Cities in Flight

“I’m importing at the moment,” Paige said, holding out the soil samples. Gunn took them reverently and dropped them in a pocket of his jacket. “But I’d enjoy seeing the labs.”

He nodded to the girl and the doors closed between them. He was inside.

The place was at least as fascinating as he had expected it to be. Gunn showed him, first, the rooms where the incoming samples were classified and then distributed to the laboratories proper. In the first of these, a measured fraction of a sample was dropped into a one-litre flask of sterile distilled water, swirled to distribute it evenly, and then passed through a series of dilutions. The final suspensions were then used to inoculate test-tube slants and petri plates, containing a wide variety of nutrient media, which went into the incubator.

“In the next lab here—Dr. Aquino isn’t in at the moment, so we mustn’t touch anything, but you can see through the glass quite clearly—we transfer from the plates and agar slants to a new set of media,” Gunn explained. “But here each organism found in the sample has a set of cultures of its own, so that if it secretes anything into one of the media, that something won’t be contaminated.”

“If it does, the amount must be very tiny,” Paige said. “How do you detect it?”

“Directly, by its action. Do you see the rows of plates with the white paper discs in their centers, and the four furrows in the agar radiating from the discs? Well, each one of those furrows is impregnated with culture medium from one of the pure cultures. If all four streaks grow thriving bacterial colonies, then the medium on the paper disc contains no antibiotic against those four germs. If one or more of the streaks fails to grow, or is retarded compared to the others, then we have hope.”

In the succeeding laboratory, antibiotics which had been found by the disc method were pitted against a whole spectrum of dangerous organisms. About 90 per cent of the discoveries were eliminated here, Gunn explained, either because they were insufficiently active or because they duplicated the antibiotic spectra of already known drugs. “What we call ‘insufficiently active’ varies with the circumstances, however,” he added. “An antibiotic which shows any activity against tuberculosis or against Hansen’s disease—leprosy—is always of interest to us, even if it attacks no other germ at all.”

A few antibiotics which passed their spectrum tests went on to a miniature pilot plant, where the organisms that produced them were set to work in a deep-aerated fermentation tank. From this bubbling liquor, comparatively large amounts of the crude drug were extracted, purified, and sent to the pharmacology lab for tests on animals.

“We lose a lot of otherwise promising antibiotics here, too,” Gunn said. “Most of them turn out to be too toxic to be used in—or even on —the human body. We’ve had Hansen’s bacillus knocked out a thousand times in the test-tube only to find here that the antibiotic is much more quickly fatal in vivo than is leprosy itself. But once we’re sure that the drug isn’t toxic, or that its toxicity is outweighed by its therapeutic efficacy, it goes out of our shop entirely, to hospitals and to individual doctors for clinical trial. We also have a virology lab in Vermont where we test our new drugs against virus diseases like the ’flu and the common cold—it isn’t safe to operate such a lab in a heavily populated area like the Bronx.”

“It’s much more elaborate than I would have imagined,” Paige said. “But I can see that it’s well worth the trouble. Did you work out this sample-screening technique here?”

“Oh, my, no,” Gunn said, smiling indulgently. “Waksman, the discoverer of streptomycin, laid down the essential procedure decades ago. We aren’t even the first firm to use it on a large scale; one of our competitors did that and found a broad-spectrum antibiotic called chloramphenicol with it, scarcely a year after they’d begun. That was what convinced the rest of us that we’d better adopt the technique before we got shut out of the market entirely. A good thing, too; otherwise none of us would have discovered tetracycline, which turned out to be the most versatile antibiotic ever tested.”

Farther down the corridor a door opened. The squall of a baby came out of it, much louder than before. It was not the sustained crying of a child who had had a year or so to practice, but the short-breathed “ah-la, ah-la, ah-la,” of a newborn infant.

Paige raised his eyebrows. “Is that one of your experimental animals?”

“Ha, ha,” Gunn said. “We’re enthusiasts in this business, Colonel, but we must draw the line somewhere. No, one of our technicians has a baby-sitting problem, and so we’ve given her permission to bring the child to work with her, until she’s worked out a better solution.”