If you think it's hard to get hold of potassium cyanide, think again. I stood there with a pound bottle in my hand. Brown glass, a nice clear label saying 'Potassium Cyanide CP' (the initials, I was told, meaning 'chemically pure') with a small skull and crossbones underneath.

The fellow who owned the bottle polished his glasses and blinked at me. He was Associate Professor Helmuth Rodney of Carmody University. He was of middle height, stocky, with a soft chin, plump lips, a budding paunch, a shock of brown hair, and a look of complete indifference to the fact that I was holding in my hand enough poison to kill a regiment.

I said, 'Do you mean to say this just stands on your shelf, Professor?'

He said in the kind of deliberate tone he probably used in lecturing his students, 'Yes, it always has, Inspector. Along with the rest of the chemicals in alphabetic order.'

I glanced about the cluttered room. Shelves lined the upper reaches of all the walls, and bottles, large and small, filled them all.

This one,' I pointed out, 'is poison.'

'A great many of them are,' he said with composure.

'Do you keep track of what you've got?'

'In a general way.' He rubbed his chin. 'I know I have that bottle.'

'But suppose someone came in here and helped himself to a spoonful of this stuff. Would you be able to tell?'

Professor Rodney shook his head. 'I couldn't possibly.'

'Well, then, who could get into this laboratory? It is kept locked?'

He said, 'It's locked when I leave in the evening, unless I forget. During the day, it isn't locked, and I'm in and out.'

'In other words. Professor, anyone could come in here, even someone from the street, walk off with some of the cyanide, and no one would ever know.'

'I'm afraid so.'

'Tell me. Professor, why do you keep this much cyanide in the place anyway? To kill rats?'

'Good heavens, no.' He seemed family repelled at the thought. 'Cyanide is sometimes used in organic reactions to form necessary intermediates, to provide a proper basic medium, to catalyze-'

'I see. I see. Now in what other labs is cyanide available in this way?'

'In most of them,' he answered at once. 'Even in the student labs. After all, it's a common chemical, routinely used in syntheses.'

'I wouldn't call its use today routine,' I said.

He sighed and said, 'No, I suppose not.' He added thoughtfully, They used to call them the "Library Twins." '

I nodded. I could see the reason for the nickname. The two girl librarians were very alike.

Not close up, of course. One had a small pointed chin on a round face, and the other had a square jaw and a long nose. Still, bend them over a desk and both had honey-blond hair parted in the middle with a similar wave. Look them quickly in the face and you would probably notice first wide-set eyes of about the same shade of blue. See them standing together at a moderate distance and you could see they were both of a height and both, probably, with the same brand and size uplift brassiere. Both had trim waists and neat legs. Today they had even dressed similarly. Both wore blue.

There was no confusing the two now, though. The one with the small chin and round face was full of cyanide, and quite dead.

The similarity was the first thing that struck me when I arrived with my partner, Ed Hathaway. There was one girl slumped in her chair and dead, her eyes open, one arm dangling straight down, with a broken teacup on the floor beneath like a period under an exclamation point. Her name, it turned out, was Louella-Marie Busch. There was a second girl, like the first one brought back to life, white and shaken, staring straight ahead and letting the police and their work flow about her without seeming to notice. Her name was Susan Morey.

The first question I asked was, 'Relatives?' They weren't. Not even second cousins.

I looked about the library. There were whole shelves of books in similar bindings, then other shelves with books in another set of bindings. They were volumes of different research journals. In another room were stacks of what I found later to be textbooks, monographs, and older books. In the back was a special alcove containing recent numbers of unbound research periodicals in dull and closely printed paper covers. From wall to wall were long tables that might have seated a hundred people if all were fully occupied. Fortunately that wasn't the case.

We got the story out of Susan Morey in flat, toneless pieces.

Mrs. Nettler, the old Senior Librarian had taken off for the afternoon and had left the two girls in charge. That, apparently, was not unusual.

At two o'clock, give or take five minutes, Louella-Marie took herself into the back room behind the library desk. There, in addition to new books that awaited cataloguing, stacks of periodicals that awaited binding, reserved books that awaited their reservers, there was also a small hot-plate, a small kettle, and the fixings for weak tea.

