A town that trebles in fifty years has to put its new people somewhere, and what it did with them killed a great many of them.
The previous lesson found real wages rising slowly while heights fell and infant deaths stayed appalling, and suggested the resolution lay in the place the wage was spent rather than in the wage. This lesson goes to that place. It is about what happens when population arrives faster than drains, why the resulting death rate was measurable long before it was understood, and how one of the cleanest natural experiments in the history of science was conducted on the water supply of south London.
The first urban society
At the 1851 census slightly more than half the population of England and Wales lived in towns, which had never been true of any country before. The change was concentrated in a few places and it was very fast.
Manchester township held about 75,000 people in 1801 and about 303,000 in 1851. Liverpool went from about 82,000 to about 376,000 over the same fifty years. Glasgow, Birmingham, Leeds and Bradford all did something similar, and Bradford, the fastest, multiplied its population by about eight. These are rates of growth that no earlier city had sustained, because no earlier city had a food supply, a water supply or a labour market that could support them.
Example. Take Manchester from 75,000 in 1801 to 303,000 in 1851. What is the annual growth rate, and how many dwellings a year did the town have to build to house the increase at five people to a house?
The factor is , so the rate is , about 2.8 per cent a year, which doubles a population in 25 years. The increase is 228,000 people, so at five to a house the town needed new dwellings across fifty years, which is 912 a year, every year, for half a century, in a place with no building regulations, no municipal corporation until 1838, and no public authority responsible for streets, water or sewers. The arithmetic is the explanation for what the housing was like. Cheap, fast and unregulated is the only kind of building that meets a requirement of nearly a thousand houses a year, and back-to-back terraces with shared privies and no through ventilation are what that produces.
Now you. Suppose Manchester's crude birth rate was 35 per thousand and its death rate 33 per thousand, giving natural increase of 0.2 per cent a year. How much of the 1851 population could natural increase account for, and what does the remainder mean?
Answer
Natural increase alone takes 75,000 to , so it supplies about 8,000 of the 228,000 increase and migration supplies roughly 220,000 of it. Manchester was therefore built almost entirely out of people who were born somewhere else, mostly in the Lancashire and Cheshire countryside, in Ireland after the famine, and in the declining handloom weaving villages of the previous lessons. Two consequences follow. The city's culture, politics and disease environment were those of a population with no local kin networks, no customary rights and often no shared language, which is why so much of the contemporary description reads as though the observers were writing about a foreign country. And the demography is self-correcting in the grimmest way: a city whose death rate is that close to its birth rate is not reproducing itself, so it can only grow by continuing to draw people in, which it did, and they kept dying at the same rate when they got there.
What the growth produced
The physical result is documented in obsessive detail, because the men who investigated it were trying to shock Parliament and succeeded.
The characteristic Manchester and Leeds housing was the back-to-back: terraces built in pairs sharing a rear wall, so each house had windows on one side only and no through draught. They were built around courts reached through a tunnel, and a court of a dozen houses shared one or two privies over a cesspool or midden that was emptied when somebody paid a nightsoil man to empty it. Water came from a standpipe or a well, ran for an hour or two on some days of the week, and had to be carried and stored.
Liverpool added a form of its own. Its cellars, dug under the houses, were let as separate dwellings, and in the early 1840s something like 39,000 people, about one Liverpudlian in eight, lived below ground in rooms that flooded when it rained. Liverpool appointed the first Medical Officer of Health in the country, William Duncan, in 1847, and it is not a coincidence that the worst-housed large town produced the first public health officer.
The urban penalty, measured
Here the evidence becomes precise, because from 1837 England and Wales had compulsory civil registration of births, marriages and deaths, and because the man put in charge of the statistics, William Farr, was one of the founders of modern epidemiology.
