SQDIUM BICARBONATE 129 



Derivation. — Pass COo through a solution of sodium 

 carbouate. Na, CO3 + CO, + H,0 = 2 Na HCO3. 



Properties. — A white, opaque powder, odorless, and 

 having a cooling, mildly alkaline taste. Permanent in dry, 

 but slowly decomposed in moist air. Soluble in 11.3 parts 

 of water, insoluble in alcohol and ether. Slight alkaline 

 reaction. 



Incompatihles. — Decomposed by acid and acid salts, as 

 bismuth subnitrate. 



Z>o.se.— H.,5ss.-ii. (15.-60.); Sh. & Sw.,3ss.-i. (2.-4.); D., 

 gr.v.-xxx. (.3-2.). 



GENERAL ACTION OF SODIUM SALTS. 



Sodium and its salts are not nearly so poisinous as 

 similar potassium compounds, but death has occurred after 

 enormous doses. The salts possess a local paralyzing action 

 on nerve and muscular tissue. They are absorbed and 

 eliminated more slowly than the corresponding potassium 

 compounds. Sodium salts alkalize the blood and urine, but 

 are only slightly diuretic. Sodium carbonate, phosphate, 

 and sulphate diminish the solids in the bile and, therefore, 

 increase its fluidity. 



Sodium Bicarbonate. 



Action Externcd. — Sodium bicarbonate lessens irritability 

 of the skin in itching and burns. 



Action Internal. — When sodium bicarbonate is given 

 after eating it neutralizes the acid products of indigestion 

 and fermentation. The constant administration of sodium 

 bicarbonate weakens the digestive powers and creates 

 anaemia, general cachexia, and scorbutic symptoms. Sodium 

 bicarbonate liberates carbonic dioxide in the stomach, and 

 thus exerts a sedative effect. It dissolves mucus and thins 

 the biliary secretion. It is, therefore, useful in catarrh of 

 the gastro-intestinal tract. 



Blood. — The blood is made more alkaline. 



Kidneys.— The urine is alkalized, but the salt is only 

 feebly diuretic. 



