently looked back, she was setting up her easel and stool, gravely assisted by Freddy.

My "round," though not a long one, took up more time than I had anticipated, and it was already past the luncheon hour when I passed the place where I had left Miss Haldean. She was gone, as I had expected, and I hurried homewards, anxious to be as nearly punctual as possible. When I entered the dining-room, I found Mrs. Haldean and our hostess seated at the table, and both looked up at me expectantly.

"Have you seen Lucy?" the former inquired.

"No," I answered. "Hasn't she come back? I expected to find her here. She had left the wood when I passed just now."

Mrs. Haldean knitted her brows anxiously. "It is very strange," she said, "and very thoughtless of her. Freddy will be famished."

I hurried over my lunch, for two fresh messages had come in from outlying hamlets, effectually dispelling my visions of a quiet afternoon; and as the minutes passed without bringing any signs of the absentees, Mrs. Haldean became more and more restless and anxious. At length her suspense became unbearable; she rose suddenly, announcing her intention of cycling up the road to look for the defaulters, but as she was moving towards the door, it burst open, and Lucy Haldean staggered into the room.

Her appearance filled us with alarm. She was deadly pale, breathless, and wild-eyed; her dress was draggled and torn, and she trembled from head to foot.

"Good God, Lucy!" gasped Mrs. Haldean. "What has happened? And where is Freddy?" she added in a sterner tone.

"He is lost!" replied Miss Haldean in a faint voice, and with a catch in her breath. "He strayed away while I was painting. I have searched the wood through, and called to him, and looked in all the meadows. Oh! where can he have gone?" Her sketching "kit," with which she was loaded, slipped from her grasp and rattled on to the floor, and she buried her face in her hands and sobbed hysterically.

"And you have dared to come back without him?" exclaimed Mrs. Haldean.

"I was getting exhausted. I came back for help," was the faint reply.

"Of course she was exhausted," said Mrs. Hanshaw. "Come, Lucy: come, Mabel; don't make mountains out of molehills. The little man is safe enough. We shall find him presently, or he will come home by himself. Come and have some food, Lucy."

Miss Haldean shook her head. "I can't, Mrs. Hanshaw--really I can't," she said; and, seeing that she was in a state of utter exhaustion, I poured out a glass of wine and made her drink it.

Mrs. Haldean darted from the room, and returned immediately, putting on her hat. "You have got to come with me and show me whore you lost him," she said.

"She can't do that, you know," I said rather brusquely. "She will have to lie down for the present. But I know the place, and will cycle up with you."

"Very well," replied Mrs. Haldean, "that will do. What time was it," she asked, turning to her niece, "when you lost the child? and which way--"

She paused abruptly, and I looked at her in surprise. She had suddenly turned ashen and ghastly; her face had set like a mask of stone, with parted lips and staring eyes that were fixed in horror on her niece.

There was a deathly silence for a few seconds. Then, in a terrible voice, she demanded: "What is that on your dress, Lucy?" And, after a pause, her voice rose into a shriek. "What have you done to my boy?"

I glanced in astonishment at the dazed and terrified girl, and then I saw what her aunt had seen--a good-sized blood-stain halfway down the front of her skirt, and another smaller one on her right sleeve. The girl herself looked down at the sinister patch of red and then up at her aunt. "It looks like--like blood," she stammered. "Yes, it is--I think--of course it is. He struck his nose--and it bled--"

"Come," interrupted Mrs. Haldean, "let us go," and she rushed from the room, leaving me to follow.

I lifted Miss Haldean, who was half fainting with fatigue and agitation, on to the sofa, and, whispering a few words of encouragement into her ear, turned to Mrs. Hanshaw.

"I can't stay with Mrs. Haldean," I said. "There are two visits to be made at Rebworth. Will you send the dogcart up the road with somebody to take my place?"

"Yes," she answered. "I will send Giles, or come myself if Lucy is fit to be left."

I ran to the stables for my bicycle, and as I pedalled out into the road I could see Mrs. Haldean already far ahead, driving her machine at frantic speed. I followed at a rapid pace, but it was not until we approached the commencement of the wood, when she slowed down somewhat, that I overtook her.

