The Ghost Map:

The Ghost Map:

Appears on page 189 facing the chapter called The Ghost Map

The Story of London’s Most Terrifying Epidemic—and How It Changed Science, Cities, and the Modern World

It is August 1854, and London is a city of scavengers. Just the names alone read now like some kind of exotic zoological catalogue: bone-pickers, rag-gatherers, pure-finders, dredgermen, mud-larks, sewer-hunters, dustmen, night-soil men, bunters, toshers, shoremen.

Monday, August 28

—————

THE NIGHT-SOIL MEN

These werethe London underclasses, at least a hundred thousand strong. Early risers strolling along the Thames…would see …

Above the river, in the streets of the city, the pure-finders eked out a living by collecting dog shit (colloquially called “pure”) while the bone-pickers foraged for carcasses of any stripe. … sewer-hunters ….

The scavengers, in other words, lived in a world of excrement and death. …

Every few months, an unusually dense pocket of methane gas would be ignited by one of their kerosene lamps and the hapless soul would be incinerated twenty feet below ground, in a river of raw sewage.

colloquially: “characteristic of or appropriate to ordinary or familiar conversation rather than formal speech or writing; informal. 2. involving or using conversation.”

Euphemistically: “The act or an example of substituting a mild, indirect, or vague term for one considered harsh, blunt, or offensive.”

But such social outrage should be accompanied by a measure of wonder and respect: without any central planner coordinating their actions, without any education at all, this itinerant underclass managed to conjure up an entire system for processing and sorting the waste generated by two million people. (p. 4)

We’re naturally inclined to consider these scavengers tragic figures, and to fulminate against a system that allowed so many thousands to eke out a living by foraging through human waste. …

No extended description of London from that period failed to mention the stench of the city. City landlords hired the men to remove the “night soil” from the overflowing cesspools of their buildings. The work was foul, but the pay was good. By the Victorian era, the night-soil men were charging, a shilling a cesspool, wages that were at least twice that of the average shilled laborer. For many Londoners, the financial cost of removing waste exceeded the environmental cost of just letting it accumulate.

…

… …

Monday, August 28

—————

THE NIGHT-SOIL MEN

On the twenty-eighth of August, all that changed. At a around six a.m., while the rest of the city struggled for a few final minutes of sleep at the end of an oppressively hot summer night, the Lewis infant began vomiting and emitting watery, green stools that carried a pungent smell.…

That is how it began.

Last paragraph of the chapter

Cholera first stepped out onto the world state in 1817.

INTRODUCTION

The Long Journey

Cholera gets its name from…

…the British doctor Ashbel Smith later described some of the cases he had witnessed…he wrote … “A sudden and great increase of a previous diarrhoea…

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Market for Cleaning Cesspools in London, 1850

John Hunt Nightman & Rubbish Carter

Night-soil men were paid by landlords to removed human waste from cesspools and sold the waste to farmers as manure.

D

Pe=1

S

PCC

QCC(hundreds of thou. per yr)

Qe ≈ 100

(shillings per cesspool)

Externality—the behavior of one agent (person or firm) affects another agent in a way that is external to markets.

Market Failure?

S

D

QCC

PCC

(private cost)

Social valuePMKT=1

External benefit (the value of in neighborhood stench)

QMKT Qefficient

(private value)

positive externalities cause QMKT < Qefficient

DWL(shillings per cesspool)

0

50

100

150

200

250

300

cholera AND (leave near/35 city)Water closets

disease and nuisance

New York Times Articles Mentioning Cholera, 1854 & 1866

Jan. March June Sept. Dec.

1866

1854

Causes of CholeraTwo Camps

1. Miasmatists (M)—Foul Air (FA)

Robert Seymour, October 1, 1831

Causes of Cholera

Two Camps

1. Miasmatists (M)—(Often smelly) Foul Air (FA)

Robert Seymour, March 1, 1832

Chadwick: “all smell is disease”

George Cruickshank, 1832

It makes me sick

We shall all have the Cholera

Give us clean water

Causes of CholeraTwo Camps

2. Contagionists (C)—Contaminated Water (CW)

mz)e(tThames

Punch, 1850

Source: Greenwood C and Greenwood J. Greenwood Map of London, 1830.

