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 

 urinein most cases of diabetes mellitus. Capezzuoli's test affords 

 a beautiful pink solution, which gradually decomposes, and 

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

 deep ?-e(/ solution, which precipitates brown u^on being boiled. 

 The cause of these reactions is capable of being removed from 

 the albumen of the white of e^g, 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 



