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 pursuit of truth is a lifelong journey.

Private notes 1845

I am often weary, but my purpose sustains me.

Diary entry 1854

The evidence speaks for itself, if only people would listen.

Letter to a local official 1854

My work is a testament to the power of careful observation.

Private notes 1856

I hope that future generations will build upon my findings.

Diary entry 1858

The fight against cholera is a fight for humanity.

Letter to a newspaper editor 1854

My dear, remember the importance of meticulous detail.

Letter to a student 1853

I am a firm believer in the power of maps to reveal patterns.

Private notes 1854

The well-being of the community is a shared responsibility.

Diary entry 1850

I often feel the weight of expectation, but I strive to meet it.

Letter to a family member 1854

The path to progress is often paved with resistance.

Private notes 1855

My greatest satisfaction comes from knowing I have helped others.

Diary entry 1858

The great question of the communication of cholera is not whether it is contagious, but whether it is communicated by the excretions of the sick.

On the Mode of Communication of Cholera 1849

It is not by the atmosphere that cholera is propagated, but by the water we drink.

On the Mode of Communication of Cholera 1854

The most convincing proof of the communication of cholera by water is afforded by the cases of the Broad Street pump.

On the Mode of Communication of Cholera 1854

The removal of the pump handle was followed by an immediate cessation of the epidemic.

On the Mode of Communication of Cholera 1854

Cholera is a disease of the alimentary canal, and its symptoms are produced by a poison acting directly on the mucous membrane of the stomach and intestines.

On the Mode of Communication of Cholera 1849

The disease is communicated by the swallowing of the morbid matter, which is contained in the evacuations of the sick.

On the Mode of Communication of Cholera 1849

The evidence is, I think, quite conclusive, that the water of the Broad Street pump was the cause of the late outbreak of cholera.

Letter to the Medical Times and Gazette 1854

The disease is not communicated by effluvia from the sick, nor by the atmosphere, but by the actual contact of the morbid matter with the alimentary canal.

On the Mode of Communication of Cholera 1849