Two o'clock tea was apparently usual, too.

I said, 'Did Louella-Marie prepare the tea every day?'

Susan looked at me out of her blank blue eyes. 'Sometimes Mrs. Nettler does, but usually Lou-Louella-Marie did.'

When the tea was ready, Louella-Marie emerged to say so and after a few moments the two retired.

'Both of you?' I asked sharply. 'Who took care of the library?'

Susan shrugged as though this were a minor point to worry about, and said, 'We can see out the door If anyone came to the desk, one of us could have gone out.'

'Did anyone come to the desk?'

'No one. It's intersession. Hardly anyone's around.'

By intersession she meant that the spring semester was over and the summer sessions had not yet started.

I learned quite a bit about college life that day.

What was left of the story was little enough. The tea bags were already out of the gently steaming cups and the sugar had been added.

I interrupted. 'You both take sugar?'

Susan said slowly, 'Yes. But mine didn't have any.'

'No?'

'She never forgot before. She knows I take it. I just took a sip or two and I was going to reach for the sugar and tell her, you know, when-'

When Louella-Marie gave a queer strangled cry, dropped the cup, and was dead in a minute. After that Susan screamed and eventually we came.

The routine passed smoothly enough. Photographs and fingerprints had been taken. The names and addresses of the men and women in the building were taken and they were sent home. Cause of death was obviously cyanide and the sugar bowl was the obvious villain. Samples were taken for official testing.

There had been six men in the library at the time of the murder. Five were students, who looked frightened, confused, or sick, depending, I suppose, on their personalities. The sixth was a middle-aged man, an outsider, who talked with a German accent and had no connection with the college at all. He looked frightened, confused, and sick, all three.

My sidekick, Hathaway, was leading them out of the library. The idea was to get them to the Co-educational Lounge and have them stay put till we could get to them in detail.

One of the students broke away and strode past me without a glance. Susan flew to meet him, clutching each sleeve above the elbow. 'Pete. Pete.'

Pete was built like a football player except that his profile looked as though he had never been within half a mile of the playing field. He was too good-looking for my taste, but then I get jealous easily.

Pete was looking past the girl, his face coming apart at the seams till its prettiness was drowned in uneasy horror. He said in a hoarse, choking way, 'How did Lolly come to...'

Susan gasped, 'I don't know. I don't know.' She kept trying to meet his eye.

Pete pulled away. He never looked at Susan once, kept staring over her shoulder. Then he responded to Hathaway's grip on his elbow and let himself be led away.

I said, 'Boyfriend?'

Susan tore her eyes from the departing student. 'What?'

'Is he your boy friend?'

She looked down at her twisting hands. 'We've been out on dates.'

'How serious?'

She whispered, 'Pretty serious.'

'Does he know the other girl, too? He called her Lolly?' Susan shrugged. 'Well...'

'Let's put it this way. Did he go out with her?'

'Sometimes.'

'Seriously.'

She snapped, 'How should I know?'

'Come on, now. Was she jealous of you?'

'What's all this about?'

'Someone put the cyanide in the sugar and put the mixture in only one cup. Suppose Louella-Marie was jealous enough of you to try to poison you and leave herself a clear field with our friend Pete. And suppose she took the wrong teacup herself by mistake.'

Susan said, That's crazy. Louella-Marie wouldn't do such a thing.'

But her lips were thin, her eyes sparkled, and I can tell hate in a voice when I hear it.

Professor Rodney came into the library. He was the first man I had met on entering the building and my feelings toward him had grown no warmer.

He had begun by informing me that as senior faculty member present, he was in charge.

I said, 'I'm in charge now, Professor.'

He said, 'Of the investigation perhaps, Inspector, but it is I who am responsible to the Dean and I propose to fulfill my responsibilities.'

And although he hadn't the figure of an aristocrat, more like a shopkeeper, if you follow me, he managed to look at me as though there were a microscope between as with himself on the large side.

Now he said, 'Mrs. Nettler is in my office. She heard the news bulletin, apparently, and came at once. She is quite agitated. You will see her?' He made it sound like an order.

'Bring her in. Professor.' I made it sound like permission.

