MISSOURI BOTANICAL GARDEN. 



lamella and the intercellular substance at the angles 

 of the cells. If a similar section is treated with chlor- 

 iodide of zinc the walls of sound wood cells are col- 

 ored yellow-brown. The cells from which the lignin ele- 

 ments have been removed stain brown likewise. This 

 indicates that they are not cellulose. In this respect the 

 disintegration of the cypress wood differs from that caused 

 in wood of the yellow pine by Trametes Pini. In the latter 

 there is one form of disintegration in which the lignin ele- 

 ments are gradually removed from the cell-wall, beginning 

 with the secondary lamella, closely followed by the tertiary 

 lamella. After this extraction a much thinner wall of pure 

 cellulose remains. Some cases were found in wood of 

 Pinus echinata, however, which could not be distinguished 

 from pecky cypress, i. e., after the extraction of the lignin 

 elements, as indicated by phloroglucin and hydrochloric 

 acid, a membrane remains which is not cellulose. Hartig* 

 describes a reaction much like the foregoing one in pine 

 wood attacked by Merulius lachrymans, of which he says : 

 ' ' It appears as if there were a certain relation between the 

 conif erin content of the cell-wall and the ease with which 

 the wood is destroyed." This test is so delicate that it 

 shows the presence of a disturbing cause in the wood 

 long before any evidence can be detected by the micro- 

 scope. Other lignin reagents give similar results, although 

 not so striking. Aniline sulfate turns sound wood brilliant 

 yellow, while it leaves the affected lamellae almost color- 

 less. Thallin and phenol give similar reactions. If the 

 sections are treated with dilute KOH the normal wood 

 cells are not affected beyond very slight swelling. The 

 diseased cells swell more or less, particularly those parts 

 which stained yellow with phloroglucin. After prolonged 

 action of KOH, the delignified parts stain blue with chlor- 

 iodide of zinc. This indicates that the first change in the 



* Hartig, R. Der achte Hausschwainm 53. Berlin. 1885. 

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