K. MiYAKE : On the Nature of the Sugars found in the Tubers of Arrowhead 3]^ 



4. Experiment witJi the residue (III)» 



On tlie qualitative tests, the residue (III) Las sliowu almost tlie same 

 reactions as those of the residue (I). A trial was then made to separate and 

 detect the sugar wliich contains the galactose group. First, we examined, how 

 much mucic acid would be produced from the residue by oxidation and the 

 following result was obtained. 



0.2 gram of the residue was x^ut in a small beaker, to wliich nitric acid of 

 sp. gi". 1.15 was added and oxidized in a Ijoiling water bath as in the usual 

 manner. The mucic acid i^roduced was collected on the filter and weighed 0.0065 

 gram corresponding to 3.25^(^, 



Next, we tried to determine its specific rotatory x>ower and the result obtained 

 was as follows : 



0.1163 gram of the residue was dissolved in water and made up into 10 cc. 

 and polarized in 100 mm. tube. The rotation was observed to be 2.8 on the 

 scale toward the right. The specific rotatory power is 



(a)T)= ^>8x 0.316x10 ^ _^ 83.35 (at 20°). 

 ^^ 0.1163x1 ^ 



If the sugar under question be raffinose, the amount of this sugar correspond- 

 ing to 0.0064 gram of mucic acid would be 0.087 gram according to Creydt^\ 

 If we assume that sucrose be formed besides raffinose, the quantitative ratio of 

 sucrose and raffinose in the residue (III) would be 1.3 : 1. Upon this ratio, if 

 we calculate tlie si^ecific rotatory power of the sample, we will then find the 

 following value which well coincides with that of actually observed facts, i.e. 



(66.803^^x1.3) + (104.^^x1) _ ,3298 

 2.3 



Methyl alcohol, which was recommended for raffinose, was found to be a good 

 solvent for the extraction of the sugar under examination. Hence, a small amount 

 of methyl alcohol was added to the total residue (III), well mixed and decanted. 

 This operation was repeated until the bulk of the residue insoluble in methyl 

 alcohol was reduced to about half of its original volume. The combined extracts 

 were evaporated to a syrup. The syrup did not show any sign of forming 



1) Creydt,- Zs. d. Ver. d. D. Zuckerind., Bd. 37, P. 153 ; Lippmann,- Chemie d. Zuckerarten, 

 Braunschweig, Bd. U. P. 1652, (1904). 



2) Specific rotatory power of sucrose according to Tollens. 



3) Specific rotatory power of raffinose according to Tollens. 



