CONTROL OF DECAY IN PULP AND PULP WOOD 27 
The writers have had very little opportunity to observe deteriora- 
tion in hydraulic-pressed ground wood, but the information at hand 
indicates that pulp so treated will not offer any greater resistance to 
decay than the wetter laps. This is to be expected, as the pressed 
pulp still contains 40 to 55 per cent moisture. The case already 
cited of a total loss in a portion of a 7,500-ton pile (PL XII, figs. 1 
and 2) after storage for somewhat less than three years is strong 
evidence on this point. 
Several writers have expressed opinions as to the sources of fun- 
gous infection in fresh pulp. Some hold that infection in the wood 
carries over through the grinding process and continues to develop 
in the pulp. Acree (1), Beadle and Stevens (4) (with reference to 
blue stain caused by Ceratostomella spp.), and Klemm (14) have 
expressed themselves as inclining to this view. Blair (5) likewise 
states : 
The process of manufacture does not affect the fungus in any way except to 
separate it into a great number of small pieces which are distributed throughout 
the pulp. When such pulp is stored, each piece of the fungus may set up a center 
of decay within the pile whether of laps or of bales. 
See (23) , in discussing the molds that injure paper, remarks that — 
the germs of these true maladies of paper are not caused by any sort of later 
infection, but preexist in the pulp from which the paper is made, and probably 
proceed from the materials used in making paper pulp, such as straw, alfalfa 
fiber, etc. 
In order to find out whether the infection in ground wood origi- 
nates in the decayed wood used in its manufacture, an experiment 
was conducted, the material used being pulp freshly ground from 
decayed spruce at one of the cooperating mills. 
The wood used was abundantly infected with Fomes roseus, 
Lenzites sepiaria, Polystictus abietinus, Stereum sanguinolentum, and 
Trametes pini. 
The rots were not so far advanced but that the mycelium of each 
of them should have been alive in all cases. Culture tests proved 
this to be true, for Fomes roseus and Stereum sanguinolentum at any 
rate. Samples of the ground wood were collected in sterile bottles 
as the pulp left the grinder. A number of samples from freshly 
ground, commercially sound wood were also collected. The tem- 
perature at the discharge varied. fron 120 to 180° F. (49 to 82° C). 
At the surface of the stone, however, the temperature was much 
higher, and it should be noted that very minute particles of the 
fungus were for a short time exposed to this heat. 
None of the samples, either from commercially sound or from 
decayed wood, produced a single wood-destroying fungus when 
plated out into Petri dishes on malt agar. Some plates remained 
sterile, but the remainder were overrun with molds, such as Tri- 
choderma spp., normally obtained from river water. As many 
plates were sterile among those representing the infected wood as 
there were among those representing the sound wood. No difference 
could be observed in the species of molds obtained on the two groups 
of plates, a condition which would indicate that water, and perhaps 
air, are the sources of infection. 
Considerable amounts of each sample were planted upon sterilized 
clean ground-wood pulp (approximately 70 per cent wet) supported 
