On the Mode of the Communication of Cholera

Abstract This chapter explores how Dr. John Snow reasoned in solving the puzzle of cholera's mode of communication. His reasoning was the secret that led him to discover the mechanism of cholera's transmission prior to any knowledge of bacteria. Snow's theory established a chain of causation by physical contact that explored both the transmission of the disease and its pathology. Snow realized that his theory gave rise to practical measures to forbid the spread of the disease. It was necessary to block the fecal-oral route. His clarification of cholera was an exemplary case of scientific reasoning.