2727. Cathartics are divided into laxatives and purgatives. The former comprise manna, tamarinds, castor oil, sulphur, and magnesia; the latter, senna, rhubarb, jalap, colocynth, buck-thorn, aloes, cream of tartar, scam-mony, calomel, Epsom salts, Glauber's salts, sulphate of potash, and Venice turpentine.

Manna

2728. Manna is a very gentle laxative, and therefore used for Children and delicate persons.

Dose for children from one to four drachms; and for adults from one to two ounces, combined with rhubarb and cinnamon water.

Tamarinds

2729. Tamarinds are generally laxative;md refrigerant. As it is agreeable, this medicine will generally be eaten by children when they will not take other medicines.

Dose from half to one ounce. As a refringent beverage in fevers it is extremely grateful.

Castor oil

2730. Castor oil is a most valuable medicine, as it generally operates quickly and mildly.

It is used externally, combined with citron ointment, as a topical application in common leprosy.

It is used internally as an ordinary purgative for infants, as a laxative for adults, and in diarrhoea and dysentery.

In colic it is very useful and safe: and also after delivery.

Dose for infants from forty drops to two drachms; for adults from half to one ounce and a half.

2731. Sulphur

Sublimed sulphur is laxative and diaphoretic.

It is used externally in skin diseases, especially itch, both in the form of ointment and as a vapour-bath.

It is used internally in haemorrhoids, combined with magnesia, as a laxative for children, and as a diaphoretic in rheumatism.

Dose from one scruple to two drachms, mixed in milk or with treacle. When combined with an equal proportion of cream of tartar it acts as a purgative.

2732. Magnesia

Calcined magnesia possesses the same properties as the carbonate.

Dose from ten to thirty grains, in milk or water.

Carbonate of magnesia is an antacid and laxative, and is very useful for children when teething, and heartburn in adults.

Dose from a half to two drachms, in water or milk.

Senna

2733. Senna is a purgative, but is apt to gripe when given alone; therefore it is combined with some aromatic, such as cloves or ginger, and the infusion should be made with cold instead of hot water. It usually acts in about four hours, but its action should be assisted by drinking warm fluids.

Dose of the confection, commonly called "lenitive electuary," from one to three or four drachms at bed-time; of the infusion, from one to two ounces; of the tincture, from one to two drachms; of the syrup (used for children), from one drachm to one ounce.

Caution. - Do not give senna in any form except confection, in haemorrhoids, and never in irritability of the intestines.

Rhubarb

2734. Rhubarb is a purgative, astringent, and stomachic.

It is used externally in the form of powder to ulcers, to promote a healthy action.

It is given internally in diarrhoea, dyspepsia, and a debilitated state of the bowels.

Combined with a mild preparation of calomel (cum cretd), it forms an excellent purgative for children.

Dose of the infusion from one to two ounces; of the pouder from one scruple to half a drachm as a purgative, and from six to ten grains as a stomachic; of the tincture and compound tincture from one to four drachms; of the compound pill from ten to thirty grains.