758 Wisconsin Academy of Sciences, Arts, and Letters. 
PART II 
Analysis of Woods 
The methods for the analysis of woods are largely empirical. 
The only determination that may be considered as accurately 
showing the amount of a definite group present is the methoxy 
determination according to Zeisel. The acetic acid obtained on 
digestion with dilute sulphuric acid may be considered as derived 
from acetyl groups (CH 3 CO-) and acetic acid residues 
(-CH 2 CO-). The decomposition of the wood is evidently con¬ 
siderable since birch sawdust loses about 30% by the above di¬ 
gestion. 
The estimation of pentosans and methylpentosans by deter¬ 
mining the amounts of furfural and methyl furfural formed 
on distillation with 12% hydrochloric acid gives closely agreeing 
results when the procedure worked out by Tollens and his pupils 
is followed. In the case of woods the difficulty lies in determin¬ 
ing the proper source of the furfural. According to Cross and 
Bevan, in addition to the pentosans, wood also contains “fur- 
furoids,” while to the cellulose is assigned the structure of an 
oxycellulose which in turn gives furfural. All the furfural 
obtained is usually calculated as pentosan though it is evident 
that this procedure is not strictly correct. It is a striking fact 
that the pentosan content of the isolated cellulose as calculated 
from the yield of furfural is practically the same as that of the 
original wood. Whether the furfural originates from the cellu¬ 
lose proper or from pentosan residues in the cellulose has not 
been definitely decided. 
The cellulose was determined by the chlorine method. As 
originally described by Cross and Bevan 1 it calls for a pre¬ 
liminary boiling of the ligneous material with lOOcc. of 1% 
NaOH. Also following chlorination and the addition of sodium 
sulphite solution, the latter is brought to boiling, 0.2% of NaOH 
are added and the solution is boiled for five minutes. Accord¬ 
ing to the investigations of Renker 2 the preliminary treatment 
1 “Cellulose”, p. 95. 
2 “Bestimmungsmethoden der Cellulose”, (1910) p. 44. 
