Summary

As medical science has steadily improved, so have life spans across the world, Bryson writes in Chapter 22. A significant discovery came in 1943 when a young Jewish soil scientist discovered gram negative antibiotics. This, along with other discoveries, improved life expectancy. The average lifespan for an American male increased from 46 years in 1900 to 74 by 2000. For American women, it improved from 48 in 1900 to 80. In other countries, lifespans are increasing even more. Causes of death have also changed drastically from 1900 to now. In the past, people died more frequently from infectious diseases like pneumonia and flu and tuberculosis. Today the leading causes of death are heart disease and cancer. Bryson brings up several issues with life expectancy and cause of death statistics, including the fact that many children died in infancy in the past. In 1950, a quarter of children died before the age...