§§ 129, 130. WAX, ETC. HI 



Camauba wax behaved similarly to chlorofovin anil alcohol, but 

 acetate of lead caused no cloudiness. It was partially soluble in 

 ether ; the ethereal solution became turbid on the addition of 

 alcohol Cold alcohol dissolved 3'25 per cent,, petroleum-spirit 

 6-04 per cent. 



Bahia vmx resembled carnauba wax in most of its properties, but 

 the addition of alcohol did not render the ethereal solution turbid. 

 Cold alcohol dissolved 9 -7 per cent., petroleum spirit 3 '32 per cent. 



For cerosin from the sugar-cane see Avequin,i Dunias,^ and 

 Lewy.^ 



Wax may be recognised microeliemically as a solid exudation on 

 tlie surface of the cells, insoluble in water and partially or wholly 

 soluble in ether. (See also §§ 14, 16, 145.) 



§ 130. Oleic and Linoleic Acids. — Oudemans* has adopted the 

 following method for the estimation of oleic acid. The soap 

 obtained by saponifying about 10 grams of the fat with potash is 

 decomposed with sulphuric acid ; the fat-acids are washed with 

 water, mixed with excess of carbonate of soda and dried. The 

 dry mass is exhausted with boiling alcohol, filtering whilst hot ; 

 to the alcoholic solution a little water and am excess of acetate of 

 lead is added. The lead precipitate is collected and dried ; and 

 from a weighed portion the oleate of lead is extracted by boiling 

 with ether. The oleic acid may be calculated from the weight of 

 the residue obtained by evaporating the ethereal solution. 



Linoleic add has not yet been isolated in a state of purity, as 

 the free acid when exposed to the air oxidizes even more rapidly 

 than the corresponding glyceryl compound. Mulder estimated it 

 approximately by separating it, together with oleic, palmitic and 

 myristic acid, from the soap, dissolving the mixed fat-acids in 

 alcohol, careftilly evaporating, allowing the palmitic and myristic 

 acids to crystallize out, and finally converting int-o the lead salts. 

 Extraction with ether then removes oleate and linoleate of lead. 

 By repeated evaporation in contact with air and re-solution in 

 ether, the linoleate of lead gradually becomes insoluble, whilst 

 oleate of lead does not change.^ 



^ Annales de Chimie et de Physique, Ixxv. 218. 

 2 Ibid. 238 ; Annal. d. Chem. und Pharm. xxxvii. 170, 1841. 

 ' Ibid. (New Series), xiiL 451. 

 * Joum. f. prakt. Chem. xcix. 407, 1877. 



» Compare Zeitschr. f. Chem. ii. 452, 1866 (Amer. Joum. Pharm. xl. 249) ; 

 Schiller, Jahresb. f. Pharm. 156, 1857. 



