There are certain animals famous to every member of the British Expeditionary Force.

There is a Welsh regiment's goat which ate up the plan of attack issued by a brigadier-general, who bore a striking resemblance to somebody who was not Napoleon, thus saving the Welsh regiment from annihilation and reproach. There is the dog of the Middlesex regiment, who always bit staff-officers and was fourteen times condemned to death by elderly and irascible colonels, and fourteen times rescued by his devoted comrades. There is the Canadians' tame chicken, who sat waiting for nine-inch shells to fall, and then scratched over the ground they had disturbed; and there is last, but not least, that famous mascot of General Hospital One-Three-One, Hector O'Brien.

Hector O'Brien was born in the deeps of a Congo forest. Of his early life little is known, but as far as can be gathered, he made his way to France by way of Egypt and Gallipoli and was presented by a grateful patient to the nursing sisters and ambulance staff of One-Three-One, and by them was adopted with enthusiasm.

Hector O'Brien did precious little to earn either fame or notoriety until one memorable day. He used to sit in the surgery, before a large packing-case, wistfully watching the skies and scratching himself in an absent-minded manner. A chimpanzee may not cogitate very profoundly, and the statement that he is a deep thinker though an indifferent conversationalist has yet to be proved; but it is certain that Hector O'Brien was a student of medicine, and that he did, on this memorable day to which reference has been made, perambulate the wards of that hospital from bed to bed, feeling pulses and shaking his head in a sort of melancholy helplessness which brought joy to the heart of eight hundred patients, some hundred doctors, nurses and orderlies, and did not in any way disturb the melancholy principal medical officer, who was wholly unconscious of Hector's impertinent imitations.

Second-Lieutenant Tam, who was a frequent visitor at One-Three-One, had at an early stage struck up a friendship with Hector and had, I believe, taken him on patrol duty, Hector strapped tightly to the seat, holding with a grip of iron to the fuselage and chattering excitedly.

Thereafter, upon the little uniform jacket which Hector wore on state occasions was stitched the wings of a trained pilot. It is necessary to explain Hector's association with the R. F. C. in order that the significance of the subsequent adventure may be thoroughly appreciated.

Tam was "up" one day and on a particular mission. He looked down upon a big and irregular checker-board covered with numbers of mad white lines, which radiated from a white center and seemed to run frantically in all directions save one. Across that course, and running parallel beneath three of them was a straight silver thread. At the edge of his vision and beyond the place where the white lines ended abruptly, there were two irregular zigzags of yellow running roughly parallel. Behind each of these were thousands of little yellow splotches.

Tam banked over and came round on a hairpin turn, with his eyes searching the heavens above and below. A thousand feet beneath him was a straggling wisp of cloud, so tenuous that you saw the earth through its bulk. Above was a smaller cloud, not so transparent, but too thin to afford a lurking place for his enemy.

Tam was waiting for that famous gentleman, the "Sausage-Killer," the sworn foe of all "O. B.'s."

He paid little attention to the flaming lines because the "Sausage-Killer" never came direct from his aerodrome. You would see him streaking across the sky, apparently on his urgent way to the sea bases and oblivious of the existence of Observation Balloons.

Then he would turn, as though he had forgotten his passport and railway ticket and must go home quickly to get them. And before anybody realized what was happening, he would be diving straight down at the straining gas-bags, his tracer bullets would be ranging the line, and from every car would jump tiny black figures. You saw them falling straight as plummets till their parachutes took the air and opened. And there would be a great blazing and burning of balloons, frantic work at the winches which pulled them to earth, and the ballooning section would send messages to the aerodrome whose duty it was to protect them, apologizing for awakening the squadron from its beauty sleep, but begging to report that hostile aircraft had arrived, had performed its dirty work and had departed with apparent immunity.

The "Sausage-Killer" was due at 11.20, and at 11.18 Tam saw one solitary airplane sweep wide of the balloon park, and turn on a course which would bring him along the line of the O. B.'s. Apparently, the "Sausage-Killer" was not so blessed in the matter of sight as Tam, for the scout was on his tail and was pumping nickel through his tractor's screw before the destroyer of innocent gas-bags realized what had happened.

"It was a noble end," said Tam after he had landed, "and A'm no' so sure that he would have cared to be coonted oot in any other saircumstances; for the shepherd likes to die amongst his sheep and the captain on his bridge, and this puir feller was verra content, A've no doot, to crash under the een of his wee—"

"Did you kill him, Tam?" asked Blackie.

