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ELEMENTS OF MATERIA MEDICA.

its effect in diminishing excessive secretion, may be correct. Sun-delin \Heilmittellehre, i. 179) thinks it may even promote the depositof bone-earth in diseases attended with a deficiency of this sub-stance. Carbonate of lime, prepared from animal matter, has beenerroneously supposed to be more digestible than chalk, and therefore lesslikely to occasion dyspeptic symptoms (Wibmer, die Wirkung, &c. ii. 10).Dr. A. T. Thomson ( Elements of Materia Medica, ii. 82) says, that “ afterchalk has been used for some time, the bowels should be cleared out, asit is apt to form into hard balls, and to lodge in the folds of the intestines.”

Uses. —As an absorbent and desiccant, prepared chalk is used as adusting powder in moist excoriations, ulcers, the intertrigo of children,burns and scalds, erysipelatous inflammation, &c.

As an antacid it is exhibited in those forms of dyspepsia accompaniedwith excessive secretion of acid; and as an antidote in poisoning by themineral and oxalic acids.

It has also been used in some diseases which have been supposed todepend on, or be accompanied by, excess of acid in the system—as ingouty affections, which are usually attended with the excessive produc-tion of uric acid, and in rachitis, which some have ascribed to a pre-ponderance of phosphoric acid, or to a deficiency of lime in the system.

To diminish alvine evacuations, it is employed in diarrhoea. Its effi-cacy can hardly be referred solely to its antacid properties; for otherantacids are not equally successful. Moreover, in many cases of diarrhoeain which chalk is serviceable, no excess of acidity can be shown to existin the bowels. Aromatics are useful adjuncts to chalk in most forms ofdiarrhoea. In old obstinate cases, astringents (as catechu or kino) maybe conjoined with great advantage; and in severe cases, accompaniedwith griping pains, opium.

Administration. —Prepared chalk is given in the form of powder ormixture, in doses of from ten grains to one or two drachms. It entersinto a considerable number of officinal preparations.

1. Mistura Greta, Ph.L.&Dub.; Potio Carbonatis Calcis, Ph.Ed.;Mistura Calcis Carbonatis, Ph . U. S. (Prepared chalk, Sss.; sugar, 5iij.;mixture of acacia, f.Siss.; cinnamon water, Sxviii . Ph. L.) In the otherPharmacopoeias the proportions are somewhat different. This is a veryconvenient form for the exhibition of chalk, and is in common use indiarrhoea. Aromatics (as the aromatic confection), astringents (as kino orcatechu), or narcotics (as opium), are frequently combined with it. Thedose is from one to three table-spoonfuls.

2. Pulpis Gretas Gompositus, Ph . L. & Dub. (Prepared chalk,fbss.; cinnamon,Siv.; tormentil and acacia, aa. Siij.; long pepper, Sss.):—This preparation is aromatic and astringent, and is used in diarrhoea.The dose is from 10 to 20 grains. The pulvis carbonatis calcis compositus(Ph. Ed.) consists of chalk flavoured with nutmegs and cinnamon.

3. Confectio Aromatica, Ph . L. & Dub. (Prepared chalk, Sxvi.;cinnamon and nutmegs, aa. jij.; cloves, 3j.; cardamoms,Sss.; saffron, Sij.;[water, tbj., Ph . D.]) The London College order the water to be addedwhen the preparation is used, in order to avoid fermentation, to whichthis compound is subject. Druggists sometimes substitute a strong infu-sion of saffron instead of the solid saffron here ordered ; and those whoare desirous of producing a very fine preparation, employ precipitatedcarbonate of lime instead of chalk. This preparation possesses the