The Song of the Cell: An Exploration of Medicine and the New Human

by Siddhartha Mukherjee

The Indian tika practitioners had likely learned it from Arabic physicians who, in turn, had learned it from the Chinese. As early as AD 900, medical healers in China had realized that people who survived smallpox did not catch the illness again, thus making them ideal caregivers for those suffering from the disease. A prior bout with an illness somehow protected the body from future instances of that illness, as if it retained a “memory” of the initial exposure. To harness this idea, Chinese doctors harvested a smallpox scab from a patient, ground it into a dry, fine powder, and used a long silver pipe to insufflate it through a child’s nose. Vaccination was a tightrope walk: if the powder contained too much inoculum of live virus, the child would acquire not immunity but the disease—a devastating outcome that occurred about one in a hundred times. But if the child survived the inoculum and its “fester,” he or she would develop merely an attenuated, local disease, with either no symptoms or mild ones, and be immunized for life.