Longevity
great age, or duration of life. Among mammals only man and the elephant live to 100 years. Authentic cases have been recorded of men living to be 108 years old, but such instances are rare. Heredity plays an important part in the records of longevity, which runs in families. It is also due to a care for the laws of health, and regard for diet, cleanliness, and exercise. Within a few centuries the human life average has nearly doubled. In France between 1817 to 1831 the average was 29, and from 1840 to 1859 the average was 39. In England during these periods it was 39 and 49 respectively. In New York the average life is now 33 and a fraction.