20 BULLETIN 1298, U. S. DEPARTMENT OF AGRICULTURE 
CHEMICAL PROPERTIES OF SOUND AND DECAYED WOODS 
AND PULP FROM SOUND AND DECAYED SPRUCE 
A knowledge of the chemical composition of sound woods and 
pulps and of the changes produced in them by the action of fungi is 
of considerable importance to an understanding of the losses sustained 
during the storage of such material and in the conversion of wood 
into pulp and of pulp into paper. In following the earlier stages 
of decay, in particular, chemical analysis is superior to visual examina- 
tion, for an infected log or lap of pulp may look relatively sound and 
yet contain wood-destroying fimgi which had chemically changed the 
fiber, rendering it of distinctly less value as a paper-making material. 
For these reasons sound and decayed specimens of spruce, hemlock, 
balsam, and aspen woods and of pulps from sound and decayed spruce 
were subjected to chemical analysis, the object of the investigation 
being to correlate, more definitely than ever before, and quanti- 
tatively where possible, the chemical evidences with the fact and the 
degree of wood and pulp decay. 
The analytical methods used were those that have been found 
of value in the study at the laboratory of the chemistry of woods, 
details of procedure having appeared in the technical journals in 
various articles 3 initiated by the laboratory. The methods cover 
determinations for moisture; ash; solubility in cold water, in 
hot water, in 1 per cent NaOH, in 7.14 per cent NaOH, in alcohol, 
and in ether; lignin; cellulose; alpha, beta", and gamma cellulose in 
the total cellulose; pentosans; methyl-pentosans ; and copper number. 
SPRUCE WOOD AND SPRUCE MECHANICAL PULP 
SOUND SPRUCE WOOD 
In order to establish a check in the present studies, cross sections 
of spruce logs were obtained from various parts of eastern North 
America and anatyzed for lignin, cellulose, and solubility in ether 
and in alcohol. These data, together with the number of annual 
rings in each log sampled, are recorded in Table 6. The samples 
were inspected microscopically and found to be sound, except as 
indicated in the table. The lignin showed variation from 26.8 per 
cent to 28.3 per cent, and the cellulose from 58.1 per cent to 61.7 
per cent. Whether these variations are indicative of differences due 
to the locality of growth it is impossible to say from the limited data. 
All of the Canadian and New England samples tested were relatively 
high in cellulose content, and those from Wisconsin and lower Mich- 
igan relatively low. The decayed spruce woods studied were mostly 
from Wisconsin. If locality were known to exert an influence on 
cellulose content, the average of the values for cellulose given in 
Table 6 would be too high for general comparison, and losses in 
cellulose due to decay would be over-accentuated. The more con- 
servative value, 58.5 per cent, obtained for the Wisconsin sample 
designated VA was therefore chosen as a standard for comparison. 
3 Schorger, A. W., Jour. Ind. and Eng. Chera. 9: 556. 1917. 
Mahood, S. A., and Cable, D. E., Jour. Ind. and Eng. Chem. 12: 873. 1920. 
Mahood, S. A., and Cable, D. E., Jour. Ind. and Eng. Chem. 14: 727. 1922. 
Bray, M. W., and Staidl, J. A., Jour. Ind. and Eng. Chem. 14: 35. 1922. 
