These are unctuous substances analogous to _Cerates_ except in
consistence, which is much less firm, and scarcely exceeds that of
butter: formerly, ointments were numerous and complicated in their
composition, and surgeons adapted with much technical formality
different ointments to answer different indications: this practice
however has undergone a very judicious reform, and it is now well
understood that _in general_ all that is required in an ointment is a
suitable tenacity and consistence, to keep the parts to which it may be
applied soft and easy, and at the same time to exclude from them the
atmospheric air; in some cases, however, these simple compositions are
made the _vehicles_ of more active remedies, as in the following
preparations, _viz._
UNGUENTUM CANTHARIDIS. L. As the active ingredient in this ointment is
derived from an infusion of the Cantharides, it is extremely mild, and
frequently inefficacious. The _ceratum cantharidis_ furnishes a more
certain application.
UNGUENTUM ELEMI COMPOSITUM. L. The elemi and turpentine in this
ointment, render it stimulant and digestive.
UNGUENTUM HYDRARGYRI FORTIUS. L. The precise nature[713] of this
compound does not appear to have been known until the late
researches[714] of Mr. Donovan, (_Annals of Philosophy_, _November,
1819_,) which promise to lead to a more uniform, efficacious, and
economical mode of preparing it; for they[715] shew that in the
officinal ointment, the mercury exists in two different conditions,—in
the state of metal, _mechanically mixed_, as asserted by Vogel, and in
that of an oxide, _chemically combined_ with the lard, and that the
medicinal activity of the ointment exclusively resides in this latter
portion, the presence of metallic mercury not only being useless but
injurious, by obstructing the absorption of the active compound of the
oxide. Mr. Donovan accordingly formed a direct chemical combination, by
continually agitating together lard and black oxide of mercury at the
temperature of 350° _Fah:_ for two hours. At the end of the process it
appeared that every ounce of lard had dissolved, and combined with 21
grains of oxide; and from the trials which have been made respecting its
activity, it would seem to be as efficient as the officinal ointment,
and moreover that it may be introduced by inunction in one third of the
time. The investigation is highly important, for it not only offers the
means of preparing a mercurial ointment more œconomically, but one more
active and manageable, and less liable to that want of uniformity in
strength, which must always attend a preparation in which so much labour
is required for its completion; for independent of that variation in
strength which will arise from imperfect triture, it is by no means an
uncommon practice to use chemical means, which are not admissible, to
facilitate the process, such as the addition of _Sulphur_, which is
found to abridge very considerably the labour requisite for the
extinction of the mercury, but it converts a portion of the metal into a
_Sulphuret_, and diminishes the power of the unguent. There is however a
method of facilitating the process, which is not liable to any apparent
objection, but the theory of its operation is obscure; it consists in
adding to the half-prepared ointment a portion of that which has been
long kept; which appears to act as a _leaven_ to the whole mass.
The following table exhibits the relative quantity of mercury contained
in each of the different ointments directed by the British Pharmacopœia,
and in that prepared according to the process of Donovan.
One Drachm { _stronger ointment_ contains of Mercury 30 grs.
of the Lond: { _weaker ointment_ 10 ——
of the Edinb: _common ointment_ 12 ——
of the Dub: { _stronger ointment_ 30 ——
{ _weaker ointment_ 20 ——
of that prepared according to Donovan 2½ ——
Mercurial ointment furnishes the most prompt, and least exceptionable
mode of impregnating the system. The external method of administering
mercury, says Mr. John Hunter, is always preferable to the internal,
because the skin is not nearly so essential to life as the stomach, and
therefore is capable in itself of bearing much more than the stomach.
