EFFECT OF KILN DRYING, ETC., ON FUNGI IN WOOD. Lt 
negative results of over 8,000 culture tests. The graphs in Figure 1 
are smoothed curves based upon the same data and represent eraphi- 
cally the time and temperature conditions required to kill the fungi 
under discussion. 
Test runs 1 to 4, in which the ordinary commercial kiln-drying 
conditions were used, show conclusively that the temperatures, hu- 
midities, and periods of time were effective in killing the various 
fungi within the 1-inch, 2-inch, and 4-inch test pieces. These data 
furnish evidence which leaves little doubt concerning a phenomenon 
which has previously been accepted at its face value without posi- 
tive proof. The additional fact that all of the samples of kiln-dried 
or steamed stock infected before drying and sent in by various lum- 
ber firms for examination gave negative results when cultured fur- 
Piel Time—Tem perature Curve 
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Fig. 1.—Curves showing the time-temperature relation of the data on i-inch, 2 2-inch, and 
4-inch test pieces from, the steaming tests. Data on the 6-inch and 8-inch test pieces 
are included for completeness and comparison. Curve A represents roughly the time- 
temperature relation as expressed by the data om the 1-inch pieces. Curve B represents 
roughly the time and temperature limits necessary to kill cer tain fungi in wood up to 
and including 4 inches in thickness. 
nishes further evidence of the sterilizing efficiency of this method of 
seasoning lumber. 
The experimental tests, runs 5 to 12, inclusive, give somewhat 
more accurate data in regard to the effect. of temperature on fungi 
in wood when acting under a constant humidity of 100 per cent. 
The effect of increasing the length of time during which the infected 
wood is subjected to a constant temperature and humidity and the 
relatively greater resistance of the larger sized test pieces to the 
penetration of heat are both clearly shown in runs numbered 6, 7, 
and 11 in Table 1 and in Figure 1. In run No. 7 the temperature 
used, 120° F., was sufficiently low to require a period of 24 hours 
before all the fungi were killed in the test pieces. This gave a fairly 
good comparison of the relative resistance to heat of the various 
fungi within the wood. 
