THE DESTRUCTION OF WOOD BY FUNGI 375 



therefore, the juice of the fruit-bodies appears to be able to brings 

 about at least nine or ten different enzyme phenomena. There 

 is every reason to believe that the destruction of wood by 

 Polyporus squamosus, or in fact by any wood-destroying fungus, 

 is chiefly due to the enzymes it is capable of producing. 



The conditions for the germination of the spores of wood- 

 destroying fungi still await a much fuller elucidation. In some 

 cases, such as Polystictus versicolor, the spores germinate readily 

 in water, and also on the surface of moist wooden blocks 

 {vide infra). We can, therefore, easily understand with this 

 species how infection of exposed wood takes place. On the 

 other hand, the spores of Lentinus lepideus and Polyporus 

 squamosus, although they germinate readily in various nutrient 

 media, such as beef-gelatine, malt-extract, and Pasteur's Fluid, 

 do not put out germ-tubes in water : nor in the last-named 

 species will the spores germinate on fresh wound surfaces of 

 branches kept moist in the laboratory. The conditions for 

 the infection of trees by the spores of Polyporus squamosus 

 in nature are therefore still unknown. It was thought that, if 

 spores were placed on large fresh wounds of living trees, 

 infection might take place. Two years ago six large and sound 

 trees, Sycamore, Beech, Ash, Elm, Lime, and Horse Chestnut, 

 were chosen. Six suitable wounds were made in each tree by 

 sawing off large branches, etc., and the wound surfaces were 

 carefully strewn with millions of some freshly-fallen spores. 

 It was hoped that infection might result, but fruit-bodies as yet 

 have failed to make their appearance upon the trees. 



The latest paper on a wood-destroying fungus (1908) is 

 that of Miss Bayliss on " The Biology of Polystictus versicolor 

 (Fries)." 1 P. versicolor is one of the most familiar objects to 

 the field mycologist, but its life-history and ecology had been 

 neglected. Miss Bayliss found that its spores germinate in 

 water, and that when they are placed on the outside of damp 

 blocks of Ash, Elm, Bird-cherry, Alder, Sycamore, Horse 

 Chestnut, and Birch, infection of the wood readily takes place. 

 The mycelium, however, would not grow in pine- and larch- 

 wood. The life-history of the fungus was traced from spore 

 to spore. Fruit-bodies developed on the infected blocks in the 

 course of a few months. It was shown that the mycelium of 

 the fungus can retain its vitality in a dried stick for at least 



J. S. Bayliss, Journ. of Economic Biology, vol. 3, 1908, pp. 1-22. 



