408 pormation of mannan in amorphophallus konjak. 
considerable quantity of plienylglucosazone that I must conclude, 
there was present in the stalk, besides mannose, glucose or 
fructose, (1) 2 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 slimy 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 the first time that it 
has been found as such in plants. 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. Lobry de Brnyn (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 these three sugars can be transformed into one another. 
