that
the salutary effects of sea-bathing may be partly due to the large
proportion of chloride of magnesium contained in the water. Acting thus
it would obviate scrofulous troubles of the skin ; whilst possibly,
indeed probably, affecting the system at large beneficially in the same
respect. The hypothesis that by wearing, or otherwise applying,
externally to the surface of the body, a magnesium-containing jewel
(the infinitesimal quantity of this constituent being favourable rather
than otherwise to its general effect on the health) need not be by any
means thought untenable. Dr. Guernsey has shown that magnesia in its
simple form, when much attenuated with inert sugar of milk, is of
excellent advantage to children troubled with disturbed action of the
bowels, wherefrom the " motions resemble the green of a frog-pond."
Meerschaum,
the light, soft, porous material used for pipes in which to smoke the
choicer tobaccos, is a hydrated silicate of magnesium. Meerschaum (or
Sea-froth), when freshly dug, has almost the consistence of wax. The
Turks spread this on bread, and eat it as a medicine. In Turkey, and in
Germany, Meerschaum pipes which have been used are more valued than
those newly made, by reason of the colouring which they have then
acquired. The Soap-stone, or Steatite, is similarly eaten by the
inhabitants of New Caledonia, when slightly baked, or when mixed with
rice.
Fluorine (which
is a special constituent of the Topaz,—• occurring likewise in the
Tourmaline), being derived from Fluor Spar,—in German—feld
(field),—spah (spar),— is, with regard to the human body, a constant
constituent of the teeth, and the bones ; also it has been detected in
the ashes of milk, and of blood. The mineral fluor
