They didn't realize they were in trouble until it was too late to stop it. The call from Morua II came in quite innocently, relayed to the ship from HQ in Standard GPP Contract code for crash priority, which meant Top Grade Planetary Emergency, and don't argue about it, fellows, just get there, fast. Red Doctor Sam Jenkins took one look at the flashing blinker and slammed the controls into automatic; gyros hummed, bearings were computed and checked, and the General Practice Patrol ship Lancet spun in its tracks, so to speak, and began homing on the call-source like a hound on a fox. The fact that Morua II was a Class VI planet didn't quite register with anybody, just then.

Ten minutes later the Red Doctor reached for the results of the Initial Information Survey on Morua II, and let out a howl of alarm. A single card sat in the slot with a wide black stripe across it.

Jenkins snapped on the intercom. "Wally," he yelped. "Better get up here fast."

"Trouble?" said the squawk-box, sleepily.

"Oh, brother," said Jenkins. "Somebody's cracked the Contract Code or something."

A moment later a tall sleepy man in green undershorts appeared at the control room, rubbing his eyes. "What happened?" he said. "We've changed course."

"Yeah. Ever hear of Morua II?"

Green Doctor Wally Stone frowned and scratched his whiskered chin. "Sounds familiar, but I can't quite tune in. Crash call?" His eye caught the black-striped card. "Class VI planet ... a plague spot! How can we get a crash-call from this?"

"You tell me," said Jenkins.

"Wait a minute. Seems to me there was some sort of nasty business—"

Jenkins nodded heavily. "There sure was. Five successive attempts to establish a Contract with them, and five times we got thrown out bodily. The last time an Earth ship landed there half the crew was summarily shot and the others came home with their ears cut off. Seems the folks on Morua II didn't want a Contract with Hospital Earth. And they're still in the jungle, as far as their medicine goes. Witch doctors and spells." He tossed the Info-card down the chute with a growl. "So now we have an emergency call from them in a Contract code they couldn't possibly know."

The surgeon in the green undershorts chewed his lip. "Looks like somebody in that last crew spilled the beans before they shot him."

"Obviously."

"Well, what are we doing on automatics? We're not going there, are we?"

"What else? You know the law. Instantaneous response to any crash-priority call, regardless of circumstances—"

"Law be damned," Stone cried. "File a protest with HQ. Cancel the course bearings and thumb our noses at them!"

"And spend the next twenty years scrubbing test tubes." Jenkins shook his head. "Sorry, it took me too long to get aboard one of these tubs. We don't do that in the General Practice Patrol, remember? I don't know how Morua II got the code, but they got it, and that's all the farther we're supposed to think. We answer the call, and beef about it later. If we still happen to be around later, that is."

It had always been that way. Since the first formal Medical Service Contract had been signed with Deneb III centuries before, Hospital Earth had laboriously built its reputation on that single foundation stone: immediate medical assistance, without question or hesitation, whenever and wherever it was required, on any planet bound by Contract. That was the law, for Hospital Earth could not afford to jeopardize a Contract.

In the early days of galactic exploration, of course, Medical Services was only a minor factor in an expanding commercial network that drew multitudes of planets into social and economic interdependence; but in any growing civilization division of labor inevitably occurs. Other planets outstripped Earth in technology, in communications, in transport, and in production techniques—but Earth stood unrivaled in its development of the biological sciences. Wherever an Earth ship landed, the crew was soon rendering Medical Services of one sort or another, whether they had planned it that way or not. On Deneb III the Medical Service Contract was formalized, and Hospital Earth came into being. Into all known corners of the galaxy ships of the General Practice Patrol were dispatched—"Galactic Pill Peddlers" forging a chain of Contracts from Aldebaran to Zarn, accepting calls, diagnosing ills, arranging for proper disposition of whatever medical problems they came across. Serious problems were shuttled back to Hospital Earth without delay; more frequently the GPP crews—doctors of the Red and Green services, representing the ancient Earthly arts of medicine and surgery—were able to handle the problems on the spot and by themselves.

It was a rugged service for a single planet to provide, and it was costly. Many planets studied the terms of Contract and declined, pleasantly but firmly—and were assured nevertheless that GPP ships would answer an emergency call if one was received. There would be a fee, of course, but the call would be answered. And then there were other planets—places such as Morua II....

