He knew only one thing - that he had been talked into attending a concert. Concerts above all were anathema to him, and in twenty years of married life he had steered clear of them with a skill and ease that only the greatest psychologist of them all could have shown. And now -

He was startled out of his stupor by the sudden discordant sounds that arose from the rear.

There was a rush of ushers to the exit where the disturbance originated, a waving of protesting uniformed arms and then a strident voice: 'I am here on urgent business direct from the Galactic Congress on Eron, Arcturus. Is Tan Porus in the audience?'

Tan Porus was out of his seat with a bound. Any excuse to leave the auditorium was nothing short of heaven-sent.

He ripped open the communication handed him by the messenger and devoured its contents. At the second sentence, his elation left him. When he was finished, he raised a face in which only his darting green eyes seemed alive.

'How soon can we leave?'

'The ship is waiting now.'

'Come, then.'

He took one step forward and stopped. There was a hand on his elbow.

'Where are you going?' asked Nina Porus. There was hidden steel in her voice.

Tan Porus felt stifled for a moment. He foresaw what would happen. 'Darling, I must go to Eron immediately. The fate of a world, of the whole galaxy perhaps, is at stake. You don't know how important it is. I tell you -'

'All right, go! And I'll go with you.'

The psychologist bowed his head.

'Yes, dear!' he said. He sighed.

The psychological board hemmed and hawed as one man and then stared dubiously at the large-scale graph before them.

'Frankly, gentlemen,' said Tan Porus, 'I don't feel too certain about it myself, but - well, you've all seen my results, and checked them too. And it is the only stimulus that will yield a canceling reaction.'

Frian Obel fingered his chin nervously. 'Yes, the mathematics is clear. Increase of hydrogen-ion activity past pH3 would set up a Demane's Integral and that- But listen, Porus, we're not dealing with space-time. The math might not hold - perhaps nothing will hold.'

'It's our only chance. If we were dealing with normal space-time, we could just dump in enough acid to kill the blasted squid or fry it with a Tonite. As it is, we have no choice but to take our chances with -'

Loud voices interrupted him. 'Let me through, I say! I don't care if there are ten conferences going on!'

The door swung open and Qual Wynn's portly figure made its entrance. He spied Porus and bore down upon him. 'Porus, I tell you I'm going crazy. Parliament is holding me, as university president, responsible for all this, and now Deana says that-' He sputtered into silence and Mir Deana, standing composedly behind him, took up the tale.

'The field now covers better than one thousand square miles and its rate of increase is growing steadily. There seems to be no doubt now that it can span interplanetary space if it wishes to do so - interstellar as well, if given the time.'

'You hear that? You hear that?' Wynn was fairly dancing in his anxiety. 'Can't you do something? The galaxy is doomed, I tell you, doomed!'

'Oh, keep your tunic on,' groaned Porus, 'and let us handle this.' He turned to Deana. 'Didn't your physicist stooges conduct some clumsy investigations as to the speed of penetration of the field through various substances?'

Deana nodded stiffly.

'Penetration varies, in general, inversely with density. Osmium, iridium and platinum are the best. Lead and gold are fair.'

'Good! That checks! What I'll need then is an osmium-plated suit with a lead-glass helmet. And make both plating and helmet good and thick.'

Qual Wynn stared horrified. 'Osmium plating! Osmium! By the great nebula, think of the expense.'

'I'm thinking,' said Porus frostily.

'But they'll charge it to the university; they'll -' He recovered with difficulty as the somber stares of the assembled psychologists fastened themselves upon him. 'When do you need it?' he muttered weakly.

'You're really going, yourself?'

'Why not?' asked Porus, clambering out of the suit.

Mir Deana said, 'The lead-glass headpiece will hold off the field not longer than an hour and you'll probably be getting partial penetration in much shorter time. I don't know if you can do it.'

'I'll worry about that.' He paused, and then continued uncertainly. 'I'll be ready in a few minutes. I'd like to speak to my wife first - alone.'

The interview was a short one. It was one of the very few occasions that Tan Porus forgot that he was a psychologist, and spoke as his heart moved him, without stopping to consider the natural reaction of the one spoken to.

One thing he did know - by instinct rather than thought -and that was that his wife would not break down or go sentimental on him; and there he was right. It was only in the last few seconds that her eyes fell and her voice quavered. She tugged a handkerchief from her wide sleeve and hurried from the room.

The psychologist stared after her and then stooped to pick up the thin book that had fallen as she had removed the handkerchief. Without looking at it, he placed it in the inner pocket of his tunic. He smiled crookedly. 'A talisman!' he said.

Tan Porus's gleaming one-man cruiser whistled into the 'death field.' The clammy sensation of desolation impressed itself upon him at once.

He shrugged. 'Imagination! Mustn't get nervy now.'

There was the vaguest glitter - a sparkle that was felt rather than seen - in the air about him. And then it invaded the ship itself, and, looking up, the Rigellian saw the five Eronian rice-birds he had brought with him lying dead on the floor of their cage, huddled masses of bedraggled feathers.

'The "death field" is in,' he whispered. It had penetrated the steel hull of the cruiser.

The cruiser bumped to a rather unskillful landing on the broad university athletic field, and Tan Porus, an incongruous figure in the bulky osmium suit, stepped out. He surveyed his depressing surroundings. From the brown stubble underfoot to the glimmering haze that hid the normal blue of the sky, all seemed - dead.

He entered Psychology Hall.

His lab was dark; the shades were still drawn. He parted them and studied the squid's tank. The water replenisher was still working, for the tank was full. However, that was the only normal thing about it. Only a few dark-brown, ragged strands of rot were left of what had once been sea-fern. The squid itself lay inertly upon the floor of the tank.

Tan Porus sighed. He felt tired and numbed. His mind was hazy and unclear. For long minutes he stared about him un-seeingly.

Then, with an effort, he raised the bottle he held and glanced at the label - 12 molar hydrochloric acid.

He mumbled vaguely to himself. 'Two hundred cc. Just dump the whole thing in. That'll force the pH down - if only hydrogen ion activity means something here.'

He was fumbling with the glass stopper, and - suddenly -laughing. He had felt exactly like this the one and only time he had ever been drunk.

He shook the gathering cobwebs from his brain. 'Only got a few minutes to do - to do what? I don't know - something anyway. Dump this thing in. Dump it in. Dump! Dump! Dumpety-dump!' He was mumbling a silly popular song to himself as the acid gurgled its way into the open tank.

Tan Porus felt pleased with himself and he laughed. He stirred the water with his mailed fist and laughed some more. He was still singing that song.

And then he became aware of a subtle change in environment. He fumbled for it and stopped singing. And then it hit him with the suddenness of a downpour of cold water. The glitter in the atmosphere had gone!

With a sudden motion, he unclasped the helmet and cast it off. He drew in long breaths of air, a bit musty, but unkilling.