These houses were considered to be ‘breeding grounds' for tuberculosis and were demolished later in the century. Bad housing became synonymous with sickness, particularly consumption. In his novel, Hard Times (1854), Charles Dickens invented Coketown, ‘an ugly citadel where nature was as strongly bricked out as killing air and gases were bricked in'. In 1830, the English physician, Thomas Southwood Smith (1788-1861), likened a slum dwelling to ‘a stagnant pool in Ethiopia full of the bodies of dead locusts. The poison generated in both cases is the same ...' In New York, tenement housing of the ‘dumb-bell' design, constructed between 1879-1901, supposedly allowed the ingress of air and particularly light which killed the tuberculosis bacilli.Source: E Walford. Old and new London. Cassell & Co, London 1873-1878.