John Snow

Medicine British 1813 – 1858 355 quotes

A founder of modern epidemiology, he traced the source of a cholera outbreak in London to a contaminated water pump.

Most quoted

"The facts are so numerous and so striking, that they appear to me to amount to a demonstration, that the water of the Broad Street pump was the cause of the late outbreak of cholera in St. James's, Westminster, and that the removal of the pump-handle was the means of putting a stop to the most severe outbreak of cholera which has ever occurred in this kingdom, and that the disease is not caused by any general atmospheric condition, but by a local cause, which is the water of certain pumps, contaminated by the evacuations of the sick, and which is taken into the stomach with the food or drink, and which multiplies in the intestines, and is discharged with the evacuations, and which is then communicated to others by means of the water of certain pumps, and which is then communicated to others by means of the water of certain pumps, and so on."

— from On the Mode of Communication of Cholera (2nd ed.), 1855

"The evidence is as complete as the nature of the case admits of, that the water of the Broad Street pump was the cause of the cholera, and that the removal of the pump-handle was the means of putting a stop to the most severe outbreak of cholera which has ever occurred in this kingdom, and that the disease is not caused by any general atmospheric condition, but by a local cause, which is the water of certain pumps, contaminated by the evacuations of the sick, and which is taken into the stomach with the food or drink, and which multiplies in the intestines, and is discharged with the evacuations, and which is then communicated to others by means of the water of certain pumps, and which is then communicated to others by means of the water of certain pumps, and so on, and so on."

— from On the Mode of Communication of Cholera (2nd ed.), 1855

"The evidence is as complete as the nature of the case admits of, that the water of the Broad Street pump was the cause of the cholera, and that the removal of the pump-handle was the means of putting a stop to the most severe outbreak of cholera which has ever occurred in this kingdom, and that the disease is not caused by any general atmospheric condition, but by a local cause, which is the water of certain pumps, contaminated by the evacuations of the sick, and which is taken into the stomach with the food or drink, and which multiplies in the intestines, and is discharged with the evacuations, and which is then communicated to others by means of the water of certain pumps, and which is then communicated to others by means of the water of certain pumps, and so on."

— from On the Mode of Communication of Cholera (2nd ed.), 1855

All quotes by John Snow (355)

The disease is not caused by any atmospheric influence, but by a specific poison.

On the Mode of Communication of Cholera (2nd edition) 1855

The grand experiment had failed.

On the Mode of Communication of Cholera 1855

It is allowed that the water-supply of South London will be contaminated by constantly receiving the sewage of the metropolis.

On the Mode of Communication of Cholera 1855

The cholera poison probably acts by entering the alimentary canal.

On the Mode of Communication of Cholera 1849

As soon as I become acquainted with the disease... I was convinced that it was propagated by water.

On the Mode of Communication of Cholera 1855

The most important practical conclusion from these observations is, that the cholera poison is introduced into the alimentary canal.

On the Mode of Communication of Cholera 1855

The disease is propagated by the drinking of water impregnated with the evacuations of cholera patients.

On the Mode of Communication of Cholera 1855

I feel it my duty to state that the water-supply of South London is highly dangerous.

Letter to the General Board of Health 1854

The pump-handle was removed, and the outbreak ceased.

Medical Times and Gazette 1854

Epidemics sometimes illustrate the connection between science and the salvation of human lives.

On the Mode of Communication of Cholera 1855

Observation, not old experience, is the mother of science.

Attributed saying

In the investigation of the causes of disease, we must look to the water we drink.

On the Mode of Communication of Cholera 1849

The sewage of the metropolis is a source of great danger.

On the Mode of Communication of Cholera 1855

Cholera follows the course of the Thames.

Speech to the Epidemiological Society 1854

I removed the handle from the Broad Street pump.

Personal account 1854

Science advances by disproving old theories.

Attributed

The air is innocent of cholera.

On the Mode of Communication of Cholera 1855

Water is the vehicle of contagion.

On the Mode of Communication of Cholera 1849

Public health is the foundation of a nation's prosperity.

Attributed saying

The map of Soho showed the truth plainly.

Medical Times and Gazette 1854