"This is the place," I said, as we reached the spot where I had parted from Miss Haldean. We dismounted and wheeled our bicycles through the gate, and laying them down beside the hedge, crossed the meadow and entered the wood.

It was a terrible experience, and one that I shall never forget--the white-faced, distracted woman, tramping in her flimsy house-shoes over the rough ground, bursting through the bushes, regardless of the thorny branches that dragged at skin and hair and dainty clothing, and sending forth from time to time a tremulous cry, so dreadfully pathetic in its mingling of terror and coaxing softness, that a lump rose in my throat, and I could barely keep my self-control.

"Freddy! Freddy-boy! Mummy's here, darling!" The wailing cry sounded through the leafy solitude; but no answer came save the whirr of wings or the chatter of startled birds. But even more shocking than that terrible cry--more disturbing and eloquent with dreadful suggestion--was the way in which she peered, furtively, but with fearful expectation, among the roots of the bushes, or halted to gaze upon every molehill and hummock, every depression or disturbance of the ground.

So we stumbled on for a while, with never a word spoken, until we came to a beaten track or footpath leading across the wood. Here I paused to examine the footprints, of which several were visible in the soft earth, though none seemed very recent; but, proceeding a little way down the track, I perceived, crossing it, a set of fresh imprints, which I recognized at once as Miss Haldean's. She was wearing, as I knew, a pair of brown golf-boots, with rubber pads in the leather soles, and the prints made by them were unmistakable.

"Miss Haldean crossed the path here," I said, pointing to the footprints.

"Don't speak of her before me!" exclaimed Mrs. Haldean; but she gazed eagerly at the footprints, nevertheless, and immediately plunged into the wood to follow the tracks.

"You are very unjust to your niece, Mrs. Haldean," I ventured to protest.

She halted, and faced me with an angry frown.

"You don't understand!" she exclaimed. "You don't know, perhaps, that if my poor child is really dead, Lucy Haldean will be a rich woman, and may marry to-morrow if she chooses?"

"I did not know that," I answered, "but if I had, I should have said the same."

"Of course you would," she retorted bitterly. "A pretty face can muddle any man's judgment."

She turned away abruptly to resume her pursuit, and I followed in silence. The trail which we were following zigzagged through the thickest part of the wood, but its devious windings eventually brought us out on to an open space on the farther side. Here we at once perceived traces of another kind. A litter of dirty rags, pieces of paper, scraps of stale bread, bones and feathers, with hoof-marks, wheel ruts, and the ashes of a large wood fire, pointed clearly to a gipsy encampment recently broken up. I laid my hand on the heap of ashes, and found it still warm, and on scattering it with my foot a layer of glowing cinders appeared at the bottom.

"These people have only been gone an hour or two," I said. "It would be well to have them followed without delay."

A gleam of hope shone on the drawn, white face as the bereaved mother caught eagerly at my suggestion.

"Yes," she exclaimed breathlessly; "she may have bribed them to take him away. Let us see which way they went."

We followed the wheel tracks down to the road, and found that they turned towards London. At the same time I perceived the dogcart in the distance, with Mrs. Hanshaw standing beside it; and, as the coachman observed me, he whipped up his horse and approached.

"I shall have to go," I said, "but Mrs. Hanshaw will help you to continue the search."

"And you will make inquiries about the gipsies, won't you?" she said.

I promised to do so, and as the dogcart now came up, I climbed to the seat, and drove off briskly up the London Road.

The extent of a country doctor's round is always an unknown quantity. On the present occasion I picked up three additional patients, and as one of them was a case of incipient pleurisy, which required to have the chest strapped, and another was a neglected dislocation of the shoulder, a great deal of time was taken up. Moreover, the gipsies, whom I ran to earth on Rebworth Common, delayed me considerably, though I had to leave the rural constable to carry out the actual search, and, as a result, the clock of Burling Church was striking six as I drove through the village on my way home.

I got down at the front gate, leaving the coachman to take the dogcart round, and walked up the drive; and my astonishment may be imagined when, on turning the corner, I came suddenly upon the inspector of the local police in earnest conversation with no less a person than John Thorndyke.

"What on earth has brought you here?" I exclaimed, my surprise getting the better of my manners.