Mrs. Nettler was in the usual quandary of the average old lady. She didn't know whether to be horrified or fascinated at the closeness with which death had struck. Horror won out after she looked into the inner office and noticed what was left of the tea things. The body was gone by then, of course.

She flopped into a chair and began crying. 'I had tea here myself,' she moaned. 'It might have been...'

I said as quietly and soothingly as I could manage, 'When did you drink tea here, Mrs. Nettler?'

She turned in her seat, looked up. 'Why-why, just after one, I think. I offered Professor Rodney a cup, I remember. It was just after one, Professor Rodney, wasn't it?'

A trace of annoyance crossed Rodney's plump face. He said to me, 'I was here a moment just after lunch to consult a reference. Mrs, Nettler did offer a cup. I was too busy, I'm afraid, to accept or to note the time exactly.'

I grunted and turned back to the old lady. 'Do you take sugar, Mrs. Nettler?'

'Yes, sir.'

'Did you take sugar?'

She nodded and started crying again.

I waited a bit. Then, 'Did you notice the condition of the sugar bowl?'

'It was-it was-' A sudden surprise at the question seemed to put her on her feet. 'It was empty and

I filled it myself. I used the two-pound box of granulated sugar and I remember saying to myself that whenever I wanted tea the sugar was gone and I wished the girls would-'

Maybe it was the mention of the girls in the plural. She broke out again.

I nodded to Hathaway to lead her away.

Between i and 2 p.m., obviously, someone had emptied the sugar bowl and then added just a bit of laced sugar- very neatly laced sugar.

Maybe it was Mrs. Nettler's appearance that pumped librarianship back into Susan, because when Hathaway came back and reached for one of his cigars-he already had the match lit-the girl said, 'No smoking in the library, sir.'

Hathaway was so surprised he blew the match out and replaced the cigar in his pocket.

Then the girl stepped briskly to one of the long tables and reached for a large volume that lay open on it. Hathaway was ahead of her. 'What are you going to do, Miss?'

Susan looked completely astonished. 'I'm just going to put it back on the shelves.'

'Why? What is it?' He looked down at the open page. I was there too, by then. I looked over his shoulder.

It was German. I can't read the language, but I can recognize it when I see it. The printing was small, and there were geometrical figures on the page with lines of letters attached at various places. I knew enough, too, to know those were chemical formulas.

I put my finger in the place, closed the book and looked at the backstrap. It said, 'Beilstein-Organische Chemie-Band VI-System Nummer 499-608.' I opened to the page again. It was 233 and the first words, just to give you an idea, were 4'-chlor-4-brom-2-nitro-diphenylather-C12H7O3 NClBr.

Hathaway was busy copying things down.

Professor Rodney was at the table too, which made four of us all gathered round the book.

The professor said in a cool voice, as though he were on a platform with a pointer in one hand and a piece of chalk in the other, 'This is a volume of Beilstein.' (He pronounced it Bile-shtine.) 'It's a kind of encyclopedia of organic compounds. It lists hundreds of thousands of them.'

'In this book?' demanded Hathaway.

This book is only one of more than sixty volumes and supplementary volumes. It is a tremendous German work which is years out of date because, first, organic chemistry is progressing at an ever-increasing pace and, second, because of the interference of politics and war. Even so, there is nothing even faintly approaching its usefulness in English. For all research men in organic chemistry, these volumes are an absolute necessity.'

The professor actually patted the book as he spoke, a fond pat. 'Before dealing with any unfamiliar compound,' he said, 'it is good practice to look it up in Beilstein. It will give you methods of preparation, properties, references, and so on. It acts as a starting point. The various compounds are listed according to a logical system which is clear but not obvious. I myself give several lectures in my course on organic syntheses which deal entirely with methods for finding a particular compound somewhere in the sixty volumes.'

I don't know how long he might have continued, but I wasn't there to learn organic syntheses and it was time to get down to cases. I said abruptly, 'Professor, I want to speak to you in your laboratory.'

I suppose I had some notion that cyanide was kept in a safe, that every bit of it was accounted for, that people had to sign out for it when they wanted some. I thought the question of opportunity to get some illicitly might supply what proof we needed.

