In 1719 Mead was asked for advice concerning an outbreak of plague in Marseilles, and replied with the above tract of 59 pages, which has been called the first epidemiological report produced by a physician at the command of the state. It underwent seven editions in one year. By the eighth edition (1722) Mead expanded it into a book of 150 pages. Mead concluded that isolation of the sick is more effective in stopping the spread of infection than general quarantine or fumigation. The book has been called almost a prophecy of what was to develop as the English public health system.