"The ultimate motive-force," he replied, "was an impulsive lady named Mrs. Haldean. She telegraphed for me--in your name."

"She oughtn't to have done that," I said.

"Perhaps not. But the ethics of an agitated woman are not worth discussing, and she has done something much worse--she has applied to the local J.P. (a retired Major-General), and our gallant and unlearned friend has issued a warrant for the arrest of Lucy Haldean on the charge of murder."

"But there has been no murder!" I exclaimed.

"That," said Thorndyke, "is a legal subtlety that he does not appreciate. He has learned his law in the orderly-room, where the qualifications to practise are an irritable temper and a loud voice. However, the practical point is, inspector, that the warrant is irregular. You can't arrest people for hypothetical crimes."

The officer drew a deep breath of relief. He knew all about the irregularity, and now joyfully took refuge behind Thorndyke's great reputation.

When he had departed--with a brief note from my colleague to the General--Thorndyke slipped his arm through mine, and we strolled towards the house.

"This is a grim business, Jervis," said he. "That boy has got to be found for everybody's sake. Can you come with me when you have had some food?"

"Of course I can. I have been saving myself all the afternoon with a view to continuing the search."

"Good," said Thorndyke. "Then come in and feed."

A nondescript meal, half tea and half dinner, was already prepared, and Mrs. Hanshaw, grave but self-possessed, presided at the table.

"Mabel is still out with Giles, searching for the boy," she said. "You have heard what she has done!"

I nodded.

"It was dreadful of her," continued Mrs. Hanshaw, "but she is half mad, poor thing. You might run up and say a few kind words to poor Lucy while I make the tea."

I went up at once and knocked at Miss Haldean's door, and, being bidden to enter, found her lying on the sofa, red-eyed and pale, the very ghost of the merry, laughing girl who had gone out with me in the morning. I drew up a chair, and sat down by her side, and as I took the hand she held out to me, she said:

"It is good of you to come and see a miserable wretch like me. And Jane has been so sweet to me, Dr. Jervis; but Aunt Mabel thinks I have killed Freddy--you know she does--and it was really my fault that he was lost. I shall never forgive myself!"

She burst into a passion of sobbing, and I proceeded to chide her gently.

"You are a silly little woman," I said, "to take this nonsense to heart as you are doing. Your aunt is not responsible just now, as you must know; but when we bring the boy home she shall make you a handsome apology. I will see to that."

She pressed my hand gratefully, and as the bell now rang for tea, I bade her have courage and went downstairs.

"You need not trouble about the practice," said Mrs. Hanshaw, as I concluded my lightning repast, and Thorndyke went off to get our bicycles. "Dr. Symons has heard of our trouble, and has called to say that he will take anything that turns up; so we shall expect you when we see you."

"How do you like Thorndyke?" I asked.

"He is quite charming," she replied enthusiastically; "so tactful and kind, and so handsome, too. You didn't tell us that. But here he is. Good-bye, and good luck."

She pressed my hand, and I went out into the drive, where Thorndyke and the coachman were standing with three bicycles.

"I see you have brought your outfit," I said as we turned into the road; for Thorndyke's machine bore a large canvas-covered case strapped on to a strong bracket.

"Yes; there are many things that we may want on a quest of this kind. How did you find Miss Haldean?"

"Very miserable, poor girl. By the way, have you heard anything about her pecuniary interest in the child's death?"

"Yes," said Thorndyke. "It appears that the late Mr. Haldean used up all his brains on his business, and had none left for the making of his will--as often happens. He left almost the whole of his property--about eighty thousand pounds--to his son, the widow to have a life-interest in it. He also left to his late brother's daughter, Lucy, fifty pounds a year, and to his surviving brother Percy, who seems to have been a good-for-nothing, a hundred a year for life. But--and here is the utter folly of the thing--if the son should die, the property was to be equally divided between the brother and the niece, with the exception of five hundred a year for life to the widow. It was an insane arrangement."

"Quite," I agreed, "and a very dangerous one for Lucy Haldean, as things are at present."

"Very; especially if anything should have happened to the child."

"What are you going to do now?" I inquired, seeing that Thorndyke rode on as if with a definite purpose.

