1914] 
COOLEY—SCLEROTINIA CINEREA 305 
ACTION OF THE FUNGUS ON CELLULOSE 
A number of investigators have regarded cellulose dissolution 
as a very important factor in the parasitism of many fungi; 
indeed, some of the earlier workers seemed to consider this the 
prime factor involved. While it is a well known fact that there 
are many fungi, especially saprophytes, which hydrolyze, or dis- 
solve, certain celluloses, research extending over a wide field 
has revealed the nature of parasitism to be a very complex one 
in which other factors are as important as the dissolution of cel- 
lulose and the cell wall. 
It has been the writer’s purpose to study from two different 
points of view the action of the brown-rot organism on celluloses, 
(1) by observing the action of the fungus on pure cellulose iso- 
lated from the host tissue, and (2) by studying microscopically 
its action on the host cell walls themselves. In the former 
study cellulose agar was used, the cellulose being isolated from 
plums by the methods discussed below. 
Methods апа Results.—In the above mentioned study of the 
action of the fungus on pure cellulose, a variety of reagents, 
media, and methods for the preparation of cellulose were em- 
ployed, a brief account of which follows. Schweizer’s reagent 
was prepared by adding a slight excess (40 grams to the liter) 
of copper carbonate to dilute ammonium hydroxide solution 
composed of three parts of water to ten parts of ammonium 
hydroxide (sp. gr. 0.90). The copper solution was then shaken 
vigorously, allowed to stand over night, and the supernatant 
solution siphoned ой. This is the procedure employed by Mc- 
Beth and Scales (38). 
Paper cellulose from filter paper was prepared according to 
the method given by McBeth and Scales (88) by dissolving 15 
grams of sheet filter paper in Schweizer’s reagent, diluting about 
ten times with water, and precipitating the cellulose with a 
solution of one part of hydrochloric acid to five parts of water. 
This mixture was then further diluted to 15 or 20 liters, the 
supernatant liquid siphoned off, and the residue washed re- 
peatedly with water until the precipitated cellulose was free 
from both copper and chlorine. After standing quietly for 
several days the clear liquid was siphoned off and the precipitate 
used for the preparation of cellulose agar. 
