Conversion of Animal Matter Into new Suhiaiiee^t. 131 



Cloths thus dyed are of so intense a colour as to appear les» 

 bright than scarlets are by the common process ; but this deeper 

 reflection of red rays may be obviated by adding to the bath 

 some turmeric or fustic. — [Biiliotheque Physico-Economique.'] 



XXI. On the Conversion of Animal Matter into new SubstanceSf 

 by the Action of Sulphuric Acid. By M. H. Braconnot. 



JUaving discovered in previous experiments that woad, barks, 

 Btraw, hemp, and every other kind of woody fibre, could by the 

 agency of sulphuric acid be changed into gum and sugar, I re- 

 solved to extend my researches to animal substances ; and as 

 many of these, such as ikin, cellular membrane, cartilage, ten- 

 don, and tendinous sheath, are entirely dissolved into gelatine 

 by boiling water, I determined first to operate on this substance. 



Action of Sulphuric Acid on Gelatine. 

 Twelve grammes of glue, reduced to powder, were digested 

 with a double weight of concentrated sulphuric acid without arti- 

 ficial heat. In twenty hours the liquid was not more coloured 

 than if mere water had been employed ; I then added a decilitre 

 of water, and boiled the whole for five hours, renewing the water 

 from time to time as it wasted. I next diluted it, saturated it 

 with chalk, filtered, and evaporated to a syrupy consistence, and 

 let it stand for about a month. In this period a number of gra- 

 nular crystals had separated, which adhered pretty strongly to the 

 bottom of the vessel, and had a very decided saccharine taste. 

 These crystals were collected by pouring off the supernatant sy- 

 rup, then washed with weak spirit to dissolve out the adherent 

 syrup, then pressed through a cloth, redissolved in a little water 

 and again crystallised, whereby they became tolerably pure. This 

 sugar might in strictness form a new species of saccharine mat^ 

 ter 3 its properties are the following : 



Sugar of Gelatine. 

 This sugar crystallises much more easily than cane-sugar. If 

 its solution be ever so little concentrated by heat, a crystallised 

 pellicle speedily forms itself, which is quickly renewed when the 

 former is broken down ; but when the evaporation is allowed to 

 proceed slowly, we obtain very hard granular crystals, grating 

 under the teeth like sugar-candy, and in the form of flattened 

 prisms or tabular groups. Its taste is nearly as saccharine as 

 grape-sugar ; its solubility in water scarcely exceeds that of sugar 

 of milk. This solution mixed with leaven gives no signs of fer- 

 mentation. Boiling alcohol, even when diluted, has no action 



R2 on 



