(p. 421) . . . , in 1928, Fred Griffith in Britain published a striking and puzzling finding. Earlier Griffith had discovered that all known types of pneumococci could exist with or without capsules. Virulent pneumococci had capsules; pneumococci without capsules could be easily destroyed by the immune system. Now he found something much stranger. He killed virulent pneumococci, ones surrounded by capsules, and injected them into mice. Since the bacteria were dead, all the mice survived. He also injected living pneumococci that had no capsules, that were not virulent. Again the mice lived. Their immune systems devoured the unencapsulated pneumococci. But then he injected dead pneumococci surrounded by capsules and living pneumococci without capsules.
The mice died. Somehow the living pneumococci had acquired cap-(p. 422)sules. Somehow they had changed. And, when isolated from the mice, they continued to grow with the capsule–as if they had inherited it.
Griffith’s report seemed to make meaningless years of Avery’s work– and life. The immune system was based on specificity. Avery believed that the capsule was key to that specificity. But if the pneumococcus could change, that seemed to undermine everything Avery believed and thought he had proved. For months he dismissed Griffith’s work as unsound. But Avery’s despair seemed overwhelming. He left the laboratory for six months, suffering from Graves’ disease, a disease likely related to stress. By the time he returned, Michael Dawson, a junior colleague he had asked to check Griffith’s results, had confirmed them. Avery had to accept them.
His work now turned in a different direction. He had to understand how one kind of pneumococcus was transformed into another. He was now almost sixty years old. Thomas Huxley said, “A man of science past sixty does more harm than good.” But now, more than ever, Avery focused on his task.
Barry, John M. The Great Influenza: The Story of the Deadliest Pandemic in History. Revised ed. New York: Penguin Books, 2005.
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