Characters. - A clear solution of a reddish-brown colour, slightly acid and astringent to the taste.

Reactions. - When to a little of it placed in a test-tube half its volume of pure sulphuric acid is added, and then a solution of sulphate of iron is poured on, the whole assumes a dark-brown colour (nitrate). It gives the reactions of a ferric salt only.

Dose. - 10 to 40 minims.

Uses. - It has been used as an astringent in the diarrhoea of children, and, also as an astringent, to diminish discharges from mucous surfaces, also to arrest haemorrhage from internal organs. It can be given along with spirit of nitrous ether or nitrate of potassium in cases of anaemia with albuminuria and dropsy.