And there I stood with a pound of it in my hand and the knowledge that anyone could have any amount for the asking, or without asking.

And he said thoughtfully, 'They used to call them the "Library Twins."'

I nodded. 'So?'

'Only that it proves how superficial the judgment of most people is. There was nothing alike about them except the accident of hair and eyes. What happened in the library, Inspector?'

I told him Susan's story briefly and watched him.

He shook his head. 'I suppose you think the dead girl planned murder.' My thoughts weren't for sale at the moment. I said, 'Don't you?'

'No. She was incapable of it. Her attitude toward her duties was a pleasant and helpful one. Besides, why would she?'

'There's a student,' I said. 'Peter is his first name.'

'Peter van Norden,' he said at once. 'A reasonably bright student, but, somehow, worthless.'

'Girls look at these things differently, Professor. Both librarians were apparently interested. Susan may have been the more successful and Louella-Marie may have decided on direct measures.'

'And then proceeded to take the wrong cup?'

I said, 'People do queer things under tension.'

'Not this queer,' he said. 'One cup was left unsugared, so the murderess wasn't taking chances. Presumably even if she had not carefully memorized which cup was which, she could count on the sweetness to give it away. She could easily have avoided a fatal dose.'

I said dryly, 'Both girls usually took sugar. The dead girl was used to sweet tea. In the excitement the accustomed sweetness didn't ring a bell.'

'I don't believe it.'

'What's the alternative, Professor? The sugar was hocused after Mrs. Nettler's tea at one o'clock. Did Mrs. Nettler do it?'

He looked up sharply. 'What possible motive?'

I shrugged. 'She might have been afraid the girls were going to be taking her job away.' That's nonsense. She's retiring before the fall session begins.'

'You were there, Professor,' I said softly.

He took it in stride, to my surprise. 'Motive?' he said.

I said, 'You're not too old to have been interested in Louella-Marie, Professor. Suppose she had threatened to report some word or act of yours to the Dean.'

The Professor smiled bitterly. 'How did I manage to make sure the right girl got the cyanide? Why should one cup remain unsugared? I may have hocused the sugar but I didn't prepare the tea.'

I began to change my mind about Professor Rodney. He hadn't bothered to work up indignation or register shock.

He simply pointed out the logical weakness and let it go at that. I liked that.

I said, 'What do you think happened?'

He said, The mirror-image. The reverse. I think the survivor told the truth inside out. Suppose it was

Louella-Marie who was getting the boy and Susan who didn't like it, rather than the reverse. Suppose it was Susan who for once was preparing the tea and Louella-Marie who was at the front desk rather than the reverse. In that case, the girl who prepared the tea would have taken the right cup and remained safe. Everything would be logical instead of ridiculously improbable.'

That did it. The man had come to the same conclusion I had and so I had to like him after all. I have a habit of feeling soft toward guys who agree with me. It comes of being Homo sapiens, I think.

I said, 'We've got to prove that beyond reasonable doubt. How? I'd come up here, hoping to prove someone had had access to potassium cyanide and others had not. That's out. Everyone had access. Now what?'

The professor said, 'Check on which girl was really at the desk at two o'clock when the tea was being prepared.'

It was obvious to me that the professor read detective stories and had faith in witnesses. I didn't, but I got up anyway.

'All right, Professor. I'll do that.'

The professor rose also. He said urgently, 'May I be present?'

I considered. 'Why? Your responsibilities to the Dean?'

'In a way. I would like to see a quick, clean end to this.'

I said, 'Come along, if you think that will help.'

Ed Hathaway was waiting for me when I came down. He was sitting in an empty library. He said. 'I got it.'

'Got what?' I wanted to know.

'How it happened. I figured it out by deduction.'

'Oh?'

He was paying no attention to Professor Rodney. The cyanide had to be smuggled in. By whom? By the joker in the deck, the outsider, the guy with the accent-whatzis-name.'

He started scrabbling through a series of cards on which he had filed information on the various presumably innocent bystanders.

I knew who he meant so I said, 'All right, never mind the name. What's in a name? Go on'-which shows that I can be as unbright as anyone.

