328 
Journal of Agricultural Research 
Vol. XXX, No. 4 
plugging the top of each cone with 
cotton wet in boiled water. In case 
the sand itself became too dry the pots 
were set in pans of boiled water. As 
soon as damp-chamber conditions were 
no longer desired (usually 2 days after 
inoculation) the cotton was removed 
from the top of the cone. Before use, 
the cones were disinfected with forma¬ 
lin or mercuric chloride solution. 
After inoculation, the pots were 
placed on stands whose legs were set 
in pans of water in order to exclude 
slugs and ants. These methods of 
inoculation, together with others, have 
been described and illustrated in a 
previous paper (4). Each experiment 
was allowed to run four days. A daily 
count was made of the damped-off 
experiment, thus making a damp 
chamber. At the end of each experi¬ 
ment each tube was again autoclaved 
to prevent the escape of the fungi. 
The results secured by the above 
methods of inoculation involving heavy 
inoculum for each seedling, seedlings 
grown on sterilized sand, boiled water, 
individual disinfected damp chambers, 
etc., do not constitute an entirely 
reliable index to the manner in which 
these fungi would act in ordinary seed¬ 
beds. They do, however, give some 
idea of the relative virulence and 
importance of the different genera of 
fungi and show which can attack 
coniferous stems under favorable con¬ 
ditions. The fungi which were only 
weakly parasitic in these tests would 
Fig. 1 . —Pot at left shows damping-off caused by Pythium debaryanum. Pot at right shows seed¬ 
lings treated at same time with sterile rice grains 
seedlings and those found diseased 
were removed. Only those seedlings 
which began to damp-off at the point 
of inoculation were considered (fig. 1). 
It was undesirable to use the above 
method for such exotic fungi as 
Phytophthora fagi and Pythiacystis 
citrophthora. Therefore seedlings 
grown in plugged test tubes were 
inoculated with these two fungi. 
Sand was placed in plugged test tubes 
and the whole sterilized in the auto¬ 
clave. Then the seeds were planted 
and watered with sterile water. In 
each tube were two or three seedlings. 
The inoculum which consisted of either 
corn meal or rice as above was 
placed on the surface of the sand in 
contact with the seedlings. The plug 
remained in the tube during the whole 
probably be entirely harmless under 
ordinary nursery conditions. 
THE TESTED FUNGI 
Over 100 different fungous lines 
were tested by the methods described 
above. By the term “line” as used 
in this paper is meant a fungous culture 
arising from one isolation. Although 
the cultures of Pythium, Corticium, 
and some others were isolated from 
tissue or soil plantings and were not 
entirely single lines, all except No. 230, 
maintained constant behavior through 
a sufficient number of generations to 
give fair assurance of their purity. 
Results obtained with many of the 
same lines have been published else¬ 
where (£, 8, 5, 6). In Table I are given 