"There is a footpath through the wood," he replied. "I want to examine that. And there is a house behind the wood which I should like to see."

"The house of the mysterious stranger," I suggested.

"Precisely. Mysterious and solitary strangers invite inquiry."

We drew up at the entrance to the footpath, leaving Willett the coachman in charge of the three machines, and proceeded up the narrow track. As we went, Thorndyke looked back at the prints of our feet, and nodded approvingly.

"This soft loam," he remarked, "yields beautifully clear impressions, and yesterday's rain has made it perfect."

We had not gone far when we perceived a set of footprints which I recognized, as did Thorndyke also, for he remarked: "Miss Haldean--running, and alone." Presently we met them again, crossing in the opposite direction, together with the prints of small shoes with very high heels. "Mrs. Haldean on the track of her niece," was Thorndyke's comment; and a minute later we encountered them both again, accompanied by my own footprints.

"The boy does not seem to have crossed the path at all," I remarked as we walked on, keeping off the track itself to avoid confusing the footprints.

"We shall know when we have examined the whole length," replied Thorndyke, plodding on with his eyes on the ground. "Ha! here is something new," he added, stopping short and stooping down eagerly--"a man with a thick stick--a smallish man, rather lame. Notice the difference between the two feet, and the peculiar way in which he uses his stick. Yes, Jervis, there is a great deal to interest us in these footprints. Do you notice anything very suggestive about them?"

"Nothing but what you have mentioned," I replied. "What do you mean?"

"Well, first there is the very singular character of the prints themselves, which we will consider presently. You observe that this man came down the path, and at this point turned off into the wood; then he returned from the wood and went up the path again. The imposition of the prints makes that clear. But now look at the two sets of prints, and compare them. Do you notice any difference?"

"The returning footprints seem more distinct--better impressions."

"Yes; they are noticeably deeper. But there is something else." He produced a spring tape from his pocket, and took half a dozen measurements. "You see," he said, "the first set of footprints have a stride of twenty-one inches from heel to heel--a short stride; but he is a smallish man, and lame; the returning ones have a stride of only nineteen and a half inches; hence the returning footprints are deeper than the others, and the steps are shorter. What do you make of that?"

"It would suggest that he was carrying a burden when he returned," I replied.

"Yes; and a heavy one, to make that difference in the depth. I think I will get you to go and fetch Willett and the bicycles."

I strode off down the path to the entrance, and, taking possession of Thorndyke's machine, with its precious case of instruments, bade Willett follow with the other two.

When I returned, my colleague was standing with his hands behind him, gazing with intense preoccupation at the footprints. He looked up sharply as we approached, and called out to us to keep off the path if possible.

"Stay here with the machines, Willett," said he. "You and I, Jervis, must go and see where our friend went to when he left the path, and what was the burden that he picked up."

We struck off into the wood, where last year's dead leaves made the footprints almost indistinguishable, and followed the faint double track for a long distance between the dense clumps of bushes. Suddenly my eye caught, beside the double trail, a third row of tracks, smaller in size and closer together. Thorndyke had seen them, too, and already his measuring-tape was in his hand.

"Eleven and a half inches to the stride," said he. "That will be the boy, Jervis. But the light is getting weak. We must press on quickly, or we shall lose it."

Some fifty yards farther on, the man's tracks ceased abruptly, but the small ones continued alone; and we followed them as rapidly as we could in the fading light.

"There can be no reasonable doubt that these are the child's tracks," said Thorndyke; "but I should like to find a definite footprint to make the identification absolutely certain."

A few seconds later he halted with an exclamation, and stooped on one knee. A little heap of fresh earth from the surface-burrow of a mole had been thrown up over the dead leaves; and fairly planted on it was the clean and sharp impression of a diminutive foot, with a rubber heel showing a central star. Thorndyke drew from his pocket a tiny shoe, and pressed it on the soft earth beside the footprint; and when he raised it the second impression was identical with the first.

"The boy had two pairs of shoes exactly alike," he said, "so I borrowed one of the duplicate pair."

He turned, and began to retrace his steps rapidly, following our own fresh tracks, and stopping only once to point out the place where the unknown man had picked the child up. When we regained the path we proceeded without delay until we emerged from the wood within a hundred yards of the cottage.

