There was no answer to that. You just didn't know, and you had to accept your ignorance.
Even while he was objecting, Dr. Meltzer began putting on the suit. It was thin and light, strong enough to withstand several atmospheres of pressure, and at the same time not so clumsy as to hamper his movements considerably. Scaled pockets carried an assortment of instruments and supplies. Perfect two-way communication would make the exchange of ideas—such as they might be—as easy as if the person he was talking to were face to face with him. With the suit came a pair of fragile-looking gloves that left his hands almost as free as if they were bare. But the apparent fragility was misleading. Mechanical strength was there.
But what about resistance to biological action? The question kept nagging him. You can't know, he told himself. About things like that you take a chance. You take a chance and hope that if anything goes wrong, they'll pull you up before the juices have time to get working on you.
They had everything in readiness. Two of the other men were also wearing uniforms like his own, and when he had put his on, and tested it, the Captain gave the signal, and they all went into a small airlock. The door sealed behind them, a door in front opened. They were in the chamber where the great beast lay and quivered dully as if in giant pain.
They tied strong thin plastic cords around Doctor Meltzer's waist, tested the oxygen lines. Then they put a ladder up in front of the beast's face. Doctor Meltzer had a little trouble breathing, but it was not because of anything wrong with the oxygen supply. That was at the right pressure and humidity, and it was mixed with the correct amount of inert gases. It was merely the thought of going down into the creature's belly that constricted his throat, the idea of going into a strange and terrible world so different from his own, of submitting to unimaginable dangers.
He said hoarsely into the radio speaker, "How do I get in anyway, knock? The mouth's at least forty feet off the ground. And it's closed. You've got to open it, Captain. Or do you expect me to pry it open myself?"
The two men with him stretched out a plastic ladder. In the low gravity of Mars, climbing forty feet was no problem. Dr. Meltzer began to pull his way up. As he went higher, he noticed that the great mouth was slowly opening. One of the men had poked the creature with an electric prod.
Dr. Meltzer reached the level of the low jaw, and with the fascinated fear of a bird staring at a snake, gazed at the great opening that was going to devour him. Inside there was a gray and slippery surface which caught the beam of his flashlight and reflected it back and forth until the rays faded away. Fifty feet beyond the opening, the passage made a slow turn to one side. What lay ahead, he couldn't guess.
The sensible thing was to go in at once, but he couldn't help hesitating. Suppose the jaws closed just as he got between them? He'd be crushed like an eggshell. Suppose that throat constricted with the irritation he caused it? That would crush him too. He recalled suddenly an ancient fable about a man who had gone into a whale's belly. What was the man's name, now? Daniel—no, he had only gone into a den of lions. Job—wrong again. Job had been afflicted with boils, the victim of staphylococci at the other end of the scale of size. Jonah, that was it. Jonah, the man whose name was a symbol among the superstitious for bad luck.
But a scientist had no time for superstition. A scientist just thrust himself forward.
He stepped off the ladder into the great mouth. Beneath him, the jaw was slippery. His feet slid out from under him, and then his momentum carried him forward, and he glided smoothly down the yawning gullet. It was like going down a Martian hillside on a greased sled, the low gravity making the descent nice and easy. He noticed that the cords around his waist, as well as the oxygen lines, were descending smoothly after him. He reached the turn, threw his body away from the gray wall, and continued sliding. Another fifty feet, and he landed with a small plash in a pool of liquid.
The stomach? Never mind what you called it, this was probably the beginning of a digestive tract. He'd have a chance now to see how resistant his suit was.
He was immersed in the liquid now, and he sank slowly until his feet touched more solid flesh again. By the beam from his flashlight, he saw that the liquid around him was a light green. The portion of the digestive tract on which he stood was slate gray, with bright emerald streaks.
A voice spoke anxiously in his ears. "Doctor Meltzer! Are you safe?"
"Fine, Captain. Having a wonderful time. Wish you were here."
"What's it like in there?"
"I'm standing at the bottom of a pool of greenish liquid. I'm fascinated, but not greatly instructed."
"See anything that might be wrong?"
"How the devil would f tell right from wrong in here? I've never been in one of these beasts before. I've got sample bottles, and I'm going to fill them in various places. This is going to be sample one. You can analyze it later."
"Fine, Doctor. You just keep on going."
He flashed the beam around him. The liquid was churning gently, possibly because of the splash he himself had made. The gray-green walls themselves were quiet, and the portion underfoot yielded slightly as he put his weight upon it, but was otherwise apparently undisturbed by his presence.
He moved ahead. The liquid grew shallower, came to an end. He climbed out and stepped cautiously forward. "Doctor, what's happening?"
"Nothing's happening. I'm just looking around." "Keep us informed. I don't think there's any danger, but—"
"But in case there is, you want the next man to know what to watch out for? All right, Captain."
"Lines all right?"
"They're fine." He took another step forward. "The ground—I suppose I can call it the ground—is getting less slippery. Easier to walk on. Walls about twenty feet apart here. No sign of macroscopic flora or fauna. No artifacts to indicate intelligent life."
The Captain's voice sounded pained. "Don't let your sense of humor carry you away, Doctor. This is important. Maybe you don't realize exactly how important, but—"
He interrupted. "Hold it, Captain, here's something interesting. A big reddish bump, about three feet across, in the gray-green wall."
"What is it?"
"Might be a tumor. I'll slice some tissue from the wall itself. That's sample number two. Tissue from the tumor, sample number three."
The wall quivered almost imperceptibly as he sliced into it. The fresh-cut surface was purple, but it slowly turned red again as the internal atmosphere of the beast got at it.
"Here's another tumor, like the first, this time on the other side of the wall. And here are a couple more. I'm leaving them alone. The walls are getting narrower. There's still plenty of room to walk, but—wait a minute, I take that back. There's some kind of valve ahead of me. It's opening and closing spasmodically."
"Can you get through?"
"I'd hate to take a chance. And even if I did make it while it was open, it could crush the oxygen lines when it closed."
"Then that's the end of the road?"
"I don't know. Let me think."
He stared at the great valve. It moved rapidly, opening and closing in a two-second rhythm. Probably a valve separating one part of the digestive system from another, he thought, like the human pylorus. The green-streaked gray flesh seemed totally unlike human muscle, but all the same it appeared to serve a similar function. Maybe the right kind of drug would cause muscular relaxation.
He pulled a large hypodermic syringe from one of the sealed pockets of his diver's uniform. He plunged the needle quickly into the edge of the valve as it paused for a fraction of a second before closing, shot a pint of drug solution into the flesh, and ripped the needle out again. The valve closed once more, but more slowly. It opened, closed again, opened once more—and stayed open.