STUDIES ON FLAX RETTING. 
53 
The sugar gave a phenylosazone, melting at 154— 155°C. and easily 
soluble in cold alcohol but not in water. The melting point of the sugar was 
found to be 143— 144 C C. The sugar under question is therefore xylose. 
Detection of Arabinose. 
The mother liquor filtered off from the crystals of xylose was allowed to 
evaporate slowly by itself. It did not show any sign of forming new crystals 
after standing for a long time. The syrup gave a pentose reaction. Attempt 
was then made to separate and detect arabinose by means of benzylphenyl- 
hydrazin. The latter forms easily with arabinose a hydrazone, which is 
hardly soluble in 75 % alcohol, while xylose-liydrazone is easily soluble in the 
same medium. 
3 grams of the syrup were dissolved in 9 grams of 75 % alcohol, to which 
a solution of 2 grams of benzylphenylliydrazin in 4 grams of absolute alcohol 
was added and the mixture well shaken. After 3 hours, crystalline 
precipitates were formed. They were separated by filtration with suction, 
washed with a small amount of 75 % alcohol and finally recrystallized from 
95 % alcohol. The light yellowish white product was dried over sulphuric 
acid in vacuum. The melting point was found to be 169.-169.5° C. 
0.101 grams of the substance was dissolved in 25 c. c. of water and levo- 
rotation of 0.3 on the scale was observed. 
The specific rotatory power is 
«D = 
0.3 x 0.346 x 25 
= -12.7° 
0.101 x 1 
The observed specific rotatory power coincides with that of arabinose- 
benzylphenylhydrazone. The small quantity of the hydrazone at hand did 
not allow the isolation of arabinose. 
From the results obtained we may conclude as follows : 
1. The gummy substance in the flax stem consists largely of simple 
pentosan, with a small amount of methyl pentosan. 
2. From the products of hydrolysis of the gummy substance, both xylose 
and arabinose were identified. 
3. The pentosan of the gummy substance is, therefore, made up of both 