'All right. The foreigner comes in with the cyanide in a little envelope. He tapes the envelope to a page in the German book, that organish whatzisname with all the volumes...' The professor and I both nodded.

Hathaway went on. 'He was German, so was the book. He was probably familiar with it. He put the envelope on a prearranged page according to a particular formula that had been picked out. The professor said there was a way to find any formula if you only knew how. Isn't that right. Professor?'

That is right,' said Rodney coldly.

'All right. The librarian knew the formula so she could find the page too. She picks up the cyanide and uses it for the tea. In the excitement, she forgets to close the book-'

I said, 'Look, Hathaway. Why should that little guy be doing this? What's his excuse for being here?'

'He says he's a furrier reading up on moth repellents and insecticides. Now isn't that phony right off. Ever hear anything so phony?'

'Sure,' I said, 'your theory. Look, no one is going to hide an envelope with cyanide in a book. You don't have to find a particular formula or page with an envelope bulging a volume out of shape. Anyone who took the volume off the shelf would find that the book would fall open to the right page automatically. A hell of a hiding place.'

Hathaway began to look foolish.

I drove on pitilessly, 'Besides, cyanide doesn't have to be smuggled in from the outside. They've got tons of it here. They can use it to make snow-slides. Anyone who wants a pound or two can help himself.'

'What?'

'Ask the professor.'

Hathaway's eyes widened and then he fumbled in his jacket pocket and drew out an envelope. Then what do I do with this?'

'What is it?'

He took out a printed page with German on it and said, 'It's the page out of that German volume that-'

Professor Rodney grew suddenly scarlet. 'You tore a page out of Beilstein?'

He shrieked it and surprised the hell out of me. I wouldn't have thought him capable of shrieking.

Hathaway said, 'I thought we could test it for stickum from the scotch tape, or maybe for a little cyanide that leaked out.'

'Give it to me!' yelled the professor. 'You ignorant fool.'

He smoothed out the sheet and looked at both sides as though to make sure that none of the print had been rubbed off.

'Vandal!' he said, and I'm sure that at the moment he could have killed Hathaway and laughed during the entire process.

Professor Rodney might be morally certain of Susan's guilt and so, for that matter, might I. Nevertheless, moral certainty cannot be taken before a jury. Evidence was needed.

So, lacking faith in witnesses, I attacked through the one weakness of any possibly guilty person-the possibly guilty person.

I brought her in to witness the new line of questioning, and if the questioning didn't pin her to her guilt, her own nerves might.

From her appearance I couldn't tell how good that 'might' would be. Susan Morey sat at her desk, hands clasped before her, eyes cold, and the skin around her nostrils tight-looking.

The little German furrier was in first, looking sick with worry. 'I did nothing,' he babbled. 'Please. I have business. How long must I stay?'

Hathaway had his name and vital statistics, so I skipped all that and got to the point.

'You came here a little before two o'clock. Right?'

'Yes. I wanted to know about moth repellents-'

'All right. When you came in you went to the desk. Right?'

'Yes. I told her my name, who I was, what I wanted-' Told whom?' That was the key question.

The little fellow stared at me. He had curly hair and a mouth that fell in as though he were toothless, but that was just appearance, for when he talked, small yellow teeth were plainly visible. He said, 'Her. I told her. The girl sitting there.'

'That's right,' said Susan tonelessly. 'He spoke to me.'

Professor Rodney was gazing at her with a look of concentrated detestation. It occurred to me that his reason for wishing to see justice done quickly might be more personal than idealistic at that. However, that was none of my business.

I said to the furrier, 'Are you sure this is the girl?'

He said, 'Yes. I told her my name and my business, and she smiled. She told me where to find books on insecticides. Then, as I was stepping away, another girl came out from inside there.'

'Good!' I said at once. 'Now here's a photograph of another girl. Tell me, was it the girl at the desk you spoke to and the girl in the photograph who came out of the back room? Or was it the girl in the photograph you spoke to and the girl at the desk who came out of the back room?'

For a long minute, the furrier stared at the girl, then at the photograph, then at me. 'They are alike.'

I swore to myself. The faintest smile had passed over Susan's lips, hovering there a moment before vanishing. She must have counted on this. It was intersession. Hardly anyone would be in the library.

