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

by Siddhartha Mukherjee

A cell brings materiality and physicality to a set of genes. A cell enlivens genes.

But 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.

Microglia nibble at the synaptic connections between neurons and pare them away. They are the brain’s “constant gardeners,” as one report put it.

Isletin was a difficult substance to work with—temperamental, unstable, unpredictable. As its name suggested: insular.