352 OHIO EXPERIMENT STATION: BULLETIN 214 
Wood that has been invaded by such fungi is reduced to the 
state called punk: that is, the wood fibers and arrangement in vessels 
to which the timber owes its strength, are broken down by the 
invasion of the fungus which flourishes at the expense of this woody 
tissue. There is no help for timber after it has once been attacked 
by rot fungi. Whatever preventive measures are taken must precede 
the attack. The most 
effective means of 
timber preservation 
is to cause it to be 
injected or permeat- 
ed with creosote or 
other antiseptics. 
‘This is done by plac- 
ing the timbers in 
vats containing the 
solution and extract- 
ing the air from the 
timbers so far as 
possible. The per- 
manence of the 
effects of such tim- 
ber treatment de- 
pends upon the 
resistance offered by 
the material used to 
t| gradual solution by 
water. In the case 
of creosote the re- 
sults are quite satis- 
factory; with chlorid 
° of zinc, subsequent 
Fig. 26. Fruiting bodies of the fatty Pholiota (Pholiota adipose, solution takes place 
in a wound of an oak tree trunk. (After Freeman). ; : : 
\ too readily, while 
with crude petroleum there is a tendency toward the evaporation of 
this substance when injected. The increasing cost of timber will 
stimulate timber treatments by making treatment profitable. One 
drawback at present is the necessity toimport creosote for use in 
such work; possibly refiinery by-products from petroleum of a 
character analogous to asphaltum may find application in timber 
treatment. 
