11 



being- invariably attached to the margins of the hole. The red of the 

 heartwood, the white of the cellulose libers, and the intermediate color 

 stages, together with the red brown of some of the fibers and the yel- 

 lowish tint of the mycelium, make a com])ination of color rarely 

 equaled. Unfortunately much of the brilliancy of the original is lost 

 in the photograph. 



The destruction of the wood tibers laterally takes place within well- 

 deiined limits, as i.-^ well shown in PI. 11. The disintegration has 

 taken place up to one annual ring, everything toward the middle of 

 the trunk being changed and every part outside of this one ring 

 remaining unchanged, which indicates that the agent which brings 

 about the change in the wood tibers permeates one ring and changes 

 it before attacking another. 



The upper and lower ends of the hole are by no moans as sharply 

 bounded. The penetration of the destroj'ing agent seems to take 

 place unevenly, eating more rapidly at some points than at others. 

 This localized disintegration shows that the ferment, for such the 

 active agent probably is, is able to pass longitudinally along the annual 

 rings more readilv than across them. 



The first form of fZ^fft^. ^Structural changes in the wood tibers 

 become visible shortly after the hyphje have entered their lumen. 

 In this form of decay ^ the primary lamella liegins to have a granu- 

 lar appearance and very soon after is dissolved. At the same time the 

 color of the secondary lamella becomes lighter, and then perfectly 

 white. With chlor-iodide of zinc these lamellaj give the characteristic 

 blue color, indicating that they are cellulose. After the solution of 

 the primary lamella the individual cells fall apart. The cellulose 

 fibers are perfecth' smooth and there are regular perforations on their 

 radial walls, indicating the former position of the bordered pits. (PI. 

 VII. fig. 5.) This mode of delignification agrees with that described 

 by Hartig ' for wood of the pine delignified by mvcelium of Trauietes 

 pini. The character of the resulting cellulose fiber is very different 

 from that of Pimcs echinata or P. palustru when delignified liy 

 Trametes pini. The change in the red cedar from wood substance to 

 cellulose is very complete and takes place over large areas. 



The chemical nature of wood substance is as y&t a matter of much 

 discussion. Substances called lignin compounds, coniferin, etc., to 

 which the characteristic properties of wood were attributed, have been 

 isolated from wood fiber. Czapek-^ has recenth' announced the dis- 

 covery of a compound, which he calls ''hadromal," that is supposed to 



^ The word decay is used to indicate changes in which substances that are not 

 normal wood are formed. 



^Hartig, R., Zersetzungserscheinungen des Holzes, p. 36. 



^Czapek, Fr., tJber die sogenannten Ligninreactionen des Holzes (Hoppe Seyler's 

 Zeitschr. f. Phys. Chem., 1899, Vol. XXVII, p. 141). 



