Percivall Pott and the Chimney Sweeps' Cancer

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Percivall Pott and the Chimney Sweeps' Cancer

Overview

The English surgeon Percivall Pott (1714-1788) was the first to establish a causal link between cancer and exposure to a substance in the environment. In 1775 he described the occurrence of cancer of the scrotum in a number of his male patients, whose common history included employment as chimney sweeps when they were young. He related the malignancy to the occupation, and concluded that their prolonged exposure to soot was the cause. Pott's description of this disease, and his concern for the plight of these "chimneyboys," sparked a series of reports by other authors and brought to light a disgrace which took another hundred years to eliminate in England. Pott may legitimately be seen as a precursor to the modern investigators who seek to prevent occupational exposure to hazardous substances.

Background

Historians have variously referred to Pott's report on scrotal cancer as a milestone in the fields of chemical carcinogenesis (development of a cancer), preventive oncology, environmental health, and occupational medicine. From the time of the Greeks and Romans cancer was viewed as a systemic disease caused by an excess of black bile. Swellings caused by infection, injury, or cancer were indistinguishable.

In the eighteenth century there was an awakening of medical thought: a new physiology based on an understanding of the circulation of the blood, and a new surgery founded on accurate knowledge of human anatomy. With the rise of medical schools and the use of cadavers to teach human anatomy, observation and experience replaced traditional theories of cancer. Pott had read widely in ancient and medieval medical texts, but in his practice he chose to rely solely on personal experience and first-hand knowledge, and thus was able to discern a cause for cancer in the environment and to develop a cure with wide surgical excision.

Workers often have more intense and prolonged exposure to environmental chemicals and conditions than the general population. Therefore many environmental diseases are first noted in the workplace. The first recorded instance of an occupational disease may be the description of lead colic in metalworkers, attributed to the Greek physician Hippocrates (460-375 b.c.). The Swiss physician and chemist Paracelsus (1493- 1541), who studied the health of miners, was responsible for the first book on the diseases of a specific occupational group. Bernardino Ramazzini (1633-1714), an Italian physician, authored the first systematic treatise on occupational diseases in 1700, in which he describes disorders associated with 54 different occupations.

The Industrial Revolution of the eighteenth century brought in its wake an alarming rise in occupational diseases. Crowded, unsanitary factories, mechanical accidents, and exposure to toxic materials were contributing factors. In eighteenth-century England it was the practice to construct long, narrow, and tortuous chimneys, often no more than 25-30 inches (63-76 cm) wide. This encouraged the employment of young boys, aged four to seven years, to clean the flues by hand, since they were thin and agile enough to maneuver inside the chimneys to loosen and remove the soot.

Called "climbing boys" or "chimney boys," some were abandoned children, others belonged to desperately poor families who apprenticed them to adults who exploited them. The climbers wore no clothing when working in the chimneys, subjecting them to abrasion and causing soot to become embedded in the skin. As bathing was infrequent for society in general, the climbers rarely washed; some reported an annual bath, and records at London's St Bartholomew's Hospital refer to children who were never washed for five or six years at a time. This was so common that the term "black as a sweep" became a national byword.

Pott's article, "Cancer Scroti," provides not only a clinical description of the cancer but also a compassionate picture of the daily lives of the child sweeps: "The fate of these people seems singularly hard; in their early infancy, they are most frequently treated with great brutality and almost starved with cold and hunger; they are thrust up narrow and sometimes hot chimnies where they are bruised, burned and almost suffocated and when they get to puberty, become particularly liable to a most noisome, painful and fatal disease." (Chirurgical Observations, 1775).

After a latent period of 20-25 years, a large number of these boys developed cancer of the skin of the scrotum, known at the time as "sootwart." The disease also occurred in persons who were not chimney sweeps, but to Pott's credit he was able to recognize the special liability of that occupation, despite the long latency period.