"I see Mrs. Haldean has been here with Giles," remarked Thorndyke, as he pushed open the garden-gate. "I wonder if they saw anybody."

He advanced to the door, and having first rapped with his knuckles and then kicked at it vigorously, tried the handle.

"Locked," he observed, "but I see the key is in the lock, so we can get in if we want to. Let us try the back."

The back door was locked, too, but the key had been removed.

"He came out this way, evidently," said Thorndyke. "though he went in at the front, as I suppose you noticed. Let us see where he went."

The back garden was a small, fenced patch of ground, with an earth path leading down to the back gate. A little way beyond the gate was a small barn or outhouse.

"We are in luck," Thorndyke remarked, with a glance at the path. "Yesterday's rain has cleared away all old footprints, and prepared the surface for new ones. You see there are three sets of excellent impressions--two leading away from the house, and one set towards it. Now, you notice that both of the sets leading from the house are characterized by deep impressions and short steps, while the set leading to the house has lighter impressions and longer steps. The obvious inference is that he went down the path with a heavy burden, came back empty-handed, and went down again--and finally--with another heavy burden. You observe, too, that he walked with his stick on each occasion."

By this time we had reached the bottom of the garden. Opening the gate, we followed the tracks towards the outhouse, which stood beside a cart-track; but as we came round the corner we both stopped short and looked at one another. On the soft earth were the very distinct impressions of the tyres of a motor-car leading from the wide door of the outhouse. Finding that the door was unfastened, Thorndyke opened it, and looked in, to satisfy himself that the place was empty. Then he fell to studying the tracks.

"The course of events is pretty plain," he observed. "First the fellow brought down his luggage, started the engine, and got the car out--you can see where it stood, both by the little pool of oil, and by the widening and blurring of the wheel-tracks from the vibration of the free engine; then he went back and fetched the boy--carried him pick-a-back, I should say, judging by the depth of the toe-marks in the last set of footprints. That was a tactical mistake. He should have taken the boy straight into the shed."

He pointed as he spoke to one of the footprints beside the wheel-tracks, from the toe of which projected a small segment of the print of a little rubber heel.

We now made our way back to the house, where we found Willett pensively rapping at the front door with a cycle-spanner. Thorndyke took a last glance, with his hand in his pocket, at an open window above, and then, to the coachman's intense delight, brought forth what looked uncommonly like a small bunch of skeleton keys. One of these he inserted into the keyhole, and as he gave it a turn, the lock clicked, and the door stood open.

The little sitting-room, which we now entered, was furnished with the barest necessaries. Its centre was occupied by an oilcloth-covered table, on which I observed with surprise a dismembered "Bee" clock (the works of which had been taken apart with a tin-opener that lay beside them) and a box-wood bird-call. At these objects Thorndyke glanced and nodded, as though they fitted into some theory that he had formed; examined carefully the oilcloth around the litter of wheels and pinions, and then proceeded on a tour of inspection round the room, peering inquisitively into the kitchen and store-cupboard.

"Nothing very distinctive or personal here," he remarked. "Let us go upstairs."

There were three bedrooms on the upper floor, of which two were evidently disused, though the windows were wide open. The third bedroom showed manifest traces of occupation, though it was as bare as the others, for the water still stood in the wash-hand basin, and the bed was unmade. To the latter Thorndyke advanced, and, having turned back the bedclothes, examined the interior attentively, especially at the foot and the pillow. The latter was soiled--not to say grimy--though the rest of the bed-linen was quite clean.

"Hair-dye," remarked Thorndyke, noting my glance at it; then he turned and looked out of the open window. "Can you see the place where Miss Haldean was sitting to sketch?" he asked.

"Yes," I replied; "there is the place well in view, and you can see right up the road. I had no idea this house stood so high. From the three upper windows you can see all over the country excepting through the wood."

"Yes," Thorndyke rejoined, "and he has probably been in the habit of keeping watch up here with a telescope or a pair of field-glasses. Well, there is not much of interest in this room. He kept his effects in a cabin trunk which stood there under the window. He shaved this morning. He has a white beard, to judge by the stubble on the shaving-paper, and that is all. Wait, though. There is a key hanging on that nail. He must have overlooked that, for it evidently does not belong to this house. It is an ordinary town latchkey."

