DURING the last three years, Great Britain has enjoyed comparative freedom from smallpox, and the Ministry of Health has therefore considered it appropriate to issue a memorandum in order to direct the attention of local authorities to the possibility which now exists of limiting the spread of smallpox by prompt and vigorous action as soon as it is reported to have appeared (Memo. 215 (Med.). London: H.M. Stationery Office. 2d.). The memorandum contains an account of the incidence of, and mortality from, smallpox in England and Wales since 1901, and a summary of the procedure which should be adopted should the disease appear in a district.