The global eradication of smallpox required techniques to manufacture vaccine on a vast scale and, eradication had to await the advent of freeze-dried vaccine, which could be preserved and transported without need for refrigeration. Smallpox, a deadly, infectious disease, had plagued humankind for millennia. In 1796 an English country physician named Edward Jenner made a discovery that proved a crucial milestone in the control of smallpox, and eventually led to its eradication. Given the unprecedented nature of Jenner's discovery, the spread of vaccination around the world was rapid. By the turn of the twentieth century, the growing acceptance of the germ theory of disease introduced new methods of disease control. The establishment of the League of Nations Health Organization after the First World War marked yet another stage in the rise of disease control as a field amenable to global action. The eradication of smallpox has often been celebrated in retrospect as the World Health Organization's crowning achievement.