250 INORGANIC AGENTS 



AciDUM Tartaricum. Tartaric Acid. HjC^H^Oe- 

 (U.S.&B.P.) 



Synonym. — Sal essentiale tartari, — aclde tartrique, 

 acide de tartre, Fr.; weinsaure, weinsteinsaure, G. 



Derivation. — Boil acid potassium tartrate or argoL 

 (incrustation in wine casks) witli chalk to form calcium 

 tartrate. 2 K H C,H,Oe + Ca C O, = Ca C.H.Oe + K,C,H,Oe 

 + H2O + C O2. Add calcium chloride, which precipitates 

 more calcium tartrate, and decompose with sulphuric acid. 

 H,S O, + Ca C,H,Oe = H^C.H.Oe + Ca S O,. 



Evaporate solution. Calcium sulphate crystals separate 

 and are removed, while tartaric acid crystallizes on further 

 evaporation. 



Properties. — Colorless, translucent, monoclinic prisms, 

 or crystalline crusts, or a white powder; odorless, having a 

 purely acid taste, and permanent in the air. Soluble in 

 about .8 part of water, and in 2.5 parts of alcohol. Not 

 commonly used in Veterinary medicine. 



Dose.—R., 3 ii.-iv. (8.-15.); !>., gr.x.-xxx. (.6-2.). 



AciDUM CiTRicuM. Citric Acid. HjCeH.O,. (U. S. & B. P.) 



Synonym. — Acidum citri S. limonum, S. limonorum, — 

 acide citrique, acide du citron, Fr.; citrouensaure, G. 



Derivation. — Usually prepared from the lemon (citrus 

 lemonum), or lime (citrus bergamia). Boiling lemon juice 

 (containing 7 per cent, of citric acid) is treated with chalk 

 to form calcium citrate. 2 HgCgHjO, +3 Ca C O3 = Ca^ 

 (CeH.O,), + 3 C O2 + 3 H^O. 



Calcium citrate is boiled with sulphuric acid and the 

 resulting citric acid is obtained by filtration, evaporation 

 and crystallization. Ca, (CeH.O,)^ + 3 H^ S O, = 2 H3CeH, 

 O, + 3 Ca S O,. 



Properties. — Colorless, translucent, right - rhombic 

 prisms; odorless, having an agreeable, purely acid taste; 

 efflorescent in warm air and deliquescent when exposed to 



