CONTROL OF DECAY IN PULP AND PULP WOOD 3 
wood with a considerable admixture of decayed material, so that a 
"normal" yield with them is not the normal for sound wood, and 
losses figured on that basis would be underestimated. In fact, 
definite data on comparative losses in pulping sound and infected 
woods, either by mechanical or chemical processes, were lacking. 
Decay in the wood yard was considered rather an u act of Providence" 
than a direct result of storage conditions highly favorable to the 
growth of wood-destroying fungi. 
Since the improvement of storage conditions in the wood yard and 
the working out of a method for the preservation of pulp by the 
addition of antiseptics appeared to be the two problems 01 greatest 
significance, it was decided to direct the investigative work especially 
along these lines. 
The present study, however, combines investigations on all phases 
of the deterioration problem. Karely is the opportunity offered, as 
in this case, to correlate mill tests and commercial practice with 
pathological and chemical laboratory investigations of the same 
material. It is the ideal way to conduct a commercial study. 
The investigations cover the cause of decay in wood and wood 
pulp and the conditions which favor it. This information, when 
adapted to commercial practice, will go far toward reducing deteriora- 
tion in these products. 
The pulping characteristics of decayed wood have been investigated 
with special reference to the losses actually occurring under present 
commercial methods of storage. Pulping value depends to a large 
degree upon the nature of the process used. With decayed wood as 
raw material, mechanical pulp is characterized by low yields, dark 
color, and to some extent low strength; soda pulp by high consump- 
tion of chemicals, low vields, and decidedly low strength. Sulphite 
Eulp, on the other hancl, unless made from wood badly deteriorated, 
as characteristics not greatly different from those of pulp made from 
sound wood. The yield, when expressed in terms of weight of both 
wood and sulphite pulp, is not materially lower, although the pulp is 
slightly darker and becomes somewhat brittle when beaten. When 
the wood has become badly decayed, however, the deterioration is 
reflected more positively in the characteristics of the pulp. 
In order to determine the relation between decay and pulping 
value, it was necessary to study the subject from both a chemical 
and a pathological angle. The investigations show that the changes 
in the wood substance leading to poor quality and quantity of pulp 
are due to a physical breaking down of the fibers accompanied by 
chemical changes in which even the cellulose is finally changed from 
a stable form to an unstable condition more soluble both in water and 
cooking liquor. 
By the application of known principles of sanitation and rotation 
it is possible to reduce materially the losses which result from decay 
during the handling and storage of pulp wood. It is not feasible, 
however, to eliminate entirely from the mill all the pulp wood which 
has become decayed. The rapidity with which the pulp wood 
supply in the United States is vanishing makes it imperative that 
even the decayed wood be used wherever economically possible. 
Many trees are attacked by fungi and begin to rot while they are still 
on the stump, especially those which have reached maturity or those 
which have suffered from attack of insects, from suppression, or from 
