44 DETECTION OP THE ADULTERATION OP CANE SUGAR. 
solution of the same sugar, to which potash has heen added, 
deposits a dirty brown precipitate. A small amount of 
starch-sugar in the cane-sugar prevents the formation of the 
violet-blue precipitate with nitrate of cobalt. The above 
experiments of Reich have been repeated and confirmed by 
Herzog, who observes that the syrup of beet-root sugar 
acts as violently on the bichromate of potash as the syrup 
of cane-sugar ; the liquid, however, does not become green, 
but retains its colour like the syrup of starch-sugar. A 
mixture of cane-sugar syrup and the syrup of beet-root 
sugar must however contain far more of the latter for the 
green colouring produced by the cane-sugar not to appear. 
Herzog likewise examined the method proposed by Reich 
to distinguish grape-sugar and cane-sugar with nitrate of 
cobalt, and likewise recommends it. Beet-root sugar and 
mannite afford, according to Herzog, when mixed with 
potash, the same precipitate with solution of cobalt as cane- 
sugar. Milk-sugar prevents the precipitation of the nitrate 
of cobalt by potash, like grape-sugar. Herzog at the same 
time asserts that mannite, when boiled with sulphate of 
copper and potash, immediately reduces the oxide of cop- 
per, which is not the case according to Dr. Knop when the 
mannite is pure and perfectly free from grape-sugar.— 
Chem. Gaz. from Jirchiv. der Pharm. 
