On a warm, still summer night in August 1999, I stood in an Indiana hospital intensive care unit and turned my head to look at the clock. It was nearly 2 a.m., the dark and deep hours before the morning light, when most human deaths occur. My dear mother’s heart raced at 140 beats per minute, but that was about to end. She was dying, the woman who had given me life. I had long devised a plan that I hoped would one day help her, a plan some 20 years in the making. It was a plan to profoundly intervene in the biology of human aging. But I must say, my best efforts seemed impotent at that moment, staring into the icy face of death.
At my request, a nurse pinched her fingernail bed one more time with a hemostat, squeezing her tender fingertip with the force of a pair of pliers. She winced, though imperceptibly. That was enough for the attending physician. She ordered the respirator that periodically forced air into my mother’s lungs to be turned off along with the intravenous dopamine that was driving her heart. My eyes were fixed on the monitors. Mom’s chest flattened. Her heart at first maintained its steady rhythm of 140 beats per minute and then slowly began its descent, drifting downward like a falling leaf in autumn—140, 125, 110, 100…
My mind flashed back to a fall day in 1960 when I was seven years old. My mother and I walked along the sidewalk, on our way to the corner store. Suddenly, from above, a red leaf began a slow descent from the top of a tree in front of us. The leaf fell among some bushes alongside the sidewalk and I stopped to pick it up. “Mom, look, a cocoon.” There among the fallen leaves was a gray cocoon, as big as your thumb, woven between the stems of a branch. I snapped it off and on we went to the store.
When we got home, my mother propped the cocoon on a ledge near a frosted kitchen window and I forgot about it over the long Michigan winter months. Then one spring day, a miracle happened. My mother and I had just stepped out of the car and my sister came running, screaming, “Hurry, you gotta see!” Running into the kitchen I stopped at the door in amazement. A spectacular moth sat perched on the windowsill, more colorful, larger, more wonderful than anything I knew existed—six inches from wing to wing, and painted in deep velvety colors of the rainbow. The miracle of this immortal cycle of metamorphosis—egg, caterpillar, moth and back to egg again—never left this young boy’s mind.
The Cycle of Life
For millennia our ancestors were observant enough to recognize the profundity of the cycle of life, and the fact that there is a sense in which life is immortal. While it is true that the individual plant ages and dies, out of the sun-drenched soil of spring a resurrection of plant life occurs every year. And while the individual zebra dies, as far back as anyone can remember there have always been zebras, and they always wear stripes. In other words, there is an immortal substratum of life, a continuum that connects the generations – a cycle of life, an immortal cycle. The individual passes away, but there is a continuity of individuals. The ancients attributed the force of this continual renewal of life to the realm of the gods.
The ancient Egyptians witnessed this immortal cycle of renewal on the banks of the river Nile. They came to revere its permanence. Like the sun that dies every evening in the western sky, only to be reborn the following morning, so the life of the individual is a transient phenomenon, but the immortal cycle of life itself is unchanging. In the mind of the ancient Egyptian mythologist, the phenomenon of immortal renewal was more than just a scientific observation; it was the cornerstone of the meaning of life itself. It was (so they reasoned) the work of a god, and they called that god Osiris.
Osiris, often depicted with his face painted green to symbolize this force of immortal renewal, was the foundation of ancient Egyptian religion. Osiris not only escaped death and corruption himself, but, inasmuch as any of his disciples could learn the mystery of the path into immortality, he too could hope for an immortal renewal of life transcending death.
I think the ancient Egyptian philosopher would have marveled to know that from the dry desert sand, future scientists would learn to make clear glass, and then to mold that glass into lenses, and then to stack those lenses together to make telescopes to magnify the night sky, and microscopes to magnify the world too small for the unaided eye. The microscope allowed early biologists to peer into the cellular substructure of life, and by the mid-1800s, it was confidently asserted that the mechanism of animal reproduction was via cells, not some amorphous “life force.” All life comes from pre-existing life, and all cells come from pre-existing cells. In other words, science had uncovered the force of immortal renewal. It was an invisible thread that connected the generations, a lineage of microscopic primordial cells.
The German scientist August Weismann clearly understood the implications of this observation. The cell theory implied that life on our planet today likely originated many millions of years ago from single-celled animals that were immortal. By immortal Weismann did not mean to imply that they could not be killed. Indeed, the struggle of the fittest implied that their less-fit cousins did indeed die. By immortal Weismann meant only that they need not die—that given proper nutrition, and barring some accident, any particular cell could continue dividing, leaving no dead ancestors in its wake.
Weismann then suggested that these original immortal cells may have clung to their daughter cells after dividing, thereby forming a small cluster of identical cells. It is then easy to imagine that these cells simply surrounded themselves with daughter cells to aid in their competition for immortality. One could imagine, for instance, that by “holding hands” in this manner, they were better able to move through the water, or perhaps better able to avoid being eaten by some other animal.
Specialization of Cells
But complex, multicellular animals like you and me do leave dead ancestors behind. When and why did that happen? Here is where Weismann made a revolu-tionary proposal. He surmised that some of the cells in this cluster changed in a profound manner. When the largest animal was still a small cluster of cells—perhaps something like the ball of cells called Volvox, the microscopic pond water animal—some of these primordial and immortal cells specialized in a subtle way to facilitate the reproduction of their sister cells. These specialized cells, which are called somatic cells (from the Greek word soma, meaning body), lost the ability to create other organisms like themselves. They had irreversibly specialized.
For the first time in history, a specialization of cell types arose. The change may have made the entire organism more fit compared to its competition, but the cost was that the somatic cells were destined to die, losing the potential for their own immortality. This, Weismann argued, was the first time programmed death appeared. As Joseph Wood Krutch (1856) put it:
“The amoeba and the paramecium are potentially immortal... But for Volvox, death seems to be as inevitable as it is in a mouse or in a man. Volvox must die as Leeuwenhoek was to die because it had children and is no longer needed. When its time comes it drops quietly to the bottom and joins its ancestors. As Hegner, the Johns Hopkins zoologist, once wrote, ‘This is the first advent of inevitable natural death in the animal kingdom and all for the sake of sex.’”