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.

[Illustration]