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54
COMPOSITION
OF
DRINKS,
ETC.
monia,
nitric
and
nitrous
acids,
shows
generally
an
impurity
of the
water
this
being
contaminated
by
filth
from
cesspools
and
other
sources.
Water,
by
various
methods,
may
be
rid
of
much
of
its
injurious
matter,
although
a
thorough
purification
is
out
of
question.
Filtering
through
charcoal
or
oxide
of
iron
will
secure
water
pure
enough
for
use;
nor
will
it
lose
much
of
its
taste.
For
special
purposes,
/.
z.,
for
use
in
hospitals,
it
is
advisable
to
boil
the
water
first,
to
cool
it,
and
to
add,
artificially,
carbonic
acid
gas.
Spring
waters,
which
have
a
large,
and
by
the
taste
easily
distinguishable,
amount
of
salts,
are
used
mostly
for
therapeutical
purposes,
some
of
them
because
be-
ing
palatable
and
refreshing
also
instead
of
ordinary
drinking
water.
We
have
to
dwell
only
on
the
latter
ones
to
which
belong
those
having
but
a
few
of
solid
ingredients
and
dissolved
carbonic
acid
gas,
not
under
40
vol.
per
cent,
as
f.
/.,
Apollinaris,
the
waters
of
Heppingen
and
Dorotheenauer
Spring
at
Carlsbad,
etc.;
likewise
the
waters
containing
alkalies
and
alkalic
muriatic
acids
with
a
certain
quantity
of
natrium
bi-
carbonicum
and
chloride
of
natrium,
besides
freely
dis-
solved
carbonic
acid
gas
are
frequently
used
as
table
waters,
as
those
of
Vichy,
Giesshuebel,
Rodna,
Ems,
Selters,
etc.
The
waters
are
either
consumed
at
the
springs
or
bottled;
preparations
containing
their
active
ingredi-
ents,
like
the
pastilles
of
Bilin,
the
Carlsbad
Salt,
etc.,