Life is immortal, but we all are mortal. On the face of it, the two parts of the above statement appear to be contradictory, but they are not, as attested to by the following facts.
The unit of life is a cell, and the individual human being is made up of millions of cells. These millions of cells arise from a single cell called the ‘ovum’ (egg) present in the mother, which is fertilized by a ‘spermatozoon’ from the father. During the remarkable process of procreation, both unite to become one cell, the fertilized ovum, which divides and re-divides into millions of cells which form various tissues and organs. We human beings are, therefore, derived from a single cell belonging to our parents and are, in effect, a part of them. Our parents, in turn, were part of their parents, and so on and the process has continued for thousands of years. All our ancestors are still living through us and we shall be living through our children and their children.
Scientific proof of an indefinitely long span of life, if not immortality, is provided by tissue culture, which is the culture of living cells. These cells can be kept alive almost indefinitely provided nutrients, water and oxygen are constantly provided to them.
What then is the immediate cause of death?
If cells are deprived of the essential nutrients, water or oxygen, they die. Oxygen deprivation, even for a short period, can prove fatal.
In a living organism the essential nutrients and oxygen reach every cell of our bodies through the blood, which is pumped into the arteries throughout the body by the heart every moment of our lives. If for some reason this life-giving blood does not reach a tissue or organ, that tissue or organ dies. If heart stops its pumping action, the whole body is deprived of blood which causes death of the body in a few minutes due to lack of oxygen. If an artery supplying blood to a particular organ becomes obstructed, the blood cannot pass through it and the organ dies. One would, therefore, appreciate why the beating of the heart uninterruptedly and the unhampered flow of blood in the arteries are so crucial to life.