454 BULLETIN OF THE BUSSEY INSTITUTION. 
wood were made before those upon maple wood, as reported 
above. It is evident enough that beside xylose and dextrose 
some other substance of higher rotatory power than dextrose is 
produced when birch wood is boiled with acids under the condi- 
tions here described. 
D. Experiments on the Acid Hydrolysis of Cotton. —- In a pre- 
liminary trial a quantity of worn out cotton cloth was boiled in 
several successive fresh portions of sulphuric acid of 2.8% H,SQ,, 
and the residual cotton left after this treatment was soaked in 
sulphuric acid of 86.3% H,SO, for 24 hours. Subsequently, 
water enough was added to reduce the acid to the strength of 
2.8%, and the mixture was heated during 5.5 hours on a boiling 
water bath. On neutralizing with calcium carbonate, evaporating 
to the consistence of a thick syrup, and mixing this syrup with 
strong alcohol a considerable quantity of sticky, gummy matter 
was left undissolved. 
In another trial 50 grms. of the cotton cloth were treated 
directly with 100 c.c. of sulphuric acid of 90% H,SO,, and the 
mixture was left to stand during 24 hours, with occasional stir- 
ring. It was then poured into enough boiling water to reduce 
the acid to the strength of 6%, and the boiling was maintained 
over a free flame for three hours. ‘The filtered liquid was neutral- 
ized with calcium carbonate, evaporated, decolorized with bone- 
black, and tested with Fehling’s liquor and in the polariscope. <A 
rotation of quasi(a) D = 75°.88 was noted. The solution was 
evaporated to dryness and the residue was treated with cold, 
strong alcohol, in which the larger part of it dissolved, the matter 
insoluble in alcohol being manifestly less in this case than in the 
preceding instance. On testing this insoluble matter, after it had 
been taken up with water and decolorized with bone-black, a rota- 
tion of quasi(a) D = 81°.58 was noted and ‘sugar’ enough to 
amount to 0.5% of the dry cloth. The matter soluble in alco- 
hol, after having been decolorized with bone-black, gave quasi 
(a2) D = 66°.62 and ‘* dextrose’? to the amount of 15.83% of 
the dry cloth. 
On again evaporating to dryness the solution of the matter 
soluble in alcohol and treating this new residue with cold, strong 
alcohol, a portion of it was left undissolved, though the undis- 
