The cause of scarlet fever is a small round bacterium known as the
streptococcus of scarlet fever. This germ is in the secretion from the
throat, and nose, in discharges from the ears, in pus from abscesses in
the neck and in the discharges from infected wounds. The germ is very
tenacious of life. In dried secretions it may remain alive for a long
time. Instances are known where clothing, worn by children when sick
with the disease, has been put away in a dark place. When this clothing
was brought out many years later and given healthy children to wear
they contracted scarlet fever.