The Lancet homed on the dismal grey planet with an escort of eight ugly fighter ships which had swarmed up like hornets to greet her. They triangled her in, grappled her, and dropped her with a bone-jarring crash into a landing slot on the edge of the city. As Sam Jenkins and Wally Stone picked themselves off the bulkheads, trying to rearrange the scarlet and green uniforms of their respective services, the main entrance lock burst open with a squeal of tortured metal. At least a dozen Moruans poured into the control room—huge bearlike creatures with heavy grey fur ruffing out around their faces like thick hairy dog collars. The one in command strode forward arrogantly, one huge paw leveling a placer-gun with a distinct air of business about it. "Well, you took long enough!" he roared, baring a set of yellow fangs that sent shivers up Jenkins' spine. "Fourteen hours! Do you call that speed?"

Jenkins twisted down the volume on his Translator with a grimace. "You're lucky we came at all," he said peevishly. "Where's your Contract? Where did you get the Code?"

"Bother the Contract," the Moruan snarled. "You're supposed to be physicians, eh?" He eyed them up and down as though he disapproved of everything that he saw. "You make sick people well?"

"That's the general idea."

"All right." He poked a hairy finger at a shuttle car perched outside. "In there."

They were herded into the car with three guards in front and three behind. A tunnel gulped them into darkness as the car careened madly into the city. For an endless period they pitched and churned through blackness—then suddenly emerged into a high, gilded hall with pale sunlight filtering down. From the number of decorated guards, and the scraping and groveling that went on as they were hurried through embattled corridors, it seemed likely they were nearing the seat of government. Finally a pair of steel doors opened to admit them to a long, arched hallway. Their leader, who was called Aguar by his flunkies, halted them with a snarl and walked across to the tall figure guarding the far door. The guard did not seem pleased; he wore a long purple cap with a gold ball on the end which twitched wildly as their whispered conference devolved into growling and snarling. Finally Aguar motioned them to follow, and they entered the far chamber, with Purple-Hat glaring at them malignantly as they passed.

Aguar halted them at the door-way. "His Eminence will see you," he growled.

"Who is His Eminence?" Jenkins asked.

"The Lord High Emperor of All Morua and Creator of the Galaxies," Aguar rumbled. "He is the Tenth Son of a Tenth Son, and it is written that he can never die. When you enter, bow," he added.

The Tenth Son of a Tenth Son couldn't have cared less whether they bowed or not. The room was dark and rank with the smell of sickness. On a pallet in the center lay a huge Moruan, panting and groaning. He was wrapped like a mummy in bedclothes of scarlet interwoven with gold; on either side of the bed braziers flickered with sickly greenish light.

His Eminence looked up at them from bloodshot eyes and greeted them with a groan of anguish that seemed to roll up from the soles of his feet. "Go away," he moaned, closing his eyes again and rolling over with his back toward them.

The Red Doctor blinked at his companion, then turned to Aguar. "What illness is this?" he whispered.

"He is afflicted with a Pox, as any fool can see. All others it kills—but His Eminence is the Tenth Son of a Tenth Son, and it is written—"

"Yes, yes, I know. He can never die." Sam gave Wally a sour look. "What happens, though, if he just up and does?"

Aguar's paw came down with a clatter on the hilt of his sword. "He does not die. We have you here now. You are doctors, you say. Cure him."

They walked to the bedside and lifted back the covers. Jenkins took a limp paw in his hand. He finally found a palpable pulse just below the second elbow joint. It was fast and thready. The creature's skin bagged loosely from his arm.

"Looks like His Eminence can't read," Wally muttered. "He's going fast, Doc."

Jenkins nodded grimly. "What does it look like to you?"

"How should I know? I've never seen a healthy Moruan before, to say nothing of a sick one. It looks like a pox all right."

"Probably a viremia of some sort." Jenkins went over the great groaning hulk with inquiring fingers.

"If it's a viremia, we're cooked," Stone whispered. "None of the drugs cross over—and we won't have time to culture the stuff and grow any new ones—"

Jenkins turned to Aguar. "How long has this gone on?"

"For days," the Moruan growled. "He can't speak. He grows hot and cannot eat. He moans until the Palace trembles."

"What about your own doctors?"

Aguar spat angrily on the floor. "They are jealous as cats until trouble comes. Then they hide in the caves like chickens. See the green flames? Death flames. They leave him here to die. But now that is all over. We have heard about you wizards from Hospital Earth. You cure all, the stories say. You are very wise, they say. You balance the humors and drive forth the spirits of the Pox like devils." He gave them a terrible grin and tightened his hand on the gold-encrusted sword. "Now we see."

"We can't promise," Jenkins began. "Sometimes we're called too late—but perhaps not in this case," he added hastily when he saw the Moruan's face. "Tenth Son and all that. But you'll have to give us freedom to work."

"What kind of freedom?"

