Notes. 
156 
than the inulin. The mucilage is removed by filtering and more 
alcohol is added, when a dense white precipitate is produced, which 
gradually settles to the bottom of the vessel. This is the inulin. The 
alcohol is poured off and the precipitate dissolved in a little cold 
water, and the solution treated again in a similar manner with alcohol. 
The operation can be repeated a third time, when a fairly pure sub¬ 
stance is obtained. 
i*457 grams of this, dried at ioo° till constant in weight, was taken 
and dissolved in water, and the volume made up to 100 cubic centi¬ 
metres. 
Angle of rotation in the 200 mm. 
tube of the polarimeter = —1*2°. 
50 c.c. were acidified with oxalic acid to the extent of 1 per cent, 
and heated for an hour on a water bath. 
After hydrolysis the angle of 
rotation in the 200 mm. tube = —2*5°. 
I then took 10 c.c. of the hydrolysed portion, and boiled this for a 
definite time with a definite amount of Fehling’s cupric reagent. The 
cuprous oxide was collected on an asbestos plug, reduced to copper 
in a current of hydrogen and weighed. 
10 c.c. yielded 0*2475 g ram °f copper. This calculates out to 
1-363 gram of fructose (levulose) in the 100 c.c. Theoretically there 
should be 1*618 gram of fructose yielded by the 1*457 gram of inulin 
originally taken. The discrepancy is probably due to impurity in 
the inulin, or possibly to reversion-products formed in the hydrolysis. 
The amount of fructose calculated from the opticity (taking the 
specific rotatory power of fructose at a temperature of 15 0 to be 
— 98*8°) is 1*265 gram, which corresponds fairly well with that derived 
from the cupric-reducing power. 
The specific rotation of the inulin, deduced from the observed 
' angle, is about — 45 0 , a number agreeing closely with such obtained 
for other monocotyledonous inulins \ 
The above results lead to the view that the carbohydrate in question 
is of the nature of inulin, yielding fructose on hydrolysis. 
There seems then no doubt that the reserve-carbohydrate accom¬ 
panying the starch in the Hyacinth bulb, is inulin rather than 
dextrin, using the word inulin in its extended sense for all those 
1 Tollens’ Handbuch der Kohlenhydrate, Band ii, pp. 239, 240. 
