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

Life’s definition, as it stands now, is akin to a menu. It is not one thing but a series of things, a set of behaviors, a series of processes, not a single property. To be living, an organism must have the capacity to reproduce, to grow, to metabolize, to adapt to stimuli, and to maintain its internal milieu.

Unlike an antibody, a gunslinging sheriff itching for a showdown with a gang of molecular criminals in the center of town, a T cell is the gumshoe detective going door to door to look for perpetrators hiding inside.

perhaps the most astonishing feature of multicellularity is that it evolved independently, and in multiple different species, not just once, but many, many times. It is as if the drive to become multicellular was so forceful and pervasive that evolution leapt over the fence again and again. Genetic evidence suggests this incontrovertibly. Collective existence—above isolation—was so selectively advantageous that the forces of natural selection gravitated repeatedly toward the collective. The transformation from single cells into multicellularity was, as the evolutionary biologists Richard Grosberg and Richard Strathmann wrote, a “minor major transition.

Why, you might ask, do the medical mysteries of the Covid-19 pandemic sit at the center of a book on cell biology? Because cell biology sits at the center of the medical mysteries.

Now we will count to twelve and we will all keep still. This one time on the face of the Earth, let’s not speak any language, let’s stop for one second, and not move our arms so much.—Pablo Neruda, “Keeping Still

The Brain—is wider than the Sky—For—put them side by side—The one the other will contain With ease—and you—beside—The Brain is deeper than the sea—For—hold them—Blue to Blue—The one the other will absorb—As sponges—Buckets—do——Emily Dickinson, c. 1862

Without an edge, there is no self.

This, rather, is the story of how the concept of the cell, and our comprehension of cellular physiology, altered medicine, science, biology, social structures, and culture.

Theories of vitalism found its richest poetic voice in Samuel Taylor Coleridge, who imagined all of animated nature trembling into existence as this vital force flowed through it, just as a breeze might resonate through a harp and produce music that is irreducible to its mere notes. Humans weren’t merely an agglomeration of “lifeless”, inorganic chemical reactions, and even if we were made of cells, the cells themselves must also possess these vital fluids.

True knowledge is to be aware of one’s ignorance. —Rudolf Virchow, letter to his father, ca. 1830s

using a virus that could glue cells together, they fused the B cell with a cancer cell. I am still awestruck by the idea. How did they even think of using the undead to resuscitate the dying? The result was one of the strangest cells in biology. The plasma cell retained its antibody-secreting property, while the cancer cell conferred its immortality. They called their peculiar cell a hybridoma—a, well, hybrid of hybrid and oma, the suffix of carcinoma. The immortal plasma cell was now capable of perpetually secreting only one kind of antibody. We call this antibody of a single type (in other words, a clone), a monoclonal antibody. Milstein and Köhler’s paper was published in Nature in 1975.

Synaptic pruning is thought to sharpen and reinforce the 'correct' synapses, while removing the weak and unnecessary ones. 'It reinforces an old intuition,' a psychiatrist in Boston told me. 'The secret of learning is the systematic elimination of excess. We grow, mostly, by dying." We are hardwired not to be hardwired, and this anatomical plasticity may be the key to the plasticity of our minds.

changed our conception of how an organism’s body works. A major point of physiological “activity,” paradoxically, was to enable stasis. Don’t just do something, stand there.

The innate system is not just among the most ancient, but, being the first responder, the most crucial to our immunity. We associate immunity with B and T cells, or with antibodies, but without neutrophils and macrophages, we would meet the fate of the decomposing fly.

Virchow had refined Schwann and Schleiden’s cell theory by adding three more crucial tenets to the two founding ones (“All living organisms are composed of one or more cells,” and “The cell is the basic unit

The reasons for this paring back of synapses is a mystery, but synaptic pruning is thought to sharpen and reinforce the "correct" synapses, while removing the weak and unnecessary ones. "It reinforces an old intuition," a psychiatrist in Boston told me. "The secret of learning is the systematic elimination of excess. We grow, mostly, by dying.

A friend told me the story of visiting a Tibetan doctor who specialized in pulses. The doctor asked him a few perfunctory questions and then checked his pulse. "You've gone through a terrible breakup," the doctor said. "Your life isn't going to be the same again." The Tibetan doctor was right: something about the pulse -- its rapidity or dullness -- had provided a clue about the longing and belonging. My friend's breakup, and life, had forever been uprooted.

Osteoarthritis, perhaps, was a disease of stem cell loss. The cells that were being worn out—in its first stages—were the cartilage-making stem cells, and they could no longer keep up the genesis of cartilage.

But if you parse that phrase carefully, it turns into a clown car of questions; all sorts of conundrums come tumbling out the doors.

A giraffe’s long neck isn’t the product of generations of its ancestors aspiring to stretch their necks to reach tall trees. It is the consequence of mutations, followed by natural selection, that produces a mammal with an extended vertebral structure that, in turn, creates a long neck.

Under the right evolutionary pressure, single cells can become multicellular aggregates over a mere few generations. Some do take longer, however: in one experiment, unicellular algae became a multicellular agglomerate over 750 generations.

In one of the most intriguing attempts, carried out at the University of Minnesota in 2014, a group of researchers led by Michael Travisano and William Ratcliff made a multicellular being evolve from a unicellular organism.

True knowledge is to be aware of one’s ignorance.—Rudolf Virchow, letter to his father, ca. 1830s

To argue against human enhancement, Saletan continues, “Sandel needs something deeper: a common foundation for the various norms in sports, arts and parenting. He thinks he has found it in the idea of giftedness. To some degree, being a good parent, athlete or performer is about accepting and cherishing the raw material you’ve been given to work with [italics my own]. Strengthen your body, but respect it. Challenge your child, but love her. Celebrate nature. Don’t try to control everything […] Why should we accept our lot as a gift? Because the loss of such reverence would change our moral landscape.