"We'll need supplies and information from our ship. We'll have to consult your physicians. We'll need healthy Moruans to examine—"

"But you will cure him," Aguar said.

Jenkins took a deep breath and gripped his red tunic around his throat tightly. "Sure, sure," he said weakly. "You just watch us."

"But what do you think we're going to do?" the surgeon wailed, back in the control room of the Lancet. "Sam, we can't touch him. If he didn't die naturally we'd kill him for sure! We can't go near him without a Bio-survey—look what happened on Baron when they tried it! Half the planetary population wiped out before they realized that the antibiotic was more deadly to the race than the virus was...."

"Might not be such a bad idea for Morua," the Red Doctor muttered grimly. "Well, what did you expect me to do—politely refuse? And have our throats slit right on the spot?" He grabbed a pad and began scribbling. "We've got to do something just to keep alive for a while."

"Yeah," said Wally. "What, for instance?"

"Well, we've got a little to go on just from looking at them. They're oxygen-breathers, which means they manage internal combustion of carbohydrates, somehow. From the grey skin color I'd guess at a cuprous or stannous heme-protein carrying system. They're carnivores, but god knows what their protein metabolism is like—Let's get going on some of these specimens Aguar has rounded up for us."

They dug in frantically. Under normal conditions a GPP ship would send in a full crew of technicians to a newly-Contracted planet to make the initial Bio-survey of the indigenous races. Bio-chemists, physiologists, anatomists, microbiologists, radiologists—survey workers from every Service would examine and study the new clients, take them apart cell by cell to see what made them tick.

Certain basic principles were always the same, a fact which accelerated the program considerably. Humanoid or not, all forms of life had basic qualities in common. Biochemical reactions were biochemical reactions, whether they happened to occur in a wing-creature of Wolf IV or a doctor from Sol III. Anatomy was a broad determinant: a jelly-blob from Deneb I with its fine skein of pulsating nerve fibrils was still just a jelly-blob, and would never rise above the level of amoeboid yes-no response because of its utter lack of organization. But a creature with an organized central nervous system and a functional division of work among organ systems could be categorized, tested, studied, and compared, and the information used in combating native disease. Given no major setbacks, and full cooperation of the natives, the job only took about six months to do—

For the crew of the Lancet six hours was seven hours too long. They herded cringing Moruan "volunteers" into the little ship's lab. Jenkins handled external examinations and blood and tissue chemistries; Stone ran the X-ray and pan-endoscopic examinations. After four grueling hours the Red Doctor groaned and scowled at the growing pile of data. "Okay. It seems that they're vaguely humanoid. And that's about all we can say for sure. I think we're wasting time. What say we tackle the Wizards for a while?"

Aguar's guards urged the tall Moruan with the purple cap into the control room at gunpoint, along with a couple of minor medical potentates. Purple-hat's name was Kiz, and it seemed that he wasn't having any that day.

"Look," said Jenkins intensely. "You've seen this illness before. We haven't. So you can at least get us started. What kind of course does it run?"

Silence.

"All right then, what causes it? Do you know? Bacteria? Virus? Degeneration?"

Silence.

Jenkins' face was pale. "Look, boys—your Boss out there is going to cool before long if something doesn't happen fast—" His eyes narrowed on Kiz. "Of course, that might be right up your alley—how about that? His Eminence bows out, somebody has to bow in, right? Maybe you, huh?"

Kiz began sputtering indignantly; the Red Doctor cut him off. "It adds up," he said heatedly. "You've got the power, you've got your magic and all. Maybe you were the boys that turned thumbs down so violently on the idea of a Hospital Earth Contract, eh? Couldn't risk having outsiders cutting in on your trade." Jenkins rubbed his chin thoughtfully. "But somehow it seems to me you'd have a whale of a lot more power if you learned how to control this Pox."

Kiz stopped sputtering quite abruptly. He blinked at his confederates for a long moment. Then: "You're an idiot. It can't be done."

"Suppose it could."

"The Spirit of the Pox is too strong. Our most powerful spells make him laugh. He eats our powders and drinks our potions. Even the Iron Circle won't drive him out."

"Won't it, now! Well, we have iron needles and potions that eat the bottoms out of their jars. Suppose they drive him out?"

The Moruan was visibly shaken. He held a whispered conference with his henchmen. "You'll show us these things?" he asked suspiciously.

"I'll make a bargain," said Jenkins. "You give us a Contract, we give you the power—fair enough?"

