SODIUM PHOSPHATE 117 



due to duodenitis, and as a laxative for foals and calves. It is occasion- 

 ally prescribed in rickets as a source of phosphorus, but the calcium 

 phosphate is more appropriate. 



SoDii SuLPHis ExsiccATUs. Exsiccated Sodium Sulphite. Na^ SO3. 

 (U. S. & B. P.) 

 Synonym.- — Natrum sulfuriosum, sulfis sodicus (natricus), sulphite of soda, 

 E.; sulfite de soude, Fr. ; schwefligsaures natron, G. 



Derivation. — Saturate a solution of sodium carbonate or hydrate with sul- 

 phurous anhydride gas. Naj CO3 -|- SO2 = Na^SOs -f COj. 



Properties. — A white powder, odorless, and having a cooling, saline, sulphur- 

 ous taste. In air it is slowly oxidized to sulphate. Soluble in 3.2 parts of water; 

 ' sparingly soluble in alcohol; neutral or feebly alkaline. 



Dose.—n. & C, §i, (30); Sh. & Sw., 3ss-i, (2-4); D., gr.v-xxx, (.3-2). 



SoDii BisuLPHis. Sodium Bisulphite. NaHSOa. 

 (Non-official.) 

 Derivation. — Obtained from sodium carbonate or bicarbonate and sulphurous 

 anhydride gas. 



Properties. — Opaque, prismatic crystals, or a granular powder, exhaling an 

 odor of sulphur dioxide and having a disagreeable, sulphurous taste. Exposed to 

 the air the salt loses sulphur dioxide and is gradually oxidized to sulphate. 

 Soluble in 4 parts of water and in 72 parts of alcohol; reaction acid. 

 Dose. — Same as sodium sulphite. 



SoDii Thiosulphas Sodium Thiosulphate. Na^SjOs 5 HjO. 

 (U. S. P.) 



Synonym. — Sodium hyposulphite, hyposulphate of soda, E.; natrum subsul- 

 furosum (hyposulfurosum), P. G.; hyposulphis sodi, hyposulflte de soude, sulfite 

 soIfur6 de soude, Fr. ; natriumthiosulfat, G. 



Derivation. — Dissolve sulphur in a boiling aqueous solution of sodium sulphite. 



Properties. — Colorless, transparent, monoclinic prisms, odorless, and having 

 a cooling, afterwards bitter, taste. Permanent in air below 33° C. (91.4° P.), but 

 efflorescent in dry air above that temperature. Slightly deliquescent in moist air. 

 Soluble in 0.5 part of water; insoluble in alcohol; slightly soluble in oil of tur- 

 pentine; reaction neutral or faintly alkaline. 



Dose. — Same as sodium sulphite. 



Administration. — The sulphites are given in solution, or may be 

 added in powder to the food of horses. 



Action of the Sulphites, Bisulphites and Hyposulphites. 



Action External. — These salts are antiseptics, deodorizers and para- 

 siticides externally and in the digestive tract. The antiseptic action is 

 due to the destructive effect of the sulphites in withdrawing oxygen from 

 organic matter to oxidize themselves into sulphates. Given internally, 

 96 per cent, of sodium sulphite escapes in the urine as a sulphate, while 

 but 3 per cent, is eliminated unchanged. It has been taught that the sul- 

 phites are converted into sulphur dioxide (SO,) by the acids in the 

 stomach, but this is very doubtful. 



Uses. — A 15 per cent, solution or ointment of the sulphites is used 

 against pruritus and parasitic skin diseases. The salts are recommended 

 in indigestion with fermentation, flatulence and foul-smelling feces and 

 in general septic conditions, but have proved as useless as most other 

 drugs in the latter states. Sternberg found that neither the sulphites nor 

 hyposulphites exerted any germicidal action on bacteria in culture media. 



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