Measles.

Measles, a childhood disease characterized by high fever, sore throat, and skin rash, was widespread in the 1920s, but was not usually fatal when patients received good care. However, in foundling hospitals half the patients might die from terminal bronchopneumonia. There was also the danger of developing blindness. Although the microorganism, or "germ," that caused measles had not been indentified, a serum made from the blood of convalescent patients was used after 1920 to provide some resistance to the disease for children who were exposed to measles. It was not completely effective in immunizing the exposed children, but those who became infected usually had a lighter case.

Scarlet Fever.

Before 1923 scarlet fever was a danger faced by children and adults on a daily basis. Through the work of a husband-and-wife scientific team, the germ responsible for the disease was recognized, and an inoculation was...