510 FIXED OILS, FATS AND WAXES 



Consists of the glyceride of oleic acid and a little linolic acid ; it 

 contains no stearic acid.^ ' Kernel ' oil, which may be used to adulterate 

 almond oil, is obtained from apricot kernels (or possibly peach kernels) ; 

 it may be detected, by shaking 1 c.c. with 5 c.c. of a cooled mixture 

 of equal parts by weight of sulphuric acid, fuming nitric acid and 

 water (Bieber's test). 



OLIVE OIL 



Source, &C. Olive oil is the oil expressed from the pericarp of the 

 ripe fruit of the olive tree, Olea europcea, Linne (N.O. Oleacece). 



The olive is a small tree widely distributed by cultivation, 

 especially in the countries bordering on the Mediterranean, and 

 has been introduced into America (California), where it promises so 

 well and is increasing so rapidly that that country will probably soon 

 be independent of Europe for her supply of olive oil. 



The tree produces a small, ovoid, drupaceous fruit about 2 or 3 cm. 

 in length, which, whilst unripe, is green in colour and in this state 

 is pickled and used as a table relish. As the fruits ripen the cells of 

 the mesocarp become filled with a fixed oil, the colour at the same 

 time changing from green to purple. They are collected in the winter 

 and spring (December to April), the ripe sorted out, crushed, and 

 subjected to a moderate pressure. The crude oil that flows from the 

 press is run into tubs and mixed with water ; the latter removes 

 colouring matter and other impurities from the oil, and the oil, after 

 it has completely separated from the water by standing, is skimmed 

 off and filtered ; in this way the finest quality of olive oil (virgin oil) 

 is obtained. The marc is again ground, mixed with hot water, and 

 again pressed, this time more strongly, and thus a second quality 

 of oil is obtained. The residue still contains a little oil which may 

 be obtained by a third pressing or by extraction with solvents ; such 

 oil is usually used for soap-making, &c. Sometimes all the fruits 

 are thrown into heaps and allowed to ferment ; on pressing, the whole 

 of the oil is obtained, but it is of inferior quality, and is used principally 

 for technical purposes. 



Description. For medicinal use only the first pressings, obtained 

 without heat, should be employed. Such oil has a pale yellow or 

 greenish yellow colour, a slight characteristic odour, and a bland 

 taste without rancidity. Its specific gravity varies from 0-915 to 

 0-918. It is liquid at ordinary temperatures, but when cooled to 

 10 it often assumes a pasty consistence, from deposition of solid 

 fats, and at it becomes a nearly solid, granular mass. 



Constituents. Olive oil consists chiefly of olein and a little 

 palmitin, together with linolein and traces of arachin, the palmitin 

 and arachin separating out in the solid form when the oil is cooled. 