"A'm no' so sure he's deid in the corporeal sense," said Tam cautiously, "but he is removed from the roll of effectives."

So far from being dead, the "Sausage-Killer," who, appropriately enough, was ludicrously like a young butcher, with his red fat face and his cold blue eye, was very much alive and had a grievance.

"Where did that man drop from?" he demanded truculently, "I didn't see him."

"I'm sorry," said Blackie; "if we had known that, we would have got him to ring a bell or wave a flag."

"That is frivolous," said the German officer severely.

"It is the best we can do, dear lad," said Blackie, and didn't trouble to invite him to lunch.

"Tam, you've done so well," said the squadron leader at that meal, "that I can see you being appointed official guardian angel to the O. B.'s. They are going to bring you some flowers."

"And a testimonial with a purse of gold," suggested Croucher, the youngest of the flyers.

"A'm no' desirin' popularity," said Tam modestly, "'tis against ma principles to accept any other presents than seegairs, and even these A'm loath to accept unless they're good ones."

He looked at his wrist watch, folded his serviette and rose from the mess-table with a little nod to the president.

It was a gratifying fact, which Blackie had remarked, that Second Lieutenant, late Sergeant, Tam, had taken to the mess as naturally as a duck to water. He showed neither awkwardness nor shyness, but this was consonant with his habit of thought. Once attune your mind to the reception of the unexpected, so that even the great and vital facts of life and death leave you unshaken and unamazed, and the lesser quantities are adjusted with ease.

Tam had new quarters, his batman had become his servant, certain little comforts which were absent from the bunk were discoverable in the cozy little room he now occupied.

His day's work was finished and he was bound on an expedition which was one part business and nine parts joy-ride, frank and undisguised, for the squadron-car had been placed at his disposal. The road to Amiens was dry, the sun was up, and the sky was blue, and behind him was the satisfactory sense of good work well done, for the "Sausage-Killer" was at that moment on his way back to the base, sitting vis-À-vis with a grimy young military gentleman who cuddled a rifle and a fixed bayonet with one hand and played scales on a mouth-organ with the other, softly, since he was a mere learner, and this was an opportunity for making joyful noises without incurring the opprobrium of his superiors.

Tam enjoyed the beauty and freshness of the early afternoon, every minute of it. He drove slowly, his eyes wandering occasionally from the road to make a professional scrutiny of the skies. He spotted the lonely watches of 89 Squadron and smiled, for 89 had vowed many oaths that they would catch the "Sausage-Killer," and had even initiated a sweepstakes for the lucky man who crashed him.

At a certain quiet restaurant on the Grand' Place he found a girl waiting for him, a girl in soiled khaki, critically examining the menu.

She looked up with a smile as the young man came in, hung his cap upon a peg and drew out the chair opposite.

"I have ordered the tea, though it is awfully early," she said; "now tell me what you have been doing all the morning."

She spoke with an air of proprietorship, a tone which marked the progress of this strange friendship, which had indeed gone very far since Tam's violent introduction to Vera Laramore on the Amiens road.

"Weel," said Tam, and hesitated.

"Please don't give me a dry report," she warned him. "I want the real story, with all its proper fixings."

"Hoo shall A' start?" asked Tam.

"You start with the beginning of the day. Now, properly, Tam."

Her slim finger threatened him.

"Is it literature ye'd be wanting?" asked Tam shyly.

She nodded, and Tam shut his eyes and began after the style of an amateur elocutionist:

"The dawn broke fair and bonny an' the fairest rays of the rising sun fell upon the sleeping 'Sausage-Killer'—"

"Who is the 'Sausage-Killer'?" asked the girl, startled.

"He'll be the villain of the piece, A'm thinkin'," said Tam, "but if ye interrupt—"

"I am sorry," murmured the girl, apologetically.

She sat with her elbows on the table, her chin resting on her clasped hands and her eyes fixed on Tam, eyes that danced with amusement, with admiration, and with just that hint of tenderness that you might expect in the proud mother showing off the accomplishments of her first-born.

"—fell aboot the heid of the Sausage-Killer,'" Tam went on, "bathin' his shaven croon wi' saft radiance. There was a discreet tap at the door, and Wilhelm MacBethmann, his faithful retainer, staggered in, bearin' his cup of acorn coffee.