Farr's life tables from the 1841 data give life expectancy at birth of about 41 years for England and Wales as a whole, and about 26 for Liverpool. That gap of fifteen years is not a matter of the poor dying young everywhere; it is a matter of where they lived. The mechanism is overwhelmingly infant and child mortality: urban infant death rates ran at 150 to 200 per thousand live births and higher in the worst districts, against something closer to 100 in healthy rural counties.
The consequence is the fact that dominates the demography of industrial Britain. The great towns did not reproduce themselves. Deaths in Liverpool and Manchester ran close to or above births, so the cities grew by consuming the surplus population of the countryside, and had they been sealed off they would have shrunk. Urbanisation raised national mortality simply by moving people from places where they survived to places where they did not, which is why national life expectancy barely improved between the 1820s and the 1860s while the country was getting richer.
Example. A city of 300,000 has a crude death rate of 33 per thousand while the national rate is 22. How many excess deaths a year is that, and how should the figure be qualified?
The excess rate is 11 per thousand, so the city loses extra people a year, and 33,000 across a decade, which is more than the British dead of most contemporary wars. The qualification matters. A crude death rate is affected by age structure, and this city is full of young migrants, whose death rates are low, so the crude comparison understates the true penalty rather than exaggerating it: correcting for the young age structure would make the excess larger. Working the other way, migrants arrived from poor rural districts already carrying the effects of a poor childhood, so not all of the excess was caused by the city. Farr's own way through this was to standardise, comparing each town with a healthy district at each age separately, and on that basis he put the avoidable excess at a scale he was willing to call a national emergency.
Now you. Why did the urban penalty make cheap food and cheap cotton clothing less useful to a worker than the wage series suggests?
Answer
Because the binding constraint on survival in an industrial city was not calories or clothing but water, excrement and crowding, and no amount of extra income buys a household out of those when the whole district shares one water supply and one cesspool. A family could double its consumption of bread, tea and washable cotton, all of which they did, and still lose the same proportion of infants to diarrhoeal disease, because the infection is in the water everyone drinks. This is the specific reason the standard of living debate of the previous lesson does not resolve: real wages measure what a household can buy in a market, and the goods that would have saved its children were not for sale to it at any price, since drains and clean water are bought collectively or not at all. It also explains the shape of the eventual solution, which was engineering paid for out of rates rather than anything a worker could purchase.
Cholera
Cholera did not cause most of the deaths, and it caused most of the legislation, which is worth being clear about.
The disease reached Britain from the Continent in 1831 and returned in 1848, 1853 and 1866. It killed something over 30,000 people in the first epidemic and about 60,000 in the second, which set against the steady annual toll from tuberculosis, typhus and infant diarrhoea is not the largest killer of the period. What made it decisive is that it was new, terrifying, sudden, and indifferent to class in a way the endemic diseases were not. A healthy adult could be dead within a day, and cholera walked into the houses of people with political power.
The explanation everyone accepted was miasma: disease arising from the foul air of decomposing filth. Chadwick believed it, Florence Nightingale believed it, and it is not a stupid theory, because it correctly predicts that filthy places are dangerous places and it motivated a great deal of useful cleaning. Its practical failure was specific and severe. Acting on it, Chadwick's sanitary reforms flushed the contents of London's cesspools into the sewers and thence into the Thames, which was where London's water companies had their intakes, and so improved the smell while distributing the disease.
Snow's experiment
John Snow, a London physician, argued from 1849 that cholera was spread by something swallowed rather than something breathed, on the evidence that the disease attacks the gut first and that it followed the movement of people and water rather than of air.
His famous investigation is the Broad Street pump in Soho in 1854, where he mapped 600 deaths in a few days around a single well and had the handle removed. The map is a fine piece of work and it is not decisive, because a cluster of deaths around a pump in a filthy district is equally consistent with a local miasma.
What is decisive is the other study, and it is one of the best natural experiments ever conducted.