More whispers. Wally Stone tugged at Sam's sleeve. "What do you think you're doing?" he choked. "These boys will cut your throat quicker than Aguar will—"

"Maybe not," said Sam. "Look, I've got an idea—risky, but it might work if you'll play along. We can't lose much."

The whispers stopped and Kiz nodded to the Red Doctor. "All right, we bargain," he said. "After you show us."

"Now or never." Jenkins threw open the door and nodded to the guards. "I'll be in the sickroom in a very short while. If you're with me, I'll see you there. If not—" He fingered his throat suggestively.

As soon as they had gone Jenkins dived into the storeroom and began throwing flasks and bottles into a black bag. Wally Stone watched him in bewilderment. "You're going to kill him," he moaned. "Prayers, promises, pills and post-mortems. That's the Medical service for you."

Sam grinned. "Maybe you should operate on him. That would open their eyes all right."

"No thanks, not me. This is a medical case and it's all yours. What do you want me to do?"

"Stay here and try your damnedest to get through to HQ," said Sam grimly. "Tell them to send an armada, because we're liable to need one in the next few hours—"

If the Tenth Son of a Tenth Son had looked bad before, three hours had witnessed no improvement. The potentate's skin had turned from grey to a pasty green as he lay panting on the bed. He seemed to have lost strength enough even to groan, and his eyes were glazed.

Outside the royal chambers Jenkins found a group of green-clad mourners, wailing like banshees and tearing out their fur in great grey chunks. They stood about a flaming brazier; as Jenkins entered the sickroom the wails rose ten decibels and took on a howling-dog quality.

Aguar met him at the door. "He's dying," he roared angrily. "Why don't you do something? Every hour he sinks more rapidly, and all you do is poke holes in the healthy ones! And then you send in this bag of bones again—" He glowered at the tall purple-capped figure bending over the bed.

Jenkins looked sharply at Kiz, and the wizard nodded his head slowly. "Try being quiet for a while," Jenkins said to Aguar. "We're going to cure the Boss here." Solemnly he slipped off his scarlet tunic and cap and laid them on a bench, then set his black bag carefully on the floor and threw it open. "First off, get rid of those things." He pointed to the braziers at the bedside. "They're enough to give anybody a headache. And tell those people outside to stop the racket. How can they expect the Spirit of the Pox to come out of His Eminence when they're raising a din like that?"

Aguar's eyes widened for a moment as he hesitated; then he threw open the door and screamed a command. The wailing stopped as though a switch had been thrown. As a couple of cowering guards crept in to remove the braziers, Red Doctor Jenkins drew the wizard aside.

"Tell me what spells you've already used."

Hurriedly, Kiz began enumerating, ticking off items on hairy fingers. As he talked Jenkins dug into the black bag and started assembling a liter flask, tubing and needles.

"First we brewed witches' root for seven hours and poured it over his belly. When the Pox appeared in spite of this we lit three red candles at the foot of the bed and beat His Eminence steadily for one hour out of four, with new rawhide. When His Eminence protested this, we were certain the Spirit had possessed him, so we beat him one hour out of two—"

Jenkins winced as the accounting of cabalistic clap-trap continued. His Eminence, he reflected, must have had the constitution of an ox. He glanced over at the panting figure on the bed. "But doesn't anybody ever recover from this?"

"Oh, yes—if the Spirit that afflicts them is very small. Those are the fortunate ones. They grow hot and sick, but they still can eat and drink—" The wizard broke off to stare at the bottle-and-tube arrangement Jenkins had prepared. "What's that?"

"I told you about the iron needles, didn't I? Hold this a moment." Jenkins handed him the liter flask. "Hold it high." He began searching for a vein on the patient's baggy arm. The Moruan equivalent of blood flowed back greenishly in the tube for an instant as he placed the needle; then the flask began to drip slowly.

Aguar let out a horrified scream and raced from the room; in a moment he was back with a detachment of guards, all armed to the teeth, and three other Moruan physicians with their retinues of apprentices. Sam Jenkins held up his hand for silence. He allowed the first intravenous flask to pour in rapidly; the second he adjusted to a steady drip-drip-drip.

Next he pulled two large bunsen burners and a gas tank from the bag. These he set up at the foot of the bed, adjusting the blue flames to high spear-tips. On the bedside table he set up a third with a flask above it; into this he poured some water and a few crystals from a dark bottle. In a moment the fluid in the flask was churning and boiling, an ominous purple color.

Kiz watched goggle-eyed.

"Now!" said Jenkins, pulling out a long thin rubber tube. "This should annoy the Spirit of the Pox something fierce." He popped the tube into the patient's mouth. His Eminence rose up with a gasp, choking and fighting, but the tube went down. The Red Doctor ground three white pills into powder, mixed in some water, and poured it down the tube.

