Dental formulary : a practical guide for the preparation of chemical and technical compounds and accessories as used in the office and laboratory by the dental practitioner : with an index to oral diseases and their treatment / by Hermann Prinz.

Prinz, Hermann, 1868-1957

Date:: 1911

Credit: Dental formulary : a practical guide for the preparation of chemical and technical compounds and accessories as used in the office and laboratory by the dental practitioner : with an index to oral diseases and their treatment / by Hermann Prinz. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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$Commerciall}, three forms of phosphoric acids are met with : i. Urthophosphoric acid, U. S. P., H.,PO^. It is a colorless, inodorous, strong!}- acid liquid of a svrup\- con- sistency which is miscible with water and alcohol in all proportions. It has a specific gravity of 1.710 and con- tains about 85 percent of absolute orthophosphoric acid. Besides this acid, weaker solutions (a 50 percent and a 10 percent solution) are also found in the market. On standing, the acid gradually deposits crystalline prisms, which are readily redissolved when slightly heated. Ortho- phosphoric acid readily absorbs water from the atmosphere. 2. ]\Ietaphosphoric acid or glacial phosphoric acid; HPO,,. It is found in commerce in glassy sticks or lumps, containing from 10 to 15 percent sodium metaphosphate, which is added to give tenacity, transparency and hardness to the sticks. The acid is readily soluble in water, the solu- tion gradually changes to orthophosphoric acid. The acid is very hygroscopic. 3. Pyrophosphoric acid ; H^PoO^. It is a white, hygro- scopic, glassy mass which gradually changes to orthophos- phoric acid. A satisfactory acid for dental cement powders may be prepared in the following manner: One part of pure zinc phosphate, twent\' parts of glacial phos]5h6ric acid in sticks, and ten parts of distilled water, all quantities bv weight, are placed in a glass stoppered bottle and set aside in a mod- erately warm place and occasionally shaken until the solu- tion is completed. The acid is then filtered through a cone of glass wool placed tightly into the neck of a glass funnel. The first portions of the filtrate are returned to the funnel until the solution runs ofl:' perfectly clear. The acid is N. B.—Parts as used in this Denial Fornudarii mean quantities$