'So you up and suspicioned the Martian animal,' said Gilmer. 'Just how in blue hell do you think that defenseless little Fur-Ball over there could make men and animals go insane?'
'Listen,' said Woods, 'don't act that way, Doc. You're on the trail of something. You broke a poker date tonight to stay here at the laboratory. You had two tanks of carbon monoxide sent up. You were shut in here all afternoon. You borrowed some stuff from Appleman down in the sound laboratory. It all adds up to something. Better tell me.'
'Damn you,' said Gilmer, 'you'd find out anyway even if I kept mum.'
He sat down and put his feet on the desk. He threw the wrecked and battered cigar into the waste-paper basket, took a fresh one out of a box, gave it a few preliminary chews and lit it.
'Tonight,' said Gilmer, 'I am going to stage an execution. I feel badly about it, but probably it is an act of mercy.'
'You mean,' gasped Jack, 'that you are going to kill Fur-Ball over there?'
Gilmer nodded. 'That's what the carbon monoxide is for. Introduce it into the cage. He'll never know what happened. Get drowsy, go to sleep, never wake up. Humane way to kill the thing.'
'But why?'
'Listen to me,' said Gilmer. 'You've heard of ultrasonics, haven't you?'
'Sounds pitched too high for the human ear to hear,' said Woods. 'We use them for lots of things. For underwater signaling and surveying. To keep check on high-speed machines, warn of incipient breakdowns,'
'Man has gone a long way with ultrasonics,' said Gilmer. 'Makes sound do all sorts of tricks. Creates ultrasonics up to as high as 20 million vibrations per second. One million cycle stuff kills germs. Some insects talk to one another with 32,000 cycle vibration. Twenty thousand is about as high as the human ear can detect. But man hasn't started yet. Because little Fur-Ball over there talks with ultrasonics that approximate thirty million cycles.'
The cigar traveled east to west.
'High frequency sound can be directed in narrow beams, reflected like light, controlled. Most of our control has been in liquids. We know that a dense medium is necessary for the best control of ultrasonics. Get high frequency sound in a medium like air and it breaks down fast, dissipates. That is, up to twenty million cycles, as far as we have gone.
'But thirty million cycles, apparently, can be controlled in air, in a medium less dense than our atmosphere. Just what the difference is I can't imagine, although there must be an explanation. Something like that would be needed for audible communication on a place like Mars, where the atmosphere must be close to a vacuum.'
'Fur-Ball used thirty million cycle stuff to talk with,' said Jack, 'That much is clear. What's the connection?'
'This.' said Gilmer. 'Although sound reaching that frequency can't be heard in the sense that your auditory nerves will pick it up and relay it to your brain, it apparently can make direct impact on the brain. When it does that it must do something to the brain. It must disarrange the brain, give it a murderous complex, drive the entity of the brain insane.'
Jack leaned forward breathlessly.
'Then that was what happened on the
Gilmer nodded, slowly, sadly.
'It wasn't malicious,' he said. 'I am sure of that. Fur-Ball didn't want to hurt anything. He was just lonesome and a little frightened. He was trying to contact some intelligence. Trying to talk with something. He was asleep or at least physiologically dormant when I took him from the ship. Probably he fell into his sleep just in time to save Cooper from the full effects of the ultrasonics. Maybe he would sleep a lot. Good way to conserve energy.
'He woke up sometime yesterday, but it seemed to take some time for him to get fully awake. I detected slight vibrations from him all day yesterday. This morning the vibrations became stronger. I had put several different assortments of food in the cage, hoping he would choose one or more to eat, give me some clue to his diet. But he didn't do any eating, although he moved around a little bit. Pretty slow, although I imagine it was fast for him. The vibrations kept getting stronger. That was when the real hell broke out in the zoo. He seems to be dozing off again now and things have quieted down.'
Gilmer picked up a box-like instrument to which was attached a set of headphones.
'Borrowed these from Appleman down in the sound laboratory,' he said. 'The vibrations had me stumped at first. Couldn't determine their nature. Then I hit on sound. These things are a toy of Appleman's. Only half- developed yet. They let you 'hear' ultrasonics. Not actual hearing, of course, but an impression of tonal quality, a sort of psychological study of ultrasonics, translation of ultrasonics into what they would be like if you could hear them.'
He handed the head-set to Woods and carried the box to the glass cage. He set it on the cage and moved it slowly back and forth, trying to intercept the ultrasonics emanating from the little Martian animal.
Woods slipped on the phones, sat waiting breathlessly.
He had expected to hear a high, thin sound, but no sound came. Instead a dreadful sense of loneliness crept over him, a sense of bafflement, lack of understanding, frustration. Steadily the feeling mounted in his brain, a voiceless wail of terrible loneliness and misery — a heart-wrenching cry of home-sickness.
He knew he was listening to the wailing of the little Martian animal, was 'hearing' its cries, like the whimperings of a lost puppy on a storm-swept street.
His hands went up and swept the phones from his head.
He stared at Gilmer, half in horror.
'It's lonesome,' he said. 'Crying for Mars. Like a lost baby.'
Gilmer nodded.
'It's not trying to talk to anyone now,' he said. 'Just lying there, crying its heart out. Not dangerous now. Never intentionally dangerous, but dangerous just the same.'
'But,' cried Woods, 'you were here all afternoon. It didn't bother you. You didn't go insane.'
Gilmer shook his head.
'No,' he said, 'I didn't go insane. Just the animals. And they would become immune after a while with this one certain animal. Because Fur-Ball is intelligent. His frantic attempts to communicate with some living things touched my brain time and time again… but it didn't stay. It swept on. It ignored me.
'You see, back in the ship it found that the human brain couldn't communicate with it. It recognized it as an alien being. So it didn't waste any more time with the human brain. But it tried the brains of monkeys and elephants and lions, hoping madly that it would find some intelligence to which it could talk, some intelligence that could explain what had happened, tell it where it was, reassure it that it wasn't marooned from Mars forever.
'I am convinced it has no visual sense, very little else except this ultrasonic voice to acquaint itself with its surroundings and its conditions. Maybe back on Mars it could talk to its own kind and to other things as well. It didn't move around much. It probably didn't have many enemies. It didn't need so many senses.'
'It's intelligent,' said Woods. 'Intelligent to a point where you can hardly think of it as an animal.'
Gilmer nodded.
'You're right,' he said. 'Maybe it is just as human as we are. Maybe it represents the degeneration of a great race that once ruled Mars…'
He jerked the cigar out of his mouth and flung it savagely on the floor.
'Hell,' he said, 'what's the use of speculation? Probably you and I will never know. Probably the human race will never know.'
He reached out and grasped the tank of carbon monoxide, started to wheel it toward the glass cage.
'Do you have to kill it, Doc?' Woods whispered. 'Do you really have to kill it?'
Gilmer wheeled on him savagely.
'Of course I have to kill it,' he roared. 'What if the story ever got out that Fur-Ball killed the boys in the ship and all those animals today? What if he drove others insane? There'd be no more trips to Mars for years to come. Public opinion would make that impossible. And when another one does go out they'll have instructions not to bring
