410

Materia Mejhca. — Ovis Aries.

PART II.

coasts, 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 ofconferva which covers these stagnant pools.' 2 The best oysterson the British shores are found at Purfleet, the worst nearLiverpool. The oyster, when good, is very digestible and nu-tritious, particularly when eaten raw; and forms an excellentarticle of food for the phthisical, and convalescents. Whenthey are sick, which is known by a black substance on thefringe or fin, or a very milky appearance of it, they are un-wholesome. The shells only are officinal.

Qualities. — Oyster shells consist of alternate layers of car-bonate of lime and an animal matter supposed to be coagu-lated albumen. When thrown into a fire, they emit a greatdeal of smoke; the animal matter is destroyed, and the carbo-nic acid dissipated in the form of gas, while pure lime remains.Medical properties and uses. —Oyster shells are antacid; butas in their unburned state they are less so than chalk, anilwhen burned differ in nothing from lime, their retention inthe list of materia medica is unnecessary.Officinal preparation. Testa prceparatcc, L.OVIS. Sj/st. Nat. Gmelin. i. 197.CI. 1. Ord. 5. Mammalia Pecora.

G. 31. Horns concave, rough, inclined outwards, and spirally twist-ed. Cutting teeth eight in the lower jaw. Tusks none.Species 1. O. Aries 3 The Sheep. Buffbn Hist. Nat. v.p. 1. 1. 1,2.Officinal. Sevum, Lond. Adeps ovillus, Edin. Sevum; Ovil-lum, Dub. Mutton Suet.

Si/n. Graisse de Mouton (P.), Hammeltalg (G.), Grasse duro (/.), Grassa (£.).

The sheep is too well known to require any description. Itis an inhabitant of almost every climate, and delights in dry,saline, moderately elevated and warm pastures. It is the most

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

- Beckman's Observations, Phil. Mag. vi. 97. In Scotland, oysters laid downto feed near the salt works on the shore, attain a large size and a gryat richness offlavour : they are called Pandoors, and are much esteemed.

3 UpoBarw Afistot, Hist. Animal, v. can. II.