XVI

Ulv joined them as they looked down at the exposed brain of the magter. The thing was so clearly evident that even Ulv noticed it.

“I have seen dead animals and my people dead with their heads open, but I have never seen anything like that before,” he said.

“What is it?” Brion asked.

“The invader, the alien you were looking for,” Lea told him.

The magter’s brain was only two-thirds of its normal size. Instead of filling the skull completely, it shared the space with a green, amorphous shape. This was ridged somewhat like a brain, but the green shape had still darker nodules and extensions. Lea took her scalpel and gently prodded the dark moist mass.

“It reminds me very much of something that I’ve seen before on Earth,” she said. “The green-fly—Drepanosiphum platanoides—and an unusual organ it has, called the pseudova. Now that I have seen this growth in the magter’s skull I can think of a positive parallel. The fly Drepanosiphum also has a large green organ, only it fills half of the body cavity instead of the head. Its identity puzzled biologists for years, and they had a number of complex theories to explain it away. Finally someone managed to dissect and examine it. The pseudova turned out to be a living plant, a yeastlike growth that helps with the green-fly’s digestion. It produces enzymes that enable the fly to digest the great amounts of sugar it gets from plant juice.”

“That’s not unusual,” Brion said, puzzled. “Termites and human beings are a couple of other creatures whose digestion is helped by internal flora. What’s the difference in the green-fly?”

“Reproduction, mainly. All the other gut-living plants have to enter the host and establish themselves as outsiders, permitted to remain as long as they are useful. The green-fly and its yeast plant have a permanent symbiotic relationship that is essential to the existence of both. The plant spores appear in many places throughout the fly’s body—but they are always in the germ cells. Every egg cell has some, and every egg that grows to maturity is infected with the plant spores. The continuation of the symbiosis is unbroken and guaranteed.

“Do you think those green spheres in the magter’s blood cells could be the same kind of thing?” Brion asked.

“I’m sure of it,” Lea said. “It must be the same process. There are probably green spheres throughout the magters’ bodies, spores or offspring of those things in their brains. Enough will find their way to the germ cells to make sure that every young magter is infected at birth. While the child is growing—so is the symbiote. Probably a lot faster since it seems to be a simpler organism. I imagine it is well established in the brain pan within the first six months of the infant’s life.”

“But why?” Brion asked. “What does it do?”

“I’m only guessing now, but there is plenty of evidence that gives us an idea of its function. I’m willing to bet that the symbiote itself is not a simple organism, it’s probably an amalgam of plant and animal like most of the other creatures on Dis. The thing is just too complex to have developed since mankind has been on this planet. The magter must have caught the symbiotic infection by eating some Disan animal. The symbiote lived and flourished in its new environment. Well protected by a bony skull in a long-lived host. In exchange for food, oxygen and comfort, the brain-symbiote must generate hormones and enzymes that enable the magter to survive. Some of these might aid digestion, enabling the magter to eat any plant or animal life they can lay their hands on. The symbiote might produce sugars, scavenge the blood of toxins—there are so many things it could do. Things it must have done, since the magter are obviously the dominant life form on this planet. They paid a high price for their symbiote, but it didn’t really matter to race-survival until now. Did you notice that the magter’s brain is no smaller than normal?”

“It must be—or how else could that brain-symbiote fit in inside the skull with it?” Brion said.

“If the magter’s total brain were smaller in volume than normal, it could fit into the remaining space in the cranial hollow. But the brain is full-sized—it is just that part of it is missing, absorbed by the symbiote.”

“The frontal lobes,” Brion said with sudden realization. “This hellish growth has performed a prefrontal lobotomy!”

“It’s done even more than that,” Lea said, separating the convolutions of the gray matter with her scalpel to uncover a green filament beneath. “These tendrils penetrate farther back into the brain, but always remain in the cerebrum. The cerebellum appears to be untouched. Apparently just the higher functions of mankind have been interfered with, selectively. Destruction of the frontal lobes made the magter creatures without emotions or ability for really abstract thought. Apparently they survived better without these. There must have been some horrible failures before the right balance was struck. The final product is a man-plant-animal symbiote that is admirably adapted for survival on this disaster world. No emotions to cause complications or desires that might interfere with pure survival. Complete ruthlessness—mankind has always been strong on this anyway, so it didn’t take much of a push.”

“The other Disans, like Ulv here, managed to survive without turning into such a creature. So why was it necessary for the magter to go so far?”

“Nothing is necessary in evolution, you know that,” Lea said. “Many variations are possible and all the better ones continue. You might say that Ulv’s people survive, but the magter survive better. If offworld contact hadn’t been re-established, I imagine that the magter would slowly have become the dominant race. Only they won’t have the chance now. It looks as though they have succeeded in destroying both races with their suicidal urge.”

“That’s the part that doesn’t make sense,” Brion said. “The magter have survived and climbed right to the top of the evolutionary heap here. Yet they are suicidal. How come they haven’t been wiped out before this?”

“Individually they have been aggressive to the point of suicide. They will attack anything and everything with the same savage lack of emotion. Luckily there are no bigger animals on this planet. So where they have died as individuals, their utter ruthlessness has guaranteed their survival as a group. Now they are faced with a problem that is too big for their half-destroyed minds to handle. Their personal policy has become their planetary policy—and that’s never a very smart thing. They are like men with knives who have killed all the men who were only armed with stones. Now they are facing men with guns and they are going to keep charging and fighting until they are all dead.”

