THE FERMENT OF MADDER ON SUGAB. 121 



the liquid never became acid, and the ferment remained 

 purple and sank to the bottom of the vessel. After standing 

 for several weeks, the filtered liquid gave with sugar of lead 

 a pinkish-white precipitate, which seemed, however, to con- 

 sist principally of carbonate of lead, as on treating a small 

 quantity of it with nitric acid it dissolved with effervescence. 

 This precipitate being decomposed with sulphuretted hydrogen, 

 and the liquid being treated in exactly the same manner as 

 that resulting from the crude succinate of lead in the other 

 experiments, a syrup was obtained, which yielded however 

 not a trace of crystalline sublimate when heated in a tube. 

 The formation of the succinic acid, as well as of the alcohol 

 and the gases, is therefore clearly due to the decomposition of 

 the sugar induced by the action of the ferment. 



Since madder itself contains a considerable quantity of 

 sugar ready formed, and an additional quantity is always pro- 

 duced by the decomposition of rubian, it was natural to 

 suppose that watery extracts of madder might be found to 

 contain succinic acid. For the purpose of ascertaining whether 

 this was the case, I took some of the brown syrup which had 

 been obtained by extracting French madder with boiling 

 water, precipitating the colouring matter &c., with oxalic 

 acid, neutralizing the excess of acid with carbonate of lime, 

 and evaporating the filtered liquid, which had been stand- 

 ing in the state of syrup for several years. A quantity of 

 this syrup having been mixed with water, I added to it 

 acetate of lead, which produced a dark brown precipitate. 

 This precipitate being treated in precisely the same manner 

 as the lead precipitate thrown down by sugar of lead from the 

 solutions of sugar fermented with erythrozym, yielded a small 

 quantity of a white crystallized acid, which, when heated in a 

 tube, was completely volatilized, giving a beautiful crystalline 

 sublimate, exactly resembling that produced by succinic acid. 

 It is therefore very probable that succinic acid is either con- 

 tained as such in madder, or is formed during or after the 

 R 



