FORMATION OF MA N NAN IN AMORPIIOPH ALLUS KONJAK. 4O7 



of this precipitate had a slimy consistency, and showed the in- 

 teresting property of losing its slimy character on prolonged 

 boiling, whereby the slimy compound separated as insoluble floc- 

 cnli. The freshly prepared solution of the mucilage yields a 

 white flocculent precipitate with basic lead acetate upon the ad- 

 dition of some ammonia, and a thick blue precipitate with either 

 FeJiling s solution or copper sulphate solution in presence of 

 sodium hydrate. On boiling with dilute sulphuric acid of 3 0 / o 

 the mucilage was, after a few hours, transformed into a sugar, 

 which, after the removal of the sulphuric acid by barium carbon- 

 ate and evaporation of the filtrate, at once yielded, on the addition 

 of phenyl-hydrazine acetate, the characteristic precipitate of 

 mannose-phenylhydrazone. (1) To test whether galactans or 

 pentosans were present in stalk and blade, the residue, w hich 

 remained after the extraction of several hundred grams with 

 alcohol and warm water, was boiled for several hours with dilute 

 sulphuric acid of 4"/,,. The syrup obtained after neutralizing 

 with barium carbonate and evaporating, was tested for the 

 presence of pentose with phloroglucin and hydrochloric acid, and 

 for galactose by evaporation with nitric acid, but neither a pentose 

 reaction nor mucic acid were obtained ; therefore neither pentos- 

 ans nor galactans n'cre present. Only a little mannose was 

 obtained from this insoluble part. 



The question whether mannose as such is present in the 

 stalk and blade I tried to answer by extracting these objects 

 with alcohol of 50 °/ 0 whereby the mannans would remain in- 

 soluble, while the sugar would be dissolved. These extracts were 

 evaporated, <2> dissolved in a little water, and basic lead acetate 

 added to remove tannin and other impurities. The nitrate freed 

 from lead with hydrogen sulphide was evaporated after neutrali- 

 zation with sodium carbonate. Upon the addition of phenylhydra- 

 zine acetate, only the extract of the stalk yielded a sufficient quan- 

 tity of the precipitate of mannose-phenylhydrazone, while there 

 was a doubtful trace in the case of the extract of the blade. The 

 filtrate of the above precipitate yielded, upon further addition of 

 phenylhydrazine acetate and heating on the water bath, such a 



(1) This mucilage of the stalk ami blade agrees therefore in its essential properties 

 with the soluble mannan which Kinoshita obtained from the ttiber (loc. cit). 



(2) Since in the case of the stalk an acid reaction of the extract was noticed, it was 

 neutralised with sodium carbonate. 



