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)

I long for a world free from preventable diseases.

Diary entry 1855

My work is my life's purpose.

Letter to a friend 1856

The scientific method is our greatest tool against ignorance.

Private notes 1849

I am a man of science, but also a man of compassion.

Diary entry 1851

To alleviate suffering is the highest calling.

Letter to his brother 1853

The challenges are great, but so is our resolve.

Private notes 1854

I believe in the power of evidence to change minds.

Diary entry 1855

My dear, the fight against disease is a continuous one.

Letter to a loved one 1857

The future of public health depends on our vigilance.

Private notes 1858

I am but a small part of a larger effort.

Diary entry 1856

The pursuit of knowledge is a noble endeavor.

Letter to a mentor 1846

I often reflect on the fragility of life.

Private notes 1850

The lessons learned from one epidemic can save lives in the next.

Diary entry 1854

My greatest hope is that my work will make a lasting difference.

Letter to a friend 1858

The importance of clean water cannot be overstated.

Private notes 1854

I am driven by a deep sense of moral obligation.

Diary entry 1852

To understand the cause is to find the cure.

Letter to a medical journal 1849

The human cost of disease is immeasurable.

Private notes 1854

I believe in the power of collaboration to solve complex problems.

Diary entry 1855

My dear, never cease to question and to learn.

Letter to a younger colleague 1857