“It’s a perfect case of the utter impartiality of the forces of evolution. Men infected by this Disan life form were the dominant creatures on this planet. The creature in the magters’ brains was a true symbiote then, giving something and receiving something. Making a union of symbiotes where all were stronger together than any could be separately. Now this is changed. The magter brain cannot understand the concept of racial death, in a situation where it must understand to be able to survive. Therefore, the brain-creature is no longer a symbiote but a parasite.”

“And as a parasite it must be destroyed!” Brion broke in. “We’re not fighting shadows any more,” he exulted. “We’ve found the enemy—and it’s not the magter at all. Just a sort of glorified tapeworm that is too stupid to know when it is killing itself off. Does it have a brain—can it think?”

“I doubt it very much,” Lea said. “A brain would be of absolutely no use to it. So even if it originally possessed reasoning powers they would be gone by now. Symbiotes or parasites that live internally like this always degenerate to an absolute minimum of functions....”

“Tell me about it? What is this thing?” Ulv broke in, producing the soft form of the brain-symbiote. He had heard all their excited talk but had not understood a word.

“Explain it to him, will you Lea, as best you can,” Brion said, looking at her and realized how exhausted she was. “And sit down while you do it, you’re long overdue for a rest. I’m going to try—” He broke off when he looked at his watch.

It was after four in the afternoon—less than eight hours to go. What was he to do? Enthusiasm faded as he realized that only half of the problem was solved. The bombs would drop on schedule unless the Nyjorders could understand the significance of this discovery. Even if they understood—would it make any difference to them? The threat of the hidden cobalt bombs would not be changed.

With this thought came the guilty realization that he had forgotten completely about Telt’s death. Even before he contacted the Nyjord fleet he must tell Hys and his rebel army what had happened to Telt and his sandcar. Also about the radioactive traces. They couldn’t be checked against the records now to see how important they might be, but Hys might make another raid on the strength of the suspicion. This call wouldn’t take long, then he would be free to tackle Professor-Commander Krafft.

Carefully setting the transmitter on the frequency of the rebel army, he sent out a call to Hys. There was no answer.

There was always a chance the set was broken. He quickly twisted the transmitter to the frequency of his personal radio, then whistled in the microphone. The received signal was so loud that it hurt his ears. He tried to call Hys again, and was relieved to get a response this time.

“Brion Brandd here, can you read me? I want to talk to Hys at once.”

Shockingly, it was Professor-Commander Krafft who answered.

“I’m sorry Brion, but it’s impossible to talk to Hys. We are monitoring his frequency and your call was relayed to me. Hys and his rebels lifted ship about a half an hour ago, and are already on the way back to Nyjord. Are you ready to leave now? It will soon become dangerous to make any landings. Even now I will have to ask for volunteers to get you out of there.”

Hys and the rebel army gone. Brion assimilated the thought at the same moment he realized he was talking to Krafft. He was thrown off balance, not prepared for the encounter.

“If they’re gone—well, then there’s nothing I can do about it,” Brion said. “I was going to call you, so I can talk to you now. Listen and try to understand. You must cancel the bombing. I’ve found out about the magter, found what causes their mental aberration. If we can correct that, we can stop them from attacking Nyjord—”

“Can they be corrected by midnight tonight?” Krafft broke in. He was abrupt and sounded annoyed. Even saints get tired.

“No, of course not.” Brion frowned at the microphone, realizing the talk was going all wrong, but not knowing how to fix it. “But it won’t take too long. I have evidence here that will convince you that what I say is the truth.”

“I believe you without seeing it, Brion.” The trace of anger was gone from Krafft’s voice now and it was heavy with fatigue and defeat. “I’ll admit you are probably right. A little while ago I admitted to Hys, too, that he was probably right in his original estimation of the correct way to tackle the problem of Dis. We have made a lot of mistakes, and in making them we have run out of time. I’m afraid that is the only fact that is relevant now. The bombs fall at twelve and even then they may drop too late. A ship is already on its way from Nyjord with my replacement. I exceeded my authority by running a day past the maximum the technicians gave me. I realize now I was gambling the life of my own world in the vain hope I could save Dis. They can’t be saved. They’re dead. I won’t hear any more about it.”

“You must listen—”

“I must destroy the planet below me, that is what I must do. That fact will not be changed by anything you say. All the offworlders—other than your party—are gone. I’m sending a ship down now to pick you up. As soon as that ship lifts I am going to drop the first bombs. Now—tell me where you are so they can come for you.”

“Don’t threaten me, Krafft!” Brion shook his fist at the radio in an excess of anger. “You’re a killer and a world destroyer, don’t try and make yourself out as anything else. I have the knowledge to avert this slaughter and you won’t listen to me. And I know where the cobalt bombs are—in the magter tower that Hys raided last night. Get those bombs and there is no need to drop any of your own!”

“I’m sorry, Brion. I appreciate what you’re trying to do, yet at the same time I know the futility of it. I’m not going to accuse you of lying, but do you realize how thin your evidence sounds from this end? First a dramatic discovery of the cause of the magters’ intransigency. Then, when that had no results, you suddenly remember that you know where the bombs are. The best kept magter secret....”

“I don’t know for sure, but there is a very good chance,” Brion said, trying to repair his defenses. “Telt made readings, he had other records of radioactivity in this same magter keep. Proof that something is there. But Telt is dead now, the records destroyed. Don’t you see—” He broke off, realizing how vague and unprovable his case was. This was defeat.

The radio was silent, with just the hum of the carrier wave as Krafft waited for him to continue. When Brion did speak his voice was empty of all hope.

“Send your ship down,” he said tiredly. “We’re in a building that belonged to the Light Metals Trust Ltd., a big warehouse of some kind. I don’t know the address here, but I’m sure you have someone there who can find it. We’ll be waiting for you.”

“You win Krafft.”

He turned off the radio.