CONTROL OF DECAY IN PULP AND PULP WOOD 31 
At the end of approximately six months, and again at about the 
end of the year, some of the laps of each of the three pulps, so se- 
lected as to be as representative as possible of the state of decay 
throughout the lot, were made into waterleaf paper on the labora- 
tory machine without the addition of other fibers. 
The hydraulic pulp, and especially the pulp made from decayed 
wood, foamed very badly on the screen and paper machine. The 
pulp made from sound wood did not. Trouble on this account in- 
creased with the age of the pulp. 
The papers from all three sources showed during storage an in- 
crease in freeness, a progressive darkening and yellowing, a loss in 
strength, and a decrease m the average length of the fibers. 
The experimental data are given in Table 12. The color change, as 
measured by the Ives tint photometer, is indicated by a decrease in 
the percentage white and an increase in the percentage red plus green 
(yellow). The change was much more rapid in the samples from 
decayed wood. The bursting strength and the tensile strength in all 
cases showed a decided decrease, this effect being more rapid for the 
samples from decayed wood. The rate of weakening was higher 
during the first than during the second six months, a result which 
is in accord with the microscopical and chemical observations on 
these samples. 
There was a marked difference in the amount of dirt and specks 
in the papers, those made from sound wood pulp being much cleaner. 
Table 12. — Physical properties of ground-wood pulps 
Description 
Green 
sedi- 
menta- 
tion 
test. 
Over- 
flow 
Color (tint pho- 
tometer) 
Aver- 
age 
length 
of 
fiber 
par- 
ticles 
Strength factrvs at 65 per 
cent'ii.cnidity 

Sam- 
ple 
No. 
White 
Black 
Red 
plus 
green 
Weight 
of 
ream 
24 by 
36—500 
Points 
per 
pound 
Aver- 
age 
break- 
ing 
length 
Aver- 
age 
stretch 
1AA 
From sound spruce: 
Cc. 
91 
100 
180 
100 
141 
160 
Per 
cent 
68.5 
67.5 
64.6 
62.5 
56.6 
54.0 
Per 
cent 
20.0 
19.8 
22.8 
27.5 
29.3 
27.4 
Per 
cent 
11.5 
12.7 
12.6 
10.0 
14.1 
18.6 
Mm. 
1.5 
.9 
1.0 
1.4 
1.0 
.7 
Pounds 
47.0 
49.8 
46.0 
48.0 
51.9 
47.0 
0.30 
.27 
.22 
.30 
.21 
.19 
Meters 
2,780 
2,340 
2,175 
2,610 
1,990 
1,780 
Per 
cent 
1.4 
lAAi 
.8 
IAA2 
After 12 months 
1.3 
2AB 
From decayed spruce: 
1.3 
2ABi 
After 6 months.- 
.6 
2AB2 
After 12 months 
1.2 
3AO 
Hydraulic pressed pulp: 
3ACi 
132 
170 
66.0 
59.8 
23.3 
26.0 
10.7 
14.2 
1. 1 
1.0 
46.0 
47.0 
.22 
.20 
1,910 
1,905 
.6 
3AC2 
After 12 months 
1.2 
PRESERVATION OF PULP BY CHEMICAL TREATMENT 
The chemical treatment of pulp is the most reliable method of 
preventing deterioration during storage, although to a considerable 
extent decay may be reduced by the methods of storage already 
recommended in this bulletin. Molding of pulp, however, appears 
to be more difficult to control than decay. Moist pulp, particularly 
ground wood, will prove highly susceptible to the attack of fungi (so 
long as the temperature is favorable to the growth of these organisms) 
unless their food supply is poisoned by the introduction of antiseptics. 
