_Aqua Lithargyri Acetati_, P. L. 1767.
Solution of Sub-acetate of Lead: _olim, Extract of Saturn_.
This preparation was introduced by M. Goulard of Montpellier, hence it
has been commonly known by the name of _Goulard’s Extract_. QUALITIES.
It is of a greenish straw colour, and has an austere, sweetish taste;
when kept it deposits a quantity of oxide, and becomes lighter coloured.
CHEMICAL COMPOSITION. It is a saturated solution of the sub-acetate of
lead, consisting, according to Berzelius, of one proportional of acid,
and three proportionals of oxide of lead; hence its name is correct. It
is the only instance with which we are acquainted of a real sub-salt
being soluble in water. INCOMPATIBLE SUBSTANCES. _Alkalies_ and _their
carbonates_ precipitate a white sub-salt; _alkaline sulphates_ and
_sulphurets_; _mucilage_. _Spring Water_, from the salts which it
contains, produces with it a very milky and turbid appearance; and even
when _distilled_, in consequence of the carbonic acid diffused through
it, it occasions precipitation. The Surgeon will remember that the
_Linimentum Saponis_ cannot be mixed with it, without mutual
decomposition. _See Sapo._ MED. USES. It is only used externally, in
superficial and phlegmonic inflammations of the skin, and in herpetic
affections. It has been a question whether _Lead_, in any form, should
ever be applied to an open wound, or to an abraded surface;[556] as a
general rule, it should not certainly be applied to such as are recent,
nor to those whose character indicates a diminished state of vitality in
the parts, and exhibits a disposition to gangrene. The abuse of
Saturnine lotions has been frequently descanted upon by foreign writers,
and, among the evils which are supposed to be thus induced, impotence is
mentioned as one of not unfrequent occurrence. See _Institutioni di
Medicina Forens_: _di Tortosa, vol._ 1. p. 58. also _Fritze Compend:
sopra le Malat: Vener_: p. 189. and _Monteggia Annotat: sopra i Mali
Venerei_, p. 36. There is a paper in the third volume of the _Medical
Transactions_, by Dr. Reynolds, in which the case of a gentleman is
detailed, who brought on a temporary paralysis of the _Sphincter Ani_,
by freely using Goulard’s lotion for the cure of the Piles. The value of
Saturnine applications in common inflammation most probably arises from
a partial paralysis of the nerves of the part, produced by the sedative
agency of the lead.