derive their character
chiefly from sulphureted hydrogen gas; which in some of them is
uncombined, while in others it is united with lime or an alkali. They
are transparent when newly drawn from the spring, and have a foetid
odour which is gradually lost from exposure to the air, and the water
becomes turbid. When they are strongly impregnated with the gas, they
redden infusion of litmus, and exhibit some other of the characteristics
of acids; and, even in a weak state, they blacken silver and lead.

Besides containing sulphureted hydrogen gas, they are not unfrequently,
also, impregnated with carbonic acid. They generally contain muriate of
Magnesia or other saline matters, which modify their powers as a remedy.

The _warm sulphureous springs_ in France are those of Bareges,
Saint-Sauveur, dep. Upper Pyrenees; Cauterets, Bonnes, Cambo, dep. Lower
Pyrenees; Bagneres-de-Luchon, dep. Haute-Garonne; Ax, dep. l'Arriege;
Greoult, Digne, dep. Lower Alpes; Castera-Verduzan, dep. Gers; Bagnols,
dep. Lozere; Evaux, dep. Creuse; Saint-Amand, dep. Nord; Loeche, right
of the Rhone; Aix-la-Chapelle. The _cold sulphureous waters_ are those
of Enghien-les-Bains, in the department of Seine-et-Oise; La
Roche-Posay, dep. Vienne; Uriage, near Grenoble.

These waters are resorted to chiefly by patients who labour under
cutaneous affections and are applied locally as well as drunk.

They are slightly sudorific and diuretic, and apt to occasion in some
patients headache of short duration, directly after they are taken.

They are also employed for curing visceral and scrofulous obstructions,
torpor of the intestines, chronic engorgements of the joints: sprains of
long standing, obstinate catarrhs, rheumatism, etc, and in some
dyspeptic and hypochondriacal cases.

The _warm_ sulphureous waters are to be preferred; attention however
should be paid to the state of the bowels during their course which
ought to be kept free from any accumulation by the aid of some mild
aperient medicine; Spa Doctors trust almost entirely to the aperient
operation of the waters and doubtless, the crises, spa-fevers, and
re-actions described by foreign writers on the spas are often
attributable to the want of combining some mild mercurial alterative and
aperient with the use of the waters, and that many cures are prevented
or rendered ineffectual by the dread of mercury entertained by
continental Physicians. The following what Dr. Johnson terms the
_Auxilio-P