ored; and in the inhabitants of the
north, they are pale and almost colorless.

646. Color of the skin has relation to energy in its action; thus, in
the equatorial region, where light and heat are most powerful, the
skin is stimulated by these agents to vigorous action, and color is
very deep; while in the temperate regions, where light and heat are
not so intense, the lungs, liver, and kidneys relieve the skin of part
of its duties. The colored layer of the cuticle has been called the
_re'te mu-co'sum_, (mucous coat of the skin,) and described as a
distinct layer by many physiologists.

_Observation._ "The various coloring of the inner layer of the cuticle
gives to some animals their varied hues; the serpent, the frog, the
lizard, and some fishes have a splendor of hue almost equal to
polished metal. The gold-fish and the dolphin owe their difference of
color and the brilliancy of their hues to the color of this layer of
the skin."

647. The nerves of the skin are the organs of the sense of touch and
feeling. Through them we receive many impressions that enhance our
pleasures, as the grateful sensations imparted by the cooling breeze
in a warm day. In consequence of their sensitiveness, we are
individually protected, by being admonished of the proximity of
destructive agents.

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In what season of the year is the coloring matter less in the white
race? 645. To what is the color of the skin referable? 646. Why have
the races of the torrid zone darker complexions than those of the
temperate or frigid zones? What is this colored layer called by many
physiologists? To what is the different hues in animals owing? 647. Of
what use are the nerves of the skin?

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_Illustration._ A man who had been afflicted some years with a severe
disease of a portion of the brain and spinal cord, was deprived of
feeling in the lower extremities. He was directed by his attending
physician to use a warm footbath. Intending to follow the directions
given him, he immersed his feet in boiling water, which he supposed of
a proper temperature. While his feet were immersed in the water, he
experienced no sensation of an unpleasant nature. On withdrawing them,
he was astonished to find the cuticle separated from the other
tissues, by the effusion of serum, and thus producing a blister over
the whole surface.

648. Portions of the skin would suffer every day, were it not for the
sentinel-