1920] E 
ZELLER—IMBIBITION BY WOOD AND SPORE GERMINATION 71 
water as a film on the wood surface the spores of Lenzites sae- 
piaria show a high percentage of germination. 
By growing Ceratostomella coerulea upon blocks of pine sap- 
wood Münch (709) found that free-water on the wood was 
necessary to sustain growth. Growth is maintained if fibre- 
saturation is maintained, but if the water of imbibition falls 
below the saturation point the wood seems to demand water at 
the expense of the mycelium. Although true for Ceratostomella 
this very probably is not true for the mycelium of such fungi as 
Lenzites saepiaria, Merulius lacrymans, or Coniophora cerebella, 
which after becoming well established, seem to maintain a 
. water supply from some unknown source. This is especially 
the case with Merulius lacrymans. Wehmer (14) found that 
this fungus would not grow on blocks of wood in ordinary cellar 
humidity unless the blocks were first saturated with water. 
After the growth was well established, however, the water con- 
tent of the wood was maintained by the fungus above that in 
sound wood under the same conditions. 
It would seem then that for the germination of the spores and 
the establishment of the mycelium of wood-destroying fungi, 
the wood must contain enough moisture to saturate the wood 
fibre. This becomes a serious problem then in such buildings as 
paper- and pulp-mills and knitting factories where high humidi- 
ties are maintained. If the temperatures fluctuate across the 
dew-point, the moisture content of any exposed woodwork is 
maintained up to fibre-saturation and the wood is sure to decay 
unless some method of treatment of the timbers is possible. 
SUMMARY 
In this paper are reported the results of experiments (1) 
showing the moisture content of wood at various atmospheric 
humidities and at 25? C. Curves are presented to illustrate this 
relation for the sap- and heart-wood of both longleaf and short- 
leaf pine. 
(2) By testing the moisture content of any one species of wood 
samples having various specific gravities at the various humidi- 
ties it is possible to approximate the fibre-saturation point of 
the wood. 
(3) The moisture-humidity curves of highly resinous samples 