“In 1830, the Southwark Water Company was located on the South bank of the River Thames between the Southwark and London Bridges. The water intake pipe went from the company to the middle of the river, a short distance to the West of the new London Bridge, which officially opened in 1831. Later in 1845 the Southwark Water Company merged with the Vauxhall Water Company to become the Southwark and Vauxhall Water Company. At about the same time, the new company closed the former Southwark Water Company (shown below), and moved up-river to Battersea.”

Data on 1848-1849 Cholera Outbreak

The Office of the Registrar-General, created in 1838, hired William Farr to compile statistics from birth and death certificates. One of his important contributions was to set up a system for recording the causes of death.

Allowed him to create, Cholera Deaths per 10,000 people!

William Farr

SOURCE: Bingham P, NQ Verlander, and MJ Cheal, “John Snow, William Farr and the 1849 Outbreak of Cholera that Affected London,” Public Health. 2004; 118(6):387-94

George Cruickshank, 1832

Hammersmith Bridge

Battersea Bridge

Vauxhall Bridge

NThe Thames runs from West to East

Waterloo Bridge

Kew Bridge

WaterCL

= 1 if the district’s water company drew its water from the Thames between Battersea Bridge and Waterloo Bridge

= 0 otherwise

Southwark Bridge

London Bridge

≈1845

0 10 20 30 40 50 60 70 80 90 1000

20

40

60

80

100

120

140

160

180

200

220

Elevation above High Water (# feet)

Cho

lera

Dea

ths (

# pe

r 10

,000

peo

ple)

Figure 1. Cholera Deaths and the Elevation of London’s Reg. Districts, 1849

Dependent Variable: Cholera Deaths per 10,000 people

Explanatory Variables (1) (2) (3)

Elevation above HighWater (# feet)

-1.326*** -0.730** -0.647**(5.72) (2.63) (2.36)

Water Intake in CentralLondon (yes=1)

80.73*** 52.136*** 48.570***(6.19) (3.21) (3.05)

Average House Value (£ per year)

-0.306*(1.72)

Constant 110.101*** 41.52*** 74.128*** 86.660***(11.27) (5.59) (5.23) (5.56)

Observations 37 37 37 37

R-squared 0.483 0.522 0.603 0.636

Absolute value of t statistics in parentheses

* significant at 10%; ** significant at 5%; *** significant at 1%

Table 1. What Explains Cholera Deaths in London in 1849?

0 10 20 30 40 50 60 70 80 90 1000

20

40

60

80

100

120

140

160

180

200

220


Cho

lera

Dea

ths (

# pe

r 10

,000

peo

ple)

)72.5( 326.1101.110 ElevationCDeaths ^

OLS Fitted Line

Interpretation of the slope: each additional foot of elevation is associated, on average, with 1.3 fewer cholera deaths per 10,000 people.

0 10 20 30 40 50 60 70 80 90 1000

20

40

60

80

100

120

140

160

180

200

220


Cho

lera

Dea

ths (

# pe

r 10

,000

peo

ple)

Figure 1. Cholera Deaths and the Elevation of London’s Reg. Districts, 1849

0 10 20 30 40 50 60 70 80 90 1000

20

40

60

80

100

120

140

160

180

200

220


Cho

lera

Dea

ths (

# pe

r 10

,000

peo

ple)

Figure 2. Cholera Deaths, Elevation and Water Supply of London’s Reg. Districts, 1849

Water from Central London

Water from upriver

0 10 20 30 40 50 60 70 80 90 1000

20

40

60

80

100

120

140

160

180

200

220


Cho

lera

Dea

ths (

# pe

r 10

,000

peo

ple)


