PAKT II.

Materia Medica. — Myrrha.

397

sistence. A mixture of resin and some volatile oil with ben-zoin is often sold for Peruvian balsam, -and the fraud is noteasily detected.

Qualities. — The balsam which we receive has a fragrantaromatic odour, much resembling that of benzoin, with a warmbitterish taste, leaving a slight sensation of burning in thethroat after it is swallowed, with some degree of sweetness.It is viscid, of a deep reddish-brown colour, being that whichis obtained by boiling the twigs, and of the consistence of fluidhoney. Water boiled on the balsam becomes acidulated, anddeposits on cooling, crystals of benzoic acid. In distillationwith water, a small portion of a volatile, limpid oil comes over,and benzoic acid sublimes in the neck of the retort. Its re-maining matter is a resin. Ether in small quantity dissolvesit readily and completely; alcohol also dissolves it, but thequantity of menstruum must be considerable. Sulphuric acidconverts it into artificial tannin and charcoal. Treated withnitric acid, some prussic acid is evolved, benzoic acid sublimes,and the residual matter is artificial tannin. 1 The alkalies andtheir carbonates form with it thick masses, which, on the ad-dition of sulphuric acid, lets fall a resinous matter, and benzoicacid crystallizes. Hence Peruvian balsam appears to consistchiefly of resin, volatile oil, and benzoic acid.

Medical -properties and uses. — Balsam of Peru is stimulantand tonic. It has been regarded as expectorant also, and re-commended in catarrh and other pulmonary affections; butit is contra-indicated wherever any inflammatory action is pre-sent; and to its stimulant operation on the pulmonary exha-lants we may ascribe its use in chronic asthma and old ob-stinate coughs. 5 In gleets, leucorrhcea, palsy, and chronicrheumatism, its tonic powers have proved beneficial; as wellas in many other cases of debility. It may be given to the ex-tent of fjj for a dose. As a local stimulant it is employed ex-ternally with great advantage for cleansing and stimulatingfoul and indolent ulcers; and a mixture composed of 5J of thebalsam and Jjiy of ox gall, I have found extremely useful whendropped into the ear every day, after syringing with a solutionof soap, in fcetid discharges of the ear.

MYRRHA.3 Lond. Edin. Myrrha ; Gummi-resina.Dub. Myrrh, a gum-resin.

Syn. Myrrhe {F.\ Myrrhen ((?.). Mirra '/.), Mirra (S.), Murr (Arab.), B61(H.), Bola (Sa/i.)

1 Hatchet. Phi/. Trims. 180G. Thomson's Chemistry, iv. ed. V. 126.

2 Sydenham gave it in phthisis.

3 Sjuupro Dioscoridis. The name Mvppu, used by Hippocrates, is derived fromfivpov, an ointment. Professor Verey (Jowrn. tie Pkarm. 1820.) derives it from thePhoenician word mor or mur. Myrrha, the daughter of Cynirus, king- of Phoe-nicia, was metamorphosed into a tree.