Jan. 17,1916 
Plenodomus fuscomaculans 
739 
reproduction came largely from filter paper. Although filter paper is 
said to be the purest form of cellulose obtainable, Schwalbe (1910-n, 
p. 600) states that appreciable amounts of oxycellulose and hydrate- 
cellulose are present. Since filter paper is known to have some ash, a 
preliminary experiment was performed to find if this ash served, in part 
at least, as a source of food. A pair of culture dishes was prepared 
with a filter-paper cone in each. Ten c. c. of ordinary distilled water 
were added. To each of two other dishes with a similar amount of 
water, the ash from a filter cone was added. These dishes were auto¬ 
claved. Inoculations were made with spores. After three weeks the 
results shown in Table XVI were obtained. 
Table XVI.— Effect of quantity of food: Test with filter paper and the ash from filter 
paper 
[Time, 3 weeks] 
Medium. 
Pycnidia. 
Growth. 
to c. c. distilled water, plus filter cone. 
+ 
Good. 
10 c. c. distilled water, plus ash. 
Scanty. 
The better growth and the pycnidial production on the filter paper, 
as opposed to the results with ash, indicate that the influential stuffs are 
not those from the ash. It may be remarked that the readings were 
taken early enough to avoid complications due to the slow pycnidium 
formation in distilled water. The effect of ash having been shown to be 
negligible, the main experiment was set up. Vive sheets of filter paper 
(S. & S. 595) about 15 cm. across were autoclaved in 500 c. c. of conduc¬ 
tivity water in a Jena flask. This furnished a stock solution, which was 
diluted with conductivity water by means of pipettes and graduates, 
which were carefully rinsed before and during the operations. -The di¬ 
lutions were prepared in Jena beakers, but were eventually put in 10 
c. c. quantities in a number of Jena test tubes. These were autoclaved 
and inoculated with a spore suspension. This experiment was done in 
duplicate with each of the strains of the fungus, with the results shown 
in Table XVII. 
Table XVII. —Effect of quantity of food: Test with filter-paper broth 
[Time, a months] 
Medium. 
Pycnidia. 
Growth. 
Filter-paper broth: 
1/1. 
+ < 3 > 
+ (i 
+ w 
Fair, easily seen. 
Fair, easily seen. 
Scant, barely visible. 
Scant, barely visible. 
Scant, barely visible. 
I/IOO. .. 
1/1,000. 
1/10,000. 
Conductivity-water check. 
_ 
