THE FIRST ONE HE got was worthless.

The base was so poorly leveled that any vibration at all disturbed it. The action of its moving parts was loose to the point of wobbling. The mirror kept moving out of position because its pivots weren't tight enough. Moreover, the instrument had no substage to hold condenser or polarizer. It had only one nosepiece, so that he bad to remove the object lens when he wanted any variation in magnification. The lenses were impossible.

But, of course, he knew nothing about microscopes, and he'd taken the first one he'd found. Three days later he hurled it against the wall with a strangled curse and stamped it into pieces with his heels.

Then, when he'd calmed down, he went to the library and got a book on microscopes.

The next time he went out, he didn't come back until he'd found a decent instrument; triple nose stage, substage for condenser and polarizer, good base, smooth movement, iris diaphragm, good lenses. It's just one more example, he told himself, of the stupidity of starting off half-cocked. Yeah, yeah, yeah, he answered disgustedly.

He forced himself to spend a good amount of time familiarizing himself with the instrument.

He fiddled with the mirror until he could direct a beam of light on the object in a matter of seconds. He acquainted himself with the lenses, varying from a three-inch power to a one-twelfth-inch power. In the case of the latter, he learned to place a drop of cedar-wood oil on the slide, then rack down until the lens touched the oil. He broke thirteen slides doing it.

Within three days of steady attention, he could manipulate the milled adjustment heads rapidly, could control the iris diaphragm and condenser to get exactly the right amount of light on the slide, and was soon getting a sharply defined clarity with the ready-made slides he'd got.

He never knew a flea looked so godawful.

Next came mounting, a process much more difficult, he soon discovered.

No matter how he tried, he couldn't seem to keep dust particles out of the mount. When he looked at them in the microscope, it looked as if he were examining boulders.

It was especially difficult because of the dust storms, which still occurred on an average of once every four days. He was ultimately obliged to build a shelter over the bench.

He also learned to be systematic while experimenting with the mounts. He found that continually searching for things allowed that much more time for dust to accumulate on his slides. Grudgingly, almost amused, he soon had a place for everything. Glass slips, cover glasses, pipettes, cells, forceps, Petri dishes, needles, chemicals—all were placed in systematic locations.

He found, to his surprise, that he actually gleaned pleasure from practicing orderliness. I guess I got old Fritz's blood in me, after all, he thought once in amusement.

Then he got a specimen of blood from a woman.

It took him days to get a few drops properly mounted in a cell, the cell properly centered on the slide. For a while he thought he'd never get it right.

But then the morning came when, casually, as if it were only of minor import, he put his thirty-seventh slide of blood under the lens, turned on the spotlight, adjusted the draw tube and mirror, racked down and adjusted the diaphragm and condenser. Every second that passed seemed to increase the heaviness of his heartbeat, for somehow he knew this was the time.

The moment arrived; his breath caught.

It wasn't a virus, then. You couldn't see a virus. And there, fluttering delicately on the slide, was a germ.

I dub thee vampiris. The words crept across his mind as he stood looking down into the eyepiece.

By checking in one of the bacteriology texts, he'd found that the cylindrical bacterium he saw was a bacillus, a tiny rod of protoplasm that moved itself through the blood by means of tiny threads that projected from the cell envelope. These hairlike flagella lashed vigorously at the fluid medium and propelled the bacillus.

For a long time he stood looking into the microscope, unable to think or continue with the investigation.

All he could think was that here, on the slide, was the cause of the vampire. All the centuries of fearful superstition had been felled in the moment he had seen the germ.

The scientists had been right, then; there were bacteria involved. It had taken him, Robert Neville, thirty-six, survivor, to complete the inquest and announce the murderer—the germ within the vampire.

Suddenly a massive weight of despair fell over him. To have the answer now when it was too late was a crushing blow. He tried desperately to fight the depression, but it held on. He didn't know where to start, he felt utterly helpless before the problem. How could he ever hope to cure those still living? He didn't know anything about bacteria.

Well, I will know! he raged inside. And he forced himself to study.

Certain kinds of bacilli, when conditions became u............