’ 
The Biology of Polyporus Pargamenus Fries 158 
These samples of finely divided wood were first suc- 
cessively submitted to a preliminary extraction, without 
heating, for twenty-four hours with ether, 95 per cent alcohol, 
a 10 per cent solution of sodium hydroxide, and a 5 per cent 
solution of hydrochloric acid so that, when the dominant 
decomposition products were extracted finally they would be 
free from many extraneous substances. Parallel tests were 
conducted on equal quantities of infiltrated wood and of the 
normal sapwood. ‘The ethereal and alcoholic filtrates, in 
both cases, contained such exceedingly small amounts of sub- 
stance that they were not further investigated. The alkaline 
filtrate from the sound wood residue, upon the addition of 
90 per cent alcohol, gave a characteristic precipitate of xylan 
(wood gum). The alkaline filtrate from the infiltrated wood, 
however, upon the addition of 90 per cent alcohol, gave a 
brown flocculent precipitate which, judging from its solu- 
bility and other chemical reactions, consisted mainly of the 
group of humic substances known as humic acid. After the 
alkaline extraction the woody residues were washed and then 
subjected to extraction with a 5 per cent solution of hydro- 
chloric acid for twenty-four hours. The acid filtrates thus 
obtained were practically colorless and the woody residues, 
in both cases, apparently remained unchanged. After this 
extraction the one from the infiltrated wood was, as far as 
could be determined by microscopic examination, as darkly 
colored as it was at the beginning of the original treatment. 
Both the woody residues were then subjected to the action 
of an oxidizing agent (hydrochloric acid and potassium 
chlorate), after which, according to Frank (1884) and 
Temne (1885), the decomposition products are rendered 
soluble in alcohol. Miinch (1910), however, considers that 
Frank and Temne are in error for giving this reaction (alco- 
hol solubility after digestion with hydrochloric acid and 
potassium chlorate) as a characteristic of wound gum, as 
they had termed the decomposition product, and shows that 
starch-containing cells which do not exhibit the slightest 
browning or gum formation likewise respond to this reaction. 
These suthors, however, did not continue to investigate the 
