On Feb. 11, a citizen of Windsor, Canada, died of hemorrhagic smallpox, so unusual in character that it was not recognized before numerous persons had come in contact with the patient. Cases soon developed in neighboring cities and in the State of Michigan. During the first six months of 1924, 3,999 cases of smallpox were reported in Michigan, of which 1,532 were in Detroit. From Jan. 1 to May 30, there were 106 deaths from smallpox in Detroit and 27 in the rest of the State. The Health Officer of the Canadian cities involved issued a report on the relation of vaccination to the outbreak: no person who had been successfully vaccinated at any time in his life died of smallpox; of those who had never been successfully vaccinated and who developed the disease, 71% died; no one who had been vaccinated successfully within the previous twelve years developed smallpox; nurses, whose only protection against the disease was recent vaccination, nursed patients for weeks without contracting smallpox.