160 



sweetish, aromatic taste; of 0"920 density; solidifies to butter- 

 consistence at — 11°; turns readily rancid, yellow, and thick at the 

 air; yields very soft soaps. [Contains, according to Fritz, mainly 

 erucic, also stearic and palmitic acids as glycerids.] 



[Oil of Zieria Smitllii. Distilled from the leaves by water. — 

 Pale-yellow, of the taste and odour of rue; of 0"950 density. 

 —Re2}. of Exil. 0/1862.] 



Oil of Zingiber officinale (ginger) = C20 Hie + HO. Obtained 

 from the tubei's by aqueous distillation. — Yellowish, very thin, 

 smells strongly of ginger, tastes burning-ai'omatic ; has a density of 

 0-893; boils at 246°. 



Oleaudriu. Alkaloid of the leaves and branches of Nerium 

 Oleander, accompanied by another alkaloid named Pseudo-curarin. 

 To prepare it, precipitate the concentrated aqueous decoction 

 exactly with tannic acid, treat the deposit, after washing with a 

 little cold water, for a short time only with an aqueous solution of 

 tannic acid. Tannate of pseudo-ciu'arin is hereby dissolved, and 

 the tannate of Oleaudriu remains. The latter, after dissolving in 

 ether, is treated with hydrate of lime, in order to remove tannic 

 acid and chlorophyll, and the filtrate is allowed to evaporate spon- 

 taneously. — Slightly yellowish, resin-like; very bitter, slightly 

 soluble in water, readily so in alcohol and in ether, forms with 

 acids uncrystallisable salts ; is precipitable by chloride of gold and 

 by chloride of platinum. It acts as a poison. 



Oleic Acid =036 H33 O3 + HO. Contained as tri-olein in most 

 of the (non-drying) liquid and solid fats. Saponify for instance 

 oil of almonds or olive-oil with soda-ley, decompose the soap with 

 hydrochloiic acid, digest the separated fat-acids for several hours 

 at 100° with lead-oxyd and treat the product with ether, the latter 

 dissolving the Oleate of lead, while leaving behind the compounds 

 of lead with the solid fatacids. The ethereous solution, when 

 agitated with an excess of aqueous hydrochloric acid, throws down 

 chloride of lead, which sinks to the bottom of the lower aqueous 

 fluid, while the Oleic acid remains with the ether and is obtained 

 after the evaporation of the solvent, though contaminated by the 

 products of Oxydation and by dyeing mattei's. To remove these, 

 allow the acid to solidify at — 6° to 7° and press between blotting 

 paper, which absorbs the impurities. — Forms beaxxtiful, snow-white 

 needles, inodorous and tasteless; has a neutral reaction even when 

 unchanged and dissolved in alcohol; fuses at 14°, congeals at 4° to 

 a hai'd crystalline mass, is of 0*898 density at 15°, evaporates in a 

 vacuum without decom})Osition, becomes brown above 100° and 

 decomposes more and more; is in the solid state unalterable at 

 the air, but absorbs, when liquid, much oxygen and turns rancid; 

 is insoluble in water and mixes with alcohol and ether in every 