The inunction is generally performed by rubbing ʒss to ʒj on some part
of the body where the cuticle is thin, generally on the inside of the
thigh, except perhaps in cases of chronic hepatitis, when it is more
usually applied to the region of the liver, care being taken that the
friction is continued until every particle of the ointment disappears;
and for obvious reasons, the operation ought if practicable to be
performed by the patient himself. Where it has been an object to
saturate the system with mercury as quickly as possible, I have
witnessed the advantage of confining, by means of slips of bladder, a
drachm of mercurial ointment in each axilla, in addition to the
mercurial friction. Camphor, turpentine, and other stimulants, have been
sometimes added to the ointment, with a view of promoting its
absorption; this however is an erroneous practice, since these acrid
ingredients soon produce pustules on the skin, which prevent the
continuance of the friction; the warm bath is a more certain, and less
objectionable _adjuvant_, many practitioners therefore advise the body
to be immersed in a warm bath, once and again, before the course is
commenced, and to repeat it once or twice a week during its continuance:
the length of time to be employed in a course of mercury, and the
quantity to be given, are circumstances that must in every case be left
to the discretion of the practitioner. Mercury, when introduced into the
body, acts as a powerful stimulant, and pervades every part of the
system; hence it is the most powerful evacuant belonging to the Materia
Medica; from its stimulant operation, exerted directly or indirectly, we
are able to explain its utility in the cure of disease, and it may be
made to act according to management and circumstances, as a tonic,
antispasmodic, diuretic, cathartic, sialogogue, emmenagogue, or
alterative; but its most important operation is that displayed in
removing the diseases induced by the syphilitic poison, although its
_modus operandi_ is still buried amongst the many other arcana of
physic. The mode of directing and controlling the influence of mercury
in the cure of the venereal disease, is now very generally understood,
and it is to be hoped that a full confidence in its antisyphilitic
powers is as universally maintained, in spite of the late opinions which
tended to depreciate its value and to question its necessity; there is
however no advantage to be gained, as was once imagined, by exciting
profuse salivation. On its next important application, that of curing
chronic affections of the liver and dropsy, a remark which has been
suggested to me by the results of practice, may not be unacceptable. I
think I have generally observed, that when the remedy has been pushed to
such an extent as to excite the salivary glands to excessive secretion,
the urinary organs cease to participate in its stimulating action, and
_vice versa_, for the mouth is rarely affected when the mercury runs off
by the kidneys; this may suggest a precaution of some practical moment
in the treatment of dropsy, and it will be generally judicious to
accompany the administration of this metal with certain diuretics, in
order to direct its operation to the kidneys;[716] and it would seem,
that for such an object those diuretic medicines should be preferred
that act _primarily_ on the organs, as alkalies and their combinations,
squill, &c. the success of such a plan of treatment will also depend
greatly upon the exact period at which these remedies are administered;
it will for instance be right to wait until the system is, to a certain
degree, under mercurial influence. It is hardly necessary to observe,
that if the mercury runs off by the bowels, we shall be deprived of all,
or of a great share of, the benefit to be expected. In certain cases,
the lymphatic vessels seem to resist the admittance of mercury, and to
refuse the conveyance of it to the general circulation: I have already
thrown out some vague hints upon the subject, at page 156, and I must
refer the reader to some farther remarks, which I apprehend bear upon
this question under the following article.
UNGUENTUM OXIDI HYDRARGYRI CINEREI. E. This consists of a mixture of
_one part_ of grey oxide of mercury, and _three parts_ of axunge: it was
reasonable to suppose, _a priori_, that, as the whole of the mercury in
this ointment is oxidized, its adoption would supersede the necessity of
the labour required for the preparation of the common mercurial
ointment, and at the same time afford a combination of equal if not
superior efficacy; but experience has not justified the conclusion, for
it has been found to possess little or no activity; the consideration of
it is therefore introduced into this work, not on account of its
utility, but as an object upon which I may pause with advantage, to
offer those observations which its history is so well calculated to call
forth and illustrate. The circumstance which renders this preparation
inert, will now receive a satisfactory explanation from the experiments
of Mr. Donovan, as related in the preceding article; in short, it is a
_mechanical mixture_ instead of a _chemical combination_; and I beg
again to urge the importance of this distinction, and to offer the
present example as a farther illustration of the views I have already
submitted upon the subject. By subjecting this ointment for some hours
to a heat of 300°, it would without doubt become an active preparation.
