109 



V On the Action of the Ferment of Madder on Sugar. 



By Edward Schunck, Ph.D , F.R.S. 



IRead April ith, 1854.] 



In a paper read before the Royal Society in 1852,* I have 

 given an account of the nature and results of the peculiar 

 process of fermentation which takes place in madder and its 

 watery extracts, when exposed to a moderate deg^e of tem- 

 perature. I have shown that during this process the bitter 

 principle of madder, to which I have given the name of 

 Rubian, is completely decomposed, giving rise to the forma- 

 tion of a number of substances, of which alizarine, the true 

 colouring matter of madder, is the most remarkable. I have 

 stated that this process is not accompanied by the evolution 

 of gas or any of the usual signs of fermentation, that the 

 access of atmospheric air is not necessary for its completion, 

 and that the rapidity with which it is effected is remarkable. 

 Lastly, I have given an account of the properties and com- 

 position of the ferment itself. I have shown, that as regards 

 the power of effecting the decomposition of rubian, none of 

 the usual fermentative substances, such as yeast, caseine, &c., 

 are capable of supplying its place, with the sole exception of 

 emulsine, which forms an imperfect substitute for it, that its 

 composition differs in a marked manner from that of the other 

 bodies of the same class in containing a much smaller propor- 

 tion of nitrogen, and that, in short, it must be considered as 



* Philotophical TransMtioni for 1853. Part I. 



