Part II.

Materia Medica.

131

grateful j their taste acrid, aromatic, and permanent. Thebest cloves are also large, heavy, brittle, and when pressedwith the nail, exude a little oil. When light, soft, wrinkled,dirty, pale, and without smell or taste, they are to be rejected.

The Dutch, from whom we had this spice, frequently mixit with cloves from which the oil has been distilled, and thefraud may be continued. These, though in time they regainfrom the others a considerable share both of taste and smell,are easily distinguishable by their weaker flavour and lightercolour.

Cloves yield by distillation with water about one-seventh oftheir weight of volatile oil; 960 parts also gave to Neumann380 of a nauseous, somewhat astringent, watery extract. Thesame quantity gave only 300 of excessively fiery alcoholic ex-tract. When the alcoholic extract is freed from the volatileoil by distillation with water, the oil that arises proves mild,and the resin that remains insipid. Its pungency thereforeseems to depend on the combination of these principles. TheDutch oil of cloves is extremely hot and fiery, and of a red-dish brown colour, but it is greatly adulterated, both with fix-ed oils and resin of cloves ; lor the genuine oil, when recent-ly distilled, is comparatively quite mild and colourless, althoughit gradually acquires a yellow colour. It is heavier than wa-ter, and rises in distillation with some difficulty, so that it isproper to use a very low-headed still, and to return the dis-tilled water several times upon the residuum.

Vauquelin obtained from the leaves of the Agathophyllumravensara an essential oil absolutely the same with oil of clovesin respect to colour, taste, smell, and gravity, being heavierthan water. It was only somewhat less limpid, owing, pro-bably, to the leaves having been long kept, and the oil inconsequence resinified.

Medical use __Cloves, considered as a medicine, are very

hot stimulating aromatics, and possess in an eminent degreethe general virtues of substances of this class.

Euphorbia officinarum. Lond.

Willd. g. 959, sp. 7. Dodecandria Trigynia. —Nat. ord.Tricoccts.

Officinal euphorbia.

Officinal —The gum resin.Euphorbia gummi resina. Lond.

The London College have restored this drastic and corrosivesubstance to their list of officinals. It is produced from severalspecies of the African genus Euphorbia; such as the E. of-