None of them would pay much attention to the librarians who are fixtures like the bookshelves, and if any did, he could never swear which of the Library Twins he had seen.

I knew she was guilty now, but knowing meant nothing.

I said, 'Well, which was it?'

He said, like one anxious to put an end to questioning, 'I spoke to her, the girl right there at the desk.'

'That's right,' said Susan, perfectly calm.

My hope in her nerves hit bottom.

I said to the furrier, 'Would you swear?' He said at once, 'No.'

'All right. Hathaway, take him away. Send him home.'

Professor Rodney leaned over to touch my elbow. He whispered, 'Why did she smile at the fellow when he stated his business.'

I whispered back, 'Why not?' but put the question to her anyway.

Her eyebrows went up a fraction of an inch. 'I was just being pleasant. Is there anything wrong with that?' She was almost enjoying herself. I could swear to that.

The professor shook his head slightly. He whispered to me again, 'She's not the type to smile at a troublesome stranger. It had to be Louella-Marie at the desk.'

I shrugged. I could see myself bringing that kind of evidence to the Commissioner.

Four of the students were a blank and took up little time. They were engaged in research, they knew what books they wanted, what shelves the books would be on. They went straight there without stopping at the desk. None could say whether Susan or Louella-Marie had been at the desk at any particular time. None had even looked up from their books, to hear them tell it, before the scream roused everything.

The fifth was Peter van Norden. He kept his eyes fixed firmly on his right thumb, which had a badly bitten nail. He did not look up at Susan as he was brought in.

I let him sit awhile and soften up.

Finally I said, 'What are you doing here this time of year? I understand it's between sessions.'

He muttered, 'My Qualifyings are coming up next month. I'm studying. Qualifying examinations. If I pass,

I can go on for my Ph.D., see?'

I said, 'I suppose you stopped at the desk when you came in here.' He mumbled.

I said, 'What?'

He said in a low voice that was hardly an improvement, 'I didn't. I don't think I stopped at the desk.'

'You don't think?'

'I didn't.'

I said, 'Isn't that strange? I understand you're good friends of both Susan and Louella-Marie. Don't you say hello?'

'I was worried. I had this test in my mind. I had to study.

'So you couldn't even take time out for a hello.' I looked at Susan to see how this was going over. She seemed paler, but that might have been my imagination.

I said, 'Isn't it true that you were practically engaged to one of them?'

He looked up with uneasy indignation. 'No! I can't get engaged before I get my degree. Who told you I was engaged?'

'I said practically engaged.'

'No! I had a few dates, maybe. So what! What's a date or two?'

I said smoothly, 'Come on, Pete, which one was your girl?'

'I tell you it wasn't like that.'

He was washing his hands of the whole matter so hard, he seemed buried and smothered in an invisible lather.

'How about it?' I asked suddenly, addressing Susan. 'Did he stop at your desk?'

'He waved as he passed,' she said.

'Did you, Pete?'

'I don't remember,' he said sullenly. 'Maybe I did. So what?'

'Nothing,' I said. Inside me, I wished Susan joy of her bargain. If she had killed for the sake of this specimen, she had done it for nothing. To me it seemed a certainty that henceforward he would ignore her even if she fell off a two-story building and hit him on the head.

Susan must have realized that too. From the look she was giving Peter van Norden, I marked him down as a second candidate for cyanide-assuming she went free-and it certainly seemed as though she would.

I nodded to Hathaway to take him away. Hathaway rose to do that and said, 'Say, you ever use those books?' and he pointed to the shelves where the sixty-odd volumes of the organic chemistry encyclopedia stretched from floor to ceiling.

The boy looked over his shoulder and said in honest astonishment. 'Sure. I've got to. Lord, is something wrong with looking up compounds in Beilst-'

'It's all right,' I assured him. 'Come on, Ed.'

Ed Hathaway scowled at me and led the boy out. He hates letting go of an exploded theory.

It was about six and I didn't see that anything more could be done. As it stood, it was Susan's word against no word. If she had been a hood with a record, we could have sweated out the truth in any of several effective, if tedious, ways. In this case, such a procedure was inadvisable.