He took the key down, and having laid a sheet of notepaper, from his pocket, on the dressing-table, produced a pin, with which he began carefully to probe the interior of the key-barrel. Presently there came forth, with much coaxing, a large ball of grey fluff, which Thorndyke folded up in the paper with infinite care.

"I suppose we mustn't take away the key," he said, "but I think we will take a wax mould of it."

He hurried downstairs, and, unstrapping the case from his bicycle, brought it in and placed it on the table. As it was now getting dark, he detached the powerful acetylene lamp from his machine, and, having lighted it, proceeded to open the mysterious case. First he took from it a small insufflator, or powder-blower, with which he blew a cloud of light yellow powder over the table around the remains of the clock. The powder settled on the table in an even coating, but when he blew at it smartly with his breath, it cleared off, leaving, however, a number of smeary impressions which stood out in strong yellow against the black oilcloth. To one of these impressions he pointed significantly. It was the print of a child's hand.

He next produced a small, portable microscope and some glass slides and cover-slips, and having opened the paper and tipped the ball of fluff from the key-barrel on to a slide, set to work with a pair of mounted needles to tease it out into its component parts. Then he turned the light of the lamp on to the microscope mirror and proceeded to examine the specimen.

"A curious and instructive assortment this, Jervis," he remarked, with his eye at the microscope: "woollen fibres--no cotton or linen; he is careful of his health to have woollen pockets--and two hairs; very curious ones, too. Just look at them, and observe the root bulbs."

I applied my eye to the microscope, and saw, among other things, two hairs--originally white, but encrusted with a black, opaque, glistening stain. The root bulbs, I noticed, were shrivelled and atrophied.

"But how on earth," I exclaimed, "did the hairs get into his pocket?"

"I think the hairs themselves answer that question," he replied, "when considered with the other curios. The stain is obviously lead sulphide; but what else do you see?"

"I see some particles of metal--a white metal apparently--and a number of fragments of woody fibre and starch granules, but I don't recognize the starch. It is not wheat-starch, nor rice, nor potato. Do you make out what it is?"

Thorndyke chuckled. "Experientia does it," said he. "You will have, Jervis, to study the minute properties of dust and dirt. Their evidential value is immense. Let us have another look at that starch; it is all alike, I suppose."

It was; and Thorndyke had just ascertained the fact when the door burst open and Mrs. Haldean entered the room, followed by Mrs. Hanshaw and the police inspector. The former lady regarded my colleague with a glance of extreme disfavour.

"We heard that you had come here, sir," said she, "and we supposed you were engaged in searching for my poor child. But it seems we were mistaken, since we find you here amusing yourselves fiddling with these nonsensical instruments."

"Perhaps, Mabel," said Mrs. Hanshaw stiffly, "it would be wiser, and infinitely more polite, to ask if Dr. Thorndyke has any news for us."

"That is undoubtedly so, madam," agreed the inspector, who had apparently suffered also from Mrs. Haldean's impulsiveness.

"Then perhaps," the latter lady suggested, "you will inform us if you have discovered anything."

"I will tell you." replied Thorndyke, "all that we know. The child was abducted by the man who occupied this house, and who appears to have watched him from an upper window, probably through a glass. This man lured the child into the wood by blowing this bird-call; he met him in the wood, and induced him--by some promises, no doubt--to come with him. He picked the child up and carried him--on his back, I think--up to the house, and brought him in through the front door, which he locked after him. He gave the boy this clock and the bird-call to amuse him while he went upstairs and packed his trunk. He took the trunk out through the back door and down the garden to the shed there, in which he had a motor-car. He got the car out and came back for the boy, whom he carried down to the car, locking the back door after him. Then he drove away."

"You know he has gone," cried Mrs. Haldean, "and yet you stay here playing with these ridiculous toys. Why are you not following him?"

"We have just finished ascertaining the facts," Thorndyke replied calmly, "and should by now be on the road if you had not come."

Here the inspector interposed anxiously. "Of course, sir, you can't give any description of the man. You have no clue to his identity, I suppose?"

