This map is from a booklet published by the Detroit Public Schools in 1958 titled, “Detroit: A Citizens Guide.” Among the many informational sections is a section on “public health” in Detroit.
“The commissioner [Department of Public Health] must also collect information on the cases of diphtheria, scarlet fever, typhoid fever, smallpox, pneumonia, and several other diseases that are reported each day. He keeps a record of where these people live, who is taking care of them, and of any deaths. This information is important for the health of the city because it supplies facts on which the health commissioner may lay plans to prevent the spread of disease and promote health. The map on page 150 gives you some of this information, according to the various sections of the city.”