CONTROL OF DECAY IN PULP AND PULP WOOD 47 
Magnesium silicqfluoride (53 pounds per ton) and zinc silicofluoride 
(33 pounds per ton) gave a considerable measure of protection, but 
further data are needed in regard to their possible action in weakening 
the pulp. 
Sodium arsenate (43 pounds per ton) and sodium ar senile (102 pounds 
per ton) protected the pulp to a considerable extent, but on account of 
their highly poisonous character can not be recommended. 
Sodium bicarbonate, ordinary baking soda, browned the pulp as 
did sodium carbonate, and also apparently softened it. 
Sodium carbonate, a white salt readily soluble in cold water, is a 
fairly strong alkali. It was found to brown the pulp to a marked 
degree. The discoloration readily bleaches out of sulphite pulp, 
without increased bleach consumption, but the pulp is somewhat 
softened by the action of the alkali. 
Thymol gave considerable protection in some cases, but the results 
were too erratic to warrant recommendation until further and more 
uniformly favorable data are obtained. The mill tests (none were 
made at the laboratory) of the two distillates from the thymol-yielding 
plant Monarda punctata resulted very favorably. However, large 
quantities of these distillates are not available at present. 
Mill tests of the three distillates from the carvacrol-yielding plant 
Monarda jistulosa also gave favorable results. Production of these 
distillates on a commercial scale would perhaps bring their cost low 
enough to permit their use. 
Zinc chloride (108 pounds per ton) gave very favorable results in 
preserving the pulp against decay but permitted heavy infections of 
speckled gray mold. 
The following preservatives, in addition to those listed in Table 13, 
have for various reasons proved unsatisfactory under the severe condi- 
tions imposed in the laboratory tests: Calcium hydrate, copper 
oleate, formaldehyde, formic acid, mercuric chloride, naphthalene 
(dry and in alcoholic solution), rongalite, sodium bifluoride, bleach 
liquor, and fresh and waste sulphite liquor. (PL XIV, fig. 3.) 
PREVALENCE OF VARIOUS FUNGI ON TREATED PULP 
The molds most commonly found on the experimental pulp, listed 
in the order of their frequency of occurrence, were those respectively 
producing neutral gray, pink, purple, and yellow spots or blotches. 
Neutral gray discolorations were attributable to any one of several 
molds that have brown mycelia. Species of Peniciilium and Fusa- 
rium produced discolorations pink to purple in tint, and some species 
of Trichoderma caused yellow areas. 
Gray discolorations were found quite generally throughout the 
packs. Certain molds were more frequently found on the outer laps 
and along the edges and folds than elsewhere. The ammonium salts, 
sodium chloride, and sulphite liquors seemed to stimulate all kinds 
of fungous growth. Pulp which had been sprayed with copper 
nitrate, lead acetate, 4 and zinc chloride was found covered with 
numerous minute gray specks. 
Mercuric chloride permitted the light-colored molds, Penicillium 
and Trichoderma especially to develop. 
4 "When prepared in zinc-lined vessels, this salt was largely changed over to zinc acetate. 
