106 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



[Vol. 6 



amounts of distilled water were added to each bottle and they 

 were then autoclaved for periods from 45 minutes to 20 hours. 

 The bottles in which the contents were not autoclaved were 

 treated as follows : After drying to constant weight in the 

 hot-air oven they were plugged with previously sterilized 

 plugs. Weighing was done with the plugs removed, every pre- 

 caution being taken to avoid contamination. Sterile distilled 

 water was then added and they were ready for inoculation. 

 Portions of the contents of three test bottles treated in this 



found 



ed on sterile agar plates and in each 



All bottles were inoculated with Fomes pinicola and the rate 

 of decay determined by the loss in weight of the sawdust at 

 the end of four months. The inoculations were made on April 

 16, 1917. On August 18, 1917, the plugs were removed and 

 the contents again dried to constant weight and the loss in 



.-> 



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ht determined. Each series contained e w 

 The details of this work are discussed under the relation of 

 bacteria to the rate of decay induced by fungi. 



Table xi clearly shows that autoclaving western hemlock 

 has a marked effect on the rate of decay induced by Fomes 

 pinicola. It is quite probable that for different fungi the effect 

 might be quite different. In this case a gradual increase in 

 the rate of decay is noted with an increase in time of auto- 

 claving up to ten hours. After twenty hours of autoclaving 

 the fungus did not attack the wood even though each bottle, 

 in this case, was inoculated the second time. There was no 

 growth of the fungus from the immediate point of inocula- 

 tion, and when, at the time of the second inoculation, 30 days 

 after the first, the small mass of fungus and agar used for the 

 first inoculation was removed from the bottles and transferred 

 to agar slants the fungus was found to be dead. At some 

 point between ten and twenty hours' autoclaving a decided 

 change in the sawdust must have taken place which made it 

 toxic to the fungus. Just what this change was is not known. 

 Suffice it here to say that when rate of decav induced bv funsri 



due 



died the time of autoclavins: of the wood 



