ABSTRACT
The skin forms the body’s defensive perimeter against what is in reality the biologically
hostile environment humans live in. As such, in the normal course of living, it suffers
more physical and chemical insult than any other tissue of the body. It is inadvertently
scraped, abraded, scratched, bruised, cut, nicked, and burned. Insects bite it, sting it, and
occasionally furrow through it. It is exposed to detergents, solvents, and myriad other
chemicals and residues. Bacteria, yeasts, molds, and fungi live on its surface and within
its cracks and crevices. It is brushed, smeared, dusted, sprayed, and otherwise anointed
with toiletries, cosmetics, and drugs. Any of these exposures can rile the skin and/or
provoke allergy. In its intact state the skin is a formidable barrier, resistant to chemicals
and tissue-harmful ultraviolet rays and virtually impenetrable to life-threatening
microorganisms. To perform these necessary functions, the skin has to be tough and at
the same time flexible, for it is stretched and flexed continually as we move around within
it. In its healthy state it is thus a remarkable fabric, strong and far more complex than any
artificial material (1).
