K. MiTAKE : On the Natubb of the Sugars found in the Tubers of Arrowhead. 25 



Mucic acid prodvicing substance by oxidation . . 1.^^% (as galactose). 



Insoluble in 95% alcohol 0.60% ( „ ). 



Soluble in 95% alcohol 0.74% ( „ ). 



Pentosane (including methyl pentosane) .... 1-S^% 



As has been shown in the above table, of the carbohydrate constituents, 

 starch is a prominent substance, its amount attaining 55.32% of the di-y matter. 

 Sugars are also present in no slight quantity, reaching the amount of 6.21% of the 

 dry matter, and they constitute an important part of the carbohydrate constituents. 



To determine the exact nature of the sugars of the arrowhead tubers, the 

 following investigation was undertaken according to plan herein described. 



1, Preparation of the syrup. 



The arrowhead tubers were j)eeled of their rind and finely chopped. The 

 chooped parts were allowed to dry in the air, requiring about two weeks for dry- 

 ing to such a state that they could be gromid easily and finely pulverized. 



The preparation of the syrup was begun by exti-acting 100 grams of the 

 finely pulverized material in a Soxlilet apparatus with ether. The residue so 

 obtained, which was freed from oil, after evaporating ether, was placed in 750 cc. 

 flask fitted with inverted condenser and treated daily with 300 cc. of 95% alcohol 

 heated in a boiling water batli. The extract was at first of a deep yellow colour, 

 l)ut it gradually became lighter from day to day. It had a sweetish taste and 

 was nearly neutral to litmus during the entire time of extraction. One week was 

 required to remove the last traces of sugars. The combined extracts were filtered to 

 remove the sediment wliich was formed in standing, and the filtrate was evaporated 

 to a small volume in a partial vacuum. The concentrated liquor was again extracted 

 many times with a small quantity of absolute alcohol, until, after the evaporation 

 of the alcohol, no more residue was produced. The residue (I) here obtained was 

 Xweserved in a desiccator as material for the later investigation. The extracts 

 were concentrated to a syrupy condition in a partial vacuum and allowed to dry 

 over sulphuric acid. 



Above method of the preparation was repeated about ten times to get a 

 sufficient quantity of the materials for investigation. 



2. Experiment tvith the syrup* 



a. Qualitative tests. 



The syrup obtained above, gave the following qualitjxtive reactions : — 