Impact

The immediate impact of Pott's widely read article was to provoke an awareness among physicians. Following Pott's report, a frequently debated topic was why sweeps in other countries were not susceptible to this disease. Several reasons gradually became evident: coal was substituted for wood in England at an earlier date than elsewhere; in many European countries great care was taken to avoid contact with soot, including wearing protective clothing; German sweeps washed daily from head to foot and used leather trousers; in Scotland, chimneys were swept by lowering a weighted broom, whereas English sweeps worked with a brush from inside.

Besides the impact on diagnosis and treatment, the social effects of Pott's startling report were far-reaching. The depiction of the deplorable state of the child sweeps created a sympathetic response among physicians and clergy, exemplified by Jonas Hanway's book A Sentimental History of Chimney Sweepers, in London and Westminster, Shewing the Necessity of Putting Them Under Regulation, To Prevent the Grossest Inhumanity to the Climbing Boys, With a Letter to aLondon Clergyman on Sunday Schools Calculated to the Preservation of the Children of the Poor (1785).

As a result of mounting public pressure, Parliament in 1788 passed The Act for the Better Regulation of Chimney Sweeps and their Apprentices. Although this was the first legislative action to address child labor, it was woefully inadequate, providing only that no boy under the age of eight should be apprenticed to a sweep. In 1803 a national organization was formed with many illustrious members from the nobility and legislature, called the Society for Superseding the Necessity of Climbing Boys, by Encouraging a New Method of Sweeping Chimneys and for Improving the Condition of Children and Others Employed by Chimney Sweepers. The Society advocated replacing chimney boys with mechanical sweeping devices, but faced strenuous opposition. Insurance companies as well as Master Sweeps opposed the idea, claiming that chimneys could only be properly cleaned and repaired by using small boys.

It was not until 1834 that further legislation was passed but it was scarcely an improvement, raising the apprenticeship age to 10, and introducing some standards for chimney construction. Bills presented to Parliament in 1817, 1818, and 1819 were thrown out by the House of Lords despite a successful passage through the House of Commons. Over the next 40 years further acts were passed raising the legal age of apprenticeship to 16, imposing regulations for protective clothing and hygiene along with prison sentences for offenders. None of these measures were effective and violations were pervasive. Finally in 1875, 100 years after Pott's report, the scandal was ended by successful legislation that established a system of licensing for sweeps, supported by police enforcement.

Occupational medicine was further advanced in England by the publication of Charles Turner Thackrah's The Effects of the Principal Arts, Trades and Professions and of Civic States and Habits of Living on Health and Longevity (1831), which played an important part in stimulating factory health and child labor legislation. In 1895 a statutory notification system was instituted in England that required the reporting of certain diseases. Other industrial nations followed, and legislative safeguards for worker health continued to be enacted throughout the nineteenth and twentieth centuries.

From Pott's time until the early twentieth century, knowledge of occupational cancer had developed due to the keen observations of individual clinicians and pathologists. After that time, the art of laboratory investigation progressively improved, increasing the chances of identifying causative agents and proving their effects, and even for predicting hazards before they caused disease. Along with this, sophisticated epidemiological studies, supported by modern technology, have greatly expanded the ability of physicians and scientists to detect disease patterns and their relationship to the environment.

A hundred years after Pott, the causative agent in soot was identified as coal tar. Forty years after that, another turning point was reached when in 1915 the Japanese scientist Katsusaburo Yamagiwa (1863-1930) produced the first experimental cancer in laboratory animals. Yamagiwa had been a student of Rudolf Virchow (1821-1902), who had emphasized the capacity of chronic chemical irritation to produce cancer, and called special attention to chimney sweeps' cancer. Virchow's theory gave rise to innumerable futile attempts to produce experimental cancer, leading to an atmosphere of failure and resignation. Yamagiwa's perseverance, along with the choice of an adequate chemical irritant, produced skin cancer in the rabbit ear by the repeated application of coal tar. The knowledge that it was possible to induce cancer in animals spurred worldwide research to isolate active carcinogens.

Pott's discovery became the model for many later investigations of workplace carcinogens, including observations of unusual cancers or a high incidence of common cancers, searches for responsible agents, experiments to demonstrate that agents cause cancer in laboratory animals, and finally implementation of preventive measures.

DIANE K. HAWKINS