78 
BULLETIN 1208, U. S. DEPARTMENT OF AGRICULTURE 
Fomes roseus, Peniophora tabacina, and cultures 82219-15, 4620-2, 
4620-1, 61020-1, and 4620-3, acted rapidly during the first six 
months of storage, as is indicated by the great changes recorded. 
After six months the rate of change decreased very noticeably. This 
is evident from the curves shown in Figure 5, which are typical of 
these cultures. The decrease in rate of deterioration may be ac- 
counted for in one or all of the following three ways : 
1. There may be a decrease in the vitality of the organism, due 
perhaps to autointoxication. 
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Fig. 5.— Graphs showing analytical constants of ground-wood pulp infected with a hymenomcete cul- 
ture, N. 4620-2 
2. The cellulose which remains after a certain period may not be 
available to the fungus. Assuming that the fungus uses the more 
accessible cellulose, leaving the lignin, the remaining cellulose in the 
ligno-cellulose complex may be more or less encrusted with pure 
lignin and so protected, to a certain extent, against further breaking 
down. 
3. The cellulose in the cell walls of the fungus, although somewhat 
different from ordinary cellulose, may cause a slight increase in the 
cellulose determination. 
