CONTROL OF DECAY IN PULP AND PULP WOOD 29 
of ground-wood pulp, aside, of course, from furnishing the requisite 
moisture, is in its reaction upon the foodstuffs in the wood, rendering 
the organic substances more or less available for the growth of 
fungi according to its softness or hardness. They also attribute to 
the mineral and nitrogenous substances in the water the possible 
function of nourishing the molds in their early development. 
Barnes (2), on the other hand, points out the necessity of keeping 
pulp out of contact with pools of water, because " the more impurities 
an organic body contains, the greater tendency there is for that body 
to decay." See (23) maintains that water used in manufacture is at 
least one source of infection, and in this Wolesky (27) concurs. See 
also remarks that in considering the molding of paper the sizing 
should be viewed with suspicion. 
After examining a large number of laps of pulp one becomes 
impressed with the fact that much of the infection is internal; that 
is, that many of the infected spots or areas originate within the laps. 
The decay has apparently been introduced through the water or 
through the air. Since many of the molds and two of the wood- 
destroying fungi commonly found on pulp have been isolated from 
river water used for manufacturing pulp, the inference is drawn that 
water probably plays a considerable part in infection. 
Air-borne infections must also play their part. All of the fungi 
produce spores that are more easily carried about by air currents 
than the finest dust. In the case of the wood destroyers not only do 
the fruit bodies produce an abundance of spores, but in some cases the 
mycelium may also develop them. The mature spores germinate 
readily on any moist surface; if they happen to fall on pulp they are 
likely to start new infections which may spread rapidly. For this 
reason, rotting wood or pulp should not be left in close proximity to 
new pulp piles. As for mold spores, they are everywhere in the air 
(6) but of course are more abundant where there are large amounts 
of organic matter in a state of partial decomposition. 
To prevent deterioration in stored pulp from the action of fungi and 
bacteria, then, the sources of infection should be eliminated so far 
as possible. Wood foundations for piles should be replaced with 
concrete or antiseptically treated lumber. The yards or sheds should 
be cleaned of infecting debris. Workmen should use care to keep 
infecting materials out of the piles. The water used in manufac- 
turing processes should be filtered and sterilized if possible. These 
precautions will all aid in maintaining the pulp in good condition, but 
for complete protection it will also probably be necessary to introduce 
an antiseptic into the pulp itself. 
PHYSICAL PROPERTIES OF PULP DECAYED IN STORAGE 
In order to demonstrate the deterioration in the quality of mechan- 
ical pulps due to decay during storage, an experimental study of 
commercial pulps was made. One lot was stored at the mill and all 
the others at the Forest Products Laboratory. 
The investigation began with two shipments of approximately 
1,000 pounds each, designated A and B, from one of the cooperating 
mills. Shipment A had decayed during six months' storage (PI. XII, 
fig. 3 and PL XVIII). Shipment B, submitted for comparison, con- 
