Ca=39.91.

1. Creta Praeparata. Prepared Chalk

Creta Praeparata. Prepared Chalk. CaCo3=99.76. Synonym. - Drop Chalk.

Source

From Chalk by levigation, elutriation and drying.

Characters

A white, amorphous powder, often moulded into conical drops, odorless and tasteless; permanent in the air. Solubility. - Almost insoluble in water; insoluble in Alcohol.

Incompatibles

Acids and sulphates.

Dose, 10 to 60 gr. .60 to 4.00 gm.

Preparations

1. Pulvis Cretae Compositus. Compound Chalk Powder

Pulvis Cretae Compositus. Compound Chalk Powder. Prepared Chalk, 30; powdered Acacia, 20; powdered Sugar, 50.

Dose, 5 to 60 gr.; .30 to 4.00 gm.

2. Mistura Cretae. Chalk Mixture

Mistura Cretae. Chalk Mixture. Compound Chalk Powder, 200; Cinnamon Water, 400; Water to make 1000.

Dose, 2 to 4 fl. dr.; 8. to 15. c.c.

3. Hydrargyrum cum Creta, see Hydrargyrum.

4. Trochisci Cretae. Troches Of Chalk

Trochisci Cretae. Troches Of Chalk. Prepared Chalk, 25; Acacia, 7 gm.; Spirit of Nutmeg, 3 c.c.; Sugar, 40 gm.; Water to make 100 troches. Each troche contains 4 gr.; .25 gm.

Dose, ad libitum.

2. Calcii Carbonas Praecipitatus. Precipitated Calcium Carbonate

Calcii Carbonas Praecipitatus. Precipitated Calcium Carbonate. CaCo3=99.76.

Source

From Calcium Chloride and Sodium Carbonate, and drying the precipitate. CaC12+Na2Co3=2NaCl+CaCO,.

Characters

A fine, white power, odorless and tasteless, permanent in the air. Solubility. - Nearly insoluble in water.

Precipitated Calcium Carbonate is used to prepare Pulvis Morphinae Com-positus and Syrupus Calcii Lactophosphatis.

Dose, 5 to 60 gr.; .30 to 4.00 gm.

Action of Creta Praeparata and Calcium Carbonate

External

It is mildly astringent and helps to dry moist surfaces.

Internal

Stomach and Intestines. - Calcium carbonate is antacid. It is a mild but certain astringent. How it acts as an instringent is unknown. It is excreted unchanged in the faeces.

Kidneys. Because certain mineral waters containing calcium bicarbonates and sulphates amongst other salts, have been used successfully in cases of urinary gravel and calculi, it has been asserted that these salts are diuretic, and solvent for uric acid, but it is more likely that the beneficial effects of these waters are due merely to the large amount of water drunk; at least, there is no proof that it is due to the salts. Such waters are those of Contrexeville, Vittel, Clarendon, and Waukesha.

Therapeutics of Creta Praeparata and Calcium Carbonate

External

Prepared chalk forms an excellent dusting powder for moist eczema.

Internal

Alimentary canal. - Because of its mechanical action it is a good tooth powder. The following is a good formula: Potassium chlorate, 4; powdered soap, 8; carbolic acid, 2; oil of cinnamon, 1; precipitated calcium carbonate to 48 parts. Chalk mixture and compound chalk powder, particularly the former, are very valuable for checking mild diarrhoea, especially in children.

Kidneys

There is no doubt that persons passing gravel or urinary calculi, especially if composed of uric acid, are benefited by drinking the waters of Contrexeville and Vittel. They should be taken in quantities of 3 to 6 pints 1500. to 3000. c.c. a day and between meals, to avoid the large amount of fluid causing indigestion. At Contrexeville the great bulk is drunk before breakfast.