r 



315 



and filtered. The filtered liquid is colourless, and upon being 

 evaporated to the consistence of a thick syrup, and allowed to 

 cool, deposits whitish grains on the sides and bottom of the 

 vessel. These grains, and the syrup from which they depo- 

 sit, have a taste, at first intensely sweet, but rapidly followed 

 by a saline after-taste. A little of the syrup, when boiled 

 with an equal bulk of potash water, acquires immediately a 

 deep claret colour. Some of the syrup having about half its 

 bulk of potash water added to it, and then a little hydrated 

 oxide of copper, the latter dissolves with the production of a 

 fine red colour; but after being exposed for some time to the 

 air, the solution decomposes, and a precipitation of red oxide 

 of copper takes place. A little of the syrup being added to 

 water of potash, in which hydrated oxide of copper was dif- 

 fused by the previous addition of a drop or two of solution of 

 sulphate of copper, the precipitate immediately redissolves, 

 and upon the application of heat red oxide of copper becomes 

 precipitated. From these properties and tests, I consider that 

 we are justified in concluding'that, by the process indicated, 

 grape sugar, contaminated with certain salts, is capable of 

 being extracted from the whites of eggs. 



" The usual tests for grape sugar are capable of affording 

 very marked indications with the white of egg, although some- 

 what modified, probably from the presence of other constitu- 

 ents present in the organ. Thus, Moore's test causes the 

 production of a deep amber colour, as well marked as with the 

 urine in most cases of diabetes mellitus. Capezzuoli'stest afl^ords 

 a beautiful pink solution, which gradually decomposes, and 

 throws down a brown precipitate. Tromsdorf's test furnishes a 

 deep rerf solution, which precipitates browti upon being boiled. 

 The cause of these reactions is capable of being removed from 

 the albumen of the white of egg, by the agency of alcohol, 

 and will then become concentrated in the alcoholic extract. 



" I was desirous of ascertaining whether the presence of 

 sugar in the white of egg might not be due to a commencing 



VOL. IV. 2 B 