Water from upriver

^OLS Fitted Line

(3.21) )63.2( 136.52730.0128.74 WaterCLElevationCDeaths

ElevationCDeathsthenWaterCLif 730.0128.74 0 ^

0 10 20 30 40 50 60 70 80 90 1000

20

40

60

80

100

120

140

160

180

200

220


Cho

lera

Dea

ths (

# pe

r 10

,000

peo

ple)


Water from upriver

^OLS Fitted Line

(3.21) )63.2( 136.52730.0128.74 WaterCLElevationCDeaths

ElevationCDeathsthenWaterCLif 730.0264.126 1 ^

52.136

Two Camps1. Miasmatists (M)—Foul Air (FA)2. Contagionists (C)—Contaminated Water (CW)

The data available after the 1948-1949 Cholera epidemic was incapable of resolving the debate.

“To measure the effects of good or bad water supply, it is requisite to find two classes of inhabitants living at the same level [Elevation]… but differing in [the water one drinks]… But of such experimenta crucis [sic] the circumstances of London do not admit.”

–William Farr (Ghost Map, p. 102)

Tuesday, September 5

—————

ALL SMELL IS DISEASEEDWIN CHADWICK

The first solid cause for home began to filter through the neighborhood Tuesday morning. For the first time in four days, Henry Whitehead let himself believe that this terrible visitation might finally be passing. The wife of Mr. G, the tailor, had died that morning, but for every new death, Whitehead could point to another dramatic recovery. The servant woman he had been tending to since Friday had risen from what she had assumed would be her deathbed, her pallor much improved. Two adolescents—a boy and girl—had also turned the corner, much to the delight of their remaining family. All three of them attributed their recovery to one thing: they had consumed large quantities of water from the Broad Street pump since falling ill. The speed and intensity of their recovery made an impression on Whitehead that would linger in his mind through the coming weeks.

b) The Exemption Proves the Rule

2. Broad Street Pump

Evidence that Cholera was waterborne from the 1854 Cholera Epidemic

Distance from the Broad Street Pump

Cholera Cases per 10,000 residents

“Snow knew that the case would be made in the exceptions to the rule.” (The Ghost Map, p. 140)

“Pockets of life where you would expect death…

…pockets of death where you would expect life.”

Distance from the Broad Street Pump






Distance from Broad Street Pump (miles)




“Pockets of life where you would expect death… …pockets of death where you would expect life.”

St. James Workhouse—93 deaths per 10,000 residents (5/535) because water supplied by Grand Junction Waterworks

Susannah Eley—93 deaths per 10,000 residents (5/535) because water supplied by Grand Junction Waterworks

Lion Brewery—no deaths among 70 workers because private pipeline and beer drinkers

5 deaths

no deaths

Eley Brothers Factory—18 deaths

Eley Factory

Work House

Brewery 1 2

Susannah lived in Hempstead


1. John Snow’s Grand Experiment

Was it a natural experiment or a difference-in-difference analysis?

“London was without cholera from the latter part of 1849 to August 1853. During this interval an important change had taken place in the water supply of several of the south districts of London. The Lambeth Company removed their water works, in 1852, from [the heart of London] to [upriver]; thus obtaining a supply of water quite free from the sewage of London” (Snow, On the Mode of Communication of Cholera, 1855, p. 68).

John Snow

Battersea Bridge

NThe Thames runs from West to East

Southwark Bridge

London Bridge

moved≈1845

Moved in 1852

Seething Wells Intake

Seething Wells was beyond the tidal reach of the Thames

Southwark & Vauxhall Water Company (S&V)

Lambeth Waterworks

“The experiment ...was on the grandest scale. No fewer than three hundred thousand people of both sexes, of every age and occupation, and of every rank and station, from gentle folks down to the very poor, were divided into two groups without their choice, and, in most cases, without their knowledge; one group being supplied with water containing the sewage of London [S&V], and the other group having water quite free from such impurity [Lambeth Company]”

