The body has a marvelous defense system against disease. Although alive with bacteria, the skin provides a protective shield for the whole body against their encroachment. If harmful bacteria enter the body through a cut or scratch, the body’s defense system goes to work.

Being elastic, the skin also permits the effects of a fall or a blow to be spread over a large area and thus reduces the extent of the injury.

Truly your body is well designed, with an ample margin of safety.

Waterproof Insulation and Heat Control

Besides protecting the body from the invasion of disease organisms and minimizing the effect of blows or falls, the skin serves to provide a waterproof covering for the body. Were it not for this feature, a walk in the rain or a bath would be hazardous. Our bodies would swell and our blood would be diluted. Swimming in seawater would result in shrinkage, since, from a chemical standpoint, salt water is more concentrated than blood.

The release of water through the skin in the form of perspiration and by diffusion, on the other hand, is essential in maintaining the body’s heat balance. Even hair growing in the skin has its place in heat control. The hair of the head shields the brain from getting overheated when subjected to the hot sun. On the palms of the hands, the fingers and the soles of the feet, the thick skin functions as a good heat insulator.

Dry skin also serves as a fine electrical insulator. This is indeed a blessing at a time when electrical appliances have come into common use.

Surely, something as attractive and versatile as human skin can rightly be labeled an “engineering marvel.”