Since the days of the cave man human life span has grown steadily longer. Agriculture, once invented, provided a more dependable food supply. And a steadier, less nomadic existence. All of which conferred a greater chance of living longer. The stage was set for the development of new tools and new ways of doing things which, over the centuries, made life easier.

Some inventions come immediately to mind: the steam engine, for example, allowed us to haul loads that previously were unthinkable. Other inventions are not as obvious. Central heating, for instance, which took a lot of dampness and chill out of everyday living. Or the flush toilet, which conferred new levels of sanitation. All of these inventions, and countless others over the centuries undoubtedly added years to the average person's life.

But it is in the last two hundred years that the average life span has made its greatest gains. In the early 1700's the average life expectancy in America was about 25 years. By 1900, however, the average life span had increased to around 48. Now, at the turn of the Millenium, the average American can expect to react almost to the age of 80. Women still outlive men in most societies. We at last have some answers to this puzzle as well.

It is in the realm of science and medicine, especially during the past century, where the greatest gains in longevity were made: insulin, penicillin and the antibiotics which followed, and advances in surgical techniques. All have added years and decades to lives that would otherwise have been cut short. Very few questioned the benefits of these life extending discoveries.

What all of this means however, is that most of us today can expect to live on into ripe old age - with the attendant aches and pains, as well as the increasing decrepitude and decay.

At least that was the case until recent years.