certained and demonstrable fact. The lower we descend
in the animal scale, the more varied we find the functions of the skin to
be, and if in the higher animals much of the complexity has disappeared,
that is only because the specialization of the various skin regions into
distinct organs has rendered this complexity unnecessary. Even yet,
however, in man himself the skin still retains, in a more or less latent
condition, much of its varied and primary power, and the analysis of
pathological and even normal phenomena serves to bring these old powers
into clear light.

Woods Hutchinson (_Studies in Human and Comparative Pathology_,
1901, Chapters VII and VIII) has admirably set forth the immense
importance of the skin, as in the first place "a tissue which is
silk to the touch, the most exquisitely beautiful surface in the
universe to the eye, and yet a wall of adamant against hostile
attack. Impervious alike, by virtue of its wonderful responsive
vitality, to moisture and drought, cold and heat, electrical
changes, hostile bacteria, the most virulent of poisons and the
deadliest of gases, it is one of the real Wonders of the World.
More beautiful than velvet, softer and more pliable than silk,
more impervious than rubber, and more durable under exposure than
steel, well-nigh as resistant to electric currents as glass, it
is one of the toughest and most dangerproof substances in the
three kingdoms of nature" (although, as this author adds, we
"hardly dare permit it to see the sunlight or breathe the open
air"). But it is more than this. It is, as Woods Hutchinson
expresses it, the creator of the entire body; its embryonic
infoldings form the alimentary canal, the brain, the spinal cord,
while every sense is but a specialization of its general organic
activity. It is furthermore a kind of "skin-heart," promoting the
circulation by its own energy; it is the great heat-regulating
organ of the body; it is an excretory organ only second to the
kidneys, which descend from it, and finally it still remains the
seat of touch.

It may be added that the extreme beauty of the skin as a surface
is very clearly brought out by the inadequacy of the comparisons
commonly used in order to express its beauty. Snow, marble,
alabaster, ivory, milk, cream, silk, velvet, and all the other
conventional similes furnish surfaces w