Modern techniques applied in both preventive and curative therapy against the acute exogenous and largely infective diseases of infancy, childhood, and youth have immensely reduced mortality in the early years of life. In the United States in the year 1900 the average life expectancy at birth was 47 years; in 1951 boy babies had an average life expectancy of more than 67 years and girl babies an expectancy of over 71 years. This increment in longevity of over 20 years in half a century, dramatic as it is, is not an unmixed blessing. The toll of prolonged disability of varying degree consequent to chronic illness is so immense as to be truly immeasurable. The burdens of chronic disease, both individually and collectively, are the source of greater tragedy than death from acute illness.
The problems of chronic illness and those engendered by the increasing number of the aging and aged