26 BULLETIN 1298, U. S. DEPARTMENT OF AGRICULTURE 
kept wood yards (PL XI, fig. 2) surrounded by rotting debris and 
subject to abundant infection from fungi. 
Storage in unheated sheds, which naturally affords protection 
against weathering and soot, and partial protection against air- 
borne spore infections, probably does not protect against deteriora- 
tion by fungi after infection has actually taken place. Where pulp 
is preserved with a volatile antiseptic, a closed building would be of 
advantage in retaining the vapors. 
Pulp piled in warm, moist basements will be especially subject to 
deterioration, and it should not be held under such conditions longer 
than is absolutely necessary. 
LENGTH OF STORAGE 
Because of manufacturing conditions, a rather long storage period 
is in many cases necessary for ground wood pulp. A large volume 
of this pulp is ground by hydroelectric power, the supply of which is 
dependent on stream flow. Thus, at many mills, production becomes 
seasonal and must be concentrated at favorable times; and storage 
of large quantities of material, for both local consumption and ship- 
ment, becomes necessary over periods of from 6 to 12 months or even 
longer. 
Chemical pulps are for the greater part converted into paper 
immediately, or within a few months. 
DETERIORATION DURING STORAGE 
Molds and wood-destroying fungi are the chief enemies of pulp. 
Molds cause physical deterioration by (1) discoloring the pulp, and 
(2) binding together the particles so that the molded spots or areas 
do not beat up well — a lumpy, speckled paper resulting. Wood- 
destroying fungi decrease the strength of the wood fibers and make 
them so brittle that they break into short lengths (PI. XI, figs. 3 
and 4) in the beater, with the result that much of the pulp is lost in 
the white water and the manufactured paper has little strength. 
The combined action of molds and wood-destroying fungi results in 
the production of paper of a very poor color and quality. 
The losses during the storage of pulp znay be large. They depend 
upon the length of the storage period and the conditions under which 
the pulp is stored. 
Chemical pulps, in ordinary commercial practice, deteriorate much 
less than do ground-wood pulps, owing to their shorter storage period 
and the complete sterilization which takes place during the process of 
cooking. Molds, however, which are more likely to develop than 
decay organisms, may cause more or less trouble in the manufacture 
of the better grades of paper; and in extended periods and poor 
conditions of storage both decay and molding may become just as 
severe in chemical pulps as in ground wood. For a further discus- 
sion see Blair (6) . 
A rather common belief among pulp manufacturers is that the 
more sulphite liquor the pulp retains the more rapid will the pulp 
deteriorate during storage. A few tests were conducted at the 
laboratory in an attempt to find out something on this point. While 
not conclusive, the tests at least indicated that traces of sulphite 
liquor remaining in the pulp do not hasten the deterioration caused 
by fungi. 