"'Rise, mein Herr,' says he, 'get oot o' bed, ma bonnie laird.'

"'What o'clock is it, Angus?' says the 'Sausage-Killer,' sitting up and rubbing his eyes.

"'It's seven, your Majesty,' says MacBethmann, 'shall I lay out yeer synthetic sausage or shall I fry up yesterday's sauerkraut?'

"But the 'Sausage-Killer' shakes his head.

"'Mon Angus,' he says, 'A've had a heedious dream. A' dreamt,' says he, 'that A' went for to kill a wee sausage and A' dived for him and missed him and before A' could recover, the sausage bit me. 'Tis a warning,' says he.

"'Sir,' says MacBethmann, trembling in every limb and even in his neck, 'ye'd be wise no' to go out the day.'

"But the prood 'Sausage-Killer' rises himself to his full length.

"'Unhand ma pants, Angus,' says he, 'ma duty calls,' and away goes the puir wee feller to meet his doom at the hands of the Terror of the Skies."

"That's you," said the girl.

"Ye're a good guesser," said Tam, pouring out the tea the waiter had brought. "Do ye take sugar or are ye a victim of the cocktail habit?"

"Did you kill him?" asked the girl.

"Poleetically and in a military sense the 'Sausage-Killer' is dead," said Tam; "as a human being he is still alive, being detained during his Majesty's displeasure."

"You will tell me the rest, won't you?" she pleaded. With her, Tam invariably ended his romances at the point where they could only be continued by the relation of his own prowess, "and I'm glad you brought him down—it makes me shudder to see the balloons burning. Oh, and do you know they bombed Number One-Three-One last night?"

"Ye don't say!"

There was amazement in his look, but there was pain, too. The traditions of the air service had become his traditions. A breach of the unwritten code by the enemy was almost as painful a matter to him as though it was committed by one of his own comrades. For his spiritual growth had dated from the hour of his enlistment, and that period of life wherein youth absorbs its most vivid and most eradicable impressions, had coincided with the two years he had spent in his new environment.

He understood nothing of the army and its intimate life, of its fierce and wholesome code. He could only wonder at the courage and the endurance of those men on the ground who were cheerful in all circumstances. They amazed and in a sense depressed him. He had been horrified to see snipers bayoneted without mercy, without being given a chance to surrender, not realizing that the sniper is outside all concession and can not claim any of the rough courtesies of war.

He had placed his enemy on a pedestal, and it hurt almost as much to know that the German fell short of his conception as it would have, had one of his own comrades been guilty of an unpermissible act.

Hospitals had been bombed before, but there was a chance that the wandering night-bird had dropped his pills in ignorance of what lay beneath him. Of late, however, hospitals and clearing stations had been attacked with such persistence that there was very little doubt that the enemy was deliberately carrying out a hideous plan.

"Ye don't say?" he repeated, and the girl noticed that his voice was a little husky. "Were ye—" he hesitated.

"I was on convoy duty, fortunately," said the girl, "but that doesn't save you in the daytime, and I have been bombed lots of times, although the red cross on the top of the ambulance is quite clear—isn't it?"

Tam nodded.

"There was no damage?" he asked anxiously.

"Not very much in one way," she said, "he missed the hospital but got the surgery and poor Hector—" She stopped, and he saw tears in her eyes.

"Ye don't tell me?" he asked, startled.

She nodded.

"Puir Hector; well, that's too bad, puir wee little feller!"

"Everybody is awfully upset about it, he was such a cheery little chap. He was killed quite—nastily." She hesitated to give the grisly details, but Tam, who had seen the effect of high explosive bombs, had no difficulty in reconstructing the scene where Hector laid down his life for his adopted country.

When he got back to the aerodrome that night he found that the bombing of hospitals was the subject which was exciting the mess to the exclusion of all others.

"It's positively ghastly that a decent lot of fellows like German airmen can do such diabolical things," said Blackie; "we are so helpless. We can't go along and bomb his collecting stations."

"Fritz's material is deteriorating," said a wing commander; "there's not enough gentlemen to go round. Everybody who knows Germany expected this to happen. You don't suppose fellows like Boltke or Immelmann or Richthoven would have done such a swinish thing?"

That same night One-Three-One was bombed again, this time with more disastrous effects. One of the raiders was brought down by Blackie himself, who shot both the pilot and the observer, but the raid was only one of many.

