74 



on the removal of the acid by barium carbonate, was tested for pentose 

 with phloroglucin and strong hydrochloric acid and for galactose by 

 evaporation with nitric acid but neither any Pentose reaction nor 

 mucic acid was obtained, while only a little mannose was detected by 

 means of phenylhydrazine acetate. Therefore, neither pentsane nor 

 glactane are present in the leaf with a little amount of the mannane. 

 To see whether mannose is present in the leaf or not, I extracted 

 separately the petiole and blade with 50 o/ alcohol in which the sugar 

 is dissolved while the mannane would remain insoluble. These extracts 

 were evaporated, 13 dissolved again in a little water and basic lead 

 acetate was added to remove tannin and other impurities. The filtrate 

 freed from lead by hydrogen sulphide was evaporated into a small 

 volume while neutralized with sodium carbonate. The concentrated 

 filtrate was treated with 85 o/ alcohol and again filtered ; and the 

 resulting filtrate was freed from the alcohol by distillation. Upon the 

 addition of phenylhydrazine acetate, only the extract from the petiole 

 yielded a sufficient quantity of the precipitate of mannose-phenylhydrazon 

 while in the case of that of the blade it was very doubtful. The 

 mannose-phenylhydrazon which was purified by recrystallization 

 from alcohol showed the proper melting point of 195° C and the 

 characteristic tabular crystalline forms. Further, It was very slightly 

 soluble in absolute alcohol or warm acetone, almost insoluble in ether 

 or benzene, and reduced very strongly Fehling's solution upon warming. 

 These essential properties of the mannose-phenylhydrazon agree very 

 well with that of pure mannose-phenylhydrazon stated by E. Fischer, 2 } 

 There is, therefore, no doubt that mannose is present in the petiole. 

 Upon the further addition of phenylhydrazine acetate and after heating 

 on a water bath, the filtrate of the above mannose phenylhydrazon 

 yielded such a considerable amount of phenylglucosazon, that I must 

 conclude, there was present, besides mannose, also glucose or fructose, 

 or both to some extent in the petiole. And it is not improbable 

 to suppose these three sugars are together contained in the petiole, 

 because very recently G. A. Lohry de Bruyn has found that those three 

 sugars can be easily transformed into one another. 33 To test for fructose, 



D The extract from the petiole only gave an acid reaction. On the evaporation of it, 

 therefore, sodium carbonate was continuously added for the neutralization. 



2) Compare E. Fischer's article: Ber. Deut. Chem. Ges. Bd. 21. (1888) S. 1805. 



3 ) Kec. Trav. Chim. 14. (1895) 201—206 and Ber. Deut. Chem. Ges., Bd. 28. (1895) S. 

 3078-3082. 



