On the Occurrence of Two Kinds of Mannan in the 
Root of Conophallus konyaku, 
BY 
Y. Kinoshita, Nogakushi. 
The root of Conophallus konyaku has been recently in¬ 
vestigated by Mr. C. Tsuji, who found that it contains a large 
amount of an anhydride of mannose, but it was not shown by him 
whether only one or several polyanhydrides are present. It 
has been proved, however, that there exist both soluble and 
insoluble mannans; to the former belongs, for instance, the 
mannan discovered in yeast, to the latter that found in the nuts 
of Phytelephas. The fact that an aqueous decoction of the 
konyaku -root is so slimy that it serves in this country for 
technical purposes, as for pasting clothes, etc., made it very 
probable that some of the mannan is present in the soluble 
form. 
Special experiments have convinced me that, by treatment 
of the konyaku-voo\. with diluted sulphuric acid, neither glucose 
nor galactose, xylose nor arabinose is formed. The sugar 
appears to be mannose and nothing else. I could neither 
obtain mucic acid by its oxidation with nitric acid nor the red 
pentose reaction with phloroglucin and hydrochloric acid, nor did 
the filtrate from the mannose-phenyl-hydrazone (prepared in 
concentrated solution) yield any notable amount of an osazone. 
I extracted a portion of the finely ground root repeatedly 
with boiling water, until the extract had no longer any slimy 
character. The residue yielded mannose, upon boiling with 
dilute sulphuric acid, as was ascertained, beyond doubt, by its 
phenyl-hydrazone. The slimy extract of the root was mixed 
with alcohol, which formed a copious, almost white, flocculent 
precipitate, that was filtered off and washed with dilute 
alcohol. Its solution in water was so opalescent that no test 
(i) This Bull. Vol. II. No. 2 . 
