K. Miyake: On the Nattjbe of the Sugaiss found in the Tubers of Arrowhead. 27 



reaction and mannose phenylhydrazone could be formed as above mentioned. 



b. Isolation of sucrose. 



When the syi'up was left untouched nearly twenty four hours, it was found 

 thickly laden with fine crystals. A small amount of 9^% alcohol was added to 

 the syriTp, mixed, filtered with suction, and washed with absolute alcohol and ether. 

 The sugar thus obtained was slightly yellowish in colour, but upon recrystallization 

 from alcohol it became perfectly white and left no ash on ignition. After drying over 

 sulphuric acid in a vacuum, its melting point was determined and found to be 159°0. 



0.5 gi-am of the dried sugar was dissolved in water and made up into 25 cc, 

 and polarized in 200 mm. tube in Schmidt and Haensch half shadow polariscope. 

 The rotation was found to Ije 7.7 on the scale toward the right. The specific 

 rotatory power of this sugar is 



{a)T>= 7.7x0.346x25 ^ +6G.6 (at 20°) 

 0.5x2 



The melting point and specific rotatory power indicates that the sugar at 

 Iiand is no other than sucrose. 



c. Osazone tests. 



The mother-liquor filtered off from the crystals of sucrose was evaporated 

 again into a syi'up. After standing for about two days, a small amount of sucrose 

 crystals was agai]i formed in it. The crystals were removed as in the above 

 experiment, and the filtrate was concentrated once more to a syi'u]:). It did not 

 show any sign of forming new crystals even after one week standing. An attempt 

 was then made to separate and detect the sugars as osazone. 



J. 1 gram of the syrup, 2 grams of phenylhydrazinhydrochloride, 3 grams 

 of sodium acetate and 20 cc. of water were mixed and heated in a boiling water 

 bath. After 15 minutes yellowish crystals had been produced. At the end of 

 one hour and a half, the heat ^^'as removed, and the crystals were examined under 

 a microscope. None of the other forms, besides the stellate form of the yellow 

 needle shaped crystals, which coincides with that of phenylglucosazone, were 

 observed. When cooled, it was filtered and washed with a little water. The 

 yellow crystals thus obtained were recrystallized from 60% alcohol and dried over 

 sulphuric acid in a vacuum. The melting point was determined and found to be 

 204°, which coincides ^\'ith that of phenylglucosazone. Consequently, the osazone 

 under question is phenylglucosazone. 



