Preparation. - By heating benzoin, when benzoic acid sublimes.

Properties. - In light, feathery, crystalline plates and needles, which are flexible, nearly colourless, and have an agreeable aromatic odour, resembling that of benzoin.

Solubility. - It is sparingly soluble in water, but is readily dissolved by rectified spirit; soluble also in solutions of the caustic alkalis and of lime.

Reactions. - When dissolved in solutions of caustic alkalis or of lime it is precipitated from them on the addition of hydrochloric acid unless the solution be very dilute. When heated to 462° F. it passes off in vapour, leaving only a slight residue.

Preparations.

B.P.

Dose.

Ammonii Benzoas..............................................................................

10-20 gr.

Tinctura Camphorae Composita.........................................................

15 min to 1 fl. dr.

Tinctura Opii Ammoniata...................................................................

1/2-1 fl. dr.

Trochisci Acidi Benzoici...................................................................

1-5 lozenges.

U.S.P

Ammonii Benzoas. Tinctura Opii Camphorata.