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copper were added to the filtered spirituous liquid, red oxide 

 of copper became deposited upon the application of heat; and 

 from this behaviour he inferred the probability that sugar was 

 a constant constituent of the white of eggs. Baron Liebig, 

 however, considered that this reaction only showed that some 

 deoxidizing substance was removed by the alcohol, and that, 

 before the existence of sugar in the white of eggs could be 

 admitted as a fact in science, it would be necessary that this 

 substance should be extracted and examined. 



" I have now to announce the discovery and isolation by 

 me of sugar, identical in properties with that obtained from 

 grapes, in the white of the egg of the domestic hen. It may 

 be obtained by beating the unboiled whites of eggs into a 

 smooth pulp, with an equal bulk of rectified spirits of wine, 

 specific gravity 0-850, and then applying heat ; when, as the 

 mixture is approaching the boiling point of alcohol, it will 

 suddenly separate into two portions, the coagulated albumen 

 and the spirit, now become of a straw colour. By straining 

 and strongly pressing the albumen, the greater part of the 

 spirituous liquid can be obtained distinct ; and this, being eva- 

 porated over a water bath, will yield a succession of pellicles, 

 transparent and gelatinous in appearance, which, according 

 as they form, will have to be removed and preserved. The 

 colour of these pellicles, at first pale yellowish, becomes 

 deeper as the evaporation proceeds, and towards the end be- 

 comes reddish brown. When one of the pellicles is immersed 

 for a short time in strong nitric acid, and then transferred into 

 water of ammonia, it changes to a deep orange colour, a cha- 

 racter in which it agrees with albumen, fibrine, and caseine, 

 although it differs from those substances in having been ob- 

 tained by evaporation from a spirituous solution, which solu- 

 tion is not precipitable by acids. It is to be remarked that 

 the spirituous solution is strongly alkaline. The various pel- 

 licles obtained by the evaporation of the spirituous liquid are 

 subsequently to be triturated with rectified spirit, then boiled 



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