Then he stepped back to view the scene, wiping cold perspiration from his forehead. He motioned to Kiz. "You see what I'm doing, of course?" he said loudly enough for Aguar and the guards to hear.

"Oh, yes—yes! Indeed, indeed," said Kiz.

"Fine. Now this is most important." Jenkins searched in the bag until he found a large mortar which he set down on the floor. Squatting behind it, he began tapping it slowly with the pestle, in perfect rhythm with the intravenous drip ... and waited.

The room was deathly still except for a heavy snuffling sound from His Eminence and the plink-plink of the pestle on the mortar. The flask of purple stuff gurgled quietly. An hour passed, and another. Suddenly Jenkins motioned to Kiz. "His pulse—quickly!"

Kiz scampered gratefully over to the bedside. "A hundred and eighty," he whispered.

Jenkins' face darkened. He peered at the sick man intently. "It's a bad sign," he said. "The Spirit is furious at the intrusion of an outsider." He motioned toward the mortar. "Can you do this?"

Without breaking the rhythm he transferred the plinking-job to Kiz. He changed the dwindling intravenous bottle. "Call me when the bottle is empty—or if there is any change. Whatever you do, don't touch anything."

With that he tiptoed from the room. Four murderous-looking guards caught Aguar's eye and followed him out, swords bared. Jenkins sank down on a bench in the hall and fell asleep in an instant.

They woke him once, hours later, to change the intravenous solution, and he found Kiz still intently pounding on the mortar. Jenkins administered more of the white powder in water down the tube, and went back to his bench. He had barely fallen asleep again when they were rousing him with frightened voices. "Quickly!" Aguar cried. "There's been a terrible change!"

In the sickroom His Eminence was drenched with sweat, his face glistening in the light of the bunsen burners. He rolled from side to side, groaning hoarsely. "Faster!" Jenkins shouted to Kiz at the mortar, and began stripping off the sodden bedclothes. "Blankets, now—plenty of them."

The plink-plink rose to a frantic staccato as Jenkins checked the patient's vital signs, wiped more sweat from his furry brow. Quite suddenly His Eminence opened bleary eyes, stared about him, let out a monumental groan and buried his head in the blankets. In two minutes he was snoring softly. His face was cool now, his heart-beat slow and regular.

Jenkins snatched the mortar from Kiz, and with a wild flourish smashed it on the stone floor. Then he grabbed the wizard's paw, raising it high. "You've done well!" he cried to the bewildered physician. "It's over now—the Spirit has departed. His Eminence will recover."

They escorted him in triumphal procession back to the Lancet, where Wally Stone stared in disbelief as Jenkins and Kiz bowed and hugged each other like long-lost brothers at a sad farewell. "I finally got through to somebody at HQ," he said as the Red Doctor climbed aboard. "It'll take them twenty days at least, to get help, considering that Morua is not a Contract planet and we're not supposed to be here in the first place, but that's the best they can do...."

"Tell them to forget the armada," said Jenkins, grinning. "And anyway, they've got things all wrong back at HQ." He brandished a huge roll of parchment, stricken through with the colors of the seven Medical Services of Hospital Earth. "Take a look, my boy—the juiciest Medical Services Contract that's been written in three centuries—" He tossed the Contract in the dry-storage locker with a sigh. "Old Kiz just finished his first lesson, and he's still wondering what went on—"

"So am I," said the Green Doctor suspiciously.

"It was simple. We cured His Eminence of the Pox."

"With what? Incantations?"

"Oh, the incantations were for the doctors," said Jenkins. "They expected them, obviously, since that was the only level of medicine they could understand. And incidentally, the only level that could possibly get us a Contract. Anyway, I couldn't do very much else, under the circumstances, except for a little supportive therapy. Without a Bio-survey we were hamstrung. But whatever the Pox is, it obviously involves fever, starvation and dehydration. I knew that His Eminence could assimilate carbohydrates, and I took a long gamble that an antipyretic wouldn't hurt him too much—"

Wally Stone's jaw sagged. "So you treated him with sugar-water and aspirin," he said weakly. "And on that you risked our necks."

"Not quite," said the Red Doctor. "You're forgetting that I had one other prescription to use—the oldest, most trustworthy healer-of-all-ills known to medicine, just as potent now as it was a thousand years ago. Without it, Hospital Earth might just as well pack up her little black bag and go home." He smiled into the mirror as he adjusted the scarlet band of the Red Service across his shoulders. "We call it Tincture of Time," he said.