42 MISSOURI BOTANICAL GARDEN. 
been extracted from the wood and which gave lignin re- 
actions with phloroglucin and thallin sulphate, thus indi- 
cating a partial delignification of the treated wood. He 
was led to conclude that, ‘‘ It is found that a gelatinous 
thickening layer which reacts at once to the various color 
tests for cellulose occurs very commonly, though very 
irregularly, in the fiber walls of the xylem as a normal con- 
dition in a great number of perfectly healthy trees, in all 
localities and situations. It may have a very partial dis- 
tribution, or may occur very generally and conspicuously 
through the stem, and may be present only in parts of the 
same annual ring. Sometimes this innermost layer is 
represented only by a thin lining, at others by avery broad 
band which appears swollen and occupies a large part of 
the lumen.”’ 
Also, ** The presence of this unlignified layer in the 
wood fibers probably represents a stage of arrested devel- 
opment. Its general prevalence having been overlooked, 
the conclusion is’ inevitable that the occurence of cellu- 
lose which has been attributed to the action of fungi must 
to some extent be ascribed to conditions already present 
and the effect of any method of sterilization must also be 
taken into account. The delignification cannot be attrib- 
uted to an enzyme secreted by fungi.”’ 
AIMS OF THE PRESENT INVESTIGATIONS. 
This paper with its rather striking results and conclu- 
sions led to the investigations here detailed. Tests were 
made: first,to determine the prevalence of cellulose in the 
stems of the trees of America; second, to confirm or dis- 
prove the results of Potter’s work in testing the effect of 
boiling water upon the lignin of wood; third, to test the 
relative solubility of the lignin of the spring and summer 
wood of the annual ring of growth; fourth, to come to 
some understanding of the conditions existing in wood 