I turned to the professor to say so, but he was staring at Hathaway's cards. At one of them, anyway, which he was holding in his hand. You know, people always talk about other people's hands shaking with excitement, but it's something you don't often see. Rodney's hand was shaking, though, shaking like the clapper of an old-fashioned alarm clock.

He cleared his throat. 'Let me ask her something. Let me...'

I stared at him, then pushed my chair back. 'Go ahead,' I said. At this point, there was nothing to lose.

He looked at the girl, putting the card down on the desk, blank side up.

He said shakily, 'Miss Morey?' He seemed to be deliberately avoiding the familiarity of her first name.

She stared at him. For a moment she had seemed nervous, but that passed and she was calm again. 'Yes, Professor?'

The professor said, 'Miss Morey, you smiled when the furrier told you his business here. Why was that?'

'I told you, Professor Rodney,' she said, 'I was being pleasant.'

'Perhaps there was something peculiar about what he said? Something amusing?'

'I was just trying to be pleasant,' she insisted.

'Perhaps you found his name amusing, Miss Morey?'

'Not particularly,' she said indifferently.

'Well, no one has mentioned his name here. I didn't know it till I happened to look at this card.' Then suddenly, tensely, he cried, 'What was his name, Miss Morey?'

She paused before answering, 'I don't remember.'

'You don't ? He gave it to you, didn't he?'

There was an edge to her voice now. 'What if he did? It's just a name. After all that's happened, you can't expect me to remember some peculiar foreign name I happened to hear one time.'

'It was foreign, then?'

She pulled up short, avoiding the trap. 'I don't remember,' she said. 'I think it was a typically German name, but I don't remember. For all I know it was John Smith.'

I had to admit I didn't see the professor's point. I said, 'What are you trying to prove. Professor Rodney?'

'I'm trying to prove,' he said tightly, 'in fact I am proving, that it was Louella-Marie, the dead girl, who was at the desk when the furrier came in. He announced his name to Louella-Marie and she smiled in consequence. It was Miss Morey who was coming out of the inner office as he turned away. It was Miss Morey, this girl, who had just finished preparing and poisoning the tea.'

'You're basing that on the fact I can't remember a man's name!' shrilled Susan Morey. That's ridiculous.'

'No, it isn't,' said the professor. 'If you had been the girl at the desk, you would remember his name. It would be impossiblefor you to forget it. If you were the girl at the desk.' He was holding Hathaway's card up now. He said. That furrier's first name is Ernest, but his last name is Beilstein. His name is Beilstein!' The air went out of Susan as though she had been kicked in the stomach. She turned white as talcum powder.

The professor went on intensely, 'No chemical librarian could possibly forget the name of anyone who came in and announced himself to be Beilstein. The sixty-volume encyclopedia we've mentioned half a dozen times today is referred to invariably by the name of its editor, Beilstein. The name is like Mother Goose to a chemical librarian, like George Washington, like Christopher Columbus. It is more second nature to her than any of them.

'If this girl claims to have forgotten the name, it is only because she never heard it. And she never heard it because she wasn't at the desk.'

I rose and said grimly, 'Well, Miss Morey'-I abandoned the first name too-'what about it?' She was screaming in earsplitting hysteria. Half an hour later, we had her confession.

***

Some years before this next story was written, two colleagues and I joined forces in writing a large and complicated textbook in biochemistry lor medical students. We spent days-literally-on the galley proofs, and frequently we came across minor inconsistencies. We would spell a chemical one way here and another way there; here a hyphen and there no hyphen; here one phrase and yon an alternate. We despaired of getting everything perfectly concordant and one of us finally said, 'To quote Emerson: "A foolish consistency is the hobgoblin of little minds."' We latched on to this with ebullient joy and thereafter, whenever the proof-reader questioned a small inconsistency, we would write 'Emerson!' in the margin and let it go. Well, the following story revolves about the possible invention of mass transference, and in preparing these stories tor inclusion in this volume, I noted that in 'The Singing Bell'-an earlier story with the same background-mass transference was taken lor granted as already existing. I was about to make certain changes to eliminate that discrepancy, when I remembered. So if you don't mind, Gentle Reader, I cry 'Emerson!' and pass on.