346 OLEACE.E 



less than 40 per cent, of whole. The varieties of manna generally 

 distinguished in our commerce are large flake, small flake and sorts. 



INFERIORITY. Inferior manna may have a greenish color due to froxin, 

 a fluorescent glucoside resembling sesculin. A new variety of manna 

 from Rhodesia, probably derived from Gymnosporia deflexa is on the 

 market, 



ADMINISTRATION. May be given to very young children as a gentle 

 laxative. Given by dissolving in milk. When administered to 

 adults it is combined with senna, rhubarb, and more energetic 

 laxatives. 



CONSTITUENTS. -Chiefly mannite (75 per cent.), a sweet principle which 

 separates out from the boiling alcoholic solution in crystals, also sugar, 

 dextrin, mucilage, and a nauseous principle, to which its laxative 

 action is doubtless due. 



ACTION AND USES. Gentle laxative, usually given in combination with 

 other purgatives. Dose: % to 2 oz. (15 to 60 Gm.). 



PREPARATION. Infusum Sennae Compositum, . . .Dose: i to 4 fl. oz. (30 to 



1 20 mils). 



430. OLEUM OLIV^:. OLIVE OIL 



SWEET OIL 

 A fixed oil expressed from the ripe fruit of O'lea europse'a Linnd. 



BOTANICAL CHARACTERISTICS. A small evergreen with hard wood. Leaves 

 short-petiolate, opposite, ovate-lanceolate, mucronate. Flowers white, in 

 axillary clusters. Fruit a drupe, J to I in. long, ovoid, purple, sarcocarp 

 firm, fleshy, filled with oil. 



HABITAT. Levant and the Mediterranean Basin and California. 



DESCRIPTION OF OIL. A pale yellow or greenish-yellow, unctuous liquid 

 when pure, having a bland, sweetish taste, but scarcely any odor. 

 Specific gravity 0.915 to 0.918 at i5C. (59F.). On exposure it ab- 

 sorbs oxygen and becomes thick and rancid and loses its color, but 

 does not dry as does linseed oil. 



The oil is obtained by crushing trie ripe fruit and subjecting the 

 pulp to strong pressure. The expressed oil is run into water and the 

 floating oil is skimmed after a few days' subsidence (virgin oil) ; the 

 expressed cake is now broken up, mixed with hot water, and again 

 subjected to pressure, resulting in a second-grade oil. The remaining 

 marc yields by solvents, such as carbon disulphide, or by a third ex- 

 pression after fermentation, a very inferior oil. 



The oil is adulterated sometimes with cotton-seed oil chiefly, with 

 oil of benne, and with peanut oil. 



