GMAT
Just as Edward Jenner used the pustules from milkmaids to inoculate against smallpox, effectively removing the specter of death that had hung over the population, so immunologists today use the pustules of infected organisms to obtain a live virus from which the modern smallpox vaccine is derived
Just as Edward Jenner used the pustules from milkmaids to inoculate against smallpox, effectively removing the specter of death that had hung over the population, the smallpox vaccine today is derived from a live virus, which immunologists have obtained from the pustules of infected organisms
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