Abstract
Pneumonia in well known to be extremely fatal at both extremes of life. In 1923 it was the cause of 3671 deaths per million living at ages under 5 years; between ages 5–24 the death-rate fell to 177 and rose to 376 at ages 25–44. after 45 the increase was rapid and the death-ate reached 2279 per million living for the ago group 65–74 and 4100 for all ages over 75 years.