MR. SCHUNCK ON RUBIAN AND ITS PRODUCTS OF DECOMPOSITION. 
75 
in an eminent degree the power of effecting the decomposition of rubian. If a quan- 
tity of it be added to a solution of rubian, and the mixture be left to stand at the 
ordinary temperature, a complete change is found to have taken place in the course 
of a few hours. The liquid is converted into a trembling jelly of a light brown colour, 
which is perfectly tasteless, insoluble in cold water, and so consistent, that if the 
solution of rubian was tolerably concentrated, the vessel may be reversed without its 
falling out. It is manifest from this experiment that it is this substance which con- 
stitutes the active fermenting principle of madder, and that for the purpose of under- 
standing the nature of the process of fermentation peculiar to madder, it is necessary 
to examine the action of this substance on rubian. I shall therefore in the first place 
describe the products resulting from this action, after which I shall return to the 
consideration of its other properties. 
On adding to a watery solution of rubian a quantity of the ferment, prepared in 
the manner just described, the latter loses its granular nature and diffuses itself in 
the solution without actually dissolving, forming a muddy, mucilaginous liquid. On 
allowing this mixture to stand in a moderately warm place, the rubian is gradually 
decomposed and converted into a brown jelly, similar in appearance and consistency 
to coagulated blood. Here and there interspersed in the mass yellow streaks and 
spots, consisting of long hair-like crystals, are sometimes discernible. If, after twenty- 
four hours, the jelly on being mixed with cold water still yields to the latter any 
yellow colour, it is a sign that the rubian is not entirely decomposed, and more 
ferment must be added, the mixture being again allowed to stand until the liquid 
has become tasteless and colourless. During this process none of the usual signs 
of fermentation are manifested. The liquid remains perfectly neutral, and no gas of 
any kind is disengaged. In order however to be perfectly sure of the latter point, I 
took a solution of rubian in water, mixed it with ferment, poured the mixture into a 
graduated glass tube, and inverted the latter over mercury. After standing in this 
way for several days, not a particle of gas had collected at the top of the tube, 
notwithstanding which the rubian was entirely decomposed, and on examination the 
products of decomposition were found to be precisely the same as those formed in 
the usual manner. This experiment proves not only that no gas is evolved during 
the fermentation of rubian, but also that, as Higgin has observed, the access of 
atmospheric air is not necessary during the process. 
The decomposition of the rubian being completed, a little water is added to the 
mass, and the gelatinous substance left undissolved by the water is placed on a filter 
and slightly washed with cold water. The percolating liquid is almost colourless. 
The gelatinous mass on the filter now consists partly of the ferment employed, and 
partly of substances formed by the decomposition of the rubian. These substances 
are six in number, of which three are bodies previously described, and three are new. 
They are , — Alizarine \ 2ndly, Verantine-, Ruhiretine 4thly, a substance 
closely resembling rubiacine, which I shall call Ruhiajine ; 5thly, a substance very 
