As our previous example demonstrates, even after the advent of the scientific method, new theories can require some time to overcome the force of authority and tradition, especially if the old ways appear to work.
Take miasma theory. Dating back at least to Hippocrates, it attributed illnesses to foul airs, which it blamed on harmful plant or animal exhalations or tiny bits of windborne, decaying matter. Because the idea drove healthful reforms in housing and sanitation, it often succeeded in reduced cases of illness, so it's no wonder it became popular in smelly, overcrowded Victorian London. Nevertheless, by masking the true culprit (bacteria), it contributed to many unnecessary deaths [sources: Science Museum UK; Sterner; UCLA].
In a somewhat ironic twist, one of London's leading proponents of miasma theory helped to disprove it, at least where cholera was concerned. William Farr, a pioneer of epidemiology and health statistics, provided vital cluster data during London's 1854 cholera outbreak. John Snow famously used this data to trace the waterborne disease to a Broad Street water pump. His work, and that of pioneers like Ignaz Semmelweis and Joseph Lister, would later help Louis Pasteur and Robert Koch prove germ theory. But, for now, it demonstrated the scientific method's invaluable capacity for self-correction [sources: BBC; Science Museum UK; UCLA].