APPENDIX 
STUDIES OF SPECIFIC FUNGI THAT DETERIORATE WOOD PULP 
Up to the present no careful systematic study of pulp-inhabiting 
fungi has been made. As far as is known by the writers, investigators 
in the past have ignored the hymenomycetes entirely, owing to the 
fact that before this study was undertaken no one used cultural 
methods in studying pulp fungi. The hymenomycetes can not often 
be detected by a mere examination of the pulp. Areas infected 
with them are commonly overrun by molds, which accounts for the 
fact that certain authors attribute serious decay of pulp to some of 
the molds. 
In the course of the investigation a large number of fungi have 
been isolated from pulp and wood. In this appendix are presented 
the cultural characters of the fungi isolated, together with a classi- 
fication of these fungi based on the color changes which they produce 
in the pulp. 
Many of the organisms were grown on ground-wood pulp in order 
to determine their specific effect on the fiber. In general, it was 
found that the loss in weight produced by molds was slight, the 
greatest loss being 3.2 per cent in 12 months. Wood-destroying 
fungi (hymenomycetes), on the other hand, produced losses as high 
as 49.5 per cent within the same period. Analyses of the various 
samples showed that the effect of molds on the chemical constitution 
of the fiber was likewise slight, but that wood-destroying fungi 
produced very marked changes in this respect also. 
WORK OF PRIOR INVESTIGATORS 
Cellulose fermentation is the outstanding factor in the decay of 
both wood and pulp. It is known to be caused by certain hymeno- 
mycetes (among which are wood-destroying fungi) , to a lesser extent 
by some of the fungi commonly called molds, and, more rarely, by 
certain groups of bacteria. The relative destructiveness of the first 
two groups, so far as concerns pulp in particular, has only lately 
been recognized — although for 70 years or more the general subject 
of cellulose fermentation has repeatedly attracted the attention of 
investigators. In 1850 Mitscherlich (17) first attributed the fermen- 
tation of cellulose to microorganisms. Workers immediately fol- 
lowing Mitscherlich interested themselves not in the organisms 
causing cellulose fermentation, but rather in the products these 
organisms formed in the fermentation processes. After about 25 
years investigators became interested in the organisms themselves, 
but more attention was then given to bacteria than to fungi. 
To Van Iterson (13) belongs the credit for the first systematic 
study, as late as 1904, of cellulose fermentation induced by fungi. 
His method was the following: Two sterile sheets of pure filter paper 
were placed in a Petri dish and moistened with tap water in which 
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