Book Review

Skin: A Natural History

N Engl J Med 2007; 356:1280-1281March 22, 2007

Article

Skin: A Natural History
By Nina G. Jablonski. 266 pp., illustrated. Berkeley, University of California Press, 2006. $24.95. ISBN: 978-0-520-24281-4

This book is a rich mix of just about everything you would want to know about the necessary and complex covering of your body. Nina Jablonski writes not only as an anthropologist but also as an ethologist, comparative biologist, and psychologist. She weaves a vivid, compelling history, which at times is intertwined with social discourse (skin color and racism) and advice (skin and sun protection).

Jablonski argues that the skin of present-day humans is not vastly different from that of the earliest vertebrates in its function: it is protective, sensitive, and capable of interactions with the outside environment. The skin of primitive vertebrates, as well as that of modern humans, contains a multiplicity of cell types, which Jablonski describes in detail. Structural elements are also detailed. One example is keratin, the protein found in the external layer of the epidermis that functions as a mechanical reinforcement and is common to adult amphibians, reptiles, birds, and mammals. Keratin can also serve in the tough appendages of the skin, as feathers and claws in birds and as hair and nails in mammals.

From a psychological viewpoint, Jablonski discusses how our skin represents the wholeness of the self. This concept is highlighted by the ways in which we use our skin as a canvas for self-expression, identity, and individualism through body art (including tattoos, piercings, and scarification) and cosmetics. Being deprived of human touch can have devastating psychological and developmental effects on young children. Verbal expressions and figures of speech using the word “skin” have the power to convey intensely personal feelings and strong sentiments about identity (e.g., “I nearly jumped out of my skin” and “She has an incredibly thin skin”). Finally, sexuality and skin are enmeshed, as Jablonski writes: “The skin is the largest sexual organ of the human body. . . . Much of the pleasure of sexual intimacy comes from the exquisite expectation of touch and the delight and relief of skin-to-skin contact with another person, before, during, and after the sex act itself.”

An Isolated Melanocyte Showing the Melanosomes (Yellow), Actin (Red), and Microtubules (Blue).

The chapter on touch is particularly fascinating. It is defined as stimulation of the skin by mechanical, thermal, chemical, or electrical means, along with the resulting sensation of pressure, vibration, temperature, or pain. The role of skin and touch in the evolution of both primates and humans is largely unrecognized, according to Jablonski. Arboreal primates required touch for rapid and sure-footed locomotion through trees. Fingerprints, now used in forensics, initially functioned to enhance friction and help ensure that fingers and toes would not slip off when grasping slippery branches or other objects. In modern society, we use touch to check the ripeness of fruit in the supermarket; similarly, animals in the wild use touch (as well as smell) to assess the texture, softness, and quality of foods. Jablonski discusses the relationship between human communication and touch, including the importance of touch between mothers and infants and the increased levels of stress hormones — and the deleterious effects on the immune system — that result from touch deprivation. Also described is the importance of the word “touch” itself to express feelings, as in “Keep in touch” or “How touching” or “I am touched.”

Skin cannot be confused with a textbook on dermatology, although it is as carefully and thoroughly researched. Still, Jablonski does review several common skin disorders as well as the damage done to the skin by ultraviolet light and the need for protection from the sun. She critiques popular cosmetic procedures and points out how the ever-popular Botox injections can cause confusion in face-to-face communication when the emotions that would otherwise be expressed on the face are absent.

Jablonski helps us to understand that human skin, which comes in a wide range of colors and which we use as a canvas for decoration, “reflects our age, our ancestry, our state of health, our cultural identity, and much of what we want the world to know about us.”

Susan C. Taylor, M.D.
Columbia University, New York, NY 10032
drstaylor1@aol.com