The Song of the Cell: An Exploration of Medicine and the New Human by Indian American oncologist, biologist, and author Siddhartha Mukherjee is a review of scientific advancement and life at the cellular level. To tell this story, Mukherjee draws on numerous sources, including personal memories, visits with scientists, patient encounters, discussions with medical professionals, and historical records. Mukherjee chronicles the discovery of the cell as the basic building block of all living organisms, including humans. The book describes how cells, which are isolated, singular units, interconnect. Mukherjee asserts that the ability to fight disease depends on the understanding of this interconnectedness. He documents how the body shifts from homeostasis to pathology. In addition, Mukherjee discusses the transformational breakthroughs emerging from a deepening understanding of cell biology and physiology—and what this means for humans. These breakthroughs are enabling science to manipulate the very essence of being human and produce something new.

The book was named a New York Times Notable Book of 2022 and a Best Book of the Year by the New York Library, Book Riot, BookPage, and Oprah Daily. Other works by this author include The Gene and The Emperor of All Maladies.

This study guide refers to the Scribner (2022) edition.

Plot Summary

In Part 1, Mukherjee focuses on the history of cell biology. This story began in the late 1600s when Dutch trader and self-taught scientist Antonie van Leeuwenhoek and English scientist and polymath Robert Hooke first viewed cells under a microscope. The microscope itself was developed because of centuries of refinement in glassblowing. Two centuries later, scientists used microscopes to view the cells of tissues and organs and then began to investigate the origin and function of cells. Among the earliest of these researchers was French scientist and revolutionary François-Vincent Raspail. He was the first to suggest that “from cells come cells” (40). His findings, which were transformational, were initially overshadowed by two scientific debates around vitalism and preformation. Findings by botanist Matthias Schleiden and zoologist Theodor Schwann—considered the founders of the field of cell biology—helped quell these debates. Schleiden and Schwann argued that cells were the building blocks of all living organisms. However, they were unable to determine the origin of cells. Building on their work, Rudolf Virchow, a German physician, pathologist, and politician, proposed that cells were the source of normal physiology and pathology. This assertion led scientists to wonder about the connection between microbial cells and human infection. French chemist and microbiologist Louis Pasteur and German physician Robert Koch discovered that bacteria caused rot, disease, and fermentation. This discovery helped lead to the invention of antibiotics in 1910. Mukherjee emphasizes how scientists build on one another’s work to continually test, refine, and sometimes even reject various hypotheses.

Part 2 focuses on cells in isolation. Mukherjee describes the discovery of a cell’s anatomy. He considers cells the basic unit of life and holds that understanding cells helps people understand their humanness. In addition, he discusses the two types of cell division: mitosis (the production of daughter cells from a mother cell) and meiosis (the creation of cells for sexual reproduction). He describes the four phases of cell division (G1, S, G2, and M) as well as the two crucial regulators of this process (cyclins and CDK proteins), which work together. He also describes breakthroughs in the understanding of embryonic development. Refining the knowledge of cell division and embryonic development led to in vitro fertilization and gene editing. These technologies have forced scientists and the public to face new ethical dilemmas about science and what it means to be human. Mukherjee cites the story of Chinese professor and biophysicist He Jiankui—the first scientist to use human genome editing—as a cautionary tale to illustrate how scientists must follow a strict code of ethics and not rush to be first.

In Part 3, Mukherjee focuses on blood because it’s akin to a cellular civilization. Each chapter in this section focuses on a different type of cell. Red blood cells are the restless cells because they flow throughout the body, a process which has been documented since ancient times. The discovery of the four main blood types revolutionized the ability to conduct successful blood transfusions. The first successful blood transfusion occurred only about 100 years ago; previous attempts (before the advent of blood typing) resulted in horrible deaths. Platelets are the healing cells that help the body clot blood at sources of injury. However, modern lifestyles have disrupted this ancient process, leading to a rise in heart disease. Drugs to dampen platelet and clot-making proteins are now needed. Experimental research is trying to remove cholesterol from the body, which could result in “new humans” (since it would modify the body’s cells). Neutrophils, a type of white blood cell, are the guardian cells, acting as the first defense in human immune systems. Vaccinations are the most successful way that scientists can manipulate innate immunity. The practice of vaccination stretches back to ancient times when healers ground up smallpox sores to help promote immunity in children. B cells are the defending cells because they help the body mount an immune response by producing antibodies. Researchers are currently trying to use antibodies to attack specific cancer cells. T cells are the discerning cells because they can detect foreign cells among self cells. Understanding how all the parts of the blood interconnect has helped fight critical diseases, including AIDS and cancer.

In Part 4, Mukherjee examines the COVID-19 pandemic. In his view, it provided a dose of humility to scientists. Before the pandemic, scientists thought they understood the human immune system. The pandemic showed that science still has much to learn, including how viruses like the coronavirus impact cells.

Mukherjee details organs and their cells in Part 5. He emphasizes how the cells of organs—particularly the heart, brain, kidneys, pancreas, and liver—come together to fulfill a common purpose. In the heart, while each cell maintains its unique identity, all the cells coordinate to ensure that the heart pumps. Mukherjee likens the heart to an orchestrated citizenship. The other four organs work together to help the body maintain homeostasis. The brain acts as the master orchestrator of balance and restoration within the body, but the kidneys, pancreas, and liver play key roles too. Through insulin, the pancreas controls metabolism. Nephrons in the kidneys help maintain water and salt levels in the blood. The liver helps remove toxic waste. When these organs successfully coordinate, the body maintains fixity. However, this balance can be thrown off by pathological aberrations like autoimmune responses—whereby immune cells attack healthy cells—or malfunctions in glial cells’ ability to prune cellular debris in the brain. Thus, cells are always battling forces of imbalance. Breakthroughs in understanding the relationships among these cells and organs could transform people into “new humans”—for example, through a brain pacemaker that helps regulate moods or an artificial pancreas that controls metabolism and potentially cures diabetes.

In Part 6, the final section of the book, Mukherjee discusses several of cell biology’s remaining mysteries, including those related to stem cells, bones, and cancer cells that defy decay. Throughout these discussions, he shows that while the understanding of individual cells has come a long way, science still can’t fully explain how all cells interconnect. Thus, Mukherjee emphasizes that humans don’t know all the songs of cell biology. Continuing to study cells, particularly how they work together can lead to breakthroughs in treatments and will continue to change thinking about cell biology as well as what it means to be human.