In the middle 1600’s, the average life span in the cities was 16 yr., and, for people who lived to be adults, the life span was about 35 yr. In sparsely populated rural areas, people lived 10-15 yr. longer. Most deaths resulted from disease, and many adults were made susceptible by rotten teeth. This situation improved slowly until the early 1900’s, when simple measures such as improved sanitation (hand washing and an outhouse instead of a chamber pot, which was emptied by throwing the contents out the back door), the pasteurization of milk, and the purification of drinking water reduced infant mortality and produced a 15-20 year increase in average life spans. Disease resistance was also improved by effective dentistry and by eating more fresh fruits and vegetables. The common serious diseases at that time were malaria, typhoid, and tuberculosis. However, many men died in accidents, and an almost equal number of women died in childbirth.