Before beginning the consideration of the individual diseases
enumerated in the title, a review of some of the things which relate
to them in common may prevent subsequent repetition. The importance of
this group of diseases is realized when one remembers that during the
ten years ending in 1922, in a large city such as Chicago, more than
one person out of every seven of the population suffered from one of
these diseases and one out of every 150 died from one of them. Combined
these diseases cause about one-fourth of the deaths among children from
one to ten years of age. Not only are they responsible for abundant
deaths, but they also leave in those that recover a legacy of permanent
damage in the heart, lungs, ears, eyes and other parts of the body.
Statistics show that more than one-fifth of the cases of deaf-mutism
follow scarlet fever, measles and diphtheria. Chronic diseases of the
heart and of the kidneys may be due to earlier attacks of scarlet fever.
The diseases here considered constitute an important part of those
which are known as contagious. Contagious diseases are those which are
transmitted from one person to others by direct or indirect contact.
They are sometimes also designated “communicable diseases.”