44? BULLETIN OF THE BUSSEY INSTITUTION. 
The high rotatory power exhibited by these products of the 
hydrolysis of wood, taken in connection with other results of 
similar import which had been obtained previously while studying 
other specimens of woods, pointed most distinctly to the presence 
of some other reducing substance beside dextrose and xylose; 
for the true specific rotation of xylose* is (a) D= 19°.2 and 
that of dextrose * is (a) D = 52°.6. Efforts were made at once 
to isolate this additional substance. To this end a part of each 
of the sulphuric acid solutions ‘‘ A” and ‘*B” were allowed, after 
neutralization, to evaporate spontaneously (in mid-winter) at the 
ordinary temperature of the laboratory. From ‘‘ A” crystals of 
sodium sulphate separated and were removed. ‘The brown resi- 
dues from the evaporation were rubbed up with three successive 
portions of strong alcohol. A part of the matter dissolved while 
there was left a sticky, stringy dextrin-like mass insoluble in 
strong alcohol, though readily soluble in cold water. The aqueous 
‘solution of this substance had a flattish, sweetish taste, as was 
noticed in other instances. That from ‘*A” gave quasi 
(a) D = 89°.69. Meanwhile, the matter soluble in alcohol, ob- 
tained from ‘' A,” was taken up with water after the alcohol 
had been driven off, and this solution gave quasi(a) D = 66°.18, 
calculated as dextrose, as was the preceding. 
From the solution ‘¢B,” which was boiled in the dilute acid 
longer than ‘‘ A”’ had been boiled, a somewhat different result was 
obtained. The matter left undissolved by strong alcohol in this 
case was not wholly soluble in water. The insoluble residue was 
granular rather than gummy, and the solution obtained by means 
of water had practically no reducing action on Fehling’s liquor. 
The matter soluble in alcohol in this case gave quasi(a) D 
= 69°.57, when examined in aqueous solution and calculated as 
dextrose. It is evident from the foregoing that that product 
of the hydrolysis which fails to dissolve in strong alcohol 
(as in ** A’) is apt to suffer decomposition when boiled for a 
long time in dilute acids. It will be noticed that in all these 
experiments no wood was left in contact with the acid during the 
second boilings; the acid then had nothing to act upon but the 
products formed by the first boiling. The nature of this decom- 
posable substance will be discussed in subsequent paragraphs. 
* Tollens, Handbuch der Kohlenhydrate. 1895, 2. 5. 
PL 
a 
