6 COMPOSITION OF GREEN RYE AND RAPE. 



The liquid separated from the albumen was evaporated on the 

 water-bath to a thickish syrup. On addition of alcohol to this 

 syrup, pectin, and gum, with some inorganic salts, were thrown 

 down. In order to remove any traces of adhering sugar, the pre- 

 cipitate was repeatedly boiled out with alcohol, until the solvent 

 ceased to take up any perceptible quantity of soluble substance 

 from the precipitate. The insoluble residue was then transferred to 

 a weighed porcelain crucible, dried in the water-bath and weighed. 

 The amount of inorganic salts contained in it was ascertained by 

 reducing it to ash, which being deducted from the weight of the 

 impure gum and pectin, gave the proportion of pure gum and pec- 

 tin. The salts soluble in alcohol were found to consist principally 

 of chlorides of sodium and potassium. 



5. Determination of Sugar. The alcoholic liquids obtained in 

 determining the gum and pectin were introduced into a retort, and 

 the alcohol distilled off in the water-bath. The residue in the re- 

 tort was transferred to a porcelain crucible, and, after evapora- 

 tion on the water-bath, dried at 230 F., until it ceased to lose 

 weight. It being exceedingly difficult to expel the water com- 

 pletely from the sugar at 212 F., a somewhat higher temperature 

 was employed for drying. In the sugar thus obtained, a consider- 

 able proportion of inorganic salts, soluble in alcohol, was present. 

 On burning this impure sugar, the inorganic salts were left be- 

 hind in the form of a white ash, the weight of which being deduct- 

 ed from that of the impure sugar, gave the proportion of pure 

 sugar. 



6. Determination of Fatty Matters. Like all vegetable produc- 

 tions, green rye and rape contain appreciable quantities of oily 

 and fatty matters. Their quantitative determination was effected 

 by repeatedly digesting 100 grains of the dried and powdered 

 substance in ether, a liquid which readily dissolves all fatty mat- 

 ters. The ethereal solutions were passed through a filter, upon 

 which the powdered substance, boiled out several times with ether, 

 was washed with this solvent, in order to remove all traces of ad- 

 hering fat. The greater part of the ether employed in this deter- 

 mination was obtained back again by distillation of the mixed 

 ethereal liquids at a moderate temperature ; the ether which passed 

 over first into the receiver was collected by itself, and in this way 

 a much stronger ether than the commercial article was obtained. 

 The residue in the retort, evaporated to dryness, was found to con- 

 tain some sugar, which had been dissolved with the oil by the 

 alcohol, usually contained in commercial ether. In order to obtain 

 the oil and fatty matters free from sugar, a small quantity of the 

 strong ether, prepared as described by fractional distillation, was 

 added to the mixture of sugar and fatty matters. The sugar was 

 left insoluble, and the oil and fat dissolved in the ether. On evapo- 

 ration of the ether, the oil was left behind quite pure ; and after 



