12 



give the reactions so characteristic for wood liber — that is. red colora- 

 tion with phloroglucin and hydrochloric acid, and has also obtained 

 an enzym' from the mycelium of 3/eruh'us lacJirymans, which acts on 

 wood fiber, destroying the hadromal and leaving pure cellulose fiber. 

 Czapek obtained this enz3^m by grinding the mjxelium with emery 

 powder and making an aqueous extract, precipitating the enzj^m with 

 excess of alcohol. He was able to demonstrate the gradual destruc- 

 tion of the hadromal, beginning with the tenth day. Owing to lack of 

 fresh material no attempt has so far been made to obtain such an 

 enzym from cedar wood. The enzym, however, has been extracted 

 by the writer from the mycelium of Polyporus suhacidus growing in 

 spruce wood. If it be assumed that such an enzym brings about the 

 above-described changes in the cedar wood, it must necessarih" be 

 regarded as very potent. 



The formation of the diastase ferment b}" the mycelium of wood- 

 destroying fungi is very insignificant when compared with this lignin- 

 siDlitting enzym, which in a single cavity mav convert several hundred 

 grams of wood into cellulose. It is hoped that the enzym itself will 

 be obtained before long. 



The second fo7'm of decay. — The second and less common form of 

 disintegration begins after much of the wood has been changed to 

 cellulose, but as to whether it has any connection with the first form 

 it is impossible to say as j^et. It is \q,yj much like the transformation 

 of cypress wood, where it is the common form of decay, while the 

 reduction to cellulose is the second or exceptional form. The first 

 noticeable symptom of the second form of decay is the failure of the 

 inner portion of the thickened ring of the bordered pits to stain as 

 deep a red as in sound wood. Soon after this the edges of the small 

 circle of the pit appear to be corroded and the size of the hole increases. 

 A tangential section through the pits shows that the secondary lamella 

 is being gradually dissolved, thus increasing the size of the cavity. The 

 tertiary lamella and the torus are as yet unafi'ected. The latter is 

 sometimes torn awa}' by the knife and may be seen hanging out on one 

 side. At this stage a thin, veil-like membrane, consisting of the ter- 

 tiary lamella, may be seen extending into the larger circle of the pit. 

 PI. VII, fig. 4, shows the same in dotted lines. Finally this membrane 

 is entirely absorbed, leaving a clear, round hole, as large as the original 

 pit (PI. VII, fig. 7). The torus likewise disappears, and the solution 

 of the secondary lamella has progressed. PI. VII, fig. -i, shows a radial 

 view of several tracheids. A stage with the round holes is shown in 

 PL VII, fig. 2, and fig. 3 represents a piece of wood at a later stage 

 which has become detached and is lying free in one of the cavities. 



The solution of the primary lamella causes adjoining tracheids to 



^Czapek, Fr., Zur Biologie der holzbewohuendeu Pilze (Ber. d. Deut. Bot. Ges., 

 1899, Vol. XVII, p. 166). 



