438 BULLETIN OF THE BUSSEY INSTITUTION. 
in trees as reserve matters and that some of them are equally 
important with starch, or possibly more important, as a means of 
carrying forward the life of the tree from one year to another. 
It has been suggested not infrequently that the cellulose or, 
better yet, some of the hemicelluloses in plants should be regarded 
as capable of supplying matters for the sustenance of the plant, 
and this idea is supported by the fact that cellulose yields 
dextrose when subjected to the action of strong acids, and that 
several observers have noticed that it is often acted upon by 
enzyms of one kind or another.* 
It would be a matter of no little interest to determine what 
other substances (if any) beside cellulose that are capable of 
yielding sugars by hydrolysis could be detected in woods, and 
the motive of the research here described was to ascertain if 
possible whether any suggestions as to the presence in woods of 
substances hitherto undetected could be got by testing roughly 
though methodically the reducing power and the rotatory power 
of various products obtained by hydrolyzing woods with acids. 
It was found by preliminary trials that after xylan had been 
removed (in some part) by boiling the powdered woods in dilute 
acids, it is easy to obtain no inconsiderable quantities of sugar. 
by treating the residual wood with strong acids and subsequently 
diluting and boiling the mixture. On neutralizing and decoloriz- 
ing (if need were) these solutions, after the hydrolysis, they were 
tested quantitatively for sugar, by means of Fehling’s liquor, and 
their rotatory power was observed with a Schmidt and Haensch 
polariscope. 
Inasmuch as the solutions necessarily contained, beside sugar, 
extractive matters of one kind or another, it would have been 
impracticable to determine the specific rotation in each case by 
the usual and conventional method; for, in order to do that, we 
need to know the quantity of sugar that is contained in a deter- 
mined weight of the solution, while in the method here employed 
we can find only the quantity of sugar in a measured volume of 
the solution. But it is still possible to compare these determina- 
tions one with another, and to obtain an approximation to the 
true specific rotation by making use of the formula 
* Green, J. R., The Soluble Ferments and Fermentation, Cambridge, 1899, 
pp. 84-103. 
