496 Dr. Schunck on Rubian and its Products of Decomposition, 



ordinary circumstances, I raised the temperature of the mixture 

 to the boiUng-point and kept it boiling for a short time. After 

 the mixtui-e had stood for some days exposed to a moderate tem- 

 perature, I found that the rubian had not undergone the least 

 change. The liquid remained yellow and bitter, and after fil- 

 tration and evaporation left a residue of rubian with its usual 

 appearance and properties. 



I took in the next place a quantity of ferment, dried it slowly 

 at a moderate temperature, reduced it to a fine powder and mixed 

 it with a solution of rubian. After the mixture had stood for 

 some days, the rubian was entirely decomposed. The filtered 

 liquid left on evaporation a quantity of sugar, and the residual 

 mass on the filter, which was interspersed with numerous small 

 yellow crystals, was treated with boiling alcohol, which, after 

 being filtered boiling hot and allowed to cool, deposited a large 

 quantity of rubiafine in crystals. The alcoholic liquid, on being 

 examined in the usual manner, was found to contain besides 

 rubiafine, alizarine, rubiagine, rubiretine and verantine, the two 

 latter being rather less in amount than usual. 



After drying the ferment at a moderate temperature, then 

 heating it for some hours in a water-bath, before adding it to a 

 solution of rubian, no apparent change took place for some time, 

 but gradually the rubian began to disappear, and after two 

 months was entirely decomposed. The filtered liquid left on 

 evaporation a quantity of sugar, and the residue on the filter, 

 on being treated with alcohol, yielded a solution which contained 

 rubiafine, and a pretty large quantity of rubiretine and veran- 

 tine, but no alizarine. 



To a solution of rubian I now added a sufficient quantity of 

 ferment to eff'ect its decomposition when used alone, and then a 

 small quantity of sulphuric acid. The mixture remained appa- 

 rently unchanged for some time. The liquid was filtered, the 

 acid was neutralized with carbonate of lead, the liquid was then 

 again filtered, and left on evaporation a yellowish-red, bitter, 

 glutinous substance, which was apparently a mixture of rubian 

 and sugar. The mass left on the filter was treated with boiling 

 alcohol, which was then found to contain a trace of alizarine, a 

 little rubiagine, and a large quantity of rubiretine and verantine. 



The same experiment was performed, substituting for the sul- 

 phuric acid a minute quantity of carbonate of soda. This had 

 the effect of completely dissolving the ferment, forming a solution 

 to which the rubian imparted a red colour. After standing for 

 some time, the rubian was entirely decomposed, for on neutral- 

 izing the soda with sulphuric acid, a yellow precipitate fell, while 

 the liquid became colourless. The latter being filtered, the acid 

 was neutralized with carbonate of lead, and the liquid being 



