ABSTRACT This historical article presents information about the public health nurse's bag as used in mid-20th century America. The bag was an essential of practice, containing items necessary for providing home care to the sick, maternity nursing, health demonstrations, and other functions within the role of public health nursing agencies or private organizations in which nurses gave home care to multiple patients. Contents of the bag and specifications for their use are described. The historical use of the bag as both a repository for the instruments of skilled care and expert knowledge and of bag technique as a means of infection control may help explain the endurance of the black bag as a symbol of public health nursing.