It is probable that the lymphatics offers less resistance to the ingress
of a mineral body into the system when it is presented to them in
combination with some animal substance, which must alone be regarded as
their peculiar stimulus, and the only matter which they are destined
perpetually to receive and convey; for the same physiological reason,
the lacteals may probably take up iron with greater readiness when in
combination with vegetable matter, than when introduced into the stomach
in a more purely mineral form.
UNGUENTUM HYDRARGYRI MITIUS. L. This weaker preparation is sometimes
preferred, as it irritates the skin less; it is however principally used
as a topical dressing to venereal sores, and as an application to kill
vermin on the body.
UNGUENTUM HYDRARGYRI NITRATIS. L.E.D. vulgo _Citrine Ointment_. It is
stimulant, detergent, and alterative; when diluted with an equal
quantity of simple ointment or almond oil, it may be almost regarded as
a specific in ophthalmia tarsi, smeared upon the cilia every night at
bedtime.
UNGUENTUM HYDRARGYRI NITRICO-OXYDI. L. An excellent stimulant
application, well adapted for giving energy to indolent ulcers. If mixed
with any ointment containing resin, it loses its red colour, passing
through olive green to black, which depends upon the conversion of the
_red_ into the _black_ oxide of mercury.
UNGUENTUM HYDRARGYRI PRÆCIPITATI ALBI. L. Stimulant and detergent. It is
said to be very efficacious in certain inveterate forms of the Itch.
With the addition of Carbonate of Potass, it has been much extolled in
various cutaneous affections.[717]
UNGUENTUM PICIS LIQUIDÆ. L.E.D. _Tar Ointment._ This ointment has been
much extolled for the removal of tetter, and for the cure of tinea
capitis.
UNGUENTUM RESINÆ NIGRÆ. L. olim, _Ung. Basilicum[718] nigrum._ Digestive
stimulant.
UNGUENTUM SAMBUCI. L.D. It possesses no advantage over the simple
ointment.
UNGUENTUM SULPHURIS. L.E.D. This ointment is a mechanical mixture of
Lard and Sulphur, although it would appear that a small proportion of
the latter exists also in a state of chemical combination. MED. USES. A
specific in the itch. Dr. Bateman proposes a combination, equally
efficacious, but which has not the same disagreeable smell; _viz_. “Take
of sub-carbonate of potass, _half an ounce_; rose water, _one ounce_;
red sulphuret of mercury, _one drachm_; essential oil of Bergamot, half
a _fluid-drachm_; sublimed sulphur, hog’s lard, of each _eleven ounces_.
Mix them.” Jasser’s Ointment also, as altered in the Prussian
Pharmacopœia, is an excellent application in Psora, _viz._ ℞._Sulphur:
Sublim:_ ℥ij, _Zinci Sulphat:_ ℥ij, _Ol:_ _Lauri, et Axung. q, s, ut
fiat Unguentum_.
UNGUENTUM SULPHURIS COMPOSITUM. L. More stimulating than the simple
ointment, from the addition of white hellebore; it is however frequently
found to excite too much irritation.
UNGUENTUM VERATRI. L.D. It is used for the cure of scabies, but is less
certain than the ointment of sulphur.
UNGUENTUM ZINCI. L.E.D. Astringent and stimulant; very beneficial in
some species of ophthalmia, smeared upon the tarsi, every night.
Very efficient preparations may be also constructed by adding together
equal weights of lard and narcotic vegetable powders, as those of
_Conium_, _Digitalis_, _Belladonna_, &c.
The addition of a small quantity of powdered white sugar will frequently
prevent ointments becoming rancid.