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 removal of the pump handle was followed by a rapid decline in the number of cases.

On the Mode of Communication of Cholera 1855

The evidence, therefore, is overwhelming, that the water of the Broad Street pump was the cause of the late outbreak of cholera.

On the Mode of Communication of Cholera 1855

The disease is not spread by effluvia from the sick, but by the actual contact of the morbid matter with the alimentary canal.

On the Mode of Communication of Cholera 1849

The disease is propagated by a morbid matter which passes from the alimentary canal of one patient to that of another.

On the Mode of Communication of Cholera 1849

The disease is not communicated through the air, but by the swallowing of the morbid matter.

On the Mode of Communication of Cholera 1849

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

On the Mode of Communication of Cholera 1855

The great number of cases of cholera in the Golden Square district were due to the people drinking the water of the Broad Street pump.

On the Mode of Communication of Cholera 1855

I am quite sure that the poison of cholera is contained in the discharges from the alimentary canal of the sick, and that it is capable of producing the disease in others, if it be swallowed, even in a highly diluted form.

Letter to the Medical Times and Gazette 1849

The most important thing is to trace the source of the contamination.

Diary entry 1854

My dear friend, the evidence is overwhelming. The Broad Street pump is the culprit.

Letter to a colleague 1854

It is not enough to treat the sick; we must prevent the disease.

Private notes 1850

The public health is paramount.

Letter to a government official 1854

I often feel a profound sense of responsibility for the lives of others.

Diary entry 1848

The pursuit of knowledge is a lonely path, but a necessary one.

Letter to a friend 1852

I find solace in my work, even amidst the suffering.

Diary entry 1854

My heart aches for those who have lost loved ones to this terrible disease.

Letter to his sister 1854

I believe in the power of observation and logical deduction.

Private notes 1847

The truth, however inconvenient, must always be sought.

Diary entry 1853

I am often met with skepticism, but I will not be deterred.

Letter to a colleague 1854

The suffering of the poor is a constant reminder of our duty.

Private notes 1850