BULLETIN OF THE BUSSEY INSTITUTION. a95 
complete, probably because the efficiency of the acid was lessened 
by the presence of the products of the hydrolysis and because 
some part of the wood was shielded by overlying portions from 
the action of the acid. In like manner, C. Schulze and Tollens,* 
in their work on brewers’ grains, were unable to hydrolize com- 
pletely, by means of dilute acid in a single operation, the pentosans 
in that material. 
Generally speaking, the quantity of pentosans obtained by the 
method of hydrolizing the woods with dilute acids, as stated in 
the foregoing tables, was less than that found by distilling the 
woods for furfurol; and it is noteworthy, that very considerable 
quantities of furfurol were obtained always on subjecting to dis- 
tillation with 12% acid the insoluble residues which were left 
after the action of the dilute acids in the experiments on hydro- 
lysis. Attention has been called by numerous observers, to the 
extreme difficulty of separating some hemicelluloses, notably xylan 
and paramannan, from cellulose proper; and it has been sug- 
gested repeatedly,t that it may well be true, that the cellulose and 
xylan in woods should be regarded as a chemical compound rather 
than as a simple mixture. 
Beside the tests upon the wood of the Gray Birch, as described 
on page 387, furfurol was determined by the same gravimetric 
method in other kinds of woods, as stated in the following table. 
Furfurol from Other Woods than Birch. 
Kind of Wood. Per cent of Furfurol obtained from materials 
dry at 100° C. 
Inner Wood. Outer Wood. Bark. 
Sugar Maple felled in October . . 20.71 18.18 10.48 
RideedelicdinJanuary ... . . 10.93 eae 11.32 
II. 10.76 
CE cs, invin o> s, «.’ (Is) 3.68 
IE Sins sss = CIT.) -3.40 
PEE gia 44's >. « - s+ (1.) O.24 
Fr " pee Sate Oe ELLIS .8h 
DONE MSEMOR ol meres ematiei s+ + 18.38 
DICH rs fs wt as oo LD.02 
Cane Sugar (commercial, granulated) .. 1.63 
DR ee ee ee fe NODE, 
* Versuchs-Stationen. 40, 374. 
+ See, for example, Krauch, Versuchs-Stationen. 25, 240; Tollens, Ibid. 
40. 377; and in his Handbuch der Kohlenhydrate. 2.251. Cf. E. Schulze, 
Landwirthschaftliche Jahrbicher. 1894, 28.2; Winterstein, Zeitschrift fiir 
physiologische Chemie. 17. 390; and Cross and Bevan, ‘+ Cellulose,” p. 156. 
