with long nervous strides, snapping his fingers as he tried toexplain.
"I'm in trouble, Karl. I've run into something I don't know how to dealwith, and I need help, I need advice, I need cooperation. I've livedalone with this thing for ten long years, hoping month after month thatsomething would turn up so I could evade the issue. But nothing has. Andnow there's going to be a showdown."
Karl touched his arm sympathetically. "My dear boy--"
"_That's it!_" shouted David.
"What's what?"
"That's what I'm trying to tell you. Why do you always call me your'dear boy?' You know I'm a year older than you are."
"It's just habit, I suppose. You _look_ so young--your hair is black,while mine is nearly white. You're full of vigor, while I begin to creakwith middle age. I didn't realize that I irritated you with my littlephrase. I should think you'd be pleased that you have somehow managed tosip at the fountain of youth."
David sank down on a stool. "I'm not pleased. I'm terrified."
"What do you mean?"
"I mean that's exactly what's happened. I have sipped at the fountain ofyouth. I've discovered how to keep people from growing old. I myselfhave not aged a bit in the last ten years."
There was a long silence. Karl sat unmoving, his face like stone.
"I don't believe you," he said at last.
"It's no longer a question of belief. In a few days everybody will know,the proof will stare you in the face. And what will happen then?"
"Evidence?" Karl asked. "I can't accept a statement as a fact."
"Would you like to see my mice? Come with me."
David Wong hurried into the small animal room and paused before a stackof wire cages in which furry creatures darted and squeaked.
"You remember when we were working on Blue Martian, those peculiarmutants we found in our mice, and how I used six of them in trying tomake antibodies to the virus?"
"I remember," said Karl. "They were spotted with tufts of white hair onthe right forelegs."
David took down a cage, thrust in his hand, and brought out two of thetiny black mice which crawled over his trembling hand. Their rightforelegs bore tufts of long white hair.
"These," he said, "are the same mice."
"Their descendants, you mean. Mice don't live that long."
"_These_ mice do. And they'll go on living. For years I've lived in fearthat someone would notice and suspect the truth. Just as for years,every time someone has laughed and told me I never seemed to age a day,I've been terrified that he might guess the truth. I'm _not_ aging."
Karl looked dazed. "Well, my boy, you've got a bear by the tail. How didyou find the elixir or whatever it is?"
"You remember the early work with radioactive tracers, a couple ofhundred years ago, that proved that all our body cells are in acontinuous state of flux? There's a dynamic equilibrium between thedisintegration and the resynthesis of the essential factors such asproteins, fats and amino groups, but the cell directs all the incomingmaterial into the right chemical structures, under the influence of someorganizing power which resides in the cell.
"Foreign influences like viruses may disrupt this order and causecancer. The cells are continually in a state of change, but alwaysreplace their characteristic molecules, and it is only as they growolder that they gradually become 'worn out.' Then the body grows old,becomes less resistant to infection, and eventually succumbs to onedisease or another. And you know, of course, that viruses also have thisself-duplicating ability.
"I reasoned that at birth a man had a definite, finite amount of thisessential self-duplicating entity--SDE--in his body cells, a kind ofdirecting factor which reproduces itself, but more slowly than do thebody cells. In that case, with the normal multiplication of the cells,the amount of SDE per cell would slowly but surely grow smaller with theyears. Eventually the time would come when the percentage would be belowthe critical level--the cells would be less resistant, would functionwith less efficiency, and the man would 'grow old.'"
Karl nodded soberly. "Reasonable hypothesis."
"But one day, by pure chance, I isolated a component which I recognizedas being the factor essential to the normal functioning of body cells.It hit me like a toothache. I found that I could synthesize the SDE inthe lab, and the only problem then was to get it into a man's cells. IfI could do that, keep the SDE level up to that of youth, a man wouldstop aging! Since viruses penetrate our cells when they infect us, itwas no trick at all to effect a chemical coupling of the SDE to thevirus. I used Martian Blue, since it was handy, and its effects areusually brief.
"Presto! Old age is held at bay for another twenty or thirty years--Ireally don't know how long. These mice were my first experiment, and asyou see, they're still alive. Next, I tried it on myself."
David put the mice back in their cage, locked it, and returned to thelab.
"Tomorrow, the whole thing is bound to come out because Tanya Hachovnikis coming back. You know her sister Leah--gray, dried-up, soured onlife. Well, I've had ways of checking, and when Tanya Hachovnik walksinto the Institute, everyone will see her as the same luscious redheadof twenty-five we knew ten years ago. I realize that what I did was acriminal act. I didn't think the thing through or I wouldn't have beensuch a fool. But when I made those final experiments, I used theHachovnik twins for a controlled pair."
"You must have been crazy!"
"Perhaps I was. I'd tried it on myself, of course, with no bad effectsexcept a few days' fever, but I realized that without a control I nevercould be sure the SDE was actually working. It might be just that myparticular genetic constitution caused me to age more slowly than theaverage. So I chose the twins. To Leah I gave the attenuated MartianBlue, but to Tanya I gave the simple Blue coupled with SDE. Theexperiment worked. Identical twins--one grows old like other people; theother remains young. I know now, Karl, how to prolong youthindefinitely. But what in the name of Leader Marley shall I do with myknowledge?"
Karl Haslam absently twisted his white hair and spoke slowly, as thoughhe found trouble in choosing his words.
"You realize, of course, that it is your duty to acquaint Leader Marleywith all the details of your discovery?"
"Is it? Can you imagine what this will do to our society? What about thegenerations of children coming into a world where no places have beenvacated for them by death? What about the struggles for power? Who willdecide, and on what basis, whether to confer or to withhold this gift?There'll be riots, civil wars. I know that I'm only a scientist; all Iever wanted from life was to be left alone, in a peaceful laboratory,and let other people worry about the world and its troubles. Butnow--don't you see that by the mere fact that I made this discovery,I've lost the right to sit by quietly and let other people make thedecisions?"
"But, David, you and I aren't able to handle such a problem! We're onlyResearch!"
"I know. We're inadequate, yet we have the responsibility. The men whocreated atomic power probably felt inadequate, too, but could they havemade as bad a mess of handling it as others did? Suppose I did turn thisover to Marley--he'd use it to become the most absolute tyrant in thehistory of the race."
Karl ran his fingers through his hair and smiled crookedly. "Well, youcould always start a revolution, I suppose, and start by assassinatingthe Leader."
"With what kind of weapon? Men like you and me are not allowed to own somuch as an old-fashioned pistol. Except for the Military, Marley's theonly man allowed to wear a Needler. And, besides, I'm a Research, not aMilitary. I hate violence and I'm naturally conditioned againstkilling."
"Then you shouldn't have got into this mess. It would have been farbetter never to have discovered this SDE. I presume your notes aresafely locked up, by the way?"
David grinned. "Don't worry about my notes; they're written in Coptic.You remember when I was still in Medschool and made my first importantdiscovery, how to prevent the development of hereditary baldness by theinjection of certain parahormones? Leader Marley rewarded me with a FreeChoice, and I chos
e to learn a dead language. Not half a dozen men inthe world could read my notes."
"If your notes are safe, why don't you just destroy your mice and getrid of your proof that way?"
"And the Hachovnik twins?"
"You could at least keep Tanya out of sight."
"Don't be a fool. That would only be a temporary measure and has nothingto do with the real problem. Lanza and Marley may suspect the truthright now, for all I know; they keep such close watch on my work.Anyway, the