Rolling his eyes to the shadow-vaulted ceiling, Klairon heaved a sigh. That was the trouble with living in this modern age. Gens took Simes so for granted that they faithfully donated selyn every month without ever bothering to learn the most elementary facts. He marshalled his thoughts while he inspected Welch with renewed curiosity.

Known affectionately as the Old Man, he was growing into the role with salt and pepper in his hair and the beginnings of a respectable paunch, and he was definitely a product of his times. He leased his ship from Stellar Trade Winds, Incorporated, and plied the trade routes, pitting his shrewd mind against the vagaries of fortune. For the five years Klairon had been with him, he'd done very well for his crew, who were paid a percentage of the profit.

He'd treated Klairon as a fellow bridge officer, and a kind of easy friendship had developed between them, with chess, Beethoven, and a fondness for exotic cheeses in common. Until this moment, Klairon had not suspected the ignorance that underlay that friendship.

"All right, I'll try to explain it to you." Klairon hated to lecture, but as with most things, he did it thoroughlywhen he had to.

"Let me draw you an analogy. Say that selyn, the by-product of Gen metabolism which we need but don't produce, is like food for us. It is, in a way, as it is essential for our life.

"Suppose," Klairon spoke slowly, choosing his wordswith great care, "a man who was accustomed to eating well were suddenly constrained to a totally nourishing and hunger satisfying diet of a substance which had the texture and flavor of the sealant we use to keep the ship air-tight. He's forced to subsist on this diet for, say, a year, all the while he's living with normal people on normal diets, even sitting at their tables, smelling their food. All this time, he's known that in exactly three hundred sixty-five days to the minute, he'll be allowed to eat anything he wants.

"On the tick of that minute, he presents himself at the kitchen, only to find that they've run out of food, and everybody is eating sealant.

"This is something of the position I'm in right now."

Klairon leaned back to observe Welch over steepled fingers, tentacles sheathed, and continued. "For a channel, the difference between selyn collected from the millions of volunteer general class Donors, stored in selyn banks, and then delivered mechanically and the selyn taken directly ... personally ... from a living TN, technical class, Donor, is the difference between such a dietary substance and real food.

"Ordinary Simes can't use selyn directly, so the channels' work is to collect selyn, pack it in selyn banks and, later, channel it to ordinary Simes, creating for them a simulated kill that is so realistic it completely satisfies the ordinary Sime.

"But who can satisfy a channel? We get no satisfaction from the exacting restraint needed when collecting selyn from the passive, general class Donors, the GN-3s, like you. Selyn thus handled is a foretaste of a hard-earned gratification yet to come, and somehow it gives us the patience to wait.

"I haven't been involved in my profession since I came to the Pebble Beach, so even this I have been denied. My routine is devoid of means to alleviate the craving," shifting his gaze to his steepled fingers, Klairon extended all eight handling tentacles and wound them in and out about his fingers in an intricate dance, "and I'm constantly exposed to very tempting selyn fields, the 'aroma' of 'food'."

Welch admired the display of agility even though it was a mannerism of Klairon's that indicated deep concern. For the thousandth time,he wondered why a QN-1 would (and howhe could get permission to) abandon the profession he was born to and sign onto a tramp freighter. But Welch was too good a spaceman to ask, and too good a merchant to question his good luck. Still trying earnestly to absorb the other's point of view, he said, "From the selyn banks it doesn't taste good, so the TNs exist to satisfy the channels, but what's so special about a TN-1?"

Studying his twining tentacles, Klairon refused to be hurried."Take the QN-3, the least skilled channel. He can provide satisfaction for twenty or thirty ordinary Simes a day depending on his Proficiency Rating on the QN-3 scale. Who can satisfy him? A TN-3 class Donor, a Gen with the technical training to be able to simulate a kill for the QN-3 without himself suffering any injury from the swift, deep draw of the unrestrained QN-3. In an emergency, a QN-2 or QN-1, a TN-2 or TN-1 could do the job,but that's a waste of talent.

"Now consider the QN-2. He'll rate at fifty or sixty ordinary Simes a day. But when he needs the real thing, he can only goto a TN-2, a QN-1, or a TN-1. His deeper draw of selyn would kill the TN-3, who doesn't have the training to handle it or the capacity to provide that much selyn.

"The QN-1 can provide for anywhere from sixty to a hundred ordinary Simes a day, depending on his Proficiency Rating. But he's the top. He can only go to a TN-1, and they're very rare people with an extraordinary talent and the will to use it. Furthermore, unlike the TN-3 or TN-2, the TN-1 continues to produce selyn beyond his capacity to retain comfortably. He needs the relief that only the special technique of the QN-1 can provide. We are bound to each other ... interdependent." Klairon spread his hands flat on the polished green table, tentacles sheathed, and eyed Welch levelly as he continued.

"The Sime Board of Standards sets the maximum time a channel is required to function while depending on the selyn banks: QN-3's no more than six weeks; QN-2s no more than seven weeks; and QN-1s no more than eight, regardless of the Proficiency Rating within their group. My eight weeks was up the day before we arrived.Today is the fourth day." His eyes narrowed as he strove to project the intensity of his feeling. "It seems more like a year and four days.

"Even if enough selyn is drawn from the banks so there's no danger of death by attrition, the increasing strain ... and it becomes much more intense than my food analogy indicates ...effects judgment, speed and concentration which are critical to astrogation. Only a TN-1 can relieve that strain for me ...and only if the need is not blunted by use of the banks. Timing is critical.

"As long as I can go to the banks, I won't die by attrition, but I won't be much good for anything ... or safe for anything... until I've had a satisfactory live transfer."

Welch's face mirrored sympathetic understanding, but his frown bespoke his determination to get his ship off the ground.

Klairon asked, "Does the crew agree to ship out with me under these circumstances?"

"The passengers and crew all agreed to the rule infringement and signed waivers under the 'Dire Necessity' clause, but I doubt if they understand it in the way you've just outlined."

"What passengers? I thought this was an ASN contract."

"They're not exactly passengers, they're more like observers or advisors. Miss Mandy Wyat is from the Xenoviral Unit of ASN that had the accident that caused this situation, and Dr. BreenThorson is the biochemist who developed the neutralizer in theASN lab here in Terwhoolie. They're civil service, not ASN."

"I see. So you've got nine people willing to space out with me. In just what way do they understand it?" Klairon's right eyebrow rose inquiringly.

"We all know that it's against regulations for you to astrogate for the very good reason that you're not in top form until you've had your transfer. We realize that a Sime can go berserk under too much stress, but there's a couple of weeks safety factor in the rule, and you're a QN-1. If anybody can take hardship, a QN-1can do it twice over. And it's only a ten day run to Port In Brim. Duck soup for an ordinary Sime, let alone a channel. And that's civilization. If here they have only one TN-1, there they have a dozen.