The Biology of Polyporus Pargamenus Fries 139 
oxalate, these crystals were found to be left perfectly intact 
after all of the surrounding woody substance was dissolved. 
From this observation it must be concluded that they are not 
only of no use to the fungal hyphee but that they are not even 
capable of being dissolved by their enzyme excretions. 
In all of the five woods studied in full detail it is evident 
that the first main chemical change brought about by the 
action of the fungal hyphe is that of delignification. It is 
due to this action that the elements lose their natural brown- 
ish color and appear as though bleached. The results 
obtained indicate that the decay begins at the interior of the 
cell-wall and destroys the cell-wall progressively from the 
internal or last-formed lamella to the middle or primary 
lamella between two adjoining cells, first removing the lignin 
constituents. It is evident, furthermore, that delignification 
commences in the tertiary layer and proceeds outward toward 
the middle lamella or primary layer. After the cell-wall is 
delignified down to the middle lamella the reduction of the 
remaining cellulose layers then commences. After the de- 
struction of the cellulose nothing is left but a skeletonized 
framework of middle lamelle which in turn break up into 
fragments and undergo dissolution. Thus within a pocket 
or unit area of decay all stages of decomposition from incip- 
ient decay to final decay may be seen, all within the range 
of a few cells. 
The results obtained from the above study of the decay 
by Polyporus pargamenus of five species of woods of such 
dissimilar structure are especially interesting in that they 
show a correlation between the structure of the wood and its’. 
detailed course of decay. The results obtained show clearly 
that the minor variations in the decay of different woods by 
this fungus are due to the dissimilar physical and chemical 
structure of the respective woods. In view of this fact it 
behooves us in describing the decay by any particular fungus 
not to draw too broad conclusions from the study of the decay 
of one or two species of woods when the fungus in question 
may attack a great number of species. ‘To illustrate more 
specifically, it would not be advisable to conclude from the 
