Koch’s discoveries, along with those of Pasteur and Joseph Lister and William Roberts and John Burdon Sanderson and others, provided the empirical bases for a swirl of late-nineteenth-century ideas that commonly get lumped as “the germ theory” of disease, which marked a movement away from older notions of malign vapors, transmissible poisons, imbalanced humors, contagious putrefaction, and magic.