Example. In south London two companies supplied water to houses along the same streets, often to adjacent houses. In 1852 the Lambeth company moved its intake upstream to Thames Ditton, above the sewage outfalls; the Southwark and Vauxhall company kept drawing from the tidal Thames at Battersea. In the first seven weeks of the 1854 epidemic Snow counted 1,263 cholera deaths in 40,046 houses supplied by Southwark and Vauxhall, and 98 deaths in 26,107 houses supplied by Lambeth. What is the death rate in each, and why is this stronger evidence than the Broad Street map?
Southwark and Vauxhall gives deaths per 10,000 houses, and Lambeth , a ratio of 8.4 to one. The strength of the design is that everything except the water is held constant. The two companies' pipes ran down the same streets to houses of the same kind, occupied by the same sort of people breathing the same air, with the supplier determined years earlier by which company's salesman had called; as Snow put it, the two groups were mingled in every way and differed in nothing except the water. A miasma cannot distinguish between neighbouring houses on one street. A water supply can, and did, by a factor of eight. Snow also had to do the legwork that made the numbers possible, calling at the house of each recorded death and, where the occupants did not know their supplier, testing the water for the chloride that distinguished tidal river water from clean.
Now you. Snow published this in 1855 and the medical establishment was not convinced for another decade. Give the strongest objection available to a competent contemporary.
Answer
That the mechanism was missing. Snow had a statistical association and no organism: nobody could see or name the thing in the water, and the germ theory of disease was not established until Pasteur and Koch, with the cholera vibrio identified by Filippo Pacini in 1854 without being noticed and by Koch in 1883. Without an agent, the correlation had to compete with an incumbent theory that also explained the data reasonably well, since the districts with bad water also had bad air, and Snow's opponents could point to that. Two further objections were available and were made: the numbers rested on Snow's own house-to-house canvass rather than on an official return, and cholera plainly did sometimes spread among people who shared no water supply, which we now attribute to contaminated food and hands but which then looked like a counterexample. The honest reading is that Snow was right, that his evidence was strong enough to justify acting even without a mechanism, and that scepticism about a bare correlation was not unreasonable in itself. The 1866 epidemic settled it, when the deaths concentrated in the one east London district still drinking unfiltered water from the River Lea.
The sanitary state
The response to all this is the most important institutional change in the whole period, and it happened because the counting made the problem impossible to ignore.
Chadwick's 1842 report sold tens of thousands of copies and argued, in terms a Treasury could follow, that disease cost more in poor relief for widows and orphans than sanitation would cost to build. The Public Health Act of 1848 followed, creating a General Board of Health and letting localities set up boards of health, with compulsion where the death rate exceeded 23 per thousand. It was permissive, underfunded and widely resisted by ratepayers who objected to being taxed for a benefit they could not see, and Chadwick, who was personally impossible, was forced out in 1854.
What broke the resistance was the Great Stink of the summer of 1858, when the Thames beside the Palace of Westminster became unbearable and Parliament voted the money for Joseph Bazalgette's intercepting sewers within eighteen days. Bazalgette built about 82 miles of main intercepting sewer and some 1,100 miles of street sewers, carrying London's waste far downstream, and he sized the pipes at roughly twice his own estimate of requirement on the grounds that it would only be done once, which is why they still work. The Sanitary Act of 1866 made action compulsory rather than permissive, and the Public Health Act of 1875 consolidated the whole into the framework that governed British sanitation for a century.
The results arrive after the period this course covers, which is the honest and uncomfortable conclusion. Urban mortality does not begin to fall decisively until the 1870s, and the biggest gains are later still. Thomas McKeown argued in the 1970s that the mortality decline was driven by better nutrition rather than by medicine or public health, and Simon Szreter's reply in 1988 used the local records to show that the timing follows the arrival of municipal water and sewerage town by town, which is now the better-supported view. Either way, the people who lived through the growth of Manchester and Liverpool got the counting, the reports and the arguments, and their grandchildren got the drains.
They did not accept any of it quietly, and the next lesson is about what they did instead.