96 



addition of carbonate of soda; reduces the alkaline tartrate of 

 copper (1 equivalent Grape-sugar forms 10 equivalents copper 

 suboxydrrCu 2 O); ferments directly with yeast, is not ])recipit- 

 able by acetate and sub-acetate of lead, but is so by ammoniacal 

 acetate of lead, and this preci2:)itate assumes by keeping at the aii-, 

 or more quickly when warmed, a red colour. 



The quantitative estimation of Grape-sugar can, like that of cane- 

 sugar, be accomplished either by fermentation or by means of a soki - 

 tion of copper. But it must be boi'ne in mind that in the first case 

 the water which cane-sugar assimilates, before it becomes convei'ted 

 into carbonic acid and alcohol, is already present in Grape-sugar. 

 Consequently, if 100 parts cane-sugar yield 49*12 parts carbonic 

 acid, and 51 "01 parts alcohol, 105-26 parts anhydrous Grape-sugar 

 will effect the same transformation; or, 46-66 parts carbonic aid 

 and 48-46 parts alcohol are obtainable from 100 parts anhydrous 

 Grape-sugar. 



In the second case, of course, the saccharine liquid wants no 

 preliminary treatment except, when acid, to be oversaturated with 

 caustic potash or soda, before it is titrated with the solution of 

 copper. 



Gratiolin = C40 H34 O14. The bitter ingredient of Gratiola 

 officinalis [and its congeners. — F, v. M.]. Precipitate the 

 aqueous decoction of the herb with subacetate of lead; mix the 

 filtered liquid with carbonate of soda, but not in excess; filter, 

 precipitate with tannic acid, collect the deposit and mix it with 

 hydrated lead oxyd; treat the mixture with alcohol, filter and 

 decolourise the tincture with animal charcoal; dry after filter- 

 ing, exhaust the residvie successively with absolute ether and 

 with cold water, diy and recrystallise in boiling alcohol 

 or in boiling water. Tlie ether dissolves mainly gratio- 

 lacrin, the cold water gratiosolin. — White powder, crystal- 

 lising from alcohol in warty masses, from water in fine silky 

 needles; tastes at first very slightly, afterwards strongly bittei-; 

 has a faint smell ; fuses at 200° without change, but is destroyed 

 in higher temperatures; mollifies on heating with water and rises 

 to the surface like an oil; dissolves in 893 parts cold and in 476 

 parts boiling water, most i-eadily in alcohol, in 1000 parts cold, 

 and in 666 parts boiling ether, in concentrated sulphui-ic acid with 

 dark-red colour, and precipitable from it by water; decomjtoses on 

 heating with diluted sulphuric acid into svigar and other products. 



Grrtti0S0lill=C4e H42 O25. The aqueous gold-coloui-ed solu- 

 tion obtained during the process of preparing gratiolin is digested 

 with animal charcoal, filtered, dried on the water-bath, and traces 

 of gratiolacrin removed by anhydrous ether. — Amorphous, bright- 

 red mass, friable to a yellow powder, has a peculiar smell and a 

 nauseous, bitter taste, is permanent at the air, fuses at 125°, is 



