Dr. SchuDck on Rubian audits Products of Decomposition, 419 



In order to prepare the peculiar substance contained in madder 

 which has the property of effecting the decomposition of rubian, 

 I proceed in the following manner. A quantity of madder having 

 been placed on a piece of calico or fine canvas, there is poured 

 on it for every pound of madder taken about four quarts of 

 distilled water, which may be either cold or of a temperature of 

 about 38° C. The latter temperature is preferable, as the water 

 then percolates more rapidly. To the extract there is added, 

 without any delay, about an equal volume of alcohol, which causes 

 the separation of a quantity of dark reddish-brown flocks. These 

 flocks are allowed to settle, and the supernatant yellowish- brown 

 liquid is decanted. Fresh alcohol is added to the flocks, which 

 are then placed on a paper filter, and washed on the filter with 

 additional quantities of alcohol, until the percolating liquid, 

 which is at first strongly coloured, becomes almost colourless. 

 This process of washing, which often lasts a long time, may be 

 assisted by removing the mass from the filter and shaking it up 

 with moderately warm alcohol. The substance on the filter has 

 now the appearance of a dark reddish-brown mass, which when 

 rubbed between the fingers produces the same granular feeling 

 as coagulated caseine, the sliminess which characterized it on its 

 first precipitation with alcohol having disappeared. Now this 

 substance possesses in an eminent degree the power of effecting 

 the decomposition of rubian. If a quantity of it be added to a 

 solution of rubian, and the mixture be left to stand at the ordi- 

 nary 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 experi- 

 ment that it is this substance which constitutes the active fer- 

 menting 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 pro- 

 ducts 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 



