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Materia Medica.

PART II.

It is cut for medicinal use when it begins to flower inJuly.

Qualities. — The odour is pleasant, and the taste moder-ately warm, bitterish, and aromatic. Both alcohol and waterextract the virtues of sweet marjoram; and in distillation withwater it yields a large portion of volatile oil, which, on beinglong kept, becomes solid.

Medical properties and uses. —Sweet marjoram is tonic, andwas formerly regarded as possessing errhine powers. It isscarcely ever used except as a culinary herb, or as an adjunctto cephalic snuff's, to which, however, it adds no efficacy.

OSSA. Bones. Edin.

Syn. Dfis Os (F.) Knochen (G.) Ossi (I.) Huesos (S.)

The bones of animals are composed of earthy salts, gelatin,albumen, and oil. According to the analysis of Fourcroyand Vauquelin, the components of ox bones are, in 100 parts,51 of animal matter, 37.7 of phosphate of lime, 10 of carbon-ate of lime, and 1 .3 of phosphate of magnesia. Besides theseM. Hatchett detected sulphate of lime, and Berzelius somefluate of lime in bones.

OSTREA. Syst. Nat. Gmelin. vi. 3315.CI. 6. Ord. 3.. Vermes Testacea.

G. 813. Animal Tethys. Shell bivalve ; the valves unequal, and some-what eared. Hinge toothless, but furnished with an ovate hollowcavity, with lateral transverse furrows. Vulva, or anus, none.Species 105. O.edulus. The common Oyster. Pennant's British

Zoology,™. 102.A. 62.Officinal. Testae. Land. The shells.

Syn. Ecailles des Huitres (F.) AuaterschaaWn (G.) (^oncl\\g\ia A' Ostrka (J.) Cas-c&ra (S.)

This well-known shell-fish inhabits the European and Indianoceans throughout; and is particularly plentiful on the Britishcoasts, which were early famed for producing the best oystersto supply the stews of ancient Rome, in the most luxuriousperiod of its history. 1 They are naturally attached to shelv-ing rocks; but for the facility of always obtaining them forthe purposes of aliment, they are generally laid down near theshore. They are hermaphrodite, and throw out a spat in springwhich gradually enlarges to a perfect oyster. The nature ofthe shell in some degree, and the taste and goodness of thefish, depend on the soil of the bed ; they are tender and friableon a calcareous bottom, thick and solid on rocks, more gluti-nous on marie, and oily and luscious on a slimy bed. The greencolour of those fed in pits on the coast of Holland has beensupposed to be owing to copper; but it arises from a species of

1 Sergius Ovata was the inventor of stews for oysters among the Romans. Pliny,lib. xiv. cap. 54.