31 subdistricts

12 served by S&V only

3 served by Lambeth only

Not random

100 cholera cases per 10,000 residents

≈ 0 cases

“relatively well-to-do suburbs”

“smog-bound

industrial zones”

16 served by both companies

≈ random via natural experiment

pipes—promiscuously interlinked households—assigned w/o knowledge

S&V households

Lambeth households

315 cases per 10,000 residents

37 cases per 10,000 residents

Same income & elevation

Table. Cholera Deaths in 16 Sub-Districts Served by 2 Water Companies, 1854

Households Deaths

(#) (#) (# per 10,000)

S&V (intake in heart of London)

40,046 1,263 315

Lambeth (intake upriver)

26,107 98 37

Rest of London 256,423 1,422 59

“In 1849 when cholera was last present in London, mortality due to cholera was similar among persons supplied by the Lambeth Company and the Southwark and Vauxhall Company.”

Epidemiologist Ralph Frerichs

0 1 2 3 40

50

100

150

200

250

300

350

400

450

500

550

600

650

700

S&VLambeth

1849 1852 1854

Lambeth moved its intake pipe from downriver to upriver.

37

Deaths per 10,000 households

315

If the subdistricts that Lambeth served exclusively were “relatively well-to-do suburbs” then it seems plausible that it might have served relatively well-off households in the areas served by both companies (i.e., the households on the border)…

Increased risk due to foul water:A

B

CD

Natural experiment

A – BDifference-in-difference

1849 epidemic was more severe

(A – B) – (C – D)

Validity rests on assignment within the natural experiment being truly random

Controls for the potential non-randomness

“The DD idea was probably pioneered by physician John Snow (1855), who studied cholera epidemics in London in the mid-nineteenth century.”

Friday, September 8

—————

THE PUMP HANDLE

“DEATH’S DISPENSARY”

On Thursday night, the Board of Governors of St. James Parish had held an emergency meeting to discuss the ongoing outbreak and the neighborhood’s response. Halfway into the meeting, they received notice that a gentleman wished to address them. It was John Snow, armed with his survey of the past week’s devastation. He stood before them, and in his odd, husky voice told them that he knew the cause of the outbreak, and could prove convincingly that the great majority of cases in the neighborhood could be traced to its original source. It is unlikely that Snow went into the intricacies of his broader case against the miasma theory—better to go straight to the telling patterns of death and life, leave the philosophizing for another day. He explained the dismal ratios of survival among the people living near the pump, and the unusual exemptions granted to people who had not drunk the water.

He told the Board of Governors of deaths that had transpired far from Golden Square, connected to the area only by the consumption of Broad Street water. He may have told them of the brewery or the workhouse on Poland Street. Death after death after death had been linked to the water at the base of the Broad Street well. And yet the pump remained in active use.

The members of the Board were skeptical. They knew as well as any other locals how highly regarded the Broad Street water was—particularly as compared to the other nearby pumps. But they also knew firsthand the smells and noxious fumes that were rampant in the neighborhood; surely these were more responsible for the outbreak than the reliable Broad Street water. Yet Snow’s argument was persuasive—and,, besides, they had few other options. If Snow was wrong, the neighborhood might go thirsty for a few weeks. If he was right, who knew how many lives they might save? And so, after a quick internal consultation, the Board voted that the Broad Street well should be closed down.

a) Spatial Pattern of Deaths

4¼ inches


Natural Experiment—random whether people choose to live on the corner of Husband St. & New Street versus at the end of William and Mary Court. One is randomly assigned to live further from the Broad Street Pump.

c) 2nd Examination of the Broad Street Pump.



After discovering the “baby Lewis” case, Rev. Whitehead hired (engineer) York who uncovered leaks from the Lewis cesspool into the Broad Street pump’s well.

Rev. Whitehead

Timeline of New York City crimes and disasters Wikipedia

http://www.nytimes.com/2008/04/15/science/15chol.html?pagewanted=all

The Ghost Map:

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