Characters. - Transparent garnet-red scales, deliquescent on exposure to air; odourless, having a bitter and slightly ferruginous taste and a slightly acid reaction.

Solubility. - Soluble in water.

Reactions. - If one gm. of the salt be dissolved in 4 c.c. of water in a small test-tube, then 1 c.c. of solution of potassa added and the mixture shaken with 2 c.c. of chloroform, the residue left on evaporating the chloroform will answer to the reaction of strychnine. (See ' Strychnina.') Dose. - 3 to 5 grains (0.20-0.33 gm.). Uses. - As tonic and chalybeate to combine the uses of strychnine and iron.

U.S.P. Ferri et Ammonii Sulphas. Sulphate of Iron and-Ammonium. Ammonio-Ferric Sulphate or Ammonio-Ferric Alum. Fe2(NH4)2(SO4)4.24H2O; 963.8.

This is an ammonia iron-alum in which the place of the aluminium oxide is occupied by the ferric oxide.

Characters. - Pale violet octahedral crystals efflorescent on exposure to air, odourless, having an acid styptic taste and a slightly acid reaction.

Dose. - 5 to 10 grains.

Uses. - It is more astringent than common alum, and has not the stimulating properties of other iron salts. It is useful in leucorrhoea. Internally it is sometimes very useful in lessening albumen in cases of intermittent albuminuria.