MEDICAL DISPENSARIES IN EIGHTEENTH CENTURY LONDON

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SILICOSIS IN WEST COUNTRY GRANITE WORKERS

The granite industry in Cornwall and Devon is briefly described, especially the production of dust in dressing the stone. In 1951, 210 granite masons were examined (about 84% of the total at that time) and 37 (17·6%) showed silicosis. These men were followed up for 10 years. No silicosis was seen in men with less than 15 years' exposure, but after this time the risk increased to 11 out of 14 in those with over 35 years' exposure. Nine deaths occurred, two of which were due to silicosis. Radiological progression was observed in 13 of the 28 survivors. It was not necessarily associated with additional exposure but was related to age. More young men progressed. In 1961, 132 of the granite masons (about 93% of the total at that time) were re-examined and nine new cases of silicosis were found to have developed during the 10-year interval. The exposure in the 1961 cases was comparable with that of similar cases in 1951. Thus the risk has not been much reduced over this period. Pulmonary tuberculosis occurred in eight of the 37 cases of silicosis in 1951, and between 1951 and 1961 a further five cases were diagnosed, four being from one locality. This was by far the most frequent and disabling complication. Only one case of progressive massive fibrosis was seen. More extensive use of protective antituberculous chemotherapy is advocated, and also better dust control.

THE SUCCESSFUL PREVENTION OF LEAD POISONING IN THE GLAZING OF EARTHENWARE IN THE NORTH STAFFORDSHIRE POTTERIES

In 1572 an extensive epidemic of disease characterized by severe abdominal colic, later identified as lead poisoning, occurred in France in the province of Poitou. Citois named the disease colica Pictonum, that is the colic of the Pictones, the ancient Celtic tribe who inhabited the area. There-after the term was used generically for lead poisoning, otherwise plumbism or saturnism. The origin of the poisoning was traced to the practice of vintners who sophisticated sour acid wines with lead oxide. This adulteration restored the sweetness of the wine by the formation of sugar of lead, lead acetate. Similar outbreaks of poisoning were traced to the same fraudulent practice in the wine-growing districts of Germany and Spain. The preparation and storage of food and drink in containers of pewter and lead glazed earthenware resulted in accidental contamination of the substances, the consumption of which caused acute and chronic plumbism. Among the most frequently lead-contaminated liquors was Devonshire cyder, hence Devonshire colic. Occupational lead poisoning was described among lead miners and smelters in the mid-sixteenth century. Thereafter the disease was observed in a wide variety of trades and processes. The subject was comprehensively reviewed by Tanquerel des Planches in 1839. Among the workmen frequently affected were dippers in the pottery industry where lead oxide and lead carbonate were constituents of the glaze. The disease appeared as a serious problem among dippers and their assistants in North Staffordshire, the centre of the manufacture of earthenware and china in Great Britain. The manifestations of the disease included colic, convulsions, paralysis of limbs, blindness, and general emaciation. Female lead workers suffered excessively from abortions and miscarriages and many of their infants died of fits. The situation became so serious that the Government were compelled to enquire into the problem through a succession of Commissions. Meantime the manufacturers experimented to discover methods of glazing their products without lead or with lead in the relatively harmless fritted state of low solubility lead glazes. The progress of the investigations and remedial measures are followed in detail leading to the final conquest of lead poisoning among dippers and their assistants.