1888-89.] On Dry-Rot. 249 



viz., from the beginning of April to the end of June. " Fell 

 not the tree," says Evelyn, " till the sap is at rest, as it com- 

 monly is about November and December, after the frost has 

 well nipped them ; the very saplings thus cut will continue 

 without decay as long as the heart of the tree." The use 

 of sapwood and of insufficiently seasoned timber are the chief 

 causes of dry-rot. Young trees have too much proportion of 

 sapwood to heartwood, and should not be felled till they arrive 

 at maturity. The winter is the best time for cutting, and 

 various experiments have been recently tried to discover 

 whether germs of dry - rot would develop in wood felled 

 during that season. Sections of fir and pine trees felled in 

 January were taken in March of the same year, and germs 

 of dry-rot sown in them. They were kept in covered vessels 

 in a dark room, at an average temperature of 60° Fahrenheit. 

 The spawn of the fungus showed itself in July. Sections of 

 similar woods felled during the previous winter were found 

 unsuitable for such experiments. A careful analysis of the 

 wood showed that there was from four to nine per cent more 

 potassium and phosphoric acid in the wood of the latter 

 season than in that of the previous. Wood where experi- 

 ments completely failed was found to have been previously 

 immersed in water. To get thoroughly seasoned wood, the 

 tree should be cut up, slowly and thoroughly dried, and then 

 completely immersed in water. It was an ancient practice in 

 England to place timber intended for dwelling-houses in run- 

 ning water to season it. Experiments have also lately been 

 tried to determine whether wood felled in the summer could 

 be rendered safe against dry-rot by the removal of the bark, 

 and protracted drying and steeping in water, but with what 

 result is not yet known. 



It is easier to prevent the disease than to cure it. The 

 timber should be perfectly sound and dry, and the basements 

 of the building thoroughly well ventilated and free from damp, 

 for the fungus cannot exist without stagnant air and wood 

 saturated with moisture. When the mycelium has only pene- 

 trated a short distance. Professor Hillhouse recommends paint- 

 ing with corrosive sublimate dissolved in methyl alcohol ; 

 but nothing is more difficult to discover than how far the 

 woodwork is infected, and it is safest to remove entirely an 