The news came through in the morning that a systematic bombing of field hospitals had been undertaken from Ypres to the Somme. At two o'clock that afternoon Blackie summoned his squadron.

"There's a retaliation stunt on to-night," he explained; "we are getting up a scratch raid into Germany. You fellows will be in for it. Tam, you will be my second in command."

At ten o'clock that night the squadron rose and headed eastward. The moon was at its full, but there was a heavy ground mist, and at six thousand feet a thin layer of clouds which afforded the raiders a little cover.

Tam was on the left of the diamond formation, flying a thousand feet above the bombers, and for an hour and a half his eyes were glued upon the signal light of his leader. Presently their objective came into sight: a spangle of lights on the ground. You could follow the streets and the circular sweep of the big Central Platz and even distinguish the bridges across the Rhine, then of a sudden the lights blurred and became indistinct, and Tam muttered an impatient "Tchk," for the squadron was running into a cloud-bank which might be small but was more likely to be fairly extensive.

They were still able to distinguish the locality, until three spurts of red flame in the very center of the town marked the falling of the first bombs. Then all the prominent lights went out. There were hundreds of feeble flickers from the houses, but after a while these too faded and died. In their place appeared the bright, staring faces of the searchlights as they swept the clouds.

Tam saw the flash of guns, saw the red flame-flowers of the bombs burst to life and die, and straining his eyes through the mist caught the "Return" signal of his leader. He banked round and ran into a thicker pall of fog and began climbing. As he turned he saw a quick, red, angry flash appear in the clouds and something whistled past his head. The guns had got the altitude of the bombers to a nicety and Tam grinned.

By this time Blackie's lights were out of sight and Tam was alone. He looked down at his compass and the quivering needle now pointed to his right, which meant he was on the homeward track. He kept what he thought was a straight course, but the needle swung round so that it pointed toward him. He banked over again to the right and swore as he saw the needle spin round as though some invisible finger was twirling it.

Now the airplane compass is subject to fits of madness.

There are dozens of explanations as to why such things occur, but the recollection of a few of these did not materially assist the scout. The thing to do was to get clear of the clouds and take his direction by the stars. He climbed and climbed, until his aeronometer pointed to twenty thousand feet. By this time it was necessary to employ the apparatus which he possessed for sustaining himself at this altitude. It was amazing that the clouds should be so high, and he began to think that his aeronometer was out of order when he suddenly dived up into the light of a cold moon.

He looked around, seeking the pole-star, and found it on his left. So all the time he had been running eastward.

And then his engine began to miss.

Tam was a philosopher and a philosopher never expects miracles. He understood his engine as a good jockey understands his horse. He pushed the nose of his machine earthward and planed down through an interminable bank of clouds until he found a gray countryside running up to meet him. There were no houses, no lights, nothing but a wide expanse of country dotted with sparse copses.

There was sufficient light to enable him to select a landing-place, and he came down in the middle of a big pasture on the edge of a forest of gaunt trees.

He unstrapped himself and climbed down, stretching his limbs before he took a gentle trot around the machine to restore his circulation. Then he climbed back into the fuselage and tinkered at the engine. He knew what was wrong and remedied the mischief in a quarter of an hour. Then he inspected his petrol supply and whistled. He had made a rough calculation and he knew within a few miles how far he was in the interior of Germany, and by the character of the country he knew he was in the marshy lands of Oosenburg, and there was scarcely enough petrol to reach the Rhine.

He left his machine, slipped an automatic pistol into the pocket of his overall and went on a voyage of exploration.

Half a mile from where he landed, he struck what he gathered was a high-road and proceeded cautiously, for the high-road would probably be patrolled, the more so if the noise of his machine had been correctly interpreted, though it was in his favor that he had shut off his engines and had planed down for five miles without a sound.

There was nobody in sight. To the left the road stretched in the diffused moonlight, a straight white ribbon unbroken by any habitation. To the right he discerned a small hut, and to this he walked. He had taken a dozen steps when a voice challenged him in German. At this point the road was sunken and it was from the shadow of the cutting that the challenge came.

"Hello," said Tam in English, and a little figure started out.

Tam saw the rifle in his hand and caught the glitter of a bayonet.

"You English?" said a voice.

"Scotch," said Tam severely.

"Aha!" There was a note of exultation. "You English-escaped prisoner! I haf you arrested and with me to the Commandant of Camp 74 you shall go."

"Is it English ye're speakin'?" said Tam.

