The Song of the Cell: An Exploration of Medicine and the New Human

by Siddhartha Mukherjee

In the early spring of 2020, the labs were closed because of Covid metastasizing through New York and the world. I was seeing limited numbers of patients in the hospital—partly because, yet unvaccinated (the vaccines were yet to be approved), I feared transmitting an infection to my chemotherapy-receiving patients whose immune systems could not battle a lethal virus. I still tended to the sickest, the most vulnerable. The oncology wing of the hospital went on heroically, kept alive by nurses. When not in the hospital or the lab, I spent my weekends in a house on a bluff that overlooked Long Island Sound. By the early light of morning, with the geometric crosshatches of sunbeams streaming across the lawn like rays of light coming out a prism, I would watch two ospreys that had come to nest there. They would fly up above the ocean, and then, miraculously, seem to sit still in midair—even while capricious gusts of wind might arrive from any direction. The writer Carl Zimmer described the same phenomenon in bats. Their miraculous fixity in midair, he wrote, was another form of homeostasis at work. The liver, pancreas, brain, and kidney are four of the principal organs of homeostasis.II The pancreatic beta cells control metabolic homeostasis through the hormone insulin. The kidneys’ nephrons control salt and water, maintaining a constant level of salinity in the blood. The liver, among many of its functions, prevents us from being soused in toxic products, including ethanol. Th...