Nafisi...

Nafisi: The widespread belief is that there is a direct correlation between the size of a body and its life span. For example, it is worth observing the difference between the short age of a moth or a fly and that of a turtle, which might live as long as two centuries. However, this correlation is not as constant as it might seem, because a parrot or a crow, more often than not, live longer than birds that are bigger in size, and even longer than the majority of the mammals.

Some fish, like salmon, live up to a hundred years; whereas a horse does not live more than thirty years. From the time of Aristotle, there has been a belief that the life span of each being is in accord with the time it takes to grow. This equation for animals, as estimated by some scholars, was eight times the period that was required for a species to mature, whereas others maintained it to be five times that period. For human beings, one hundred years is regarded as a normal span.

This opinion is widely held even now. However, David, the Prophet, has regarded seventy years as a natural age. In those ancient periods several individuals are believed to have lived for over a hundred years. However, their identity and the actual scale of their life may not be as accurate as it seems.

Among these individuals are Henry Jenkins, who died in December 1670 at the alleged age of 169 years; Thomas Parr, who died in November 1635 at the alleged age of 152 years; and Catherine, countess of Desmond, who died in 1604 at the alleged age of 140 years[^1]. Some other names appear in different journals across the world today. The Reasons for Longevity Mr. Hoshyar: What are the factors that lead to longevity? Dr. Nafisi: The following have been considered as probable factors of longevity.

(1) Heredity: The significance and the influence of heredity in longevity are self-evident. There are families whose members have been observed to live longer than the average human life expectancy, except in cases where death occurs because of an accident. In this connection it is relevant to mention the research done by Raymond Peril. In a book that he co-authored with his daughter, he studied a family that had a record of longevity going back seven generations.

The total number of years going back seven generations in that family was 699 years, including two persons who were killed in an accident.