A tribasic organic acid, H3C6H507,H20, usually prepared from the juice of limes or lemons.

Properties : Citric acid forms colorless, transparent crystals: odorless and having an agreeable purely acid taste. It is very soluble in water (1:0.54) and freely soluble in alcohol (1:1.5).

Action and Uses. Citric acid may be used as a substitute for lemon-juice. Like the other organic acids, it is oxidized in the system to carbonic acid, so that its acid effects are much reduced. If an alkaline carbonate be added an effervescing mixture is obtained which gives the therapeutic effects of the alkalies.

0.5 gm. or 7 grains. It may be prescribed in the form of syrupus acidi citrici or as lemonade.

Acidum Diaethylbarbituricum.

See Under Veronal.