"We have only his footprints," Thorndyke answered, "and this fluff which I raked out of the barrel of his latchkey, and have just been examining. From these data I conclude that he is a rather short and thin man, and somewhat lame. He walks with the aid of a thick stick, which has a knob, not a crook, at the top, and which he carries in his left hand. I think that his left leg has been amputated above the knee, and that he wears an artificial limb. He is elderly, he shaves his beard, has white hair dyed a greyish black, is partly bald, and probably combs a wisp of hair over the bald place; he takes snuff, and carries a leaden comb in his pocket."

As Thorndyke's description proceeded, the inspector's mouth gradually opened wider and wider, until he appeared the very type and symbol of astonishment. But its effect on Mrs. Haldean was much more remarkable. Rising from her chair, she leaned on the table and stared at Thorndyke with an expression of awe--even of terror; and as he finished she sank back into her chair, with her hands clasped, and turned to Mrs. Hanshaw.

"Jane!" she gasped, "it is Percy--my brother-in-law! He has described him exactly, even to his stick and his pocket-comb. But I thought he was in Chicago."

"If that is so," said Thorndyke, hastily repacking his case, "we had better start at once."

"We have the dogcart in the road," said Mrs. Hanshaw.

"Thank you," replied Thorndyke. "We will ride on our bicycles, and the inspector can borrow Willett's. We go out at the back by the cart-track, which joins the road farther on."

"Then we will follow in the dogcart," said Mrs. Haldean. "Come, Jane."

The two ladies departed down the path, while we made ready our bicycles and lit our lamps.

"With your permission, inspector," said Thorndyke, "we will take the key with us."

"It's hardly legal, sir," objected the officer. "We have no authority."

"It is quite illegal," answered Thorndyke; "but it is necessary; and necessity--like your military J.P.--knows no law."

The inspector grinned and went out, regarding me with a quivering eyelid as Thorndyke locked the door with his skeleton key. As we turned into the road, I saw the light of the dogcart behind us, and we pushed forward at a swift pace, picking up the trail easily on the soft, moist road.

"What beats me," said the inspector confidentially, as we rode along, "is how he knew the man was bald. Was it the footprints or the latchkey? And that comb, too, that was a regular knock-out."

These points were, by now, pretty clear to me. I had seen the hairs with their atrophied bulbs--such as one finds at the margin of a bald patch; and the comb was used, evidently, for the double purpose of keeping the bald patch covered and blackening the sulphur-charged hair. But the knobbed stick and the artificial limb puzzled me so completely that I presently overtook Thorndyke to demand an explanation.

"The stick," said he, "is perfectly simple. The ferrule of a knobbed stick wears evenly all round; that of a crooked stick wears on one side--the side opposite the crook. The impressions showed that the ferrule of this one was evenly convex; therefore it had no crook. The other matter is more complicated. To begin with, an artificial foot makes a very characteristic impression, owing to its purely passive elasticity, as I will show you to-morrow. But an artificial leg fitted below the knee is quite secure, whereas one fitted above the knee--that is, with an artificial knee-joint worked by a spring--is much less reliable. Now, this man had an artificial foot, and he evidently distrusted his knee-joint, as is shown by his steadying it with his stick on the same side. If he had merely had a weak leg, he would have used the stick with his right hand--with the natural swing of the arm, in fact--unless he had been very lame, which he evidently was not. Still, it was only a question of probability, though the probability was very great. Of course, you understand that those particles of woody fibre and starch granules were disintegrated snuff-grains."

This explanation, like the others, was quite simple when one had heard it, though it gave me material for much thought as we pedalled on along the dark road, with Thorndyke's light flickering in front, and the dogcart pattering in our wake. But there was ample time for reflection; for our pace rather precluded conversation, and we rode on, mile after mile, until my legs ached with fatigue. On and on we went through village after village, now losing the trail in some frequented street, but picking it up again unfailingly as we emerged on to the country road, until at last, in the paved High Street of the little town of Horsefield, we lost it for good. We rode on through the town out on to the country road; but although there were several tracks of motors, Thorndyke shook his head at them all. "I have been studying those tyres until I know them by heart," he said. "No; either he is in the town, or he has left it by a side road."

