A former believer in the
miasma theory of disease, Whitehead worked to disprove false theories, but eventually came to prefer
John Snow's idea that cholera spreads through water contaminated by human waste. Snow's work — and Whitehead's own investigations — convinced Whitehead that the
Broad Street pump was the source of the local infections. Whitehead then joined with Snow in tracking the contamination to a
cesspool that leaked into the water table which led to the outbreak's
index case. Whitehead identified a "Baby Lewis" at 40 Broad Street where a leakage in the basement contaminated the well as
patient zero of the outbreak. Whitehead's work with Snow combined
demographic study with scientific observation, setting an important precedent for the burgeoning science of
epidemiology. == Later work ==