SOLUTION OF HYDROGEN DIOXIDE 115 



centrated urine from which calculi are liable to be deposited. 

 High rectal injections of water are absorbed, and conse- 

 quently flush out the kidneys. 



Solution of Hydrogen Dioxide. 



Aqua Hydrogenii Dioxidi. Solution of Hydrogen Dioxide. 



Synonym. — Hydrogen Peroxide. A slightly acid aqueous 

 solution of hydrogen dioxide (H2O2) containing, when freshly 

 prepared, about 3 per cent, by weight, of the pure dioxide, cor- 

 responding to about 10 volumes of available oxygen. U.S.P. 



Derivation. — Add barium dioxide, 300, to cold, distilled 

 water, 500 ; agitate and keep at a temperature of 100° C. 

 (50^ F.j. To this mixture (of barium hydrate) add a solu- 

 tion of phosphoric acid, 96, in cold distilled water, 320, and 

 shake them together thoroughly. Filter, and wash the 

 precipitate (barium phosphate) with distilled water until the 

 filtrate measures 1000. Add diluted sulphuric acid to the 

 filtrate (until cloudiness disappears in a small filtered por- 

 tion of it ; absence of barium), and starch 10. Agitate fre- 

 quently. Filter and refilter till the solution becomes clear 



Properties. — A colorless liquid, without odor, acidulous 

 to the taste and producing a peculiar sensation and soapy 

 froth in the mouth ; liable to deteriorate by age, exj^osure 

 to heat, or protracted agitation. Spec. gr. 1,006 to 1,012. 



Keaction slightly acid. When exposed to the air at the 

 ordinary temperature, or when heated in a water bath at a 

 temperature not exceeding 60^ C. (140^ F.) the solution 

 loses chiefly water. When rapidly heated it is liable to 

 decompose suddenly. (The value of a given sample of 

 hydrogen dioxide may be roughly ascertained by adding a 

 few drachms to a few crystals of potassium permanganate 

 in a test tube. The greater the amount of efi'ervescence the 

 better the hydrogen dioxide. — Wallian.) 



Dose.—&. k C, I i.-ii. (30.-60.); D., 3 i.-ii. (4.-8.) 



Action and Uses. — Hydrogen dioxide is probably the 

 most powerful surgical antiseptic and disinfectant in use. 



