408 PORMATION OF MANNAN IN AMORPHOPH ALLUS KONJAK. 



considerable quantity of phenylglucosazone that I must conclude, 

 there was present in the stalk, besides mannose, glucose or 

 fructose, (I) or both to some extent.' 2 ' The mannose-phenylhy- 

 drazone first obtained was recrystallized and showed the proper 

 melting point of I95°C and the characteristic tabular crystalline 

 forms. It was, like pure mannose-phenylhydrazone, hardly 

 soluble in absolute alcohol and warm acetone, almost insoluble 

 in ether and benzene, and reduced Fehling's solution very 

 strongly upon warming. 



The fact that the slim)' mannan is present in the cells of the 

 leaf makes it highly probable that it plays to some extent the 

 role of starch in this plant, but whether mannose is really the 

 first product of assimilation, can not yet be answered. I hope 

 however to settle this question by further investigations. On the 

 other hand, the presence of mannose as such in the stalk is evid- 

 ently of high physiological interest as this is t lie first time that it 

 has been found as such in plajits. I am indebted to my most 

 honoured former teacher, Dr. OSCAR LOEW, Professor in the 

 Imperial University, for kind suggestions. 



(1) A portion of the above syrup obtained from the extract of the stalk was tested for 

 fructose with resorcin and concentrated hydrochloric acid, whereby a cherry red colou- 

 ration resulted. Another portion of the syrup was treated with a mixture of ether and 

 alcohol ; on evaporation of the extract I obtained the proper red colouration with the 

 above reagent. It is therefore, probable that some fructose was present in the stalk. 



(2) C. A. I.obry de Bruyn (Rec. Trav. Chim. 14 (1895) 201-206 and Ber. Chem. 

 Ges. 28(1895) 3078-3082) has recently discovered the highly interesting fact, that by 

 simply treating with alkalies the?e three sugars can be transformed into one another. 