The little man came closer to him. He stood four feet three and he was very fat. He wore no uniform, and was evidently one of those patriotic souls who undertake spare-time guard duty. His presence was explained by his greeting. Some men had escaped from the German prison-camp seven miles away and he was one of the sentries who were watching the road.

"You come mit me, vorwÄrts!"

Tam obeyed meekly and stepped out to the hut.

"I keep you here. Presently the Herr Leutnant will come and you shall go back."

He walked into the hut and waited in silence while the little man struck a match and lit an oil-lamp. The sentry fixed the glass chimney and turned to face the muzzle of Tam's automatic pistol.

"Sit down, ma wee frien'," said Tam; "let ma take that gun away from ye before ye hairt yeersel'—maircifu' Heavens!"

He was staring at the little man, but it was not the obvious terror of the civilian which fascinated him, it was the big, white, unshaven face, the long upper lip, and the low corrugated brow under the stiff-bristling hair, the small twinkling eyes, and the broad, almost animal, nose that held him for a moment speechless.

"Hector O'Brien!" gasped Tam, and almost lost his grasp of the situation in the discovery of this amazing likeness. "A' thought ye was dead," said Tam. "Oh, Hector, we have missed ye!"

The little man, his shaking hands uplifted, could only chatter incoherently. It needed this to complete the resemblance to the deceased mascot of One-Three-One.

"Ma puir wee man," said Tam, as he scientifically tied the hands of his prisoner, "so the Gairmans got ye after all."

"You shall suffer great punishment," his prisoner was spurred by fear to offer a protest. "Presently the Herr Leutnant will come with his motor-car."

"God bless ye for those encouraging words," said Tam. "Now will ye tell me how many soldiers are coming along?"

"Four—six—" began the prisoner.

"Make it ten," said Tam, examining the magazine of his pistol. "A' can manage wi' ten, but if there's eleven, A' shall have to fight 'im in a vulgar way wi' ma fists. Ye'll sit here," said he, "and ye will not speak."

He went to the untidy bed, and taking a coarse sacking-sheet he wound it about the man's mouth. Then he went to the door and waited.

Presently he heard the hum of the car, and saw two twinkling lights coming from the eastward. Nearer and nearer came the motor-car and pulled up with a jerk before the hut.

There were two men, a chauffeur and an officer, cloaked and overcoated, in the tonneau. The officer opened the door of the car and stepped down.

"Franz!" he barked. Tam stepped out into the moonlight.

"Is it ma frien' ye're calling?" he asked softly. "And will ye pit up yeer hands."

"Who—who—" demanded the officer.

"Dinna make a noise like an owl," said Tam, "or you will frighten the wee birdies. Get out of that, McClusky." This to the chauffeur.

He marched them inside the hut and searched them. The officer had come providentially equipped with a pair of handcuffs, which Tam used to fasten the well-born and the low-born together. Then he made an examination of the car, and to his joy discovered six cans of petrol, for in this deserted region where petrol stores are non-existent a patrol car carries two days' supply.

He brought his three prisoners out, loosened the bonds of the little man, and after a little persuasion succeeded in inducing his three unwilling porters to carry the tins across a rough field to where his plane was standing.

In what persiflage he indulged, what bitter and satirical things he said of Germans and Germany is not recorded. They stood in abject silence while he replenished his store of petrol and then—

"Up wi' ye," said he to Hector O'Brien's counterpart.

"For why?" asked the affrighted man.

"Up wi' ye," said Tam sternly; "climb into that seat and fix the belt around ye, quick—A'm taking ye back to yeer home!"

His pistol-point was very urgent and the little man scrambled up behind the pilot's seat.

"Now, you, McClusky," said Tam, following him and deftly strapping himself, "ye'll turn that propeller—pull it down so, d'ye hear me, ye miserable chauffeur!"

The man obeyed. He pulled over the propeller-blade twice, then jumped back as with a roar the engine started.

As the airplane began to move, first slowly and then gathering speed with every second, Tam saw the two men break into a run toward the road and the waiting motor-car.

Behind him he felt rather than heard slight grunts and groans from his unhappy passenger, and then at the edge of the field he brought up the elevator and the little scout, roaring like a thousand express trains, shot up through the mist and disappeared from the watchers on the road in the low-hanging clouds, bearing to the bereaved and saddened staff of One-Three-One Hector O'Brien's understudy.