35° 



Indigofera 20, Polygonuin ^, aethyl-acetate-yeast 2.5, emulsine i. In the graphic 

 figure the lengrth of the ordinates is taken proportionately with these numbers. 



So we find that the cuire of the Polygonum-tmyvat is about uniform with that 

 01 the much .sfronger enzjine of Indigofera, but at o" C. they cross each ether, so 

 that at a still lower temperature the action becomes an inverse one. 



The great difterence in intensiti.- of action is also proved by the fact, that, for 

 the manifest appearance of indigo in 10 cc. of the indican-solution, there is at least 

 required of the different crude enzymes 2 milligrams of Indigofera. 20 of Polygonum 

 and Saccharomyces sphaericus, and 60 of emulsine. 



C O X C L U S I O X S. 



The splitting of the indican by the cell tan occur in two ways: by ferment-action 

 of the living protoplasm itself (katabolism), and by enzjines. 



All examined bacteria, which act on indican, split by katabolism and hence are in 

 dead condition inactive. The most important among them are the common ferment- 

 bacteria (Aërohacter) of sugar-containing plant infusions. 



.■\11 indican-plants and some species of alcohol-ferments contain indigo-enzymes 

 and consequently can decompose the indican in dead condition too. Indigo-enzymes 

 originate only at abundant access of air. Five of these enzymes proved specifically 

 different, with temperature optima of 61» (Indigofera), 55» (emulsine), 53° (Phajus), 

 44" (Saccharomyces sphaericus) and 42» (Polygonum). For all of them the action is 

 favoured by free acid to an amount of 0.5 cc. normal per 100 cc. of the employed 

 indican-solution : more acid, like alkali, opposes the action. 



Indigofera decomposes the indican only by enzyme-action ; in the case of Poly- 

 gonum tinctorium and Phajus grandiüorus the indican is decomposed partly by 

 katabolism, partly by enzyme-action. 



In the leaves of Phajus grandifiorus indican is localized in the colourless proto- 

 plasm of mesophyll and epidermis, the indigo-enzyme exclusively in the chloro- 

 phyll-granules. 



