PART III.

PtASTEltS.

853

theory, nor indeed utility, of burnt Hurt's horn for any purposeas a remedy.

Officinal preparation. Mistura Cornu usti, L.

SP0NGIA USTA, Lond. Burnt Sponge.

" Cut Sponge into small pieces and bruise it, in order tofree it from any adhering extraneous substances : then burn itin a covered iron vessel, until it become black and friable;finally, rub it to a very fine powder."

The properties of fresh sponge have been already noticed:when burnt, the residue consists of carbonate and phosphateof lime, subcarbonate of soda, iodine, and charcoal. The ac-tive ingredients are the subcarbonate of soda and the iodine.

Medical properties and uses. — Burnt Sponge is tonic, deob-struent, and antiacid. It has been much recommended inbronchocele, scrophulous affections, and herpetic eruptions :and I have witnessed its efficacy in scirrhous testicle, whengiven in combination with cinchona bark. It seems to deriveits efficacy from the iodine it contains. (See Appendix, No. 2.)The dose is from 5j- to ~>ii). mixed into the form of an electu-ary, with powdered cinnamon and honey. In bronchocele thepatient is directed to swallow the portion of electuary veryslowly, from a supposition that some local effect is produced.

TESTAE PRiEPARAT^E, Lond. Prepared Shells.

" Wash the shells with boiling water, having previouslyfreed them from extraneous matters, then prepare them in themanner directed for the preparation of chalk."

Ostrearum Testte PRiEPARATJE, Dub. Prepared OysterShells.

" These are to be prepared in the same manner as chalk."

OVORUM TESTAE PRvEPARAT/E, Dub. PreparedEgg Shells.

** These are to be prepared in the same manner as chalk."

Both in oyster and egg shells the predominating ingredientis carbonate of lime, and therefore these prepared shells do notdiffer from chalk, except in containing a small portion of gelatinor albumen. But as this does not in any degree affect theirmedicinal properties, which are exactly the same as those ofchalk, they might well be spared from the list of preparations.The dose is from grs. x. to 3h\ or more.

EMPLASTRA.

Plasters.

These are solid, tenacious compounds, adhesive in the or-dinary heat of the human body. The base of the majority of

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