2707. Oxide of Zinc is an anti-spasmodic, astringent, and tonic.

Used externally, as an ointment, it forms a useful astringent in affections of the eyelids, arising from relaxation, or as a powder it is an excellent detergent for unhealthy ulcers.

Used internally, it has proved efficacious in St. Vitus' dance, and some other spasmodic affections.

Dose, from one to six grains, twice a day.

2708. Calomel is an anti-spasmodic, alterative, deobstruent, purgative, and errhine.

Used internally, combined with opium, it acts as an anti-spasmodic in locked jaw, cholera, and many other spasmodic affections.

As an alterative and deobstruent, it has been found useful in leprosy and itch, when combined with antimonials and guaiacum, and in enlargement of the liver and glandular affections.

It acts beneficially in dropsies, by producing watery motions.

In typhus it is of great benefit when combined with antimonials; and it may be given as a purgative in almost any disease, provided there is not any inflammation of the bowels, irritability of the system, or great debility.

Dose, as a deobstruent and alterative, from one to five grains, daily; as a cathartic, from five to fifteen grains; to produce pytalism or salivation, from one to two grains, in a pill, with a quarter of a grain of opium, night and morning.

Caution. When taking calomel, exposure to cold or dampness should be guarded against, as such an impru dence would bring out an eruption of the skin, attended with fever. When this does occur, leave off the calomel and give bark, wine, and purgatives; take a warm bath twice a day, and powder the surface of the body with powdered starch.

2709. Tonics are given to improve the tone of the system, and restore the natural energies and general strength of the body. They consist of bark, quassia, gentian, chamomile, worm-wood, and angostura bark.

2710. Quassia is a simple tonic, and can be used with safety by any one as it does not increase the animal heat or quicken the circulation.

Used internally in the form of infusion, it has been found of great benefit in indigestion and nervous irritability, and is useful after bilious fevers and diarrhoea.

Dose, of the infusion, from one and a half to two ounces, three times a-day.

2711. Gentian is an excellent tonic and stomachic; but when given in large doses, it acts as an aperient.

It is used internally in all cases of general debility, and, when combined with bark, is used in intermittent fevers. It has also been employed in indigestion, and it is sometimes used, combined with volatile salt, in that disease; but at other times alone, in the form of infusion.

After liarrhoea it proves a useful tonic.

Used externally, its infusion is sometimes applied to foul ulcers.

Dose, of the infusion, one and a half to two ounces; of the tincture, one to four drachms; of the extract, from ten to thirty grains.