Abbot’s knees buckled, and from somewhere Titus found the strength to grab him around the waist as together, almost in rhythm, they emptied themselves convulsively of every last drop of the foreign substance. As H’lim stood helplessly aside, Inea turned on the water to wash the stench away.

She made them rinse their mouths out with water, which almost triggered more retching, and said to H’lim, “I guess that experiment was a failure.”

This jarred him into action. From somewhere, he produced a blood pressure monitor and a body fluid specimen collector. Pushing the two down into chairs, he administered a very thorough, very competent medical once-over sampling tears, saliva, blood, sweat, and vomitus while demanding an exact description of what had happened.

In the end, it appeared that Titus had swallowed more than Abbot before experiencing the rejection, and the two rejections had been different.

“My eyes are still burning,” said Titus, “and my head feels full of hot coals.”

“My stomach,” said Abbot. “I’ve never had such cramps.”

H’lim pondered for a moment, then speculated. “Abbot, perhaps it’s just as well that you tried it unenergized at first and that caused you to reject it. It could be wholly incompatible with your metabolism. But Titus-you seem to have had a central nervous system reaction. Nutrient had begun to pass into your blood before you rejected it.”

“Those are the worst poisons,” agreed Titus. “I probably swallowed more than Abbot because I’m used to the flatness of uninfused chemical.” He glanced at Inea. “It’s a hellishly difficult thing to learn to tolerate.”

Abbot climbed to his feet. “Some difficult things are worth doing,” he observed, “and some aren’t. Thank you for the instructive experience, H’lim, but I won’t try it again.”

“Wait until I’ve done some more tests,” protested H’lim. “I can tolerate human blood. Certainly you can-”

“If you clone an orl, I may consider trying it again.” With that Abbot was gone.

Titus glanced at Inea. “Maybe we should have tried to infuse his first?” Could I order her-even to feed Abbot?

H’lim said, “No, I don’t think so. He might have drunk more, and it might have poisoned him.”

“You think I’m poisoned?” The way his head felt, Titus could easily believe he was about to die the final death.

“Your genetic makeup is very different from his. I think there’s something in orl blood that your body is equipped to use, but that you’ve never encountered before.”

“You mean that I’m more luren than he is? I don’t think so. He’s much older, has fewer human ancestors.”

“Yes, that much is immediately evident. But the interbreeding has selected for different factors. It will take some time, but I can determine if orl blood is really a poison for him-or for you for that matter.”

“Interbreeding,” said Titus heavily. “Just why is that even possible?”

Ignoring Titus’s direct question, as always, H’lim mused, “Perhaps I can filter out the incompatible factors for Abbot.”

“It wouldn’t be worth the time,” said Inea unexpectedly.

“Why?” asked H’lim blankly.

“Haven’t you figured Abbot out yet?” she asked. “It’s not the blood that nourishes him, it’s the subjugation. He is a vampire, not a luren.”

H’lim frowned. Titus, unsure if it was in disapproval or disagreement, changed the subject. “Inea’s got a good point. We don’t have time for pure research. You not only have to do this in odd moments stolen from Colby’s work, but you have to hide it from everyone looking over your shoulder. Between the limited time and the risk, I think your better investment would be your booster. If that works on Abbot or on humans to stimulate blood and ectoplasm replacement, it would be acceptable to Abbot and would let us survive.”

“Time,” said H’lim heavily. He toyed with the specimen kit. “Do you know if you’ll be getting a shipment soon?”

“No. If any convoy does get through, though, I’d expect some of my supplies to be on it.” Connie is that good.

H’lim seemed skeptical, but he said, “Since the booster was designed for orl, the two projects are related. I’ll pursue both goals simultaneously. It’s not as difficult as it sounds, you know. I’ve made orl for use in medical testing. The genetics is flexible and the blood composition can be altered to mimic that of diverse peoples.” Staring at the Thermos, he lapsed into the luren tongue.

Titus puzzled over the words “teelee-odd” and “metajee”. Those were the only terms he could separate from the mass of the unfamiliar ones, and he realized that his own lack of a biological and biochemical vocabulary had left H’lim unable to think professionally in English. What other flaws had he left him with.“

What other communications problems lurked beneath the facade of normality?

Inea followed H’lim’s gaze and rose to fill a glass with the orl blood, returning with it cradled between her hands. H’lim tracked her movements with a quiet reverence then dragged his attention from the glass she held and asked Titus, “Did you tell her to do this?”

“No. It’s her own idea.” He wasn’t sure it was even a good idea, but he followed her reasoning and her heart, so he said nothing as H’lim savored the act of a sentient orl-a willing human. Ectoplasm carried a different texture when it was a deliberate, wholehearted gift.

He was curious to see how this would strike H’lim. But the luren didn’t reach for the proffered glass. He clasped trembling hands in his lap. “Titus, she wears your Mark.”

“Only to keep you or Abbot from taking what you will of her. She’s a human being, free to give what she chooses to whom she chooses. You’ve partaken of her gift before.”

“I don’t like being discussed in the third person.”

H’lim seemed perplexed, so Titus explained, “It’s impolite most places to ignore a person’s presence.”

“Oh, I’m sorry. I didn’t intend-Inea, there’s no way I could ignore your pervasive presence. I would like very much to accept your gift.” He held his hands out just short of the glass waiting for her to place it in his grasp.

She breathed on it one last time, then put it in his hands, cupping hers about them. “This is so you’ll have the strength to find a way to feed Titus-and Abbot too. I just wish I could do more to help.”

Titus thought H’lim didn’t even hear her last words. His attention was riveted on the glass and he was shaking. When at last he drank the energized orl blood, the beatific expression on his face made Titus’s hunger surge like a trapped tiger. She is free

0 give as she chooses. Besides, damn it, she’s right!

Two weeks later, Titus was in the centrifuge with Abbot and H’lim. Colby had noted the drawn, haggard appearance both of them presented and had ordered them off duty to sleep, eat, and exercise. “I don’t care what the medical records show about you two, you’re both about to fall on your faces. You’ve each been doing the work of three men for months now. Nobody can sustain that kind of pace.”

She had gone on to warn them that a parts shipment for the probe vehicle would arrive soon, and then the pace would increase tenfold. “So I’m doubling your rations for a week, and taking you off the duty roster-except for escorting H’lim. If I catch either of you at work, I’ll commit you to the psych ward!”

Looking in the mirror, Titus couldn’t argue with her appraisal, only with her therapy regimen.

But he did need the time in the centrifuge, as did H’lim, who was willing to wear a special suit Abbot had made for him to attenuate the noise the centrifuge motors made. As uneasy as the centrifuge made Titus, especially the first time he’d gone in there after nearly being killed, it was worse for H’lim.

For the alien, they dimmed the lights, increased the gravity and adjusted the air mixture. Biomed invented half a dozen new telemetry sensors, and the physical therapists who ran the gym devised a new exercise machine to accommodate H’lim’s physique. When H’lim used the centrifuge, only Titus and Abbot stayed with him-and that was only after Abbot had reprogrammed the computers to show proper human stress patterns under the new conditions.