Source: The Handle (the magazine of the University of Alabama School of Public Health), Fall 2002, pp. 4-5.

THE PUZZLE WAS A MADDENING ONE.

Pressure on public officials was intense, at times hysterical. The clock was ticking, and people were dying by the dozens.

The year was 1854; the scene was the Soho District of west London. During the stifling beat of August, there had been a handful of deaths from the dreaded disease cholera. Not unusual, in itself. But on August 31, the situation exploded: In a single evening, within a radius of only blocks, doctors reported 56 new cholera cases. By the next evening there were 143, and the death toll had reached 70 and was climbing. Residents started fleeing the district in panic. Medical authorities debated around the clock but couldn't settle on a plan of action.

STUDYING THE SPREAD OF A SCOURGE

Among those not consulted on the subject was a 41-year-old physician named John Snow. Though well-regarded as an anesthesiologist, Snow was something of a maverick because of his unconventional ideas. At medical conferences in 1849, and again in 1853, Snow-balding, with an unassuming manner and an Abe Lincoln-style beard-had delivered impassioned papers arguing that several diseases (cholera among them) that were thought to be spread via the air were in fact transmitted through drinking water. His presentations were politely ignored by the establishment.

But the 1854 cholera emergency seemed to bear out his waterborne theory: The initial deaths were all within walking distance of a popular water hand-pump at the intersection of Cambridge and Broad. On his own, Snow inspected the pump but found the contamination to be negligible-unconvincing evidence for such a virulent epidemic.

Next, he went to the Register of Deaths and made a detailed list of the past two days' cholera fatalities. But his heart sank as the specifics of the deaths seemed to shoot more holes in his theory. None of the workers at a large brewery adjacent to the pump had contracted cholera, and a nearby workhouse with more than 500 inmates had reported only five deaths. What's more, fatalities had now been reported several miles away, in the rural villages of Hampstead and Islington.

The death toll reached 127. New cases leveled offbut only, officials realized, because the area was by now nearly deserted-except for victims and their families.

DISEASE DETECTIVE DELIVERS ANSWER

Snow redoubled his efforts, going from building to building, house to house, asking questions of the people who remained. Finally, one piece of the puzzle fit: He discovered that the workhouse that had largely escaped the epidemic had its own private well. Then, another piece fell into place-at the unaffected brewery, the workers told Snow that they were afraid of the public water supply, so they drank only beer.

With a growing sense of excitement and purpose, Snow rode to the outlying homes where the two most recent cholera deaths had occurred. At the house in Hampstead, a surviving relative told him that the lady who died there had a large bottle of water carted to her house every day from the Broad Street pump, because she preferred its taste above all others. Her visiting niece, Snow was told, also drank the Broad Street water and later died at her own home.

The writing pen in Snow's hand poises over his notebook. And her niece lived ... where?

"Islington," came the reply.

Snow methodically sketched his findings into a rough statistical map of the area. He presented the map-which today resides in a British museum-and his report to the Board of Guardians of St. James Parish. They were finally convinced, and they disabled the infamous pump by removing its handle. Immediately, new cases of cholera started to dwindle, and then disappeared.

A detailed investigation of the pump determined that, more than 20 feet underground, a sewer pipe passed within a few feet of the well. The raw sewage was gradually seeping through the dirt barrier into the drinking water.

Scattered witnesses came forward to report a "bad smell" near the pump just before the outbreak began.

FATHER OF A NEW FRONTIER

Snow, the establishment outsider, had, as one historian writes, "used meticulously gathered data and the power of statistics to bring about the beginning of the end for cholera in Britain." Today, while John Snow is a hero among modern epidemiologists, his name is little known to those outside the field. But at least two people are hoping to remedy that oversight. One is Ralph Frerichs, chair of epidemiology at the UCLA School of Public Health, who has created a substantial Web site honoring the 19th-century physician's achievements. The other is UAB School of Public Health Dean Max Michael, who selected the title The Handle as the name of the school's magazine as way of recognizing Snow's contributions to modern public health procedures.

Return to John Snow site