There was nothing for it but to put up the horse and the machines at the hotel, while we walked round to reconnoitre; and this we did, tramping up one street and down another, with eyes bent on the ground, fruitlessly searching for a trace of the missing car.

Suddenly, at the door of a blacksmith's shop, Thorndyke halted. The shop had been kept open late for the shoeing of a carriage horse, which was just being led away, and the smith had come to the door for a breath of air. Thorndyke accosted him genially.

"Good-evening. You are just the man I wanted to see. I have mislaid the address of a friend of mine, who, I think, called on you this afternoon--a lame gentleman who walks with a stick. I expect he wanted you to pick a lock or make him a key."

"Oh, I remember him!" said the man. "Yes, he had lost his latchkey, and wanted the lock picked before he could get into his house. Had to leave his motor-car outside while he came here. But I took some keys round with me, and fitted one to his latch."

He then directed us to a house at the end of a street close by, and, having thanked him, we went off in high spirits.

"How did you know he had been there?" I asked.

"I didn't; but there was the mark of a stick and part of a left foot on the soft earth inside the doorway, and the thing was inherently probable, so I risked a false shot."

The house stood alone at the far end of a straggling street, and was enclosed by a high wall, in which, on the side facing the street, was a door and a wide carriage-gate. Advancing to the former, Thorndyke took from his pocket the purloined key, and tried it in the lock. It fitted perfectly, and when he had turned it and pushed open the door, we entered a small courtyard. Crossing this, we came to the front door of the house, the latch of which fortunately fitted the same key; and this having been opened by Thorndyke, we trooped into the hall. Immediately we heard the sound of an opening door above, and a reedy, nasal voice sang out:

"Hello, there! Who's that below?"

The voice was followed by the appearance of a head projecting over the baluster rail.

"You are Mr. Percy Haldean, I think," said the inspector.

At the mention of this name, the head was withdrawn, and a quick tread was heard, accompanied by the tapping of a stick on the floor. We started to ascend the stairs, the inspector leading, as the authorized official; but we had only gone up a few steps, when a fierce, wiry little man danced out on to the landing, with a thick stick in one hand and a very large revolver in the other.

"Move another step, either of you," he shouted, pointing the weapon at the inspector, "and I let fly; and mind you, when I shoot I hit."

He looked as if he meant it, and we accordingly halted with remarkable suddenness, while the inspector proceeded to parley.

"Now, what's the good of this, Mr. Haldean?" said he. "The game's up, and you know it."

"You clear out of my house, and clear out sharp," was the inhospitable rejoinder, "or you'll give me the trouble of burying you in the garden."

I looked round to consult with Thorndyke, when, to my amazement, I found that he had vanished--apparently through the open hall-door. I was admiring his discretion when the inspector endeavoured to reopen negotiations, but was cut short abruptly.

"I am going to count fifty," said Mr. Haldean, "and if you aren't gone then, I shall shoot."

He began to count deliberately, and the inspector looked round at me in complete bewilderment. The flight of stairs was a long one, and well lighted by gas, so that to rush it was an impossibility. Suddenly my heart gave a bound and I held my breath, for out of an open door behind our quarry, a figure emerged slowly and noiselessly on to the landing. It was Thorndyke, shoeless, and in his shirt-sleeves.

Slowly and with cat-like stealthiness, he crept across the landing until he was within a yard of the unconscious fugitive, and still the nasal voice droned on, monotonously counting out the allotted seconds.

"Forty-one, forty-two, forty-three--"

There was a lightning-like movement--a shout--a flash--a bang--a shower of falling plaster, and then the revolver came clattering down the stairs. The inspector and I rushed up, and in a moment the sharp click of the handcuffs told Mr. Percy Haldean that the game was really up.

       *       *       *       *       *

Five minutes later Freddy-boy, half asleep, but wholly cheerful, was borne on Thorndyke's shoulders into the private sitting-room of the Black Horse Hotel. A shriek of joy saluted his entrance, and a shower of maternal kisses brought him to the verge of suffocation. Finally, the impulsive Mrs. Haldean, turning suddenly to Thorndyke, seized both his hands, and for a moment I hoped that she was going to kiss him, too. But he was spared, and I have not yet recovered from the disappointment.