THE PROFESSOR OF SOIL SCIENCE SELMAN WAKSMAN was hoping that the rain would stop, since every time there was a good downpour, he and all his graduate students had to don galoshes to make their way around the basement laboratory at Rutgers University. Though all of them were students of the soil—working on humus, colloid chemistry, protozoa-bacteria symbiosis—it seemed more likely that they would write a new chapter of Notes from the Underground than any dry-eyed work of scientific inquiry.
It was after nine in the evening. Most of the investigators had stopped work for the day. With two bright and promising grad students from Europe, Waksman sat sipping coffee, trying to keep his feet dry.
The young Frenchman was having a hard time of it. His wife had contracted tuberculosis and was desperately sick. More than two centuries before, their countryman Manget had given the classical description of the effect of the disease upon the lungs. Reporting the autopsy of a young woman, he noted her lungs were “strewn with white bodies rather hard, of the size of millet seed, of the white poppy, and some of the size of a hemp seed, closely joined together, scarcely leaving any part of the lung free from them.”
This was very nearly the condition of the young student’s wife. It was virtually certain that she soon would die. The professor and the other student tried to comfort their colleague, but it was no good.
Just then, one of them asked a question that had been waiting almost a hundred years to be expressed. “Why is it,” he said, “that when you bury a dead body in the ground, the earth is not poisoned?”
It was suddenly very quiet in the basement lab. None of them knew that they were asking the very same question that the poet Walt Whitman had asked three quarters of a century earlier in “This compost": “O how can it be that the ground itself does not sicken?” Neither was any of them yet in a position to discover the detailed truth of the statement. Yet it occurred to them in a flash that perhaps this was the question that they, as students of the soil, had been born to answer.
The corollary question was even more exciting: What diseases might the soil cure? Might it even destroy tuberculosis, the disease that prior to cancer was the greatest scourge? Could such a discovery save the French-man’s wife?
In light of these questions, some of the folk remedies for tuberculosis came to seem far less crazy than previously. During the eighteenth century, the Methodist divine John Wesley recommended that the sufferer take cold baths, breathe into a hole cut into fresh earth, and “suck an healthy woman daily.” Whatever use cold water and mother’s milk may have been, it is not impossible that the soil would actually have been therapeutic. Another folk cure involved eating butter made from the milk of a cow that had grazed on churchyard earth.
But just where in the soil lay this healing virtue? Selman Waksman, the professor, and René Dubos, his French graduate student, set out to find the answer. On Waksman’s recommendation, Dubos went to the Rockefeller Institute, where he succeeded in isolating from a soil bacterium the chemical that he named gramicidin. The first of the antibiotics, it was the basis for the discovery of penicillin.
But penicillin did not cure tuberculosis, much to the dismay of Dubos, whose wife had meanwhile died of the disease. Waksman, still working out of his damp lab, found the answer in another soil organism with the unpronounceable name Streptomyces griseus. The common creature—common as dirt, you might say—lives in many soils around the world, meaning that a person following Wesley’s cure might actually have breathed in some of these. To destroy the tuberculosis organism, Waksman isolated the active chemical that streptomyces makes.
Streptomycin controlled tuberculosis for the first time. Along with penicillin and the whole stream of soil-derived antibiotics that followed—tetracycline, neomycin, etc.—it changed medicine forever. Now for the first time, it was possible to use the power of one group of microbes against that of another, operating at the molecular level. The cures effected were little short of miraculous.
Dirt is the source of the greater part of our drugs against infectious diseases. And it may soon do for cancer what it did for tuberculosis. A certain kind of deep-living soil bacteria that exists without breathing oxygen creates in itself chemicals called enedeynes (een-DYE-ins). These complex molecules insinuate their way into the nuclei of cancer cells, where they cause an explosion that instantly ruptures the cell, killing it. No other drug yet found has shown such consistent and dramatic effects. There is now reason to hope that the soil may yet cure cancer.
However we succeed in manipulating it, though, dirt always outruns us. As Whitman wrote, “It gives us such fine materials and accepts such leavings from us at the end.” Contrary to the scientific method, dirt works by ramifying possibilities. Instead of seeking a single solution to cure TB, for example, it elaborates hundreds of organisms capable of killing or arresting TB. The disease, meantime, organizes itself to resist the invader, limiting its losses to a minimum. In this way, a healthy ecological community can be maintained.
Molecular medicine intervenes directly in soil process, as well as in human growth. It cures human bodies before they have died and been buried, but it does so by means of soil organisms. It cannot, however, respond as fast to changes as the soil does.
The cycles of resistance in a living soil help to keep it in balance. If a bacterium is too badly depleted by another, it evolves new structures to withstand the threat. No creature is immune to competition, yet every creature is needed to keep up the web of reciprocal feeding.
This property, so important in ecosystems and in human physiology, means that nothing can permanently be cured. Nature is intent upon distributing her benefits to all her creatures, not only to man. If streptomycin attacks tuberculosis, someday a resistant TB will appear.
In 1991, new resistant forms of TB appeared in New York City, finding victims in a diverse population of drug users and AIDS sufferers. The currently available medicines are comparatively powerless against it. As a result, there has been a scramble to find sources of streptomycin, which had over the decades been replaced by other soil-based drugs. The reemergence of TB and other infectious diseases has led the Rockefeller Institute scientist Sandra Handweger to declare, “It is time to go back to the soil.” That is where new cures are to be found.