Mainly copper, some tin, and a little bit of lead! He put the patterns one on top of the other. They matched now.

There was another code book, very thick, called “Composite Ore Bodies for Drone Scan Analysis,” and because it had about ten thousand characters in it he had shunned it. But this one he had just done made a look-up easy. He looked under “Copper Deposits,” and then its subheading, “Tin Deposits,” and then its sub-subheading, “Lead Deposits,” and he found his squiggle. Not only that, he found, by comparing it to variations, that the analysis of "per-elevens" (Psychlos used the eleven integer) was five copper, four tin, and two lead.

He went further and looked this up in a man-book and it said “Bronze” for such a combination. Apparently it was a very durable alloy that lasted for centuries and there had even been a “Bronze Age” where implements were mainly “bronze.” Great. But it struck him as funny that an advanced technical race should be using ancient bronze in a skull. Amusing.

He went back inside with his findings to discover that MacKendrick, with a

hammer and chisel-like instrument, had been taking the head apart. Jonnie was just as glad not to have been around to watch that.

“We searched all through the rest of the skull with the machine,” said Angus. “That's the only odd thing in there.”

“I went through its pockets,” said Robert the Fox. “He is the lowest-class miner. His identity card says his name was Cla and he had forty-one years' service and three wives back on Psychlo."

“The company paid them benefits?” said Dunneldeen.

“No,” said Robert the Fox, showing him the crumpled record, “it says here the company paid him also for the female earnings in a company 'house,' whatever that is.”

“The economics of Psychlo husbandry,” said Dunneldeen, “are a credit to their morality.”

“Don't joke,” said Jonnie. “The object in his head is an alloy called 'bronze.' It is not magnetic, worse luck. It would have to be operated out. It can't be pulled out with a magnet.”

Dr. MacKendrick now had the brain laid bare. With a surgeon's skill, he was parting things that looked like cords.

And there it was!

It was shaped like two half-circles back to back and the circles were slightly closed, each one around a separate cord.

“I think these are nerves,” said MacKendrick. “We will know shortly.” He was delicately pulling the objects off the cords. He wiped the green blood off it and put it on the table.

“Don't touch any of this,” said

MacKendrick. “Autopsies can be deadly.”

Jonnie looked at the thing. It was a dull yellow. It was about half an inch across at its widest point.

Angus picked it up with a tweezer and put it on the analysis machine plate. “It’s not hollow,” he said. “It’s just solid. Just a piece of metal.”

MacKendrick had a little box with wires and clips on it. It had a small fuel cartridge in it to generate electricity. But before he connected anything with his gloved hands he was distracted by the character of these cords in the head. It was a brain, but it was vastly different from a human brain.

He cut off a small cord end and a slice of skin from the cadaver's paw and went over to an old makeshift microscope. He made a slide from a thin specimen and looked into the eyepiece.

MacKendrick whistled in surprise. “A Psychlo isn't made of cells. I don't know their metabolism but their structure isn't cellular. Viral! Yes. Viral!” He turned to Jonnie. “You know, big as a Psychlo is, his basic structure seems to be clumps of viruses.” He saw Jonnie looking at him askance and added, “Purely academic interest. It does mean, however, that their bodies probably hold together much tighter and have a greater density. Probably of no interest to you. Well, let's get to work on these cords.”

He attached one clip to the end of a cord in the brain and grounded the other on an arm and, watching a meter, measured the resistance of the cord to electrical flow. When he had determined that, he stood back and touched a button to send electricity through the cord. The others felt their hair rise.

The Psychlo cadaver moved its left foot.

“Good,” said MacKendrick. “Nerves. There is no rigor mortis in these bodies and they're still flexible. I have found the nerve that relays walk commands.” He put a little tag on the nerve. He had marked the places from which they had removed the metal with a spot of dye on each of the two nerves involved with it. But he wasn't checking those yet.

His spectators were quite horrified to see, as MacKendrick identified nerves with tags, a Psychlo cadaver that moved its claws, clenched the remains of its jaw, moved an ear, and lolled out its tongue, one after the other as various nerves were given an electrical jolt.

MacKendrick saw their reaction. “Nothing new in this. Just electrical impulses approximating brain commands. Some man-scientist did this maybe thirteen hundred years ago and thought he'd found the secret of all thought and made up a cult about it called 'psychology.' Forgotten now. It wasn't the secret of thought; it was just the mechanics of bodies. They started with frogs. I’m cataloging this body's communication channels, that's all.”

But it was very weird. The depths of superstition stirred in them as they saw a corpse move and breathe and saw, for a couple of pumps, its heart beat.

MacKendrick's gloved hands were slimy with green blood but he moved in a very efficient and businesslike fashion until he had more than fifty little tags clipped to the nerve cords.

“Now for the answer!” said

MacKendrick. He sent pulses through the two nerves to which the bronze item had been attached.

It was difficult work. The room was cold. The corpse stank, having gone even mustier than the common, rank smell of a Psychlo.

MacKendrick stood up, a little tired. "I’m sorry to say that I don't think that piece of metal would cause any of these monsters to commit suicide.

But I can make a pretty good guess now as to what it does do.”

He pointed to his tags. “Taste and sexual impulses branch off from that one as near as I can tell. Emotion and action branch off from the other one there.

“This metal clip was installed when it was an infant. See the faint, ancient scars in this side of the skull. At that time the bones would be soft and would heal fast.”

“And what does it do?” said Angus.

“My guess,” said MacKendrick, “is that it short-circuits pleasure with action. Maybe they did it to make a Psychlo happy only when he was working. But– and I can't tell fully unless I dissect a lot of these nerves further down– I think its actual effect was to make a Psychlo enjoy cruel action.”

Suddenly Jonnie recalled an expression of Terl’s. He had seen him do something cruel and heard him mutter, “Delicious!”

“The effort,” said MacKendrick, “to make them industrious I think was miscalculated by their ancient metal specialists, and they made a race of true monsters.”

Everyone agreed with that.

“That wouldn't make them commit suicide to protect technology!” said Robert the Fox. “You got another corpse here. He was an assistant mine manager by his papers and got twice the pay of the one you just did. Get him on the table, man.”

MacKendrick got another table. He would have to picto-record and sketch the work he had just done.

They put the mammoth head of the second one on the machine. They had the setting now. And they looked into the dead brain of one who had been called Blow.

And Jonnie, who had been getting despondent, gruesome as this job was, suddenly smiled.

There were two metal pieces in this one's head!

The whir-flap of the machine took the recording and he rushed out to tear through the analysis code books.

There it was, bright and clear: silver!

When he reentered the room, MacKendrick, being practiced now, had the brain stripped down. He was spot-dyeing the connections of the second bit of metal before he took it out.