>, STUDIES ON THE LIGNIN AND CELLULOSE OF WOOD. 55 
any doubt that the thickness of the healthy wall is greater 
by a decided difference than is that of the cellulose fiber 
walls which are left in the badly rotted tissues. Such 
measurements have shown a difference of about a third of 
the total thickness of the original healthy wall between the 
two series. It has been stated distinctly by practically all 
workers with this group of fungi that delignification is a 
very common phenomenon as a result of the action of the 
mycelium of these fungi, which grows in the wood and dis- 
integrates it to a greater or less extent as the case may be. 
That cellulose is left by many of the fungi in the last 
stages of decay of the wood in which they are growing is 
but a very natural phenomenon to one who is familiar with 
the structure of woody cell walls. Chemical analyses have 
shown that cellulose is the basis of the structure of the wall 
and makes up a large percentage of it by dry weight. The 
methods of analysis are, to be sure, not satisfactory for 
exact quantitative results since each method gives results 
varying from the others by a small margin, yet the figures 
obtained may be used provided we keep in mind the fact 
that they are but approximate. Czapek * has given a sum- 
mary of what has been done in this connection by differ- 
ent chemists. The following table shows the results ob- 
tained by two of the best methods of analysis. 
LANGE. SCHULZE. 
Beech ...- =. . + 54,0-53.0-53.0 51.0-50.5-50.0 
MPS ee ees cee ce 51.0-50.0-50.6 48,0-48.2-49.0 
tie Sa 55.0-56.0-56.0 52.0-52.0-52.5 
The figures indicate the percentage of cellulose found 
in the woods named by the two methods of analysis and 
also show the amount of variation in the results obtained. 
Analyses of pine wood showed that the percentage of cel- 
lulose varied from 47.5 to 53.5 per cent, and it was found 
that the sap wood was richer in cellulose than was the 
* Czapek. Biochemie der Pflanzen. 1: 563-564. ( 1905.) 
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